Researchers Database

KAJIWARA Takashi

FacultyFaculty Division of Natural Sciences Research Group of Chemistry
PositionProfessor
Last Updated :2024/04/11

researchmap

Profile and Settings

  • Name (Japanese)

    Kajiwara
  • Name (Kana)

    Takashi

Research Interests

  • Coordination Chemistry, Magnetochemistry, Lanthanoid Chemistry

Research Areas

  • Nanotechnology/Materials, Inorganic and coordination chemistry

Education

  • Tohoku University, Graduate School of Science

Association Memberships

  • 日本化学会
  • 錯体化学会
  • 分子科学会
  • 日本希土類学会
  • American Chemical Society

Ⅱ.研究活動実績

Published Papers

  • Refereed, 2023, 11, 2082, 2088
  • Refereed, 2023, 127, 3295, 3306
  • Refereed, 2022, 9, 6271, 6278, 10.1039/d2qi01607a
  • Refereed, 2022, 12, 1, 16601, 10.1038/s41598-022-20893-2
  • 2020, 124, 7930, 7937, https://dx.doi.org/10.1021/acs.jpcc.9b11057
  • Refereed, Magnetochemistry, MDPI, Correlation between Slow Magnetic Relaxations and Molecular Structures of Dy(III) Complexes with N5O4 Nona-Coordination, KAJIWARA Takashi; K. Kobayashi; Y. Harada; K. Ikenaga; Y. Kitagawa; M. Nakano; T. Kajiwara, A series of Dy(III) mononuclear complexes [DyA(2)L](+) (L denotes Schiff base N-5 ligand that occupies equatorial positions and A(-) denotes bidentate anionic O-donor ligands such as NO3- (1), AcO- (2), and acac(-) (3)) were synthesized to investigate the correlation between the slow magnetic relaxation phenomena and the coordination structures around Dy(III). The Dy(III) ion in each complex is in a nona-coordination with the anionic O-donor ligand occupying up-and down-side positions of the N5 equatorial plane. 2 and 3 show slow magnetic relaxation phenomena under a zero bias-field condition, and all complexes showed slow magnetic relaxation under the applied 1000-Oe bias-field conditions. Arrhenius analyses revealed that the Delta E/k(B), the barrier height for magnetization flipping, increases in this order, with the values of 24.1(6), 85(3), and 140(15) K. The effects of the exchanging axial ligands on the magnetic anisotropy were discussed together with the DFT calculations., Apr. 2019, 5, 2, 27, Scientific journal, 10.3390/magnetochemistry5020027
  • Refereed, Angewandte Chemie - International Edition, Wiley-VCH Verlag, A Holmium(III)-Based Single-Molecule Magnet with Pentagonal-Bipyramidal Geometry, Takashi Kajiwara, 2017, 56, 38, 11306, 11308, Scientific journal, 10.1002/anie.201703022
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Light Lanthanide Complexes with Crown Ether and Its Aza Derivative Which Show Slow Magnetic Relaxation Behaviors, Hisami Wada; Sayaka Ooka; Tomoo Yamamura; Takashi Kajiwara, Two sets of isostructural Ln(III) mononuclear complexes, [Ln(NO3)(3)(18-crown-6)] (Ln = Ce (1), Pr (2), and Nd (3)) and [Ln(NO3)(3)(1,10-diaza-18-crown-6)] (Ln = Ce (4), Pr (5), and Nd (6)), were synthesized, and their slow magnetic relaxation behavior was investigated. Since Ln(III) ions are located in an axially stressed ligand field in both sets of complexes, they can exhibit single-molecule magnet (SMM) behavior owing to the oblate-type electronic distributions of the ground sublevels found in Ce(III), Pr(III), and Nd(III). Field-induced slow magnetic relaxation was observed for Ce(III) and Nd(III) complexes 1, 3, 4, and 6 under an applied bias dc field of 1000 Oe, whereas no slow relaxation was observed for Pr(III) complexes 2 and 5. The slow magnetic relaxation behavior of 1, 3, 4, and 6 was correlated with the even-numbered J(z) sublevels of Ce(III) and Nd(III) ions, known as the Kramers system., Jan. 2017, 56, 1, 147, 155, Scientific journal, 10.1021/acs.inorgchem.6b01764
  • Refereed, Magnetochemistry, Slow Magnetic Relaxation of Lanthanide(III) Complexes with a Helical Ligand, KAJIWARA Takashi; Hisami Wada; Sayaka Ooka; Daichi Iwasawa; Miki Hasegawa; Takashi Kajiwara, Dec. 2016, 2, 43, 10.3390/magnetochemistry2040043
  • Refereed, NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, One-dimensional Magnus-type platinum double salts, Christopher H. Hendon; Aron Walsh; Norinobu Akiyama; Yosuke Konno; Takashi Kajiwara; Tasuku Ito; Hiroshi Kitagawa; Ken Sakai, Interest in platinum-chain complexes arose from their unusual oxidation states and physical properties. Despite their compositional diversity, isolation of crystalline chains has remained challenging. Here we report a simple crystallization technique that yields a series of dimer-based 1D platinum chains. The colour of the Pt2+ compounds can be switched between yellow, orange and blue. Spontaneous oxidation in air is used to form black Pt2.33+ needles. The loss of one electron per double salt results in a metallic d(z2) state, as supported by quantum chemical calculations, and displays conductivity of 11 S cm(-1) at room temperature. This behaviour may open up a new avenue for controllable platinum chemistry., Jun. 2016, 7, 11950, Scientific journal, 10.1038/ncomms11950
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Structural switching from paramagnetic to single-molecule magnet behaviour of LnZn(2) trinuclear complexes, Poh Ling Then; Chika Takehara; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, Five LnZn(2) trinuclear complexes, [Ln(NO3){Zn(L)(SCN)}(2)] (H2L is a Schiff base ligand derived from o-vanillin and ethylenediamine; Ln = Tb 1, Dy 2, La 3, Tb0.14La0.86 4, and Dy0.21La0.79 5), were synthesised in which the Zn-II-Ln(III)-Zn-II array exhibits two slightly different arrangements: 1 and 2 exhibited slightly bent arrangements, whereas 3-5 exhibited more linear arrangements. These differences in the arrangements lead to a slightly different coordination geometry around Ln(III). From the detailed studies of dynamic susceptibility, 1 and 2 were found to be paramagnetic, whereas 4 and 5 were SMMs with barriers for the flipping of magnetisation with a height of 41.2(4) K and 156(4) K, respectively., 2015, 44, 41, 18038, 18048, Scientific journal, 10.1039/c5dt02965a
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Slow magnetic relaxation of light lanthanide-based linear LnZn(2) trinuclear complexes, Chika Takehara; Poh Ling Then; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, Four isostructural LnZn(2) trinuclear complexes, [Ln(NO3){Zn(L)(SCN)}(2)] (H2L is a Schiff base ligand derived from o-vanillin and ethylenediamine), were synthesized, which include light lanthanide ions as spin carriers (Ln = Ce 1, Pr 2, Nd 3, and Sm 4). These complexes involve a linear Zn(II)-Ln(III)-Zn(II) array, which leads to an axially stressed ligand field and can also cause single-moleluce magnet (SMM) behavior in oblate-type electronic distributions of ground sublevels found in Ce(III), Pr(III), and Nd(III). Slow magnetic relaxation behavior was observed in 1 and 3 under an applied bias dc field of 1000 Oe, whereas such a slow relaxation was not observed in 2 and 4. The appearance of field-induced SMM behavior in 1 and 3 was correlated with the even-numbered J(z) sublevels of Ce(III) and Nd(III) ions known as the Kramers system., 2015, 44, 41, 18276, 18283, Scientific journal, 10.1039/c5dt03148f
  • Refereed, ORGANOMETALLICS, AMER CHEMICAL SOC, Electron-Deficient Pt2M2Pt2 Hexanuclear Metal Strings (M = Pt, Pd) Supported by Triphosphine Ligands, Eri Goto; Rowshan Ara Begum; Chiaki Ueno; Aya Hosokawa; Chie Yamamoto; Kanako Nakamae; Bunsho Kure; Takayuki Nakajima; Takashi Kajiwara; Tomoaki Tanase, Electron-deficient Pt2M2Pt2 hexanuclear clusters, [Pt4M2(mu-dpmp)(4)(XylNC)(2)](PF6)(4) (M = Pt (7), Pd (8); dpmp = bis((diphenylphosphino)methyl)phenylphosphine), were synthesized by oxidation of hydride-bridged hexanuclear clusters [Pt4M2(mu-H)(mu-dpmp)(4)(XylNC)(2)](PF6)(3) (M = Pt (2), Pd (3)) and were revealed to involve a linearly ordered Pt2M2Pt2 array joined by delocalized bonding interactions with 84 cluster valence electrons, which are discussed on the basis of DFT calculations. The central MM distances of 7 and 8 are significantly reduced upon the apparent loss of a hydride unit from the MHM central part of 2 and 3, indicating that the bonding electrons in the adjacent MPt bonds migrate into the central MM bond to result in a dynamic structural change during two-electron oxidation of the hexanuclear metal strings. A similar Pt-6 complex terminated by two iodide anions, [Pt6I2(mu-dpmp)(4)](PF6)(2) (9), was synthesized from [Pt-6(mu-H)I-2(mu-dpmp)(4)](PF6) (5) by treatment with [Cp2Fe][PF6]. Complexes 7 and 8 were readily reacted with the neutral two-electron donors XylNC, CO, and phosphines to afford the trinuclear complexes [Pt2M(mu-dpmp)(2)(XylNC)L](PF6)(2) (M = Pt, L = XylNC (la), CO (10), PPh3 (11); M = Pd, L = XylNC (1b)) through cleavage of the electron-deficient central M-M bond. 'When complex 7 was reacted with the diphosphines (PP) trans-Ph2PCH=CHPPh2 (dppen) and Ph2P(CH2)(2)PPh2 (dppe), the diphosphine was inserted into the central M-M bond to afford [(XylNC)Pt-3(mu-dpmp)(2)(PP)Pt-3(mu-dpmp)(2)(XylNC)](PF6)(4) (12), which was transformed by treatment with another 1 equiv of diphosphine into the asymmetric trinuclear complexes [Pt-3(mu-dpmp)(2)(XylNC)(PP)](PF6)(2) (13). A further ligand exchange reaction of 13a (PP = trans-dppen) provided the diphosphine-terminated symmetrical Pt3 complex [Pt-3(mu-dpmp)(2)(L)(2)](PF6)(2) (L = trans-dppen (14a)). Complexes 7 and 8 were also reacted with [AuCl(PPh3)] to yield the Pt2MAu heterotetranuclear complexes [Pt2MAuCl(mu-dpmp)(2)(PPh3)(XylNC)RPF6)(2) (M = Pt (15), Pd (16)), in which the Pt2M trinuclear fragment is inserted into the Au-Cl bond in a 1,1-fashion on the central M atoms of the Pt2M2Pt2 string., Apr. 2014, 33, 8, 1893, 1904, Scientific journal, 10.1021/om401211d
  • Refereed, CHEMICAL PHYSICS, ELSEVIER SCIENCE BV, Magnetic relaxations in a Tb-based single molecule magnet studied by quasielastic neutron scattering, Maiko Kofu; Takashi Kajiwara; Jason S. Gardner; Giovanna G. Simeoni; Madhusudan Tyagi; Antonio Faraone; Kenji Nakajima; Seiko Ohira-Kawamura; Motohiro Nakano; Osamu Yamamuro, By using ac magnetic susceptibility and quasielatic neutron scattering (QENS) techniques, we have investigated a magnetization relaxation phenomenon of a rare-earth based single molecule magnet, TbCuC19H20N3O16. We clearly identified and characterized two magnetic relaxations. The slower relaxation observed in the ac susceptibility is at the ms timescale around T = 2 K and its activation energy is 16 K. On the other hand, the faster relaxation in the QENS measurements occurs on the timescale between ns and ps with activation energy of 174 K. The slower relaxation may occur through thermally activated tunneling among magnetic substates. We discuss two possible origins for the faster relaxation; one is a thermally activated tunneling between the higher excited states, the other is the magnetic relaxation coupled with the motion of ligands around the magnetic ions. This is the first clear observation of magnetic relaxation on the single molecule magnet revealed by QENS. (C) 2013 Elsevier B. V. All rights reserved., Dec. 2013, 427, 147, 152, Scientific journal, 10.1016/j.chemphys.2013.10.004
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, SMM Behavior Observed in Ce(III)Zn(II)(2) Linear Trinuclear Complex, Shiori Hino; Moe Maeda; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, The second example of the Ce(III)-based single-molecule magnet (SMM), which involves only one 4f electron as a spin carrier, was realized based on similar magnetostructural correlations with Tb(III)-based SMMs. The estimated energy barrier for spin flipping was Delta E/k(B) = 37(1)K, which is higher than that for the first Ce(III)-SMM, and slow magnetic relaxation was observed up to 15 K., Oct. 2013, 42, 10, 1276, 1278, Scientific journal, 10.1246/cl.130602
  • Refereed, PHYSICAL REVIEW B, AMER PHYSICAL SOC, Hyperfine structure of magnetic excitations in a Tb-based single-molecule magnet studied by high-resolution neutron spectroscopy, M. Kofu; O. Yamamuro; T. Kajiwara; Y. Yoshimura; M. Nakano; K. Nakajima; S. Ohira-Kawamura; T. Kikuchi; Y. Inamura, We report inelastic neutron scattering results on a rare-earth-based single-molecule magnet, the Tb-Cu dinuclear complex. By means of a high-resolution neutron chopper spectrometer, the details of the excitations were clarified. The magnetic excitations are clearly observed at (h) over bar omega=1.7 and 12.3 meV. The transition energy of 1.7 meV corresponds to the energy barrier of magnetic relaxation estimated from an ac magnetic susceptibility measurement. This indicates that the magnetization reversal occurs through quantum tunneling between pairs of degenerated excited states at 1.7 meV, which is called a thermally activated tunneling process. Interestingly, these excitations exhibit further peak splitting in energy and their energies are independent of momentum transfer Q. Our calculation, which is based on a spin Hamiltonian, suggests that (i) the excitation at 1.7 meV originates from the exchange coupling between Tb3+ and Cu2+, (ii) the excitation at 12.3 meV corresponds to the transition between the multiplets J of the Tb3+ moment, and (iii) the fine peak splitting in energy is due to the hyperfine interaction between the nuclear spin and electron spin and orbital magnetic moments., Aug. 2013, 88, 6, 064405, Scientific journal, 10.1103/PhysRevB.88.064405
  • Refereed, Dalton Transactions, Royal Society of Chemistry, A luminescent single-molecule magnet: Observation of magnetic anisotropy using emission as a probe, Kei Yamashita; Rie Miyazaki; Yumiko Kataoka; Takayuki Nakanishi; Yasuchika Hasegawa; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, An assemblage of a Tb(iii) ion and two mononuclear [Zn< sup> II< /sup> (L)] complexes as antenna chromophores (H< inf> 2< /inf> L: Schiff base ligand) afforded a luminescent single-molecule magnet. The f-f emission spectrum had partially resolved fine structure which provides detailed information on the magnetic anisotropy of the < sup> 7< /sup> F< inf> 6< /inf> ground multiplet of the Tb(iii) ion. © The Royal Society of Chemistry 2013., 14 Feb. 2013, 42, 6, 1987, 1990, Scientific journal, 10.1039/c2dt32785f
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Linear trinuclear Zn(II)-Ce(III)-Zn(II) complex which behaves as a single-molecule magnet, Shiori Hino; Moe Maeda; Kei Yamashita; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura; Hiroyuki Nojiri; Maiko Kofu; Osamu Yamamuro; Takashi Kajiwara, Linear Zn(II)-Ce(III)-Zn(II) complex, which involves only one 4f electron as a spin source, behaves as an SMM. Easy-axis magnetic anisotropy for the ground F-2(5/2) state of Ce(III) was achieved by a uni-axial crystal field, which is formed with four phenoxo oxygens as axial donors with the other five oxygens as equatorial donors., 2013, 42, 8, 2683, 2686, Scientific journal, 10.1039/c2dt32812g
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Wheel-Shaped Icosanuclear Homo- and Heterometallic Complexes of Ni-II, Co-II, and Cu-II Ions Supported by Unsymmetrical Aminoalcohol Ligands, Takayuki Nakajima; Keiko Seto; Fumihiro Horikawa; Isao Shimizu; Andreas Scheurer; Bunsho Kure; Takashi Kajiwara; Tomoaki Tanase; Masahiro Mikuriya, Reactions of M(OAc)(2)center dot 4H(2)O (M = Ni, Co) with 3-[benzyl(2-hydroxyethypamino]-1-propanol (H2L) in the presence of pyridine or triethylamine afforded novel homometallic icosanuclear wheel-shaped complexes [M20L4(HL)(4)(OAc)(28)] (M = Ni (1), Co (2)), which consist of a central M-12(II) single-stranded, nearly planar loop with four peripheral [M-2(HL)(OAc)(2)] fragments attached in an S-4 symmetrical fashion. The complexes can alternatively be recognized as saddle-shaped wheel structures, in which four tetranuclear units of [M4L(HL)(OAc)(2)](2-) are connected by four M2+ ions (M5). The tetranuclear unit itself can be derived from an ideal C-2 symmetrical [M-4(HL)(2)(mu-eta(2)-OAc)(4)(mu-eta(1),eta(1)-OAc)(2)(eta(1),eta(1)-OAc)](-) structure through deprotonation of the HL- ligand, and is composed of two plane shared M3O4 incomplete cubanes in which the M2 and M3 atoms are involved in the central fused plane and the M1 and M4 atoms are disposed at the apex sites. Mixed-metal icosanuclear complexes [NixM20-xL4(HL)(4)(OAc)(28)] (3, M = Co, x = 9.5) and [Ni12M8L4(HL)(4)(OAc)(28)] (4, M = Cu) were also synthesized by using equimolar amounts of Ni-II and ions, and were shown to have similar structures to 1 and 2. X-ray crystallographic and fluorescent analyses revealed that complex 3 contains nonstoichiometric amounts of Ni2+ and Co2+ ions in the ratio of 9.5:10.5 and that these are disordered at every metal site. In striking contrast, complex 4 has a stoichiometric formula of Ni12Cu8, which was confirmed by the Jahn-Teller elongation of Cu2+ ions, and consequently, the M2 and M5 positions are occupied exclusively by the Cu2+ ions. The temperature-dependent direct current (dc) magnetic susceptibility data showed the presence of ferromagnetic exchange interactions in the Ni homometallic (1) and NiCu bimetallic (4) complexes, while the Co homometallic (2) and NiCo bimetallic (3) complexes exhibited antiferromagnetic interactions due to spin-orbit coupling effects of the octahedral Co-II ions. The present results demonstrate that the unsymmetrical aminoalcohol ligand H2L is quite effective in organizing the homo- and heterometallic icosanuclear wheel-shaped metal arrangements., Nov. 2012, 51, 22, 12503, 12510, Scientific journal, 10.1021/ic3019106
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Correlation between slow magnetic relaxation and the coordination structures of a family of linear trinuclear Zn(II)-Ln(III)-Zn(II) complexes (Ln = Tb, Dy, Ho, Er, Tm and Yb), Moe Maeda; Shiori Hino; Kei Yamashita; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, Six linear trinuclear [Ln{Zn(L)(AcO)}(2)]BPh4 complexes (H2L denotes the Schiff-base ligand formed by a condensation reaction between ethylenediamine and two equivalents of o-vanillin), including Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5) and Yb (6) were synthesized and were confirmed to be isostructural via X-ray crystallographic analyses. The Ln(III) ion in each complex is deca-coordinated by four equatorial oxygen donors from the methoxo groups of the Schiff-base ligands, two oxygen donors from the acetate anions and four axial oxygen donors from the phenoxo groups of the Schiff-base ligands. AC susceptibility measurements, with an oscillating frequency of 10 to 10 000 Hz, revealed that 1, 2, 4 and 6 show slow magnetic relaxation under a 1000 Oe DC bias field, which occurs via a single process, as confirmed by the semi-circular Cole-Cole plots. These complexes are considered to be field-induced single-molecule magnets under these conditions. The presence or absence of the slow magnetic relaxation process is discussed by correlating the characteristic magnetic anisotropy of each Ln(III) ion with the ligand field anisotropy., 2012, 41, 44, 13640, 13648, Scientific journal, 10.1039/c2dt31399e
  • Refereed, CHEMISTRY-A EUROPEAN JOURNAL, WILEY-V C H VERLAG GMBH, Magnetic Relaxation of Single-Molecule Magnets in an External Magnetic Field: An Ising Dimer of a Terbium(III)-Phthalocyaninate Triple-Decker Complex, Keiichi Katoh; Takashi Kajiwara; Motohiro Nakano; Yasuhiro Nakazawa; Wolfgang Wernsdorfer; Naoto Ishikawa; Brian K. Breedlove; Masahiro Yamashita, 2011, 17, 1, 117, 122, Scientific journal, 10.1002/chem.201002026
  • Refereed, CHEMISTRY-A EUROPEAN JOURNAL, WILEY-BLACKWELL, Structural Design of Easy-Axis Magnetic Anisotropy and Determination of Anisotropic Parameters of Ln(III)-Cu-II Single-Molecule Magnets, Takashi Kajiwara; Motohiro Nakano; Kohei Takahashi; Shinya Takaishi; Masahiro Yamashita, Four dinuclear Le(III)-Cu-II complexes with Ln = Tb (1), Dy (2), Ho (3), and Er (4) were synthesized to investigate the relationship between their respective magnetic anisotropies and ligand-field geometries. These complexes were crystallographically isostructural, and a uni-axial ligand field was achieved by using three phenoxo oxygen groups. Complexes 1 and 2 displayed typical single-molecule magnet (SMM) behaviors, of which the out-of-phase susceptibilities were observed in the temperature range of 1.8-5.0 K (1) and 1.8-20.0 K (2). The Cole-Cole plots exhibited a semicircular shape with alpha parameters in the range of 0.08-0.18 (2.6-4.0 K) and 0.07-0.24 (3.5-7.0 K). The energy barriers Delta/k(B) were estimated from the Arrhenius plots to be 32.9(4) K for 1 and 26.0(5) K for 2. Complex 3 displayed a slow magnetic relaxation below 3.0 K, whereas complex 4 did not show any frequency-dependent behavior for both in-phase and out-of-phase susceptibilities, which indicates that easy-axis anisotropy was absent. The temperature dependence of the dc susceptibilities for the field-aligned samples of 1-3 revealed that the chi T-M value continuously increased as the temperature was lowered, which indicates the presence of low-lying Stark sublevels with the highest vertical bar J(z)vertical bar values. In contrast, complex 4 displayed a smaller and temperature-independent chi T-M value, which also indicates that easy-axis anisotropy was absent. Simultaneous analyses were carried out for 1-3 to determine the magnetic anisotropy parameters on the basis of the Hamiltonian that considers B-2(0), B-4(0), and B-6(0)., 2011, 17, 1, 196, 205, Scientific journal, 10.1002/chem.201002434
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-BLACKWELL, Wheel-Shaped (ErZn3II)-Zn-III Single-Molecule Magnet: A Macrocyclic Approach to Designing Magnetic Anisotropy, Aika Yamashita; Akiko Watanabe; Shigehisa Akine; Tatsuya Nabeshima; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, 2011, 50, 17, 4016, 4019, Scientific journal, 10.1002/anie.201008180
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Real time and space observation of domain wall migration in a MX-chain complex with a quasi-2D CDW state by using STM, Shinya Takaishi; Hashen Wu; Takashi Kajiwara; Brian K. Breedlove; Hitoshi Miyasaka; Masahiro Yamashita, In STM images of [Pd(chxn-d(4))(2)Br]Br-2, which is in a quasi-2D-CDW state, we observed domain wall migration due to fast soliton motion at neighboring chains to the domain wall., 2011, 40, 10, 2160, 2162, Scientific journal, 10.1039/c0dt01051k
  • Refereed, CRYSTENGCOMM, ROYAL SOC CHEMISTRY, Metal-organic frameworks with rare topologies: lonsdaleite-type metal formates and their magnetic properties, Hyunuk Kim; Yinyong Sun; Yonghwi Kim; Takashi Kajiwara; Masahiro Yamashita; Kimoon Kim, Single-crystal X-ray analysis revealed that isomorphous metal formates [M-6(HCOO)(12)]center dot DEF (M = Mg2+, Fe2+, Co2+, Zn2+) have a framework with the lonsdaleite net, which is one of the rare topologies in metal-organic frameworks; iron and cobalt formates with metal sites bridged by single atoms showed dominant ferromagnetic and antiferromagnetic interactions, respectively., 2011, 13, 7, 2197, 2200, Scientific journal, 10.1039/c1ce05031a
  • Refereed, Journal of Physics: Conference Series, Magnetic properties of lanthanoid(III) phthalocyaninato triple-decker complexes in an external magnetic field and electronic transport properties for molecular spintronics, K. Katoh; K. Yamamoto; T. Kajiwara; J. Takeya; B. K. Breedlove; M. Yamashita, Lanthanoid phthalocyaninato complexes of Dy2(obPc)3 (1) and Tb2(obPc)3 (2) are shown to be a single-molecule magnet. The relationships among the magnetic relaxation properties of 1 in a direct current (dc) magnetic field in comparison to 2 and the electronic properties of a cast film are discussed., 2011, 303, 1, 012035-012044, International conference proceedings, 10.1088/1742-6596/303/1/012035
  • Refereed, CHEMISTRY-A EUROPEAN JOURNAL, WILEY-BLACKWELL, Multi-Path Magnetic Relaxation of Mono-Dysprosium(III) Single-Molecule Magnet with Extremely High Barrier, Akiko Watanabe; Aika Yamashita; Motohiro Nakano; Tomoo Yamamura; Takashi Kajiwara, Jun. 2011, 17, 27, 7428, 7432, Scientific journal, 10.1002/chem.201003538
  • Refereed, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, WILEY-V C H VERLAG GMBH, Systematic Expansion of Supercubane Cores in Manganese Oxo Clusters with Tricarboxylate Ligands, Yayoi Okui; Florina Aurelia Catusanu; Ryoko Kubota; Bunsho Kure; Takayuki Nakajima; Tomoaki Tanase; Takashi Kajiwara; Masahiro Mikuriya; Hitoshi Miyasaka; Masahiro Yamashita, A novel class of high-nuclearity Mn-17 and Mn-19 mixed-valent complexes, [Mn-17(mu-O)(12)(mu-OMe)(2)(mu-kta)(6)(MeOH)(4)] (1), [Mn-17(mu-O)(14)(mu-kta)(6)L-4] [L = bpy (2a), phen (2b), 4,7-Ph(2)phen (2c), dmf (3)], and [Mn-19(mu-O)(14)(mu-kta)(6)(bpy)(6)]X-3 [X = PF6 (4a), BF4 (4b)], were synthesized by utilizing Kemp's tricarboxylate ligands (H(3)kta = cis,cis-1,3,5-trimethylcyclohexane-1,3,5- tricarboxylic acid). The complexes were characterized by X-ray crystallography and reveal mineralomimetic Mn-13 supercubane units, [Mn-13(mu-O)(14)], in which their oxidation states systematically altered, depending on their vertex face-capping ligands and Mn-II satellite fragments. Complex 2a was converted by treatment with benzoic acid and [Mn2O2(bpy)(4)](BF4)(3) to a cage-type Mn-14 complex, [Mn-14(mu-O)(12)(mu-OH)(6)(mu-Hkta)(6)(bpy)(6)](BF4)(4) (5), which show ferro- and antiferromagnetic interactions and slow magnetic relaxation at low temperature., Oct. 2011, 28, 4325, 4330, Scientific journal, 10.1002/ejic.201100781
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Non-oxo 5-coordinate and 6-coordinate vanadium(IV) complexes with their precursor [LVIII(CH3OH)](0), where L = a trianionic aminetris(phenolate)-[N,O,O,O] donor ligand: a magnetostructural and EPR study, Takashi Kajiwara; Rita Wagner; Eckhard Bill; Thomas Weyhermueller; Phalguni Chaudhuri, Ligating properties of a tripodal, potentially tetradentate aminetris(phenol) ligand, tris(2-hydroxy-3,5-di-tert-butylbenzyl) amine, H3L, containing [N,O,O,O] donor atoms toward the vanadium ions in +III and IV oxidation states have been studied. The structures of complexes 1 [LVIII(CH3OH)](0), 2[LVIV(OCH3)](0) and 3[LVIV(acac)](0) were determined by X-ray diffraction methods as having five-coordinate V(III), 1, five-coordinate non-oxo-vanadium(IV), 2, and six-coordinate non-oxo-vanadium(IV) 3, respectively. Compounds 1-3 were also studied with electrochemical methods, variable-temperature (2-295 K) magnetic susceptibility measurements and X-band electron paramagnetic resonance (EPR) spectroscopy. The electrochemical results of 2 and 3 suggest metal-centered oxidation, i.e. the generation of a V-V-phenolate species. EPR investigations indicate a (d(xy))(1) ground state showing a considerable increase in the in-plane p-bonding, as is expected for a phenolate ligand., 2011, 40, 47, 12719, 12726, Scientific journal, 10.1039/c1dt11277e
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Structural Study of Electronic States in Quasi-One-Dimensional Halogen-Bridged Mixed-Metal Complexes [Ni1-xPdx(chxn)(2)Br]Br-2, Shinya Takaishi; Hashen Wu; Jimin Xie; Takashi Kajiwara; Brian K. Breedlove; Hitoshi Miyasaka; Masahiro Yamashita, The electronic structures of quasi-one-dimensional halogen-bridged mixed-metal compounds [Ni1-xPdx(chxn)(2)Br]Br-2 were investigated by means of powder X-ray diffraction measurements. Unit cell lengths of all directions obeyed a linear relationship when x < 0.9, whereas those deviated when x > 0.9 especially in the case of the b and c axes. This deviation can be explained by a phase change from an M-III Mott-Hubbard state to an M-II-M-IV charge-density-wave state because of chemical pressure caused by the substitution of Pd ions into [Pd(chxn)(2)Br]Br-2 with smaller Ni ions., Apr. 2010, 49, 8, 3694, 3696, Scientific journal, 10.1021/ic1001368
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Single-Chain Magnets Constructed by Using the Strict Orthogonality of Easy-Planes: Use of Structural Flexibility to Control the Magnetic Properties, Takashi Kajiwara; Hiroki Tanaka; Motohiro Nakano; Shinya Takaishi; Yasuhiro Nakazawa; Masahiro Yamashita, A family of single-chain magnets (SCMs), of which the SCM character originated from the spatial arrangement of high spin Fell ions with easy-plane anisotropy, was synthesized, and their magnetic properties were investigated. The chain complexes including alternating high-spin Fell ions and low-spin Fe" ions, catena-Fell(C104)2{Felll(bpca)2}1C104 3MeNO2 (1.3MeNO(7)), catena-[Fell(C104)(H20){Feu(MeL)2}(CI04)2 2MeN04 H20 (2- 2MeNO2. H20), catena-Fell(C104)(H20){Fe(III)Bu ( L)2}i(uu 4)2.3.5MeNO2 (3- 3,5MeNO2), and catena-[{F ell (C104)(F120)F ell (H20)21 0.5{Fe"( L)211(C104)2.5.4EtNO2 (4.4EtNO2), were synthesized with the use of bridging ligand Hbpca (bis-(2-pyridylcarbonyl)amine)) and its derivatives of eel., HBI, and HPhL each incorporating methyl, tert-butyl, or phenyl group on the 4-position of pyridyl ring. These complexes showed a typical ferrimagnetic behavior on direct current (dc) susceptibility data, and from an alternating current (ac) susceptibility measurements, SCM or superparamagnetic behaviors were confirmed with the A/kB values of 22.5(4), 21.8(18), and 28.8(3) K for 1.3MeNO2, 2- 2MeNO2" H20, and 3 -3.5MeNO2, of which the easy-axis anisotropy was originated from the orthogonal arrangement of easy-planes of Fen ions. In the crystal structures, cylindrical voids were formed along the chain axis being surrounded by four chains in 1 -3MeNO2, 2 -2MeNO(2)- H(2)O, and 4 4EtNO(2) and two chains in 3 "3.5MeNO2, and solvent molecules as well as coordination-free perchlorate anions occupied these voids in a slightly different fashion depending on the complexes. 2.2MeNO2-1-120 maintains its chemical composition in a dried condition, whereas 1 "3MeNO2, 3 -3.5MeNO2, and 4 " 4EtNO2 easily release solvent molecules to give 1, 3, and 4, respectively. 1 and 3 maintain the crystalline character showing slightly different X-ray diffraction (XRD) patterns from those of 1 3MeNO2 and 3- 3.5MeNO2, and an enhancement of SCM character after release of the solvent molecules was observed for both. 4 lost crystalline character to become amorphous, and it lost the SCM character at the same time., Sep. 2010, 49, 18, 8358, 8370, Scientific journal, 10.1021/ic100843k
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Effect of an In-Plane Ligand on the Electronic Structures of Bromo-Bridged Nano-Wire Ni-Pd Mixed-Metal Complexes, [Ni1-xPdx(bn)(2)Br]Br-2 (bn=2S,3S-Diaminobutane), Mari Sasaki; Hashen Wu; Daisuke Kawakami; Shinya Takaishi; Takashi Kajiwara; Hitoshi Miyasaka; Brian K. Breedlove; Masahiro Yamashita; Hideo Kishida; Hiroyuki Matsuzaki; Hiroshi Okamoto; Hisaaki Tanaka; Shinichi Kuroda, Single crystals of quasi-one-dimensional bromo-bridged Ni-Pd mixed-metal complexes with 2S,3S-diaminobutane (bn) as an in-plane ligand, [Ni1-xPdx(bn)(2)Br]Br-2, were obtained by using an electrochemical oxidation method involving mixed methanol/2-propanol (1:1) solutions containing different ratios of [Ni-II(bn)(2)]Br-2 and [Pd-II(bn)(2)]Br-2. To investigate the competition between the electron-correlation of the Ni-III states, or Mott-Hubbard states (MH), and the electron-phonon interaction of the Pd-II-Pd-IV mixed valence states, or charge-density-wave states (CDW), in the Ni-Pd mixed-metal compounds, X-ray structure analyses, X-ray oscillation photograph, and Raman, IR, ESR, and single-crystal reflectance spectra were analyzed. In addition, the local electronic structures of Ni-Pd mixed-metal single crystals were directly investigated by using scanning tunneling microscopy (STM) at room temperature and ambient pressure. The oxidation states of [Ni1-xPdx(bn)(2)Br]Br-2 changed from a M-II-M-IV mixed valence state to a M-III MH state at a critical mixing ratio (x(c)) of similar to 0.8, which is lower than that of [Ni1-xPdx(chxn)(2)Br]Br-2 (chxn=1R,2R-diaminocyclohexane) (x(c) approximate to 0.9) reported previously. The lower value of x(c) for [Ni1-xPdx(bn)(2)Br]Br-2 can be explained by the difference in their CDW dimensionalities because the three-dimensional CDW ordering in [Pd(bn)(2)Br]Br-2 observed by using X-ray diffuse scattering stabilizes the Pd-II-Pd-IV mixed valence state more than two-dimensional CDW ordering in [Pd(chxn)(2)Br]Br-2 does, which has been reported previously., Aug. 2009, 48, 15, 7446, 7451, Scientific journal, 10.1021/ic901067z
  • Refereed, Journal of the American Chemical Society, Direct observation of lanthanide(III)-phthalocyanine molecules on Au(111) by using scanning tunneling microscopy and scanning tunneling spectroscopy and thin-film field-effect transistor properties of Tb(III)- and Dy(III)-phthalocyanine molecules, Keiichi Katoh; Yusuke Yoshida; Masahiro Yamashita; Hitoshi Miyasaka; Brian K. Breedlove; Takashi Kajiwara; Shinya Takaishi; Naoto Ishikawa; Hironari Isshiki; Feng Zhang Yan; Tadahiro Komeda; Masakazu Yamagishi; Jun Takeya, The crystal structures of double-decker single molecule magnets (SMM) LnPc2 (Ln = Tb(III) and Dy(III); Pc = phthalocyanine) and non-SMM YPc2 were determined by using X-ray diffraction analysis. The compounds are isomorphous to each other. The compounds have metal centers (M ) Tb3+, Dy3+, and Y3+) sandwiched by two Pc ligands via eight isoindole-nitrogen atoms in a square-antiprism fashion. The twist angle between the two Pc ligands is 41.4°. Scanning tunneling microscopy was used to investigate the compounds adsorbed on a Au(111) surface, deposited by using the thermal evaporation in ultrahigh vacuum. Both MPc 2 with eight lobes and MPc with four lobes, which has lost one Pc ligand, were observed. In the scanning tunneling spectroscopy images of TbPc molecules at 4.8 K, a Kondo peak with a Kondo temperature (TK) of ∼250 K was observed near the Fermi level (V = 0 V). On the other hand, DyPc, YPc, and MPc2 exhibited no Kondo peak. To understand the observed Kondo effect, the energy splitting of sublevels in a crystal field should be taken into consideration. As the next step in our studies on the SMM/Kondo effect in Tb-Pc derivatives, we investigated the electronic transport properties of Ln-Pc molecules as the active layer in top- and bottom-contact thin-film organic field effect transistor devices. Tb-Pc molecule devices exhibit p-type semiconducting properties with a hole mobility (μH) of ∼10-4 cm2 V-1 s-1. Interestingly, the Dy-Pc based devices exhibited ambipolar semiconducting properties with an electron mobility (μe) of ∼10-5 and a μH of ∼10-4 cm2 V-1 s-1. This behavior has important implications for the electronic structure of the molecules. © 2009 American Chemical Society., 29 Jul. 2009, 131, 29, 9967, 9976, Scientific journal, 10.1021/ja902349t
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Electroconductive Porous Coordination Polymer Cu[Cu(pdt)(2)] Composed of Donor and Acceptor Building Units, Shinya Takaishi; Miyuki Hosoda; Takashi Kajiwara; Hitoshi Miyasaka; Masahiro Yamashita; Yasuyuki Nakanishi; Yasutaka Kitagawa; Kizashi Yamaguchi; Atsushi Kobayashi; Hiroshi Kitagawa, We synthesized a new porous coordination polymer Cu[Cu(pdt)(2)], which shows relatively high electrical conductivity (6 x 10(-4) S cm(-1) at 300 K) by the introduction of electron donors and acceptors as building units. This compound is applicable as a porous electrode with high power density. In addition, this compound forms a triangular spin lattice and shows spin frustration., Oct. 2009, 48, 19, 9048, 9050, Scientific journal, 10.1021/ic802117q
  • Refereed, JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY, SPRINGER, One-step heterogeneous assembly of terbium(III) and silver(I) with thiacalix[4]arene ligands to form a cage including terbium(III) in an octa-oxygen cube, Teppei Tanaka; Nobuhiko Iki; Takashi Kajiwara; Masahiro Yamashita; Hitoshi Hoshino, A heterogeneous one-step self-assembly of Ag+, Tb3+, and thiacalix[4]arene (TCAS), of which the donor atoms S and O showed high selectivity toward Ag+ and Tb3+ ions, respectively, afforded a supramolecular cage compound, Ag-4(+)center dot Tb3+center dot TCAS(2), at the center of which an octa-oxygen cube encapsulated the Tb3+ center to completely shield it from solvent molecules., Aug. 2009, 64, 3-4, 379, 383, Scientific journal, 10.1007/s10847-009-9567-0
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Syntheses, Structures, and Magnetic Properties of Tetramanganese(III) and Hexamanganese(III) Complexes Containing Derivative of Biguanidate Ligand: Ferromagnetic Interaction via Imino Nitrogen, Asako Igashira-Kamiyama; Takashi Kajiwara; Motohiro Nakano; Takumi Konno; Tasuku Ito, The tetramanganese(III) and hexamanganese(III) complexes, [Mn-4(mu-pzbg)(2)(Hpzbg)(2)(MeO)(4)(MeOH)(H2O)]Cl-2 (1) and [Mn6O4(Hpzbg)(4)(AcO)(4)(MeO)(2)] (2), were synthesized by using a monopyrazolyl biguanide derivative (H(2)pzbg) as a multinucleating ligand, which was newly prepared by the nucleophilic addition of pyrazole to Dicyandiamide. Single-crystal X-ray analysis revealed that 2 possesses a face-sharing double cubane structure, in which six Mn(III) ions are bridged by six MeO- with four terminal kappa N-2-Hpzbg(-). On the other hand, 1 possesses an incomplete face-sharing double cubane structure in which four Mn(III) ions are bridged by four MeO- and two kappa N-2:kappa N-2-pzbg(2)-accompanied by two terminal kappa N-2-Hpzbg(-). In 1, both ferromagnetic and antiferromagnetic interactions occur between manganese(III) ions, of which the ferromagnetic one is assigned to be the interaction via the imino nitrogen atom, while all manganese(III) ions are connected in an antiferromagnetic manner in 2., Dec. 2009, 48, 23, 11388, 11393, Scientific journal, 10.1021/ic901219f
  • Refereed, POLYHEDRON, PERGAMON-ELSEVIER SCIENCE LTD, Coordination enhancement of single-molecule magnet behavior of Tb(III)-Cu(II) dinuclear systems, Takashi Kajiwara; Kohei Takahashi; Tomonari Hiraizumi; Shinya Takaishi; Masahiro Yamashita, Tb(III)-Cu(II) based single-molecule magnets (SMMs) were synthesized to investigate the relationship between magnetic anisotropy and the symmetry of the ligand field, by the reaction of [TbCu(o-vanilate)(2)(NO(3))(3)] with 2,2-dimethyl-1,3-propanediamine (3), followed by the reaction of one another equivalent of o-vaniline (4). Both complexes behave as SMM in the temperature range of 2.8-4.0 K (3) and 2.8-5.2 K (4), showing semi-circle shapes of Cole-Cole plots with alpha parameters in the ranges of 0.27-0.41 and 0.11-0.32. The energy barriers Delta/k(B) for the spin flippings were estimated from the Arrhenius plots to be 29(2) K for 3 and 32.2(6) K for 4, respectively. (C) 2009 Elsevier Ltd. All rights reserved., Jun. 2009, 28, 9-10, 1860, 1863, Scientific journal, 10.1016/j.poly.2009.02.010
  • Refereed, CRYSTENGCOMM, ROYAL SOC CHEMISTRY, Structural correlations between the crystal field and magnetic anisotropy of Ln-Cu single-molecule magnets, Takashi Kajiwara; Kohei Takahashi; Tomonari Hiraizumi; Shinya Takaishi; Masahiro Yamashita, Mixed ligand Ln(2)Cu(2) tetranuclear complexes, [{LnCu(L4)(L5)(NO(3))(2)}(2)] (L4(-) is a Schiff base ligand derived from o-vanilate, L5(2-) is a nitromethyl derivative of L4(-); Ln=Gd(4), Tb(5), and Dy(6)), were synthesized by reacting the corresponding dinuclear complexes [LnCu(o-vanilate)(2)(NO(3))(3)] with ethylamine in a nitromethane solution. From detailed studies of magnetic anisotropies 5 was shown to behave as an SMM, whereas 6 was not an SMM., 2009, 11, 10, 2110, 2116, Scientific journal, 10.1039/b906182g
  • Refereed, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, CHEMICAL SOC JAPAN, Structures and Magnetic Properties of Dinuclear Copper(II) Complexes Containing a Bulky Diamine Ligand, 1,2-Dipiperidinoethane, Machiko Arakawa-Itoh; Kana Tokuman; Yukie Mori; Takashi Kajiwara; Masahiro Yamashita; Yutaka Fukuda, A reaction of copper(II) perchlorate with a sterically hindered diamine, 1,2-dipiperidinoethane (dipe), yields two dinuclear complexes: di-mu-hydroxo dinuclear complex [{Cu(ClO4)(dipe)(mu-OH)}(2)] (1) and di-mu-alkoxo dinuclear complex [{Cu(ClO4)(dipe-O)}(2)] (2) (dipe-O- is 1-(2-piperidinoethyl)piperidin-3-olate which was newly obtained in this work). The structures of complexes 1 and 2 were confirmed by X-ray crystallography. Complex 2 is meso form containing (R)- and (S)-dipe-O-. Dipe-O- acts as a tridentate ligand with an N,N,O-donor set and bridges two copper(II) ions through the oxygen atom. The oxygen atom is incorporated into dipe from atmospheric molecular oxygen during the reaction of dipe with copper ion. The temperature dependences of chi T-m values were different between 1 and 2 depending on the bridging structures. Complex 1 shows ferromagnetic interaction and the value of 2J = 117cm(-1) is in agreement with that predicted from the angle Cu-O-Cu bridging angle of 96.9 degrees. Complex 2, the bridging angle of which is 100.59 degrees, shows a strong antiferromagnetic interaction (-2J > 400cm(-1)). The singlet-triplet energy gap for complex 2 was estimated from DFT calculation., Mar. 2009, 82, 3, 358, 363, Scientific journal, 10.1246/bcsj.82.358
  • Refereed, JOURNAL OF PHYSICAL CHEMISTRY C, AMER CHEMICAL SOC, A Low-Temperature Scanning Tunneling Microscope Investigation of a Nonplanar Dysprosium-Phthalocyanine Adsorption on Au(111), Yan-Feng Zhang; Hironari Isshiki; Keiichi Katoh; Yusuke Yoshida; Masahiro Yamashita; Hitoshi Miyasaka; Brian K. Breedlove; Takashi Kajiwara; Shinya Takaishi; Tadahiro Komeda, Self-assemblies of a nonplanar dysprosium-phthalocyanine (DyPc) molecule on the reconstructed Au(111) substrate have been examined with a low-temperature scanning tunneling microscope (STM). A four-lobed structure with a dark center hole is imaged as an isolated DyPc molecule, where the Dy atom is expected to be positioned below the Pc plane and bound,to the Au substrate. Careful measurements reveal that the axes of isolated DyPc molecules align well with the high symmetry directions of Au. This fact illustrates a strong molecule-substrate interaction. In a monolayer film, a square molecule lattice is observed, where the geometries of the molecules can be determined by our submolecularly resolved STM images. The deduced lattice vectors and the azimuthal angles of the molecules account for a dominant molecule-molecule interaction. In a bilayer growth regime, the bonding configurations of the molecules in the second layer coincide with that of the first layer. A similar azimuthal angle appearing in the two layers may indicate a columnar packing geometry of DyPc molecules., Aug. 2009, 113, 32, 14407, 14410, Scientific journal, 10.1021/jp9045935
  • Refereed, JOURNAL OF PHYSICAL CHEMISTRY C, AMER CHEMICAL SOC, Low-Temperature Scanning Tunneling Microscopy Investigation of Bis(phthalocyaninato)yttrium Growth on Au(111): From Individual Molecules to Two-Dimensional Domains, Yan Feng Zhang; Hironari Isshiki; Keiichi Katoh; Yusuke Yoshida; Masahiro Yamashita; Hitoshi Miyasaka; Brian K. Breedlove; Takashi Kajiwara; Shinya Takaishi; Tadahiro Komeda, We show a 4.8 K STM observation of a double-decker bis(phthalocyaninato)yttrium (YPc(2); Pc = phthalocyanine) molecule adsorption on Au(111) substrate. An eight-lobed structure was imaged as the submolecule STM contrast of a single molecule both in an isolated state and in a molecule film. This feature arises from the top Pc group, where both sides of the four phenyl rings are highlighted. As an isolated molecule, the adsorption orientation is determined by the lower Pc, the diagonal axis of which aligns parallel to the close-packed direction of Au(111). In a 2D film, a near-square molecule lattice appears with a unit of similar to 1.47 x 1.38 nm(2), and one of the lattice vectors is rotated by similar to 15 degrees from the close-packed direction. A tentative model is provided to illustrate the molecule array where neighboring molecules are rotated by similar to 30 degrees from each other. In this way, the lower Pcs should align along the [10 (1) over bar] and [(2) over bar 11] directions (or their equivalent directions) alternately. All these facts illustrate the molecule-substrate and the molecule-molecule interactions in the initial adsorption and in the film accumulation., Jun. 2009, 113, 22, 9826, 9830, Scientific journal, 10.1021/jp902410q
  • Refereed, JOURNAL OF INORGANIC AND ORGANOMETALLIC POLYMERS AND MATERIALS, SPRINGER, Direct Synthesis and Crystal Structure of Dehydrated State in Vapochromic MMX-type Quasi-One-Dimensional Iodide-Bridged Platinum Complexes, Hiroaki Iguchi; Shinya Takaishi; Takashi Kajiwara; Hitoshi Miyasaka; Masahiro Yamashita; Hiroyuki Matsuzaki; Hiroshi Okamoto, The dehydrated vapochromic 1D coordination polymer, (H(3)NC(4)H(8)NH(3))(2)[Pt(2)(pop)(4)I] (1) was synthesized directly from methanol solution. Although vapochromic 1 center dot A 4H (2) O has been synthesized, dehydrated high-temperature structure has never been determined because of lowering the quality of crystal by dehydration. The crystal structure of 1 was determined by X-ray crystal structure analysis, and we confirmed that it was identical to the dehydrated high-temperature structure of 1 center dot A 4H (2) O by comparing the powder X-ray diffraction (XRD) patterns. The Pt-I-Pt distance (d(Pt-I-Pt)) of compound 1 center dot A 4H (2) O was shortened for approximately 1.1 A... by desorption of water to form compound 1, accompanied with phase transition in electronic states. The other crystal including methanol molecule as lattice solvent, 1 center dot A 2MeOH, was also obtained as by-product. The synthesis from various kinds of organic solvent has the great potential to develop the field of vapochromism accompanying phase transition of electronic state., Mar. 2009, 19, 1, 85, 90, Scientific journal, 10.1007/s10904-008-9242-8
  • Refereed, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, WILEY-V C H VERLAG GMBH, Highly Luminescent Superparamagnetic Diterbium(III) Complex Based on the Bifunctionality of p-tert-Butylsulfonylcalix[4]arene, Takashi Kajiwara; Miki Hasegawa; Ayumi Ishii; Kensuke Katagiri; Munkhtsetseg Baatar; Shinya Takaishi; Nobuhiko Iki; Masahiro Yamashita, A diterbium(III) complex was synthesized by using p-tert-butylsulfonylcalix[4]arene, which adopts a 1,2-alternate conformation, acts as a sensitive optical-antenna chromophore for UV and near-UV light and causes easy-axis magnetic anisotropy in the Tb(III) ions. The complex showed efficient If emission with a corrected quantum yield of ca. 85% even at room temperature. In addition, it showed superparamagnetic behaviour due to slow magnetic relaxation at low temperatures. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008), Dec. 2008, 36, 5565, 5568, Scientific journal, 10.1002/ejic.200800706
  • Refereed, Inorg. Chem., Coordination-Tuned Single-Molecule-Magnet Behavior of Tb(III)-Cu(II) Dinuclear Systems, KAJIWARA Takashi; T. Kajiwara; M. Nakano; S. Takaishi; M. Yamashita, 2008, 47, 8604 - 8606
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, Charge-density-wave to Mott-Hubbard phase transition in quasi-one-dimensional bromo-bridged Pd compounds, Shinya Takaishi; Mitsuhito Takamura; Takashi Kajiwara; Hitoshi Miyasaka; Masahiro Yamashita; Muneaki Lwata; Hiroyuki Matsuzaki; Hiroshi Okamoto; Hisaaki Tanaka; Shin-ichi Kuroda; Hiroyuki Nishikawa; Hiroki Oshio; Kenichi Kato; Masaki Takata, A-Pd-III-Br-Pd-III-Mott-Hubbard state was observed in a quasi-one-dimensional bromo-bridged Pd compound [Pd(en)(2)Br](C-5-Y)(2)center dot H2O (en = ethylenediamine, C-5-Y = dipentylsulfosuccinate) for the first time. The phase transition between Mott-Hubbard and charge-density-wave states occurred at 206 +/- 2 K and was confirmed by using X-ray, ESR, Raman and electronic spectroscopies, electrical resistivity, and heat capacity. From X-ray powder diffraction patterns and Raman spectra of a series of Pd-Br compounds, [Pd(en)(2)Br](C-n-Y)(2)center dot H2O (n = 4, 5, 6, 7, 8, 9, and 12), chemical pressure from the alkyl chains of the counterions caused the phase transition., Sep. 2008, 130, 36, 12080, 12084, Scientific journal, 10.1021/ja8032026
  • Refereed, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, WILEY-V C H VERLAG GMBH, Three-dimensionally ordered CDW state in quasi-one-dimensional iodo-bridged dinuclear platinum mixed-valence compounds, A(4)[Pt2I(POP)(4)]center dot nH(2)O (A = aromatic ammonium cations), Satoshi Matsunaga; Kouichi Takizawa; Daisuke Kawakami; Hiroaki Iguchi; Shinya Takaishi; Takashi Kajiwara; Hitoshi Miyasaka; Masahiro Yamashita; Hiroyuki Matsuzaki; Hiroshi Okamoto, Linear-chain iodo-bridged dinuclear Pt mixed-valence compounds with aromatic ammonium countercations, A(4)[Pt2I(POP)(4)]center dot nH(2)O [POP = P2O5H22-, A = benzyl ammonium (n = 2; 1), anilinium (n = 2; 2), and p-methoxy anilinium (n = 2; 3)], that have three-dimensionally ordered structures were synthesized. In the case of 1-3 the aromatic ammonium countercations were located between neighboring Pt chains and stacked in 1D columns. pi-pi Interactions between the phenyl rings and hydrogen bonds between the -NH3+ moieties and the oxygen atoms of the pop ligand link the Pt chains together, thus giving rise to a three-dimensionally ordered CDW state. This is the first observation of this phenomenon in compounds of this type. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)., Jul. 2008, 21, 3269, 3273, Scientific journal, 10.1002/ejic.200701276
  • Refereed, Inorg. Chim. Acta, Hybridized complexes of [MnIII2] single-molecule magnets and Ni dithiolate complexes, KAJIWARA Takashi; H. Hiraga; H. Miyasaka; S. Takaishi; T. Kajiwara; M. Yamashita, 2008, 361, 3863-3273
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, Synthesis of a sulfur-bridged diphosphine ligand and its unique complexation properties toward palladium(II) ion, Naoya Morohashi; Yuki Akahira; Shinya Tanaka; Kensuke Nishiyama; Takashi Kajiwara; Tetsutaro Hattori, Sulfur-bridged phenol dimer 3(2) is converted into P-S-P ligand 5, mono- and dinuclear palladium complexes of which are selectively synthesized and characterized by X-ray crystallography., Apr. 2008, 37, 4, 418, 419, Scientific journal, 10.1246/cl.2008.418
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Why does the disorder of R-pn and rac-pn ligands in the quasi-one-dimensional bromo-bridged Ni-III complexes, [Ni(pn)(2)Br]Br-2 (pn=1,2-diaminopropane) afford similar STM patterns?, Hashen Wu; Daisuke Kawakami; Mari Sasaki; Jimin Xie; Shinya Takaishi; Takashi Kajiwara; Hitoshi Miyasaka; Masahiro Yamashita; Hiroyuki Matsuzaki; Hiroshi Okamoto, The disordered patterns of R- and rac-1,2-diaminopropane (pn) in quasi-one-dimensional bromo-bridged Ni(III) complexes, [Ni-III(pn)(2)Br]Br-2, have been investigated by single-crystal X-ray structure determination and scanning tunneling microscopy (STM). X-ray structure determination shows that the methyl moieties are disordered on the right- and left-hand sides with half occupancies in both compounds, while the carbon atoms of the ethylene moieties of pn ligands are disordered in [Ni(rac-pn)(2)Br]Br-2 and not disordered in [Ni(R-pn)(2)Br]Br-2. In the STM images of both compounds, the bright spots are not straight but fluctuated with the similar patterns. We have concluded that tunnel current from the STM tip to metal ions are detected via methyl groups of pn ligands., Sep. 2007, 46, 18, 7410, 7413, Scientific journal, 10.1021/ic700379m
  • Refereed, POLYHEDRON, PERGAMON-ELSEVIER SCIENCE LTD, Synthesis, structure, and magnetic property of a new Fe(II)-Fe(III) alternating single-chain magnet constructed with a methyl-substituted bpca(-) ligand, Hiroki Tanaka; Takashi Kajiwara; Yukihiro Kaneko; Shinya Takaishi; Masahiro Yamashita, A new Fe(II)-Fe(III) alternating single chain magnet, catena-[Fe-II(ClO4)(H2O){Fe-III(bmpca)(2)}](ClO4)(2), was synthesized using methyl-substituted bpca(-) ligand, bmpca(-) (Hbpca and Hbmpca denote bis(2-pyridylcarbonyl)amine and bis(4-methyl-2-pyridylcarbonyl)amine, respectively). The one-dimensional complex shows the ferrimangetic behavior and frequency dependent out-of-phase ac susceptibility X ''(m), with the alpha parameter of 0.25 estimated by the semicircle Cole-Cole plot. The activation energy Delta was estimated to be 19(1) K from an Arrhenius plot. (c) 2006 Elsevier Ltd. All rights reserved., Jun. 2007, 26, 9-11, 2105, 2109, Scientific journal, 10.1016/j.poly.2006.10.015
  • Refereed, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, CHEMICAL SOC JAPAN, Tetra- and di-nuclear copper(II) complexes with stereoisomers of sulfinylcalix[4]arene arising from the disposition of four S=O groups, Nobuhiko Iki; Yusuke Yamane; Naoya Morohashi; Takashi Kajiwara; Tasuku Ito; Sotaro Miyano, A systematic investigation was conducted on the structures of tetra- and di-nuclear copper(II) complexes with three stereoisomers of sulfinylcalix[4]arenes (H4L), the isomerism of which is determined by the disposition of the sulfinyl oxygen with respect to a reference oxygen from the mean plane containing four sulfur atoms. The sulfinylcalix[4]arene with a trans-cis-trans S = O orientation (H4Lrtct) reacted with Cu(OAc)(2) to form [Cu(II)4(L-rtct)(OAc)(3)(mu-MeO)(MeOH)] (1), in which Lrtct4- adopts a cone conformation to afford tetrakis fac-tridentate coordination through four phenoxo oxygens and four sulfinyl groups giving a square Cu-4(II) core. Ligands H4Lrccc and H4Lrctt having cis-cis-cis and cis-trans-trans configurations formed [Cu-4(II)(L-rccc)(OAc)(3)(mu-OH)] (2) and [Cu-4(II)(L-rctt)(OAC)(3)(mu-OH)] (3), respectively, which have common features, such as a cone-type conformation of L4-, tetrakis fac-tridentate coordination fashion, and tetra-copper(II) core in a square-pyramidal geometry. The similarities among 1-3 clearly show that sulfinylcalix[4]arenes can coordinate to Cu-II in a fac-tridentate fashion via a donor atom X (O or S) from a sulfinyl group and two flanking phenoxo O-s(-) and that X is simply determined by the X-Cu distance. Using [Cu(acac)(2)] as a copper(II) source, H4L(rctt) formed [Cu-2(II)(H2Lrctt)(2)] (4), suggesting the significance of auxiliary ligand for bridging copper(II) centers to assemble the core, that is, the acetato ligands in complexes 1-3 are needed to form the core structure. Metal-metal interactions were investigated by means of magnetic susceptibility, and it was found that both ferro- and antiferromagnetic interactions occur in tetracopper(II) complex 3. In contrast, antiferromagnetic interaction is present in dicopper(II) complex 4., Jun. 2007, 80, 6, 1132, 1139, Scientific journal, 10.1246/bcsj.80.1132
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, Direct observation of the ground-spin alignment of Fe(II)-Fe(III) single-chain magnet by muon-spin relaxation, Takashi Kajiwara; Isao Watanabe; Yukihiro Kaneko; Shinya Takaishi; Masaya Enomoto; Norimichi Kojima; Masahiro Yamashita, Zero field and longitudinal field muon-spin relaxation measurements were carried out for the single-chain magnet catena -[Fe-II(ClO4)(2){Fe-III(bpca)(2)}]ClO4, to reveal the growth of short-range spin ordering in the zero-external magnetic field below 6 K., Oct. 2007, 129, 41, 12360, +, Scientific journal, 10.1021/ja0741877
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Hybrid molecular material exhibiting single-molecule magnet behavior and molecular conductivity, Hiroki Hiraga; Hitoshi Miyasaka; Kazuya Nakata; Takashi Kajiwara; Shinya Takaishi; Yugo Oshima; Hiroyuki Nojiri; Masahiro Yamashita, Two unique materials based on Mn-4 single-molecule magnet (SMM) clusters (S-T = 9) and integer or non-integer average valent platinum maleonitriledithiolate (mnt(2-)) complexes, [{(Mn2Mn2III)-Mn-II(hmp)(6)(MeCN)(2)},{Pt(mnt)(2)}(2)][Pt(mnt)(2)](2)center dot 2MeCN (1) and [{(Mn2Mn2III)-Mn-II(hMP)(6)(MeCN)(2)},{Pt(mnt)(2)}(4)][Pt(mnt)(2)](2) (2), were synthesized by the material diffusion method and electrochemical oxidation, respectively (hmp(-) = 2-hydroxymethylpyridinate). 1 and 2 are comprised of four and six [Pt(mnt)(2)](n-) units, respectively, in addition to a common (Mn2Mn2III)-Mn-II double-cuboidal unit, [Mn-2(II)-Mn (III)(2)(hmP)(6)(MeCN)(2)](4+) (hereinafter [Mn-4](4+)). Among the [Pt(mnt)(2)](n-) units, two units in 1 and four units in 2 are coordinated with the [Mn-4](4+) unit, forming a 1D chain of {-[Mn-4]-[Pt(mnt)(2)](2)-} for 1 and a discrete subunit of [Pt(mnt)(2)](2)-[Mn-4]-[Pt(mnt)(2)](2)} for 2. The other two [Pt(mnt)(2)](n-) units, occupying void space of the packing, form a stacking column with the coordinating [Pt(mnt)(2)](n-) units, finally constructing hybrid frames of aggregates consisting of [Mn-4](4+) units and [Pt(mnt)(2)](n-) units. Electronic conductivity measurements revealed that 1 is an insulator and 2 is a semiconductor with sigma = 0.22 S center dot cm(-1),at room temperature and an activation energy of 136 meV. Detailed magnetic measurements proved that the [Mn-4](4+) units in 1 and 2 behave as SMMs with an S-T = 9 ground state at low temperatures. There is no significant interaction between [Mn-4](4+) units and [Pt(mnt)(2)](n-) units, but interactions between localized spins of [Pt(mnt)(2)](n-) were detected even in 2 at low temperatures where the conductivity is electronically insulated. 2 is the first example of a hybridized material exhibiting SMM behavior and electronic conductivity., Nov. 2007, 46, 23, 9661, 9671, Scientific journal, 10.1021/ic700727n
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, Metal-insulator transition of charge-transfer salts based on unsymmetrical donor DMET and metal halide anions (DMET)(4)(MCl4)(TCE)(2) (M = Mn, Co, Cu, Zn; TCE=1,1,2-trichloroethane), Hiroshi Ito; Daichi Suzuki; Harutaka Watanabe; Hisaaki Tanaka; Shin-ichi Kuroda; Masamichi Umemiya; Norihito Kobayashi; Makoto Goto; Ken-ichi Sugiura; Hitoshi Miyasaka; Shinya Takaishi; Takashi Kajiwara; Masahiro Yamashita; Eiji Ohmichi; Toshihito Osada, New charge-transfer salts based on an unsymmetrical donor DMET [dimethyl(ethylenedithio)diselenadithiafulvalene] and metal halide anions (DMET)(4)(MCl4)-Cl-II(TCE)(2) (M = Mn, Co, Cu, Zn; TCE = 1,1,2-trichloroethane) have been synthesized and characterized by transport and magnetic measurements. The crystal structures of the DMET salts are isostructural, consisting of a quasi-one-dimensional stack of DMET and insulating layers containing metal halide anions and TCE. Semimetallic band structures are calculated by the tight-binding approximation. Metal-insulator transitions are observed at T-MI = 25, 15, 5-20, and 13 K for M = Mn, Co, Cu, and Zn, respectively. The M = Cu salt exhibits anisotropic conduction at ambient pressure, being semiconducting in the intralayer current direction but metallic for the interplane current direction, down to T-MI. The metal-insulator transitions are suppressed under pressure. In the M = Co and Zn salts, large magnetoresistances with hysteresis are observed at low temperatures, on which Shubnikov-de Haas oscillations are superposed above 30 T. In the M = Cu salt, no hysteresis is observed but clear Shubnikov-de Haas oscillations are observed. The magnetoresistance is small and monotonic in the M = Mn salt. Paramagnetic susceptibilities of the spins of the magnetic ions are observed for the M = Mn, Co, and Cu salts with small negative Weiss temperatures of similar to 1 K. In the nonmagnetic M = Zn salt, Pauli-like pi-electron susceptibility that vanishes at T-MI is observed. The ground state of the pi-electron system is understood as being a spin density wave state caused by imperfect nesting of the Fermi surfaces. In this pi-electron system, the magnetic ions of the M = Mn, Co, and Cu salts interact differently, exhibiting a variety of transport behaviors., Jul. 2007, 129, 27, 8510, 8518, Scientific journal, 10.1021/ja070672q
  • Refereed, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, CHEMICAL SOC JAPAN, Tuning of electronic structures of quasi-one-dimensional bromo-bridged Pd-II-Pd-IV mixed-valence complexes by substituting counter anions, Hisamitsu Arakawa; Daisuke Kawakami; Shinya Takaishi; Takashi Kajiwara; Hitoshi Miyasaka; Ken-ichi Sugiura; Masahiro Yamashita; Hideo Kishida; Hiroshi Okamoto, New quasi-one-dimensional bromo-bridged Pd-II-Pd-IV mixed-valence complexes with long chain alkylsufonates [Pd(en)(2)][PdBr2(en)](CnH2n+1SO3)(4)center dot 2H(2)O (en = ethylenediamine, n = 7, 8, 9, and 10) were synthesized. With increasing alkyl-chain length (n) of the counter anions, the (PdPdIV)-Pd-center dot center dot center dot distances decreased, indicating that the oxidation states of the Pd atoms are close to the Pd-III state., Jan. 2007, 80, 1, 189, 191, Scientific journal, 10.1246/bcsj.80.189
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-V C H VERLAG GMBH, A nickel(II) gold(I) D-penicillaminate coordination system with multiple switching in color, magnetism, and chirality, Mai Taguchi; Asako Igashira-Kamiyama; Takashi Kajiwara; Takumi Konno, 2007, 46, 14, 2422, 2425, Scientific journal, 10.1002/anie.200604728
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Spin coupling in the supramolecular structure of a new tetra(quinoline-TEMPO)yttrium(III) complex, Luca Maretti; Marilena Ferbinteanu; Fanica Cimpoesu; Saiful S. M. Islam; Yasunori Ohba; Takashi Kajiwara; Masahiro Yamashita; Seigo Yamauchi, The newly synthesized tetra(quinoline-TEMPO)yttrium(III) potassium salt shows interesting structural features at the molecular and supramolecular levels, revealed by the analysis of the X-ray diffraction data. The magnetic susceptibility and EPR data corroborated with structural considerations showed that the exchange and dipolar spin coupling interactions are taking place at the nodes assembling the supramolecular 2D structure. The Y(III) center shows antiprismatic octacoordination, close to the idealized D-2 symmetry. The diamagnetic transition metal plays no role in mediating the radical interactions since the TEMPO-type fragments are remote from the chelating moieties of the ligand. In turn, significant interaction occurs on the nodes consisting in the quasi-rectangular coordination of potassium counterions by the spin-bearing TEMPO groups coming from four distinct complex units. The antiferromagnetic susceptibility was consistently modeled by a spin Hamiltonian based on the rectangle topology of four spins S = (1)/(2). The fitted exchange parameters are J(a) = -5.1 cm(-1) and J(b) = -3.4 cm(-1) for the edges, imposing J(d) = 0 for the diagonal. These values are in excellent agreement with the ab initio results J(a) = -4.83 cm(-1), J(b) = -3.44 cm(-1), J(d) = -0.07 cm(-1) obtained in a CASSCF(12,8) calculation. Based on the reliability of the ab initio results we were able to select the presented J parameters among several versions of multiple solutions with acceptable goodness of the fit. A methodological caveat about the artifacts of the automatic use of best fit parameters, in the absence of supplementary criteria, in the context of relative blindness of magnetic susceptibility modeling, is raised. The details of the EPR spectrum at 10 K are also consistent, in the frame of dipolar approximation, with the model of four interacting spins at the nodes of the supramolecular assembling., Feb. 2007, 46, 3, 660, 669, Scientific journal, 10.1021/ic0610841
  • Refereed, POLYHEDRON, PERGAMON-ELSEVIER SCIENCE LTD, The magnetic anisotropy and assembling of the lanthanide coordination units in [Fe(bpca)(2)][Er(NO3)(3)(H2O)(4)]NO3, Marilena Ferbinteanu; Takashi Kajiwara; Fanica Cimpoesu; Kensuke Katagiri; Masahiro Yamashita, The magnetic properties of the title compound are discussed in correlation with the molecular and crystal structure. The bimetallic complex [Fe(bpea)(2)][Er(NO3)(3)(H2O)(4)](NO3) (where Hbpca = bis(2-pyridilcarbonyl)amine) crystallizes in the triclinic space group P1(-) exhibiting stacks of [Fe(bpca)(2)](+) and [Er(NO3)(3)(H2O)(4)] entities connected by hydrogen bonds. The [Er(NO3)(3)(H2O)(4)] units are connected by hydrogen bonds established between coordinated aqua and nitrate ligands. Static and dynamic magnetic properties are reported. The complex exhibits the magnetization lag in ac magnetic field of 10-1400 Hz, above 1.8 K, under a static magnetic field. The ab initio calculations, including ligand field and spin orbit effects illuminated the anisotropy properties of the lanthanide ions in the complex, revealing the orientation and extension of the lobes corresponding to the easy magnetization axes. (c) 2006 Elsevier Ltd. All rights reserved., Jun. 2007, 26, 9-11, 2069, 2073, Scientific journal, 10.1016/j.poly.2006.10.003
  • Refereed, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, CHEMICAL SOC JAPAN, Versatile vapochromic behavior accompanied by a phase change between charge-polarization state and charge-density-wave state in a quasi-one-dimensional iodo-bridged dinuclear platinum mixed-valence compound, [{NH3(CH2)(5)NH3}(2)]-[Pt-2(pop)4I]center dot 4H(2)O, Masahiro Yamashita; Kouichi Takizawa; Satoshi Matsunaga; Daisuke Kawakami; Hiroaki Iguchi; Shinya Takaishi; Takashi Kajiwara; Fumiyasu Iwahori; Tomohiko Ishii; Hitoshi Miyasaka; Ken-ichi Sugiura; Hiroyuki Matsuzaki; Hideo Kishida; Hiroshi Okamoto, This communication describes versatile vapochromic behavior that is accompanied by a phase change between charge-polarization (CP) and charge-density-wave (CDW) states with increasing and decreasing temperature in [{NH3(CH2)(5)NH3}(2)][Pt-2(pop)(4)I](.)4H(2)O (pop = P2H2O52-) (1)., Sep. 2006, 79, 9, 1404, 1406, Scientific journal, 10.1246/besj.79.1404
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Ferromagnetic coupling promoted by k(3)N : k(2)N bridging system, Asako Igashira-Kamiyama; Takashi Kajiwara; Takumi Konno; Tasuku Ito, Syntheses, structures, and magnetic properties of novel trinuclear complexes of the same motif [M{Cu(pz(2)bg)(2)}M](4+) (M) Cu-II, Ni-II, Co-II, Mn-II), catena-[Cu-2{Cu(pz(2)bg)(2)}(Hpz)(2)(PhSO3)(2)](PhSO3)(2), 4H(2)O(2, 4H(2)O), [Ni-2{Cu(pz(2)bg)(2)}(MeOH)(2)(H2O)(4)](NO3)(4)(3), [Co-2{Cu(pz(2)bg)(2)}(NO3)(2)(EtOH)(2)](NO3)(2) (4), and [Mn-2{Cu(pz(2)bg)(2)}(NO3)(4)(MeCN)(2)] (5), which include the complex ligand [Cu(pz(2)bg)(2)] (1), are reported (Hpz) pyrazole, pz(2)bg(-) = di(pyrazolecarbimido)aminate; bispyrazolyl derivative of biguanidate). The reaction of Cu(ClO4)(2), 6H(2)O, sodium dicyanamide, Hpz, and PhSO3H center dot H2O (1:2:4:4) in MeOH yielded blue crystals of [Cu-2(1)(Hpz)(2)(PhSO3)(2)](PhSO3)(2), 4H(2)O (2, 4H(2)O). In 2, the tricopper(II) units, which consist of two CuII ions bridged by 1, are linked by benzenesulfonate anions to form a ladder structure. Complex 1 was isolated by removing the terminal Cu-II ions from 2 with use of Na(4)edta. Complexes 3-5 were obtained by the reaction of 1 with an excess of each M-II ion. In 2-5, the adjoining metal ions are ferromagnetically coupled via the pz(2)bg(-) ligand with J values of +7.2(1), +7.5(1), +2.7(1), and +0.3(1) cm(-1), respectively, using a spin Hamiltonian H = -2J(SM1SCu + SCuSM2). The ferromagnetic interaction was attributed to the strict orthogonality of magnetic d sigma orbitals, which are controlled by the kappa N-3:kappa N-2 bridging geometry of the pz(2)bg(-) ligands., Aug. 2006, 45, 16, 6460, 6466, Scientific journal, 10.1021/ic0520925
  • Refereed, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, WILEY-V C H VERLAG GMBH, Highly symmetrical tetranuclear cluster complexes supported by p-tert-butylsulfonylcalix[4]arene as a cluster-forming ligand, T Kajiwara; T Kobashi; R Shinagawa; T Ito; S Takaishi; M Yamashita; N Iki, Square-planar tetranuclear clusters [M-4(L)(AcO)(4)(mu(4)-OH)](-) (M = Mn-II, Co-II, and Ni-II) are synthesized using tetra-anionic p-tert-butylsulfonylcalix[4]arene (L4-) as a cluster-forming ligand. Three complexes are crystallographically isostructural, being crystallized in the triclinic crystal system with space group Pi. The calix[4]arene acts as a tetrakis fac-tridentate ligand through four phenoxo and four sulfonyl oxygen atoms to form square arrangement of four metal ions, which are further bridged by four chelating acetate ions and one hydroxo ion in a mu(4) manner to complete the hexacoordination of each metal center. Although the whole molecule of each complex is crystallographically independent, the molecule is highly symmetrical with a pseudo-four-fold axis lying on the mu(4)-OH- group. The tetranuclear clusters are stable enough to maintain the core structures even in highly dilute solution (approximate to 10 mu m), which was confirmed by mass spectroscopic study, however, bridging acetates were easily exchanged by other carboxylate chelates to form derivatives such as [M-4(L)(BzO)(4)(OH)](-). Metal-metal interactions were investigated by means of magnetic susceptibility, and it was revealed that both ferro- and antiferromagnetic interactions occur in the Ni-II complex depending on the bridging angles of Ni-O-Ni. (c) Wiley-VCH Verlag GmbH & Co., May 2006, 9, 1765, 1770, Scientific journal, 10.1002/ejic.200501086
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Conformation-controlled luminescent properties of lanthanide clusters containing p-tert-butylsulfonylcalix[4]arene, T Kajiwara; K Katagiri; M Hasegawa; A Ishii; M Ferbinteanu; S Takaishi; T Ito; M Yamashita; N Iki, Dinuclear and cubane-shaped lanthanide cluster complexes containing Eu-III and Tb-III were synthesized by step-by-step construction using p-tert-butylsulfonylcalix[4]arene as a cluster-forming ligand. The sulfonylcalixarene adopts a pinched-cone conformation in the dinuclear complexes and a cone conformation in the cubane complexes. Because the calixarene has a large pi-conjugate system expanding over the entire molecule, it behaves as a good antenna chromophore for UV and near-UV light, and a slight conformational change of the calixarene ( from cone to pinched-cone and vice versa) has an effect on the energy levels of excited S-1 and T-1 states. As a result, selectivity is observed in the luminescent properties of dinuclear and cubane-shaped systems of Eu-III and Tb-III., Jun. 2006, 45, 13, 4880, 4882, Scientific journal, 10.1021/ic060397t
  • Refereed, CHEMISTRY-AN ASIAN JOURNAL, WILEY-V C H VERLAG GMBH, A dodecalanthanide wheel supported by p-tert-butylsulfonylcalix[4]aren, Takashi Kajiwara; Kensuke Katagiri; Shinya Takaishi; Masahiro Yamashita; Nobuhiko Iki, A dodecaholmium wheel of [Ho-12(L)(6)(mal)(4)(AcO)(4)(H2O)(14)] (1; mal=malonate) was synthesized by using p-tert-butylsulfonylcalix[4]arene (H4L) as a cluster-forming ligand. The wheel consists of three fragments of mononuclear A(3-) ([Ho(L)(mal)(H2O)](3-)), trinuclear B3- ([Ho(H2O)(2) (mal)(Ho(L)(AcO))(2)](3-)), and C3+ ([Ho(H2O)(2)](3+)), and an alternate arrangement of these fragments (A(3-)-C3+-B3--C3+-A(3-)-C3+-B3--C3+-) results in a wheel structure. The longest and shortest diameters of the core were estimated to be 17.7562(16) and 13.6810(13) angstrom, respectively, and the saddle-shaped molecule possesses a pocketlike cavity inside., Sep. 2006, 1, 3, 349, 351, Scientific journal, 10.1002/asia.200600057
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, Dynamical valence fluctuation at the charge-density-wave phase boundary in iodide-bridged Pt compound [Pt(chxn)(2)I]I-2, Shinya Takaishi; Daisuke Kawakami; Masahiro Yamashita; Mari Sasaki; Takashi Kajiwara; Hitoshi Miyasaka; Ken-ichi Sugiura; Yusuke Wakabayashi; Hiroshi Sawa; Hiroyuki Matsuzaki; Hideo Kishida; Hiroshi Okamoto; Harutaka Watanabe; Hisaaki Tanaka; Kazuhiro Marumoto; Hiroshi Ito; Shin-ichi Kuroda, We synthesized a novel iodo-bridged linear chain platinum compound, having the quasi-two-dimensional charge-density-wave (CDW) ground state and the smallest band gap. In this compound, we discovered an anomalous valence state in the boundary region at which the CDW phase alternates in the crystal by means of ESR, X-ray diffuse scattering, STM, and electrical resistivity. This anomalous state can be explained by the fast fluctuation between Pt-IV-(IPtII)-Pt-... and (PtI)-I-II...-Pt-IV in the double well potential. This is the first observation of the dynamical fluctuation of the CDW phase among the quasi one-dimensional halogen-bridged complexes., May 2006, 128, 19, 6420, 6425, Scientific journal, 10.1021/ja060193b
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-V C H VERLAG GMBH, Halogen-bridged Pt-II/Pt-IV mixed-valence ladder compounds, Daisuke Kawakami; Masahiro Yamashita; Satoshi Matsunaga; Shinya Takaishi; Takashi Kajiwara; Hitoshi Miyasaka; Ken-ichi Sugiura; Hiroyuki Matsuzaki; Hiroshi Okamoto; Yusuke Wakabayashi; Hiroshi Sawa, 2006, 45, 43, 7214, 7217, Scientific journal, 10.1002/anie.200602987
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, A binuclear Fe(III)Dy(III) single molecule magnet. Quantum effects and models, Marilena Ferbinteanu; Takashi Kajiwara; Kwang-Yong Choi; Hiroyuki Nojiri; Akio Nakamoto; Norimichi Kojima; Fanica Cimpoesu; Yuichi Fujimura; Shinya Takaishi; Masahiro Yamashita, Jul. 2006, 128, 28, 9008, 9009, Scientific journal, 10.1021/ja062399i
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, Topological variation between hexa- and trithiacalix[6]arene-copper(II) complexes: From sphere to wheel by reducing the number of the sulfur bridges, Noriyoshi Kon; Nobuhiko Iki; Takashi Kajiwara; Tasuku Ito; Sotaro Miyano, Contrary to hexathiacalix [6] arene (H6L6S) forming [Cu-10(L-6S)(2)]-type spherical decacopper(II) complex, trithiacalix[6]arene (H6L3S), in which three sulfur bridges of H6L6S are replaced with methylenes in an alternate manner, affords nanosized wheel-shaped octanuclear complex [Cu-8(H2L3S)(4)] consisting of four [Cu2H2L3S] units., Apr. 2006, 35, 4, 430, 431, Scientific journal, 10.1246/cl.2006.430
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, New charge-transfer salts based on unsymmetrical donor DMET and metal complex anions: (DMET)(3)[Cr(isoq)(2)(NCS)(4)] and (DMET)(3)[Cr(phen)(NCS)(4)]center dot CH3CN, Masamichi Umemiya; Makoto Goto; Norihito Kobayashi; Shinya Takaishi; Takashi Kajiwara; Masahiro Yamashita; Hitoshi Miyasaka; Ken-ichi Sugiura; Harutaka Watanabe; Daichi Suzuki; Hiroshi Ito; Shin-ichi Kuroda, Two charge-transfer salts (DMET)(3)[Cr(isoq)(2)(NCS)(4)] (1) and (DMET)(3)[Cr(phen)(NCS)(4)]-CH3CN (2) have been prepared and characterized. The single-crystal X-ray crystallography revealed that the structures of both salts consist of segregated columns of DMET and metal complex anions. The magnetic and transport properties have shown that these salts are paramagnetic semiconductors., Apr. 2006, 35, 4, 368, 369, Scientific journal, 10.1246/cl.2006.368
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, A single-chain magnet formed by a twisted arrangement of ions with easy-plane magnetic anisotropy, T Kajiwara; M Nakano; Y Kaneko; S Takaishi; T Ito; M Yamashita; A Igashira-Kamiyama; H Nojiri; Y Ono; N Kojima, Jul. 2005, 127, 29, 10150, 10151, Scientific journal, 10.1021/ja052653r
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Novel excited quintet state in porphyrin: Bis(quinoline-TEMPO)-yttrium-tetraphenylporphine complex, L Maretti; SSM Islam; Y Ohba; T Kajiwara; S Yamauchi, New mono- and bis[4-(3-hydroxy-2-methyl-4-quinolinoyloxy)-2,2,6,6-tetramethylpiperidin-1-oxy](meso-tetraphenylporphyrinato)yttrium(III) complexes have been synthesized, and the properties of the excited states generated by photoexcitation of porphyrin were studied by time-resolved (TR) and pulsed two-dimensional electron paramagnetic resonance (EPR) spectroscopy. A TR-EPR spectrum was observed in the quartet (S = 3/2) or quintet (S = 2) states generated from interactions of one or two radicals with the photoexcited triplet state of the porphyrin. The zero-field splitting D values of these states were analyzed in terms of those of the triplet and the radical-triplet pair. The spin states of the excited states were definitely assigned by measuring the nutation frequencies with pulsed EPR., Dec. 2005, 44, 25, 9125, 9127, Scientific journal, 10.1021/ic0511827
  • Refereed, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, WILEY-V C H VERLAG GMBH, 1,3,5-triazapentanediene, a novel tridentate ligand that bridges two metal ions in kappa N-1 :kappa N-2 bridging mode with C-2 symmetry, T Kajiwara; T Ito, The new mononuclear complexes [Ni(Htap)(2)](ClO4)(2) (1) and [Ni(tap)(Htap)]ClO4 (2) were synthesized by the reaction of nickel(II) perchlorate and 1,3,5-triazine (Htap = 1,3,5-triazapentanediene). In 1 and 2, neutral Htap and a monoanionic tap- coordinate in a square-planar mode to the nickel(II) ions (low-spin state) in a bidentate, chelating fashion. Using the central N of tap- of 2 as a donor atom, multinuclear complexes [{Cu(tren)}(2){Ni(tap)(2)]}(ClO4)(4) (3) and [Ni(Htap)(2)](2)-[Ni{Ni(tap)(Htap)}(2)(NCS)(4)][Ni{Ni(tap)(Htap)}(NCS)(5)](2) (4) were synthesized. In both complexes, tap- binds two metal ions in a kappa(1)N:kappa(2)N bridging mode, with C-2 symmetry along the Ni-Cu axis for 3 and Ni-Ni axis for 4. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)., Aug. 2004, 15, 3084, 3088, Scientific journal, 10.1002/ejic.200400122
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-V C H VERLAG GMBH, Octalanthanide wheels supported by p-tert-butylsulfonylcalix[4]arene, T Kajiwara; HS Wu; T Ito; N Iki; S Miyano, 2004, 43, 14, 1832, 1835, Scientific journal, 10.1022/anie.200353449
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, BLACKWELL MUNKSGAARD, Ba19In9, a subnitride containing isolated [In-5](5-) and [In-8](12-) Zintl anions, H Yamane; S Sasaki; T Kajiwara; T Yamada; M Shimada, Single crystals of nonadecabarium nonaindium nonanitride, Ba19In9N9, were synthesized by the Na flux method under N-2 pressure. The compound crystallizes in the monoclinic space group C2/m, with Z = 2. Polyanionic indium clusters [In-5](5-) and [In-8](12-) are surrounded by Ba2+ cations and are located in a at cage built of linked nitrogen-centred NBa6 octahedra. The structural formula is expressed as (Ba38N18)[In-5](2)[In-8]., Oct. 2004, 60, I120, I123, Scientific journal, 10.1107/S160053680402224X
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, A p-tert-butyldithiacalix[4]arene-copper(II) complex having double-cone shape of unique heteroditopic inclusion behavior, N Kon; N Iki; T Kajiwara; T Ito; S Miyano, X-ray diffraction revealed a single crystal of a Cu(II) complex of p-tert-butyldithiacalix[4]arene 5 (H4L) to be [CU3(HL)(H2L)(AcO)], in which three Cu(II) ions are sandwiched by two calixarene ligands including different guest molecules, CHCl3 and hexane, in each cone-shaped cavity., Aug. 2004, 33, 8, 1046, 1047, Scientific journal
  • Refereed, JOURNAL OF ALLOYS AND COMPOUNDS, ELSEVIER SCIENCE SA, Single crystal growth of manganese gallium nitride using Mn-Ga-Na melt, M Aoki; H Yamane; M Shimada; T Kajiwara, Manganese gallium nitride (Mn4-xGaxN) single crystals as well as Mn-doped GaN single crystals were prepared by heating a Mn-Ga-Na melt at 750degreesC and 5 MPa of N-2 pressure. The Mn4-xGaxN crystals had the cubic anti-perovskite-type structure (space group: Pm (3) over barm) with a lattice parameter a = 3.8886(9) Angstrom. The single crystals exhibited magnetic transitions from a ferrimagnetic phase with a spin-glass-like disorder to an antiferromagnetic phase at 107 K, and then to a paramagnetic phase at 270 K. From these magnetic transition temperatures, the composition of the Mn4-xGaxN single crystals was estimated to be Mn3.07Ga0.93N. (C) 2003 Elsevier B.V. All rights reserved., Feb. 2004, 364, 1-2, 280, 282, Scientific journal, 10.1016/S0925-8388(03)00506-1
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, BLACKWELL MUNKSGAARD, Bis[tris(2,2 '-bipyridine-kappa N-2,N ')ruthenium(II)] hexacyanoferrate(III) chloride octahydrate, K Sakai; Y Uchida; T Kajiwara; T Ito, In the title compound, [Ru-II(C10H8N2)(3)](2)[Fe-III(CN)(6)]Cl.8H(2)O, the [Ru(bpy)(3)](2+) (bpy is 2,2'-bipyridine) cations and water molecules afford intriguing microporous honeycomb layers, while the [Fe(CN)(6)](3-) anions and the remainder of the water molecules form anionic sheets based on extensive hydrogen-bonding networks. The cationic and anionic layers alternate along the c axis. The Fe atom in [Fe(CN)(6)](3-) lies on an inversion centre and the axial cyano ligands are hydrogen bonded to the water molecules encapsulated within the micropores [N...O = 2.788 (5) Angstrom], giving an unusual interpenetration between the cationic and anionic layers. On the other hand, the in-plane cyano ligands are relatively weakly hydrogen bonded to the water molecules [N...O = 2.855 (7) and 2.881 (8) Angstrom] within the anionic sheets., Feb. 2004, 60, M65, M68, Scientific journal, 10.1107/S0108270103028841
  • Refereed, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, CHEMICAL SOC JAPAN, p-tert-Butylthiacalix[6]arene as a clustering ligand. Syntheses and structures of Co-5(II), Ni-4(II), and mixed-metal (MNi4II)-Ni-II (M = Mn, Co, and Cu) cluster complexes, and a novel metal-induced cluster core rearrangement, T Kajiwara; R Shinagawa; T Ito; N Kon; N Iki; S Miyano, Using p-tert-butylthiacalix[6]arene (H6L) as a clustering ligand, five cluster complexes having Co-5(II) (2), Ni-4(II) (3) and (MNi4II)-Ni-II (M = COII (4), Mn-II (5), and Cu-II (6) cores were synthesized. In all the complexes except for 3, a pinched conic L6- acts as a pentanucleating ligand that involves a similar pyramidally arranged cluster core. Each mixed metal complex 4-6 involves four tetragonally arranged Ni-II ions occupying the basal plane of the pyramid and a M-II ion placed at the apex position. In 3, H2L4- is in a cone conformation and the four Ni-II ions are arranged on the donor surface of H2L4- in a zigzag manner. The mixed metal complexes 4-6 are synthesized by reacting 3 and the appropriate M(AcO)(2) in a 1: 1 ratio with a novel metal-induced core rearrangement occurring. In this reaction, the insertion of a M-II ion at the apex position forces the calixarene to take a cone conformation and the Ni-4(II) array rearranges to form a tetragonal cluster., Dec. 2003, 76, 12, 2267, 2275, Scientific journal, 10.1246/bcsJ.76.2267
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, BLACKWELL MUNKSGAARD, A ferroelectric barium titanate, BaTi2O5, T Kimura; T Goto; H Yamane; H Iwata; T Kajiwara; T Akashi, The crystal structure of monobarium dititanium pentaoxide, BaTi2O5, synthesized by a floating-zone method, was studied by X-ray diffraction. Previous reports describe the structure as being in the monoclinic centrosymmetric space group C2/m. We have recently found that this material exhibits ferroelectricity, and therefore BaTi2O5 should have lower symmetry. The crystal structure of BaTi2O5 was refined in space group C2, revealing a displacement of the Ti atoms along the b axis. This result is consistent with the fact that the ferroelectricity of BaTi2O5 was only observed along the b axis., Dec. 2003, 59, I128, I130, Scientific journal, 10.1107/S0108270103021395
  • Refereed, CRYSTENGCOMM, ROYAL SOC CHEMISTRY, Controlling the construction of trinuclear, 1-D, and 2-D Ni(II)Fe(II)/Fe(II)Fe(II) complexes: selective syntheses, structures, and magnetic properties, A Kamiyama; T Noguchi; T Kajiwara; T Ito, The reaction of [Ni(bpca)(2)] (1) and [Fe(H2O)(6)](ClO4)(2) gave a trinuclear complex 3, five 1-D chain complexes 4a - e, and a 2-D honeycomb complex 5. The selective syntheses of these complexes were achieved by controlling the reaction conditions such as reaction stoichiometry, solvents, and the presence/absence of supporting ligands. 3 consists of a central {Fe(trans-H2O)(2)}(2+) moiety and two units of 1 acting as terminal bidentate ligands. 4a - e consist of an alternating arrangement of Fe(II) ions and 1 which acts as a bis-bidentate bridging ligand. 5 has a honeycomb structure with hexagons involving twelve metal ions, six Ni( II) ions in 1 and six Fe( II) ions, and holds the large cavity which includes counter ions, chloroform, and water molecules. The reaction of [Fe(bpca)(2)] (2) and [Fe(H2O)(6)](ClO4)(2) also gave a 2-D honeycomb complex 6 which is isostructural to 5. Magnetic data for 3 and 4a indicate a ferromagnetic interaction between adjoining Ni(II) ions and the Fe(II) ions, due to the strict orthogonality of the magnetic orbitals., Jun. 2003, 5, 231, 237, Scientific journal, 10.1039/b302413j
  • Refereed, POLYHEDRON, PERGAMON-ELSEVIER SCIENCE LTD, Ferromagnetic interactions through control of the bridging geometry, T Kajiwara; A Kamiyama; T Ito, A novel trinuclear Ni(II)-Cu(II)-Ni(II) complex (3) and three Cu(II)-Cu(II) (4), Ni(II)-Cu(II) (5), and Mn(II)-Cu(II) (6) alternating chain complexes were synthesized using the complexed ligand [Cu(bptap)(2)] (1) which acts as a bis-mer- tridentate ligand (bptap(-) = 2,4-bis(2-pyridyl)-1,3,5-triazapentanedienate). In all complexes, two adjoining metal ions are connected by bptap- in a kappa(2)N:kappa(3)N bridging fashion with local C-2 symmetry. The bridging geometry forces the two dsigma orbitals directed towards the ligating atoms to orthogonal to each other. Ferromagnetic interaction occurs between Cu(II)-Cu(II), Cu(II)-Ni(II), and Cu(II)-Mn(II) due to the orthogonality of the magnetic orbitals with the magnitudes of J = 1.1 cm(-1) for 3 (H = -2J(S-Nil.S-Cu +S-Cu.S-Ni2)), J = 1.4 cm(-1) for 4 (H = -2JSigma(i) S-Cui SCul + 1), and theta = 7.5 K for 5 and 1.1 K for 6 (Curie-Weiss model), respectively. (C) 2003 Elsevier Science Ltd. All rights reserved., Jul. 2003, 22, 14-17, 1789, 1793, Scientific journal, 10.1016/S0277-5387(03)00169-4
  • Refereed, JOURNAL OF SOLID STATE CHEMISTRY, ACADEMIC PRESS INC ELSEVIER SCIENCE, Synthesis and crystal structure analysis of Sr8Cu3In4N5 and Sr0.53Ba0.47CuN, H Yamane; S Sasaki; S Kubota; M Shimada; T Kajiwara, Single crystals of new quaternary compounds Sr8Cu3In4N5 and Sr0.53Ba0.47CuN were prepared, respectively, from a Sr-Cu-In-Na melt under 7 MPa of N-2 and from a Sr-Ba-Cu-In-Na melt under 0.5 MPa of N-2 by slow cooling from 1023 to 823 K. The crystal structures were determined by single-crystal X-ray diffraction. Sr8Cu3In4N5 has an orthorhombic structure (space group, Immm, Z=2, a=3.8161(5)Angstrom, b=12.437(2),Angstrom, c=18.902(2)Angstrom), and is isostructural with Ba8Cu3In4N5. It contains nitridocuprates of isolated units (0)[CuN2] and one-dimensional linear chains [CuN2/2] and one-dimensional indium. clusters I [In2In2/2. 0C Sr0.53Ba0.47CuN crystallizes in an orthorhombic cell, space group Pbcm, Z = 4, a = 5.4763(7) Angstrom, b = 9.2274(12) Angstrom, c = 9. 0772(12) Angstrom. The structure contains infinite zig-zag chains (1)(proportional to) [CuN2/2] which kink at every second nitrogen atom. (C) 2002 Elsevier Science (USA). All rights reserved., Feb. 2003, 170, 2, 265, 272, Scientific journal, 10.1016/S0022-4596(02)00083-X
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, BLACKWELL MUNKSGAARD, Di-mu-pivalato-bis[cis-diammineplatinum(II)] bis(perchlorate) pivalic acid solvate, K Sakai; E Ishigami; K Yokokawa; T Kajiwara; T Ito, The intradimer Pt-Pt distance [3.0928 (9) Angstrom] in the title compound, [Pt-2(mu-C5H9O2)(2)(NH3)(4)](ClO4)2.C5H10O2, is much longer than that reported for [Pt-2(mu-C5H9O2)(2)(NH3)(4)](SO4).H2O [2.9011 (9) Angstrom; Sakai, Ishigami, Yokokawa, Kajiwara & Ito (2003). Acta Cryst. E59, m443-m445]. The complex cation has a crystallographic mirror plane perpendicular to the Pt - Pt bond. The crystal packing is stabilized by both the hydrophilic and hydrophobic layers, which stack alternately along the c axis., Dec. 2003, 59, M1178, M1180, Scientific journal, 10.1107/S1600536803026503
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, WILEY-BLACKWELL, A head-to-tail isomer of bis[mu-2-(N '-methyl-4,4 '-bipyridinium-1-yl)acetamidato]bis[cis-diammineplatinum(II)] hexaperchlorate dihydrate, K Sakai; Y Ikuta; T Tsubomura; K Kato; Y Yokoyama; T Kajiwara; T Ito, In the title compound, [Pt-2(mu-C13H14N3O)(2)(NH3)(4)](ClO4)(6).2H(2)O, the dinuclear Pt-II cation is found to be a head-to-tail isomer having pseudo-C-2 symmetry. Two positively charged viologen moieties tethered to the diplatinum unit are located at the farthest position to minimize the electrostatic repulsion between the moieties, and also serve as relatively strong electron-withdrawing groups, giving rise to a very long intradimer Pt...Pt distance [3.0852 (13) Angstrom] which is the longest distance among those reported for amidate-bridged cis-diammineplatinum(II) dimers to date., Sep. 2003, 59, M780, M783, Scientific journal, 10.1107/S1600536803017756
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, WILEY-BLACKWELL, A head-to-head isomer of bis(mu-N-methylisonicotinamidato)bis[cis-diammineplatinum(II)] tetraperchlorate, K Sakai; M Shiomi; T Tsubomura; K Kato; Y Yokoyama; T Kajiwara; T Ito, In the title compound, [Pt-2(C7H8N2O)(2)(NH3)(4)](ClO4)(4), the head-to-head isomer of the PtII dimer has a mirror plane through the Pt-Pt bond axis. The intradimer Pt-Pt distance is 3.0569 (8) Angstrom, while the shortest interdimer Pt...Pt distance is 7.2325 (9) Angstrom. Two adjacent dimers are associated with one another, with a pi-stacking interaction between the N-methyl-pyridinium moieties, where the plane-to-plane separation is 3.27 (1) Angstrom., Aug. 2003, 59, M559, M561, Scientific journal, 10.1107/S1600536803014521
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, BLACKWELL MUNKSGAARD, A head-to-head isomer of di-mu-alpha-pyrrolidinonato-bis[cis-diammine-bromoplatinum(III)] dinitrate, K Sakai; T Sakamoto; T Kajiwara; T Ito, In the title compound, [Pt2Br2(C4H6NO)(2)(NH3)(4)](NO3)(2), the intradimer Pt-Pt distance is 2.6476 (4) Angstrom. The axial Pt-III-Br bond distances at the N-4- and N2O2-coordinated sites are 2.5647 (9) and 2.5889 (8) Angstrom, respectively. The two Pt coordination planes are tilted by 18.1 (3)degrees, and the average torsional twist of the ligands about the Pt-Pt axis is estimated as 1.0degrees., Jul. 2003, 59, M553, M555, Scientific journal, 10.1107/S1600536803014405
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, BLACKWELL MUNKSGAARD, Di-mu-pivalato-bis[cis-diammineplatinum(II)] sulfate monohydrate, K Sakai; E Ishigami; K Yokokawa; T Kajiwara; T Ito, The title compound, [Pt-2(NH3)(4)(C5H9O2)(2)](SO4) . H2O, does not form an infinite chain, but has discrete dimeric cations in the crystal structure. The intradimer Pt - Pt distance in the pivalate dimer [2.9011 (9) Angstrom] is effectively shorter than that reported for the acetate analog [2.9713 (8) Angstrom], demonstrating the strong electron-donating property of the bridging pivalate ligand., Jul. 2003, 59, M443, M445, Scientific journal, 10.1107/S1600536803012224
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, BLACKWELL MUNKSGAARD, A head-to-head isomer of di-mu-pivalamidato-kappa N-4,O-bis[(1,10-phenanthroline-kappa N-2,N ')platinum(II)] dinitrate dihydrate, K Sakai; M Kurashima; N Akiyama; N Satoh; T Kajiwara; T Ito, In the title compound, [Pt-2(C5H10NO)(2)(C12H8N2)(2)](NO3)(2).2H(2)O, the intradimer Pt - Pt distance is relatively short [2.8489 (17) Angstrom], which must be due to the strong intramolecular pi-pi-stacking interactions between the phenanthroline moieties. The dimers stack along the c axis, forming one-dimensional columns in which very intriguing d - d, pi-pi and d-pi interactions exist. Although the dimer - dimer Pt...Pt distances are very long [4.340 (2) and 4.231 (2) Angstrom], some short interdimer Pt...C contacts leading to strong interdimer associations are found [3.325 (19) and 3.402 (19) Angstrom]., Sep. 2003, 59, M345, M349, Scientific journal, 10.1107/S0108270103015920
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-V C H VERLAG GMBH, Zinc(III) slides on a ligand surface: The X-ray crystal structure and dynamic behavior in solution of [Zn(H2L)(tacn)], T Kajiwara; S Yokozawa; T Ito; N Iki; N Morohashi; S Miyano, 2002, 41, 12, 2076, 2078, Scientific journal
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, Synthesis, structure, and ferromagnetic behavior of decacopper(II) cluster complex supported by hexaanionic p-tert-butylthiacalix[6]arene, T Kajiwara; N Kon; S Yokozawa; T Ito; N Iki; S Miyano, Sep. 2002, 124, 38, 11274, 11275, Scientific journal, 10.1021/ja0273391
  • Refereed, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, New partially oxidized 1-D platinum chain complexes consisting of carboxylate-bridged cis-diammineplatinum dimer cations, K Sakai; E Ishigami; Y Konno; T Kajiwara; T Ito, Oct. 2002, 124, 41, 12088, 12089, Scientific journal, 10.1021/ja0275461
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, Syntheses, structures, and properties of trinuclear complexes [M(bpca)(2){M '(hfaC)(2)}(2)], constructed with the complexed bridging ligand [M(bpca)(2)] [M, M ' = Ni(II), Mn(II); Cu(II), Mn(II); Fe(II), Mn(II); Ni(II), Fe(II); and Fe(II), Fe(II); hbpca = bis(2-pyridylcarbonyl)amine, hhfac = hexafluoroacetylacetone], A Kamiyama; T Noguchi; T Kajiwara; T Ito, Five trinuclear complexes [M(bpca)(2){M'(hfac)(2)}(2)] (where MM'(2) = NiMn2, CuMn2, FeMn2, NiFe2, and FeFe2; Hbpca = bis(2-pyridyloarbonyl)amine; and Hhfac = hexafluoroacetylacetone) were synthesized almost quantitatively by the reaction of [M(bpca)(2)] and [M'(hfaC)(2)] in 1:2 molar ratio, and their structures and magnetic properties were investigated. Three complexes, with M' = Mn, crystallize in the same space group, Pna2(1), whereas two complexes, with M' = Fe, crystallize in P4(1), and complexes within each set are isostructural to one another, In all complexes, [M(bpca)(2)] acts as a bis-bidentate bridging ligand to form a linear trinuclear complex in which three metal ions are arranged in the manner W-M-W. The central metal ion is in a strong ligand field created by the N-6 donor set, and hence the Fe(II) in the {Fe(bpca)(2)} moiety is in a low-spin state. The terminal metal ions (M') are surrounded by O-6 donor sets with a moderate ligand field, which leads to the high-spin configuration of Fe(II). Three metal ions in all complexes are almost collinear, and metal-metal distances are ca. 5,5 Angstrom. The, magnetic behavior of NiMn2 and NiFe2 shows a weak ferromagnetic interaction between the central Ni(II) ion and the terminal Mn(II) or Fe(II) ions. In these complexes, sigma-spin orbitals of the central Ni(II) ion and those of terminal metal ions have different symmetry about a 2-fold rotation axis through the Ni-N-amide-M'(terminal) atoms, and this results in orthogonality between the neighboring sigma-spin orbitals and thus ferromagnetic interactions., Feb. 2002, 41, 3, 507, 512, Scientific journal, 10.1021/ic010731f
  • Refereed, CRYSTAL GROWTH & DESIGN, AMER CHEMICAL SOC, Morphology and polarity of GaN single crystals synthesized by the Na flux method, M Aoki; H Yamane; M Shimada; T Kajiwara; S Sarayama; FJ DiSalvo, The correlation between morphology and polarity was investigated for GaN single crystals synthesized by the Na flux method. The polarity was identified by using anomalous X-ray dispersion. Colorless transparent prismatic single crystals were classified into three types. The first had a smooth blasal plane face and no hexagonal pyramidal faces, the second had smooth pyramidal faces, and the third had a rough basal plane face and rough pyramidal faces. The prismatic crystals with smooth surfaces had N-polarity and grew in the -c direction, whereas the crystals having rough surfaces had Ga-polarity and grew in the +c direction. In colorless transparent platelet single crystals, one side of the basal planes had a mirror smooth surface, while the other side had many step edges and hexagonal pits. The smooth basal plane and the rough basal plane were the (0001) N-face and (0001) Ga-face, respectively. Black pyramidal crystals had a smooth (0001) basal plane face corresponding to the Ga-face., Jan. 2002, 2, 1, 55, 58, Scientific journal, 10.1021/cg015548b
  • Refereed, CHEMICAL COMMUNICATIONS, ROYAL SOC CHEMISTRY, Complexed bridging ligand, {Cu(bptap)(2)}, as a ferromagnetic coupler, T Kajiwara; A Kamiyama; T Ito, A novel complexed bridging ligand [Cu(bptap)(2)] which acts as a ferromagnetic coupler forms one dimensional chain consisting of tri-copper(II) [Cu-2{Cu( bptap)(2)}](4+) units in which adjoining copper( II) ions are ferromagnetically coupled., 2002, 12, 1256, 1257, Scientific journal, 10.1039/b202967g
  • Refereed, INORGANICA CHIMICA ACTA, ELSEVIER SCIENCE SA, Syntheses, structures, and magnetic properties of multinuclear complexes constructed with complexed ligands, [M(bpca)(2)](+) (M = Cr(III), Fe(III), Co(III); Hbpca = bis(2-pyridylcarbonyl)amine), T Kajiwara; R Sensui; T Noguchi; A Kamiyama; T Ito, Two trinuclear complexes [Fe(II)(ClO4)(2) {M(III)(bpca)(2)}(2)](ClO4)(2) (M=Co for 1 and Fe for 2) and three chain complexes catena[Fe(II)(ClO4)(2) {M(III)(bpca)(2)}] ClO4 (M=Co for 3, Cr for 4, and Fe for 5) were synthesized and structures for all complexes and magnetic properties for 3-5 were investigated (Hbpca=bis(2-pyridylcarbonyl)amine). All of these complexes consist of {trans Fe(II)(ClO4)(2)} unit(s) and cationic complexed ligands, {M(III)(bpca)(2)}(+), in an alternate arrangement. In 3-5, perchlorate anions in the {trans -Fe(II)(ClO4)(2)} unit are bound to a high-spin Fe(II) ion with relatively short distances in the range from 2.131(3) to 2.157(3) Angstrom. The cationic complex ligands in 1 and 2 act as a bidentate terminal ligand whereas in 3-5 they act as a bis-bidentate bridging ligand. In 3, very weak ferromagnetic interaction occurs between Fe(II) ions via the diamagnetic complexed ligand [Co(III)(bpca)(2)](+). In both 4 and 5 antiferromagnetic interactions occur between high-spin Fe(II) and Cr(III) ions in 4 and high-spin Fe(II) and low-spin Fe(III) ions in 5, respectively. Compound 5 shows ferrimagnetic behavior at low temperature. A plot of 1/chi(M) versus T above 50 K for 4 and 5 obey the Curie-Weiss law with negative Weiss constants of theta = -12.5(4) K for 4 and -15.3(6) K for 5, respectively. The temperature dependence of chi(M)T for 5 was further analyzed by the Seiden model from which the J value was estimated as -13.8(3) cm(-1) (H = -J[S-Fe(II)i + SFe(II)i+1].S-Fe(III)i). (C) 2002 Elsevier Science B.V. All rights reserved., Sep. 2002, 337, 299, 307, Scientific journal
  • Refereed, J. Solid State Chem.,, Synthesis and Structure of Ba8Cu3In4N5 with Nitridocuprate Groups and One-Dimensional Infinite Indium Clusters, KAJIWARA Takashi; H. Yamane; S. Sasaki; S. Kubota; R. Inoue; M. Shimada; T. Kajiwara, 2002, 163, 449-454
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, Cage-type hexacopper(II) complex formed by chloride template, A Kamiyama; T Kajiwara; T Ito, A novel cage complex [CU6C](MeO)(2)(pz)(9)] (1) was synthesized via a chloride ion template reaction and structurally characterized. In 1, two trinuclear units, {Cu-3 (MeO)(pz)(3))(2+), are linked by three pyrazolate ligands, six copper(II) ions form a trigonal prism, and a chloride ion is located at the center of the cage. 1 shows rather strong anti ferromagnetic coupling between the copper(II) ions through the MeO- and pyrazolate ligands., Oct. 2002, 10, 980, 981, Scientific journal
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, BLACKWELL MUNKSGAARD, Ba14Cu2In4N7, a new subnitride with isolated nitridocuprate groups and indium clusters, H Yamane; S Sasaki; S Kubota; T Kajiwara; M Shimada, Single crystals of Ba14Cu2In4N7, tetradecabarium dicopper tetraindium heptanitride, were synthesized by slow cooling from 1023 K at 7 MPa of N-2 using an Na flux. The compound crystallizes in the monoclinic space group P2/m with Z = 2, and contains (0)[CuN2] nitridocuprate units and distorted (0)[In-4] clusters. One Ba atom, not connected to any N atoms, is surrounded by 12 other Ba atoms in a barium cuboctahedron. The structural formula is expressed as (Ba)Ba27N6[CuN2](4)-[In-4](2)., Apr. 2002, 58, I50, I52, Scientific journal, 10.1107/S010827010200361X
  • Refereed, JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, CrN single-crystal growth using Cr-Ga-Na ternary melt, M Aoki; H Yamane; M Shimada; T Kajiwara, Regular octahedral CrN single crystals with a maximum size of 75 mum were obtained by heating Cr-Ga-Na ternary melt at 850degreesC and 3 MPa of N-2 for 200 It. X-ray powder and single-crystal diffractometry revealed that the CrN single crystals had the cubic rock-salt structure with the lattice parameter a = 4.1467(8) Angstrom. The CrN single crystals exhibited antiferromagnetism below the Neel temperature of 290 K. (C) 2002 Elsevier Science B.V. All rights reserved., Dec. 2002, 246, 1-2, 133, 138, Scientific journal
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, Synthesis and structural characterization of a Pd2+ complex with p-tert-butylsulfinylcalix[4]arene, N Morohashi; N Iki; S Miyano; T Kajiwara; T Ito, Single-crystal X-ray analysis has shown that p-tert-butyl-sulfinylcalix[4]arene (H4L) can bind Pd2+ ion by using either S or O atoms of bridging S=O groups in addition to phenolic oxy gen atoms to form in [Pd-2(H2L)(H3L)(2)] complex., Jan. 2001, 1, 66, 67, Scientific journal
  • Refereed, CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, Sulfonylcalix[4]arene as a bis-tridentate facial ligand: Syntheses and structures of dinuclear complexes, [M-2(L)(H2O)(2)(dmf)(4)] (M = Co(II), Ni(II); H4L = p-tert-butylsulfonylcalix[4]arene), T Kajiwara; S Yokozawa; T Ito; N Iki; N Morohashi; S Miyano, Cobalt(II) and nickel(II) complexes with a tetraanionic ligand of p-tert-butylsulfonylcalix[4]arene were synthesized and their X-ray structures show that the calixarene acts as a bis-tridentate dinucleating ligand with the 1.2-alternate conformation., Jan. 2001, 1, 6, 7, Scientific journal
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-V C H VERLAG GMBH, A graphite-like complex with large cavities constructed with the complex ligand [Ni-II(bpca)(2)], A Kamiyama; T Noguchi; T Kajiwara; T Ito, 2000, 39, 17, 3130, 3132, Scientific journal
  • Refereed, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, WILEY-V C H VERLAG GMBH, Mixed-valent heptairon complex with a ground-state spin value of S=12/2 constructed from a triiron cluster ligand, T Kajiwara; T Ito, 2000, 39, 1, 230, +, Scientific journal
  • Refereed, JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, JAPAN J APPLIED PHYSICS, Zinc-blende-type cubic GaN single crystals prepared in a potassium flux, H Yamane; T Kajiwara; T Sekiguchi; M Shimada, Single crystals of zinc-blende-type cubic GaN (c-GaN, space group F (4) over bar 3m, lattice parameter a = 4.5062(9) Angstrom) were synthesized at 750 degrees C by the reaction of Ga and N-2 in a potassium flux. The crystal structure was analyzed by single-crystal X-ray diffraction with an R1-factor of 2.1% (R1 = Sigma parallel to F-o - F-c parallel to /Sigma\F-o\), where F-o is the observed structure factor and F-c is the calculated structure factor). A peak of near-band-edge emission was observed at 3.20 eV in the cathodoluminescence spectrum measured at 25 degrees C., Feb. 2000, 39, 2B, L146, L148, Scientific journal
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, MUNKSGAARD INT PUBL LTD, Na3Ca2TaO6, a rock-salt superstructure phase with a fully ordered cation arrangement, H Yamane; H Takahashi; T Kajiwara; M Shimada, The title quaternary oxide, trisodium dicalcium tantalum hexaoxide, is isostructural with Li3Ni2TaO6, a partially ordered rock-salt phase. The Na, Ca and Ta atoms occupy octahedral sites in an orderly manner and form a cation-ordered superstructure., Oct. 2000, 56, 1177, 1178, Scientific journal
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, MUNKSGAARD INT PUBL LTD, [Fe(C12H8N3O2)Cl-2(ROH)], with R = Me and Et, T Kajiwara; T Ito, The title octahedral complexes, [bis(pyridine-2-carbonyl)aminate]dichloro (methanol)iron(III), [Fe(C12H8N3O2)Cl-2(CH4O)], and [bis (pyridine-2-carbonyl) aminate] dichloro(ethanol)iron(III), [Fe(C12H8N3O2)Cl-2(C2H6O)], both crystallize in space group P (1) over bar and have similar structures. Monoanionic bpca(-) [bis(pyridine-2-carbonyl)aminate] acts as a planar tridentate ligand in both cases. Coordination bond distances are in the range typical of high-spin Fe-III complexes. Carbon-oxygen distances are typical of a C=O double bond suggesting the negative charge of the bpca(-) ligand is localized on the central N atom., Jan. 2000, 56, 22, 23, Scientific journal
  • Refereed, MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS, GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP, Fe(II)-Fe(III) alternate ferrimagnetic chain constructed with complexed-ligand [Fe(bpca)(2)](+) (Hbpca = bis(2-pyridylcarbonyl) amine), T Kajiwara; T Ito, The reaction of [Fe(bpca)(2)]. H2O with Fe(ClO4)(3). 6H(2)O in MeNO2-CHCl3 solution and MeNO2-CH2Cl2 solution afforded black crystals of a trinuclear complex, [Fe(H2O)(2) {Fe(bpca)(2)}2](ClO4)(4) (1), and a linear chain complex, catena-[Fe(ClO4)(2) {Fe(bpca)(2)}]ClO4 (2), respectively (Hbpca = bis(2-pyridylcarbonyl)amine). In both complexes, iron atoms in {Fe(bpca)2}(+) units are in a low-spin 3(+) state, whereas irons coordinated by four carbonyl oxygen atoms and two axial oxygen atoms (from coordinated water molecules or perchlorate anions) take a high-spin 2(+) state. In both 1 and 2 antiferromagnetic interactions operated between high-spin Fe(II) and low-spin Fe(III) ions. 2 shows the ferrimagnetic ordering at 2.5 K. The plot of 1/chi(m) vs T above 50 K for 2 obeys the Curie-Weiss law with a negative Weiss constant of theta = -15.3 K., 1999, 335, 785, 792, Scientific journal
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, MUNKSGAARD INT PUBL LTD, A trinuclear Pd2Ni complex, [(C6H5)(4)P](2)-[(PdCl3)(2)(Ni(C12H18N2O2)}], A Kamiyama; T Kajiwara; T Ito, In the title complex, bis(tetraphenylphosphonium) di-mu-chloro-1:3 kappa(2)Cl, 2:3 kappa(2)Cl-tetrachloro-1 kappa(2)Cl, 2 kappa(2)Cl-mu(3)-[4,4'-(1,2-ethanediyldinitrilo)bis(pentan-2-onato)]-1 kappa C-3:2 kappa(4)O,N,N',O':3 kappa C-3'-dipalladium(II)nickel(II), (C24H20P)(2)[Pd2NiCl6(C12H18N2O2)], the trinuclear complex anion, [(PdCl3)(2){Ni(acen)}](2-), has twofold crystallographic symmetry and consists of a central {Ni(acen)} unit and two terminal {PdCl3} moieties. These are connected through Pd-C [2.120(2) Angstrom] and Cl-Ni bends [2.4919 (5) Angstrom], giving an elongated octahedral coordination geometry around the central Ni-II ion. The {PdCl3} moiety acts as a pendant ann attached to the {Ni(acen)} unit, and the geometry around the Pd atom is of the square-planar type., Aug. 1999, 55, 1282, 1284, Scientific journal
  • Refereed, ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, MUNKSGAARD INT PUBL LTD, Na2Ca3Ta2O9 with a simple stacking of oxygen triangular nets, H Yamane; H Takahashi; T Kajiwara; M Shimada, The crystal structure of the title quaternary oxide, disodium tricalcium ditantalum nonaoxide, has a distorted simple hexagonal packing of the O atoms. The Na, Ca and Ta atoms are positioned in oxygen trigonal prisms. Two oxygen prisms containing Ta atoms constitute face-sharing prisms of [Ta2O9](8-)., Dec. 1999, 55, 1978, 1980, Scientific journal
  • Refereed, JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Complexed bridging ligand, [M(bpca)(2)] (M = Mn(II) or Fe(II); Hbpca = bis(2-pyridylcarbonyl)amine), as a building block for linear trinuclear complexes, T Kajiwara; T Ito, The antiferromagnetically coupled trimanganese complex [Mn-II(bpca)(2){Mn-II(hfac)(2)}(2)] (Hbpca = bis(2-pyridylcarbonyl)amine; Hhfac = hexafluoroacetylacetone) and its iron-manganese mixed metal derivative, [Fe-II(bpca)(2){Mn-II(hfac)(2)}(2)], were synthesized by the reaction of two equivalents of [Mn(hfac)(2)(H2O)(2)] with one equivalent of [M(bpca)(2)], the latter acting as a bridging complexed-ligand., Oct. 1998, 20, 3351, 3352, Scientific journal
  • Refereed, JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Mercury-carbon bond formation promoted by the co-ordinated ligand reaction of a beta-diiminate chelate, T Kajiwara; R Murao; T Ito, Reaction between [Ni(tmtaa)] and HgBr2 in dichloroethane afforded the mercury-carbon bonded tetranuclear complex [Ni(tmtaa)HgBr](2)[Hg2Br6] (H(2)tmtaa = 5,14-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine)., Aug. 1997, 15, 2537, 2538, Scientific journal
  • Refereed, JOURNAL OF COORDINATION CHEMISTRY, GORDON BREACH SCI PUBL LTD, Hydrogenation of a delocalized diiminate six-membered chelate ring in tetraazamacrocyclic nickel(II) complexes by sodium borohydride in water - Effect of protonation-deprotonation equilibria and stereoselective reduction, K Mochizuki; T Kondo; S Manaka; T Kajiwara; T Ito, Charge delocalized diiminate six-membered chelate rings in the 5,7-dimethyl-1,4,8,11-tetraazacyclotetradecane-4,6-dienatonickel(II) ion(1) and the alpha,alpha'-bis(5,7-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,6-dienato-6-yl)-xylenedinicke(II) ion(2) were hydrogenated in aqueous media by sodium borohydride. In the reduction reactions, control of the pH of the reaction mixture was essential, and the pH of the solution was kept during the reaction at 3 and at 5-6 for hydrogenations of 1 and 2, respectively. The delocalized diiminate chelate ring is in protonation-deprotonation equilibrium with the beta diimine form and the pK(a) of the equilibrium for 2 was determined to be 9.0 for 2a (o-xylylene bridged complex), 9.3 for 26 (m-xylylene bridged complex), and 10.0 for 2c (p-xylylene bridged complex). The appropriate pH values in the hydrogenation reactions were based on the pK(a)'s. X-ray structure analyses on two reduction products of 1 show that the chirality of the two asymmetric carbons in the cyclam ring is of the meso-form in the major reduction product whereas that in the minor product is of the racemic form. In the major reduction product of 2, two chiral carbons in each cyclam ring take the meso-form., 1996, 37, 1-4, 205, 216, Scientific journal
  • Refereed, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, CHEMICAL SOC JAPAN, SYNTHESIS, STRUCTURE, AND MAGNETIC PROPERTY OF LINEAR CHLORO-BRIDGED NICKEL(II) TETRAMER WITH DINUCLEATING BIS-DIMETHYLCYCLAM LIGAND, T KAJIWARA; T YAMAGUCHI; H OSHIO; T ITO, A new nickel(II) complex with the composition of Ni2Cl2(L)(ClO4)2.1.5H2O (L = alpha,alpha'-bis(5R(S), 7S(R)-5,7-dimethyl-1,4,8,11-tetraazacyclotetradecan-6-yl)-o-xylene) has been prepared via a four coordinate complex [Ni2(L)] (ClO4)4.3H2O from [Ni2(mu-Br)Br2(L)]Br.H2O. The compound crystallizes in orthorhombic space group Ccm2(1) with cell parameters at -80-degrees-C, a=21.90(1), b=20.28(1), c=19.63(1) angstrom, V =8718(1) angstrom3, Z=8. The crystal consists of the cationic dinuclear unit [Ni2(mu-Cl)Cl2(L)]+, the counter anion ClO4-, and water of crystallization. In [Ni2(mu-Cl)Cl2(L)]+, three chloride ions and two nickel ions are alternately arranged in an almost linear manner, and two cyclam rings with the most stable trans-III type conformation are arranged in a face-to-face manner. This cationic dinuclear unit is further connected to each other by sharing the terminal Cl ligand to form pseudo one-dimensional chain structure of the ...Cl-Ni-Cl-Ni-Cl... type. However, one of the Cl atoms which bridges the dinuclear units is statistically disordered at two positions along the chain and thereby the repeating unit in the chain is a chloro bridged dimer of the dinucleating ligand complex. The neighboring Ni-Cl distances range from 2.568(4) to 2.855(4) angstrom. The temperature dependent magnetic behavior in the range of 25-300 K has been interpreted by the usual Heisenberg-Dirac-Van Vleck model, assuming that only three Ni(II) ions in {Ni2Cl2(L)}2 are paramagnetic. The best fit parameters were J = -48.2(3) and J' = - 11.2(3) cm-1 for H=- 2J(S1.S1') -2J' (S1.S2)., Aug. 1994, 67, 8, 2130, 2135, Scientific journal
  • Refereed, JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, ROYAL SOC CHEMISTRY, DESIGN OF COMPLEX-LIGAND SYSTEMS BASED ON THIOURACIL - A NOVEL CYCLIC TETRAMER OF COBALT(III) WITH 1-(2-THIOURACIL-4-METHYLENE)-3,6-DIAZAHEXANE, T KAJIWARA; T ITO, A Schiff base derived from 2-thiouracil-4-aldehyde and dien reacts with COII (CF3SO3)(2) to afford a novel cyclic tetramer of cobalt(III) by self-assembly; the complex has a columnar cavity at its centre with an effective diameter of ca. 1.8 Angstrom., Aug. 1994, 15, 1773, 1774, Scientific journal
  • Refereed, INORGANIC CHEMISTRY, AMER CHEMICAL SOC, A DINUCLEATING BIS(DIMETHYLCYCLAM) LIGAND AND ITS DINICKEL(II) AND DIZINC(II) COMPLEXES WITH THE FACE-TO-FACE RING ARRANGEMENT, T KAJIWARA; T YAMAGUCHI; H KIDO; S KAWABATA; R KURODA; T ITO, A new dinucleating ligand (L) with two dimethylcyclam rings was synthesized. In[Ni2(mu-Br)Br2(L)]-Br.H2O and [Zn2(mu-CO3)(L)](ClO4)2.2H2O, two cyclam rings are arranged in a face-to-face manner with Br- and CO3(2-) bridging in the former (Ni-Ni = 5.802(2) angstrom) and the latter (Zn-Zn = 5.806(2) angstrom). [Zn2(mu-CO3)(L)](ClO4)2.2H2O has been obtained via the spontaneous CO2 uptake from the air by [Zn2(L)](ClO4)4., Nov. 1993, 32, 23, 4990, 4991
  • Not Refereed, 教育システム研究, サイエンス・オープンラボを通した化学(化学発光、金属イオンの色)学習 −大学生による演示実験を動機付けにした高等学校授業開発研究−, Takayuki Nakajima; Yuji Mikata; Takashi Kajiwara; Takae Takeuchi; Yasuyuki Ura; Hiroshi Takashima; Noriyuki Matsuura, Mar. 2020
  • Refereed, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, WILEY-V C H VERLAG GMBH, Tetranuclear Nickel and Cobalt Complexes with an Incomplete Double-Cubane Structure-Homo- and Heterometallic Complexes and Their 1D Coordination Polymers, Takayuki Nakajima; Keiko Seto; Andreas Scheurer; Bunsho Kure; Takashi Kajiwara; Tomoaki Tanase; Masahiro Mikuriya; Hiroshi Sakiyama, The reactions of M(OAc)(2 center dot)4H(2)O (M = Ni, Co) with three unsymmetrical amine-did l ligands RN(CH2CH2OH)-(CH2CH2CH2OH) (H2Ln: n =1 , R = benzyl, n = 2, R = 4-methylenzyl]; n = 3, R = 2-naphthalenylmethyl) in the presence of NEt3 or pyridine in MeOH or BnOH gave the tetranuclear complexes [M-4(HLn)(2)(OAc)(6)(MeOH)(2)] {M = Ni, n = 1 (la), 2 (lb), 3 (1c) M = Co, n = 1 (4a), 2 (4b), 3 (4c)} and [M-4(HLn)(2)-(OAc)(6)(BnOH)(2)] {M = Ni, n = 1 (2a), 2 (2b), 3 (2c); M = Co, n = 1 (5a), 2 (5b), 3 (5c)}. When p-xylene-alpha,alpha'-diol was used instead of monoalcohols, the tetranuclear (M4O6) units were linked by p-xylene-alpha,alpha'-diol to form the 1D coordination polymers [M-4(HLn)(2)(OAc)(6)(p-HOH2C6H4CH2OH)](m) {M = Ni, n = 1 (3a), 2 (3b); M = Co, n = 1 (6a), 2 (6b)). The structures of 1-6 were determined by X-ray crystallography and consist of centrosymmetrical tetranuclear (M4O6)) face-shared defective double-cubane cores supported by two monodeprotonated (HLn-) ligands. The mixed-metal letranuclear complexes [Ni2.2Co1.8(HL1)(2)(OAc)(6)(MeOH)(2)] (7) and [Mn1.7Ni2.3(HL1)(2)(OAc)(5)(OMe)(2)] (8) were also synthesized by using e.quimolar amounts of Ni2+ and M2+ (M = Co, Mn) ions. X-ray crystallographic and :fluorescent analyses.revealed that 7 is isomorphous with 1a and 4a and contains.nonstoichiometric amounts of disordered Ni2+ and Co2+ ions in an average ratio of 2.2:1.8 with different occupancies for the two crystallographically independent metal centers. In contrast, 8 consists of a C-2-symmetrical face-shared defective doublecubane ((M3MnO6)-Mn-II-O-III) core with a Ni/Mn ratio of 2.3:1.7, the amounts of Ni2+ and Mn2+ ions vary depending on the metal sites, and one of the C-2 axial positions is exclusively occupied by Nin ions. Detailed magnetostru.ctural analyses on the nickel (1a, 2a, 3a) mid cobalt (4a) complexes with appropriate spin-Hamiltoulau. models showed that both iferro- and antiferromagnetic spin exchange interactions were involved within the tetranuclear units, and their extent depends on the combination of the metal ions and -the ligand systems in a delicate fashion., Oct. 2014, 29, 5021, 5033, Scientific journal, 10.1002/ejic.201402536
  • Refereed, SOLID STATE SCIENCES, ELSEVIER SCIENCE BV, Magnetic anisotropy and molecular assembling in d complex cation-f complex anion type coordination compounds, Marilena Ferbinteanu; Fanica Cimpoesu; Takashi Kajiwara; Masahiro Yamashita, The system [Fe(bpca)(2)][Er(NO(3))(4)(H(2)O)(2]) (1) (Hbpca = bis(2-pyridil-carbonyl)amine) is a complex cation-complex anion type coordination compound consisting of distinct d and f units, interlinked by hydrogen bonds. Particularly, the association of f-type complex anions in dimers is remarked and discussed. The energy decomposition analyses based on DFT calculations offered supplementary insight into the coordination effects at the lanthanide ions and the hydrogen bond driven supramolecular association of the complex units. Special ab initio procedures and subsequent modeling afforded the computation of anisotropic magnetization tensors of the [Er(NO(3))(4)(H(2)O)(2)(-) f-type units. The computed results are in line with the experimental data for compound 1. (C) 2008 Elsevier Masson SAS. All rights reserved., Apr. 2009, 11, 4, 760, 765, Scientific journal, 10.1016/j.solidstatesciences.2008.06.008
  • Refereed, Journal of the American Chemical Society, Mixed Charge-Ordering State of MMX-Type Quasi-One-Dimensionl Iodide-Bridged Platinum Complexes with Binary Countercations, H. Iguchi; S. Takaishi; T. Kajiwara; H. Miyasaka; M. Yamashita; H. Matsuzaki; H. Okamoto, Dec. 2008, 130, 17668-17669, 10.1021/ja807901p
  • Refereed, COORDINATION CHEMISTRY REVIEWS, ELSEVIER SCIENCE SA, Transition metal and lanthanide cluster complexes constructed with thiacalix[n]arene and its derivatives, Takashi Kajiwara; Nobuhiko Iki; Masahiro Yamashita, This review deals with the formations, structures, and properties of transition metal and lanthanide clusters supported by thiacalix[n]arene and its oxidized derivatives, sulfinylcalix[4]arene and sulfonylcalix[4]arene. Each thiacalix[n]arene possesses donor atoms both on the lower rim position (phenol oxygen atoms) and on the cyclic framework itself (-S-, -SO-, or -SO2-), and behaves as a multidentate multi-nucleating ligand to support the formation of a phenoxo-bridged cluster core. For first row transition metals, calix[4]arenes offer a platform for assembling the metal ions via four fac-tridentate coordination sites, and planar tri- and tetra-nuclear clusters are formed. A larger and more flexible thiacalix[6]arene could bind up to five metal ions inside the coordination cavity formed when it adopts the pinched cone conformation. Sulfonylcalix[4]arene shows a strong affinity to lanthanide ions through phenoxo and sulfonyl oxygen donors, and yields a variety of cluster compounds involving di-, tetra-, octa-, and dodeca-nuclear cores, achieved by controlled synthetic conditions. (C) 2007 Elsevier B.V. All rights reserved., Jul. 2007, 251, 13-14, 1734, 1746, Scientific journal, 10.1016/j.ccr.2007.01.001
  • Refereed, Angew. Chem. Int. Ed.,, Halogen-Bridged Two-Leg Ladder PtII-PtIV Mixed-Valence Complexes: Syntheses, Structures and Optical, M. Yamashita; D. Kawakami; S. Matsunaga; S. Takaishi; T. Kajiwara; H. Miyasaka; K. Sugiura; H. Matsuzaki; H. Kishida; H. Okamoto; Y. Wakabayashi; H. Sawa, Apr. 2006, 45, 7214, 7217, Scientific journal
  • Refereed, JOURNAL OF SOLID STATE CHEMISTRY, ACADEMIC PRESS INC ELSEVIER SCIENCE, Synthesis and crystal structures of CaY2Ge3O10 and CaY2Ge4O12, H Yamane; R Tanimura; T Yamada; J Takahashi; T Kajiwara; M Shimada, New compounds Cay(2)Ge(3)O(10) and CaY2Ge4O12 were prepared by heating mixtures of CaCO3, Y2O3 and GeO2 at 1200 degrees C. CaY2Ge3O10 is stable at 1300 degrees C, while CaY2Ge4O12 decomposes into a melt and CaY2Ge3O10 at approximately 1250 degrees C. We obtained single crystals of CaY2Ge3O10 by cooling a sample with an initial composition of Ca:Y:Ge = 1:2:8 from 1300 degrees C with a rate of -6 degrees C/h. The crystal structure of CaY2Ge3O10 was determined by single crystal X-ray diffraction. CaY2Ge3O10 crystallizes in the monoclinic space group P2(1/)c with a = 6.0906(8), b = 6.8329(8), c = 18.752(2) angstrom and beta = 109.140(3)degrees, Z = 4. and R, = 0.029 for I > 2 sigma(I). In the structure of CaY2Ge3O10, Ca and Y atoms are situated disorderly in three 7-fold coordination sites between isolated Germanate groups of triple GeO4 tetrahedra, Ge3O10. The structural formula of CaY2Ge3O10 is expressed as (Ca0.45Y0.55)(Ca0.46Y0.54)(Ca0.09Y0.91)Ge3O10. The crystal structure of CaY2Ge4O12 was analyzed by the Rietveld method for the X-ray powder diffraction pattern. CaY2Ge4O12 is isotypic with SrNa2P4O12, crystallizing in the orthorhonibic space group P4/nbm, a = 9.99282(6), c = 5.06701(4) angstrom, Z = 2, R-wp = 0.092, R-p = 0.067. CaY2Ge4O12 contains four-membered GeO4-tetrahedra rings, Ge4O12. Eight-fold coordinated square-anitiprism sites and 6-fold octahedral sites between the layers of the Ge4O12 rings are occupied by Y atom and Ca/Y atoms, respectively The structural formula is Y(Ca0.5Y0.5)(2)Ge4O12. (c) 2005 Elsevier Inc. All rights reserved., Jan. 2006, 179, 1, 289, 295, Scientific journal, 10.1016/j.jssc.2005.10.023
  • Refereed, Bull. Chem. Soc. Jpn.,, Versatile Vapochromic Behavior Accompanied by Phase Change between Charge-Polarization State and, M. Yamashita; K. Takizawa; S. Matsunaga; D. Kawakami; H. Iguchi; S. Takaishi; T.,Kajiwara; F. Iwahori; T. Ishii; H. Miyasaka; K. Sugiura; H. Matsuzaki; H. Kishida; H. Okamoto, 2006, 79, 1404, 1406, Scientific journal, 10.1246/bcsj.79.1404
  • Refereed, Mater. Res. Bull., Single crystal growth of Mn2N using an In-Na flux, M. Aoki; H. Yamane; M. Shimada; T. Kajiwara, 05 May 2004, 39, 6, 827, 832, Scientific journal, 10.1016/j.materresbull.2004.02.014
  • The Journal of Physical Chemistry C, American Chemical Society (ACS), Anisotropy of Spin–Lattice Relaxations in Mononuclear Tb3+ Single-Molecule Magnets, Piotr Konieczny; Robert Pel̷ka; Yuka Masuda; Shiomi Sakata; Saori Kayahara; Natsumi Irie; Takashi Kajiwara; Stanisl̷aw Baran, 09 Apr. 2020, 124, 14, 7930, 7937, Scientific journal, 10.1021/acs.jpcc.9b11057
  • Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 16aPS-55 Inelastic neutron scattering studies on Zn-Ln-Zn single-molecule magnets, Kofu M.; Kajiwara T.; Kikuchi T.; Ohira-Kawamura S.; Nakajima K.; Yamamuro O., 2015, 70, 760, 760, 10.11316/jpsgaiyo.70.2.0_760
  • Not Refereed, PURE AND APPLIED CHEMISTRY, INT UNION PURE APPLIED CHEMISTRY, Single-chain magnets constructed with a twisting arrangement of the easy-plane of iron(II) ions, Takashi Kajiwara; Hiroki Tanaka; Masahiro Yamashita, A novel class of single-chain magnets (SCMs), catena-[Fe-II(ClO4)(2){Fe-III(bpca)(2)}]ClO4 and its derivative, were synthesized using the spin-carrier components possessing hard-axis anisotropy (or easy-plane anisotropy, D > 0). The easy-axis-type anisotropy of whole molecules of these compounds, which is essential for the formation of SCMs, arises from the twisted arrangement of easy-planes of Fe(H) along the chain axis. Alternating high-spin Fe(H) and low-spin Fe(Ill) chain complexes behave as an SCM with a typical frequency-dependent ac susceptibility which obeys Arrhenius law. Below 7 K, catena-[Fe-II(ClO4)(2){Fe-III(bpca)(2)}]ClO4 showed a short-range spin-ordering even in zero external field in a time range of Mossbauer spectroscopy as well as the muon-spin-relaxation (pSR) spectroscopy. Since the easy-axis-type magnetic anisotropy originated from the structural motif of the twisting arrangement of Fe(II) ions, the overall magnetic property was very sensitive to the small structural changes arising from adsorption/desorption of the crystal solvents, and catena-[Fe-II(ClO4)(2){Fe-III(bpca)(2)}]ClO4 showed a reversible change in magnetism that has been referred to as "a magnetic sponge". In its derivative, controls of the molecular structure, the arrangement of chains in the crystal, and magnetic properties both in dc and ac susceptibility have been achieved by the introduction of methyl group on a bpca(-) ligand, which bridges and mediates the magnetic interaction of the adjoining Fe(II)/Fe(III) ions., Nov. 2008, 80, 11, 2297, 2308, Scientific journal, 10.1351/pac200880112297
  • Refereed, DALTON TRANSACTIONS, ROYAL SOC CHEMISTRY, Electron-rich linear triplatinum complexes stabilized by a spinning tetraphosphine, tris(diphenylphosphinomethyl)phosphine, Tomoaki Tanase; Kanako Koike; Miho Uegaki; Satoko Hatada; Kanako Nakamae; Bunsho Kure; Yasuyuki Ura; Takayuki Nakajima, Linear triplatinum complexes with 48e(-), [Pt3(mu-tdpmp)(2)(RNC)(2)](PF6)(2) (R = 2,6-xylyl (3), Bu-t (4)), were synthesized by using a branched tetraphosphine, tris(diphenylphosphinomethyl) phosphine (tdpmp), and characterized by crystallographic and spectroscopic analyses to show their novel dynamic behaviour in the solution state, in which the linear Pt3 unit was stabilized by two spinning tetraphosphine ligands., 2016, 45, 17, 7209, 7214, Scientific journal, 10.1039/c6dt00624h
  • Refereed, The Journal of Physical Chemistry C, American Chemical Society (ACS), Slow Magnetic Relaxation of Linear Trinuclear M(II)–Gd(III)–M(II) Complexes with D3 Point Group Symmetry (M(II) = Zn(II) and Mg(II)), Yuka Masuda; Shiomi Sakata; Saori Kayahara; Natsumi Irie; Maiko Kofu; Yohei Kono; Toshiro Sakakibara; Yoji Horii; Takashi Kajiwara, 06 Feb. 2023, Scientific journal, 10.1021/acs.jpcc.2c08323
  • Refereed, Journal of Materials Chemistry C, Royal Society of Chemistry (RSC), Construction of a two-dimensional metal–organic framework with perpendicular magnetic anisotropy composed of single-molecule magnets, Ikumi Aratani; Yoji Horii; Daisuke Takajo; Yoshinori Kotani; Hitoshi Osawa; Takashi Kajiwara, A robust network structure of single-molecule magnets that exhibits perpendicular magnetic anisotropy preferred for memory devices was constructed utilizing coordination chemistry at the air–liquid interface., 2023, 11, 6, 2082, 2088, Scientific journal, 10.1039/d2tc04963e
  • Refereed, Scientific Reports, Springer Science and Business Media LLC, Rotating magnetocaloric effect in highly anisotropic TbIII and DyIII single molecular magnets, Piotr Konieczny; Dominik Czernia; Takashi Kajiwara, Abstract The magnetocaloric effect (MCE) was investigated in highly anisotropic single crystals of two single molecule magnets (SMMs): [LnIII(ZnIIL)2]CF3SO3, where Ln = Tb, Dy and L = tripodal hexadentate Schiff base ligand. The structure of these paramagnetic compounds consists of identically oriented linear trinuclear clusters in a trigonal system with an easy direction c∥Zn–Ln–Zn array and a hard plane ab⊥Zn–Ln–Zn array. The magnitude of MCE measured for c∥H was significantly greater than MCE for ab∥H at a wide temperature range regardless of the studied SMM. Therefore, the rotating magnetocaloric effect (RMCE) was evaluated. The maxima of the magnetic entropy change for RMCE were obtained at 2.0 K and moderate fields: 3.9 J K−1 kg−1 at µ0H = 1.3 T for Ln = Tb and 3.3 J K−1 kg−1 at µ0H = 1.1 T for Ln = Dy. The relative efficiency of RMCE compared to the MCE measured in c∥H was as high as 99% at low magnetic fields., 05 Oct. 2022, 12, 1, Scientific journal, 10.1038/s41598-022-20893-2
  • Inorganic Chemistry Frontiers, Royal Society of Chemistry (RSC), Solid polymorphism and dynamic magnetic properties of a dodecylated vanadyl–porphyrinato complex: spin–lattice relaxations modulated by phase stabilisation, Yoji Horii; Momo Makino; Taro Yamamoto; Shoichi Tatsumi; Hal Suzuki; Mariko Noguchi; Takefumi Yoshida; Takashi Kajiwara; Zhao-Yang Li; Masahiro Yamashita, Phase stabilisation elongates spin–lattice relaxation times., 2022, Scientific journal, 10.1039/d2qi01607a
  • Not Refereed, 25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PART 4, IOP PUBLISHING LTD, Single-Crystal Growth of Pb2V3O9 and the Bose-Einstein Condensed State of Triplons Studied by Thermal Conductivity, Specific Heat and Magnetization Measurements, T. Kawamata; N. Sugawara; M. Uesaka; N. Kaneko; T. Kajiwara; H. Yamane; K. Koyama; K. Kudo; N. Kobayashi; Y. Koike, We have succeeded in growing large-size single crystals of the quasi-one-dimensional S = 1/2 spin-dimer system Pb2V3O9 by the floating-zone method, and also investigated the thermal conductivity, specific heat and magnetization in magnetic fields. In high magnetic fields, it has been found that the suppression of the thermal conductivity by the application of magnetic field is relaxed. This behavior is caused by the enhancement of the thermal conductivity due to triplons and/or phonons owing to the extension of the mean free path of triplons and/or phonons in the Bose-Einstein condensed (BEC) state of field-induced triplons. We have estimated the critical field H-c(T) between the BEC state of triplons and the gapped normal state from the thermal conductivity, specific heat and magnetization measurements and obtained the value of the critical exponent phi similar to 2.0 in [H-c(T)-H-c(0)] proportional to T-phi using H-c(T)'s at low temperatures., 2009, 150, International conference proceedings, 10.1088/1742-6596/150/4/042087
  • Journal of the Ceramic Society of Japan, The Ceramic Society of Japan, Synthesis, crystal structure and physical properties of layered cobalt oxide Ca_xCoO_2 (x〜0.47), MIYAZAKI Yuzuru; HUANG Xiangyang; KAJIWARA Takashi; YAMANE Hisanori; KAJITANI Tsuyoshi, We have synthesized a single-phase sample of the compound known as CaCo_2O_4 and investigated its crystal structure by means of a single crystal X-ray diffraction technique. The compound crystallizes in a triclinic system (space group P1) with lattice parameters of a=492.4(2)pm, b=568.3(3)pm, c=568.5(3)pm, α=75.400(9)°, β=89.974(9)° and γ=81.261(9)° at 293(2)K. The structure consists of an alternate stack of a CdI_2-type CoO_2 triangular sheet and a layer of Ca atoms, showing great similarity to that of β-Na_xCoO_2 (x〜0.67). However, the Ca atom has four crystallographic sites with different occupation probabilities, leading to the structure formula Ca_<1.87(5)>Co_4O_8 (Ca_<0.47(1)>CoO_2). Due to a low bulk density as well as a small number of hole carriers, equivalent to the nominal valence state of Co ions close to 3.06, a polycrystalline sample of the Caphase exhibits much higher electrical resistivity ρ=680μΩm, relative to that of the Na-phase ρ=1.2μΩm, with a large positive Seebeck coefficient of S=145μV/K at 300K., 01 Jan. 2009, 117, 1361, 42, 46, 10.2109/jcersj2.117.42
  • Chemical Communications, Royal Society of Chemistry (RSC), Molecular elastic crystals exhibiting slow magnetic relaxations, Hinako Kato; Yoji Horii; Mariko Noguchi; Hiroki Fujimori; Takashi Kajiwara, We report an elastic crystal of a copper(II) porphyrinato complex that exhibits slow magnetic relaxations and is a promising candidate for an external-force-responsive spin qubit., Nov. 2023, Scientific journal, 10.1039/d3cc04770a
  • Journal of Materials Chemistry C, Royal Society of Chemistry (RSC), Two-dimensional metal–organic nanosheets composed of single-molecule magnets: structural modulation and enhanced magnetism utilizing steric hindrance effect, Ikumi Aratani; Yoji Horii; Yoshinori Kotani; Hitoshi Osawa; Hajime Tanida; Toshiaki Ina; Takeshi Watanabe; Yohko F. Dr Yano; Akane Mizoguchi; Daisuke Takajo; Takashi Kajiwara, Two-dimentional arrays of single-molecule magnets (SMMs) are a prerequisite for the construction of devices with ultrahigh-density magnetic memory based on molecular spintronics. The advantage of using such molecules in inorganic-based..., Nov. 2023, Scientific journal, 10.1039/d3tc03360k

MISC

  • Not Refereed, POLYHEDRON, PERGAMON-ELSEVIER SCIENCE LTD, Solvent induced reversible change of magnetic properties in a Fe(II)-Fe(III) single chain magnet, Yukihiro Kaneko; Takashi Kajiwara; Hisanori Yamane; Masahiro Yamashita, A single chain magnet (SCM), catena-[Fe-II(ClO4)(2)(Fe-III(bpca)(2)})ClO4 (1) includes three nitromethane molecules per a Fe(II)-Fe(III) unit as crystallized solvent which occupy the pores surrounded by four chains. Compound I can release or reabsorb these MeNO2 molecules like "sponges" possessing the chain structure of 1, accompanied by a reversible changing of SCM behavior during this process. Compound I is the first nano-magnet which shows the solvent induced reversible change of magnetic properties. (c) 2006 Elsevier Ltd. All rights reserved., Jun. 2007, 26, 9-11, 2074, 2078, 10.1016/j.poly.2006.10.005
  • Not Refereed, Molecular Physics, A New Series of Radical-Triplet Pair System : Modulation of Radical-Triplet Interaction by a Counter Ion, L. Maretti; I. SM Saiful; T. Kajiwara; R. Miyamoto; Y. Ohba; S.Yamauchi, 2006, 104, 1619, 1626, 10.1080/00268970500493334
  • Meeting abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 29aXW-3 Neutron scattering study on spin dynamics in rare-earth based single-molecule magnets III, Kofu M.; Kajiwara T.; Nakano M.; Nakajima K.; Simeoni Giovanna; Gardner Jason; Tyagi Madhusudan; Yamamuro O., 26 Mar. 2013, 68, 1, 560, 560
  • Meeting abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 27aTE-5 Structures and Physical Properties of Mn_4 Single-Molecule Magnets with Pt(mnt)_2 Molecular Conductors, NAKATA Kazuya; Hiraga Hiroki; Miyasaka Hitoshi; Takaishi Shinya; Kajiwara Takashi; Yamashita Masahiro; Oshima Yugo; Nojiri Hiroyuki, 04 Mar. 2006, 61, 1, 424, 424
  • Meeting abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 26aWL-7 Neutron scattering study on spin dynamics in rare-earth based single-molecule magnets, Kofu M.; Kajiwara T.; Nakano M.; Nakajima K.; Kawamura S.; Kikuchi T.; Inamura Y.; Yamamuro O., 18 Aug. 2010, 65, 2, 447, 447
  • Meeting abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 22pGP-11 Neutron scattering study on spin dynamics in rare-earth based single-molecule magnets II, Kofu M.; Kajiwara T.; Nakano M.; Nakajima K.; Kawamura S.; Kikuchi T.; Inamura Y.; Ymamuro O., 24 Aug. 2011, 66, 2, 434, 434
  • 日本物理学会講演概要集, 一般社団法人日本物理学会, 20aWB-7 新規擬一次元ハロゲン架橋Ni-Pd混合金属錯体Ni_<1-x>Pd_x(R,R-bn)_2Br_3の合成とその電子構造(導電性高分子,金属鎖(ポリマー,MX,MMX),領域7(分子性固体・有機導体)), 高石 慎也; 佐々木 真理; 梶原 孝志; 山下 正廣; 岸田 英夫; 岡本 博; 若林 裕助; 澤 博, 19 Aug. 2005, 60, 2, 687, 687

Books etc

  • 978-4-7827-0800-2 C3043

Presentations

  • Oral presentation
  • Oral presentation
  • KAJIWARA Takashi, 希土類討論会, Gd(III)錯体における遅い磁化緩和現象, Oral presentation, May 2019
  • KAJIWARA Takashi, 日本化学会第99春季年会, トリスジピコリナトGd(III)単核錯体における遅い磁気緩和の発現, Oral presentation, Mar. 2019, 甲南大学岡本キャンパス
  • KAJIWARA Takashi, 日本化学会第99春季年会, トリスジピコリナトDy(III)単核錯体のSMM特性における対カチオン交換の効果, Mar. 2019, 甲南大学岡本キャンパス
  • KAJIWARA Takashi; Takashi Kajiwara, The 2nd International Symposium on Coordination Ionic Compounds, Lanthanide-based Single Molecule Magnets - Correlation between the Molecular Structure and the Magnetic Anisotropy, Dec. 2018, True
  • KAJIWARA Takashi; K. Kobayashi; Y. Harada; Y. Kataoka; T. Kajiwara, International Conference on Coordination Chemistry, 2018, Sendai, Syntheses and SMM properties of Ln(III) complexes supported by an N5-Schiff base ligand, Aug. 2018, True
  • KAJIWARA Takashi; M. Kudo; Y. Kataoka; T. Kajiwara, International Conference on Coordination Chemistry, 2018, Sendai, Sensing Ability of Luminescent Lanthanide Complexes for Anions Supported by Cyclen-based Ligands, Aug. 2018
  • KAJIWARA Takashi; Y. Masuda; S. Sakata; S. Kayahara; N. Irie; Y. Kataoka; T. Kajiwara, International Conference on Coordination Chemistry, 2018, Sendai, Slow Magnetic Relaxation Properties of M(II)?Ln(III)?M(II)\nTrinuclear Complexes (Ln = Gd, Tb; M = Mg, Zn), Aug. 2018
  • KAJIWARA Takashi; S. Sakata; Y. Masuda; N. Irie; S. Kayahara; Y. Kataoka; T. Kajiwara, International Conference on Coordination Chemistry, 2018, Sendai, Syntheses, structures, and SMM behaviors of M-Ln(III)-M trinuclear complexes with threefold symmetry (Ln = Ce, Nd; M = Mg), Aug. 2018
  • KAJIWARA Takashi, 日本化学会第98春季年会, N5-Schiff塩基配位子をエカトリアルに持つ Ln(III)錯体の合成と単分子磁石特性, Mar. 2018, False
  • KAJIWARA Takashi, 日本化学会第98春季年会, サイクレン骨格を有する発光性希土類錯体によるアニオン認識能の検討, Mar. 2018, False
  • KAJIWARA Takashi, 日本化学会第98春季年会, IDA骨格を基盤とする新規四座配位子を含むEu(III)錯体の水溶液中における錯体形成挙動と発光特性の検討(IDA:iminodiacetic acid), Mar. 2018, False
  • KAJIWARA Takashi, 兵庫県立大学フロンティア機能物質創製センターシンポジウム, 希土類を基盤とする単分子磁石の設計と物性, Jan. 2018
  • KAJIWARA Takashi; Takashi Kajiwara, One Day Symposium of Research Center for Structural Thermodynamics, Lanthanide-based single molecule magnets?design of the magnetic anisotropy, Dec. 2017
  • KAJIWARA Takashi, 錯体化学会第67回討論会, 三回対称性をもつMg(II)-Ln(III)-Mg(II)三核錯体(Ln = Ce, Nd)における磁気希釈が磁気特性に及ぼす効果, Sep. 2017, False
  • KAJIWARA Takashi, 錯体化学会第67回討論会, オキシ二酢酸を配位子としたLnIII単核錯体における遅い磁化緩和の発現, Sep. 2017, False
  • KAJIWARA Takashi, 錯体化学会第67回討論会, 直線状M(II)-Ln(III)-M(II)三核錯体の磁気特性に対して及ぼす因子の解明 (Ln = Gd, Tb, M= Mg, Zn), Sep. 2017, False
  • KAJIWARA Takashi, 錯体化学会第67回討論会, 3回対称を持つLn(III)単分子磁石に対するプロトン化の効果, Sep. 2017, False
  • KAJIWARA Takashi, 日本化学会第97春季年会, 三回対称性をもつMg(II)?Ln(III)?Mg(II)三核錯体 (Ln = Ce, Pr, Nd)の合成と構造および磁気特性の比較, Mar. 2017, False
  • KAJIWARA Takashi, 日本化学会第97春季年会, 直線状TM(II)?Tb(III)?TM(II)三核錯体において反磁性金属イオンがTb(III)イオンの遅い磁化緩和に及ぼす効果 (TM(II) = Mg(II),Zn(II),Cd(II)), Mar. 2017, False
  • KAJIWARA Takashi, 日本希土類学会第34回講演会, 分子サイズの磁石を作る~分子磁性体の仕組みと設計 Syntheses of Molecular-based Magnets ? Designing of Magnetic Anisotropy ?, Nov. 2016, False
  • KAJIWARA Takashi, 錯体化学若手の会 第55回 近畿支部 勉強会, 分子磁性体の最近の話題~d金属とf金属の違いを中心に, Nov. 2016, False
  • KAJIWARA Takashi; Saori Kayahara; Natsumi Irie; Poh Ling Then; Chika Takehara; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, ICMM2016 The 15th International Conference on Molecule-Based Magnets, Synthesis and Single Molecule Magnet behavior of linear Zn(II)-Tb(III)-Zn(II) trinuclear complex which possesses three-fold symmetry, Sep. 2016, True
  • KAJIWARA Takashi; Natsumi Irie; Saori Kayahara; Chika Takehara; Poh Ling Then; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, ICMM2016 The 15th International Conference on Molecule-Based Magnets, Syntheses, structures, and SMM behaviors of a Zn(II)-Ce(III)-Zn(II)complexes with threefold symmetry, Sep. 2016, True
  • KAJIWARA Takashi; Saki Nakanishi; Haruna Ogawa; Saori Kayahara; Natsumi Irie; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, ICMM2016 The 15th International Conference on Molecule-Based Magnets, Slow magnetic relaxation behaviors of Ln(III) complexes which belong to the D3 point group, Sep. 2016, True
  • KAJIWARA Takashi; Haruna Ogawa; Saki Nakanishi; Saori Kayahara; Natsumi Irie; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, ICMM2016 The 15th International Conference on Molecule-Based Magnets, Syntheses and SMM behaviors of prolate-type Ln(III) mononuclear complexes which belong to the D3 point group, Sep. 2016, True
  • KAJIWARA Takashi, 錯体化学会第66回討論会, 結晶学的に三回対称を持つZn(II)-Ln(III)-Zn(II)三核錯体の合成と単分子磁石特性, Sep. 2016, False
  • KAJIWARA Takashi, 錯体化学会第66回討論会, 三回対称を持つCe(III)単分子磁石の合成と磁気特性の比較, Sep. 2016, False
  • KAJIWARA Takashi, 錯体化学会第66回討論会, 溶液中での五配位座Pybox誘導体を用いたEu(III)錯体の構造と発光特性の相関, Sep. 2016, False
  • KAJIWARA Takashi, 錯体化学会第66回討論会, Pybox配位子を含むEu(III)/Tb(III)混合希土類錯体による発光性アニオンセンシング, Sep. 2016, False
  • KAJIWARA Takashi, 錯体化学会第66回討論会, 点群D3の対称性を持つLn(III)単核錯体における遅い磁化緩和の発現, Sep. 2016, False
  • KAJIWARA Takashi, 錯体化学会第66回討論会, 3回対称を持つLn(III)単分子磁石に対する側鎖導入の効果, Sep. 2016, False
  • KAJIWARA Takashi; Takashi Kajiwara; Poh Ling Then; Chika Takehara; Yumiko Kataoka; Tomoo Yamamura, Rare Earths 2016 in Sapporo, Single Molecule Magnet behaviors of isostructural Zn(II)-Ln(III)-Zn(II) tri-nuclear complexes (Ln = Ce, Nd, Tb, and Dy), Jun. 2016, Sapporo, Japan, True
  • KAJIWARA Takashi; Saori Kayahara; Natsumi Irie; Poh Ling Then; Chika Takehara; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, Rare Earths 2016 in Sapporo, Syntheses and Single Molecule Magnet Behaviors of Linear Zn(II)-Ln(III)-Zn(II) Trinuclear Complexes which Possess Pseudo Three-fold Symmetry (Ln = Tb, Dy), Jun. 2016, Sapporo, Japan, True
  • KAJIWARA Takashi, 日本化学会第96春季年会, 点群D3の対称性を持つLn(III)単核錯体における遅い磁化緩和の発現, Mar. 2016, False
  • KAJIWARA Takashi, 日本化学会第96春季年会, 点群D3の対称性を持つYb(III)単核錯体の合成とSMM特性, Mar. 2016, False
  • KAJIWARA Takashi, 日本化学会第96春季年会, 擬似的な三回対称を持つ直線状Zn(II)-Ln(III)-Zn(II)三核錯体の合成とSMM特性 (Ln = Tb, Dy), Mar. 2016, False
  • KAJIWARA Takashi; Kajiwara, Takashi; Takehara, Chika; Then, Poh Ling; Kataoka,Yumiko, The International Chemical Congress of Pacific Basin Societies 2015, SMM behaviors of isostructural Zn(II)-Ln(III)-Zn(II) tri-nuclear complexes (Ln = Ce, Nd, Tb, and Dy), Dec. 2015, True
  • KAJIWARA Takashi; Kayahara, Saori; Irie, Natsumi; Ooka, Sayaka; Wada, Hisami; Takehara, Chika; Then, Poh Ling; Kataoka, Yumiko; Kajiwara, Takashi; Yamamura, Tomoo, The International Chemical Congress of Pacific Basin Societies 2015, Syntheses and SMM behaviors of linear ZnII - LnIII - ZnII trinuclear complexes with pseudo threefold symmetry\n(Ln = Pr, Nd), Dec. 2015, True
  • KAJIWARA Takashi; Nakamura, Kaho; Nokami, Misa; Tomotsuka, Ikumi; Harai, Maki; Kataoka, Yumiko; Kajiwara, Takashi, The International Chemical Congress of Pacific Basin Societies 2015, Luminescence Anion Sensing with Mixed-Ln(III) Complex containing Tridentate Pybox Ligand, Dec. 2015, True
  • KAJIWARA Takashi; Nokami, Misa; Nakamura, Kaho; Tomotsuka, Ikumi; Harai, Maki; Kataoka, Yumiko; Kajiwara, Takashi, The International Chemical Congress of Pacific Basin Societies 2015, Syntheses and Luminescence Properties of Ln(III) Complexes containing Pentadentate Pybox Derivative, Dec. 2015, True
  • KAJIWARA Takashi; Wada, Hisami; Ooka, Sayaka; Then, Poh Ling; Takehara, Chika; Kataoka, Yumiko; Kajiwara, Takashi; Yamamura, Tomoo, The International Chemical Congress of Pacific Basin Societies 2015, Syntheses and SMM behaviors of lanthanide(III) azacrown-ether complexes; correlation between magnetic\nbehaviors and crystal structures, Dec. 2015, True
  • KAJIWARA Takashi, 錯体化学会第66回討論会, 結晶学的に三回対称を持つZn(II)-Ln(III)-Zn(II)三核錯体の合成と単分子磁石特性, Sep. 2015, False
  • KAJIWARA Takashi, 錯体化学会第65回討論会, 多座キレート配位子を用いたEr(III)単分子磁石合成の試み, Sep. 2015, False
  • KAJIWARA Takashi, 錯体化学会第65回討論会, Pybox誘導体を用いた希土類錯の構造と発光特性相関について, Sep. 2015, False
  • KAJIWARA Takashi, 日本化学会第95春季年会, 擬似的な三回対称を持つ直線状Zn(II)-Ln(III)-Zn(II) 三核錯体の合成とSMM特性 (Ln = Pr, Nd), Mar. 2015, False
  • KAJIWARA Takashi, 日本化学会第95春季年会, 擬似的な三回対称を持つ直線状Zn(II)-Ce(III)-Zn(II) 三核錯体の合成と構造、およびSMM特性の比較, Mar. 2015, False
  • KAJIWARA Takashi, 日本化学会第95春季年会, Ln(III) azacrown-ether錯体の合成と単分子磁石特性; 磁気特性と\n結晶構造の相関, Mar. 2015, False
  • KAJIWARA Takashi, 日本化学会第95春季年会, 五配座Pybox誘導体を含むEu(III) / Tb(III)錯体におけるアニオン依存の発光応答性, Mar. 2015, False
  • KAJIWARA Takashi, 日本化学会第95春季年会, クラウン骨格を有するPybox配位子を含むEu(III)錯体によるアニオン-カチオン認識, Mar. 2015, False
  • KAJIWARA Takashi, 日本化学会第95春季年会, Pybox配位子を含むEu(III)-Tb(III)混合錯体によるマルチアニオンセンシング, Mar. 2015, False
  • KAJIWARA Takashi, 第2回東北大学研究会プログラム 「金属錯体の固体物性最前線‐金属錯体と固体物性物理と生物物性の連携新領域をめざして‐」, 軽希土類を基盤とする単分子磁石, Feb. 2015, False
  • KAJIWARA Takashi, アルファ放射体実験室・基盤研究(S)(価数不安定性をもつアクチノイド化合物)合同研究会, 希土類単分子磁石における磁化緩和の詳細な解析, Feb. 2015, False
  • KAJIWARA Takashi, 錯体化学会第64回討論会, 軽希土類単分子磁石の合成と磁気特性の比較, Sep. 2014, False
  • KAJIWARA Takashi; Maki Harai; Ikumi Tomotsuka; Yumiko Kataoka; Takashi Kajiwara, 41st International Conference on Coordination Chemistry, Syntheses and Luminescence Properties of LN(III) Complexes with Pybox Derivatives, Jul. 2014, True
  • KAJIWARA Takashi; Ikumi Tomotsuka; Maki Harai; Yumiko Kataoka; Takashi Kajiwara, 41st International Conference on Coordination Chemistry, Syntheses and Luminescence Properties of Lanthanide complexes with Pyboc Ligands Connected to 15-crown-5-ether Moiety, Jul. 2014, True
  • KAJIWARA Takashi; Hisami Wada; Sayaka Ooka; Chika Takehara; Poh Ling Then; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, 41st International Conference on Coordination Chemistry, Synthesis and SMM Behavior of Cerium(III) Crown-ether Complex, Jul. 2014, True
  • KAJIWARA Takashi; Sayaka Ooka; Hisami Wada; Chika Takehara; Poh Ling Then; Yumiko Kataoka; Takashi Kajiwara; Tomoo Yamamura, 41st International Conference on Coordination Chemistry, Syntheses and SMM Behaviors of Ln(III) Crown-ether Compelxes, Jul. 2014, True
  • KAJIWARA Takashi; Chika Takehara; Shiori Hino; Poh Ling Then; Yumiko Kataoka; Takashi Kajiwara; Motohiro Nakano; Tomoo Yamamura, 41st International Conference on Coordination Chemistry, Syntheses and Magnetic Properties of Cerium(III)-SMMs, Jul. 2014, True
  • KAJIWARA Takashi; Poh Ling Then; Chika Takehara; Kei Yamashita; Takashi Kajiwara; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura, 41st International Conference on Coordination Chemistry, Syntheses and SMM Behaviours of Linear Zn(II)-Dy(III)-Zn(II) Trinuclear Complexes, Jul. 2014, True
  • KAJIWARA Takashi, 日本化学会第94春季年会, 15-クラウン-5-エーテル骨格を有するPybox配位子を含む希土類錯体の合成と発光特性, Mar. 2014, False
  • KAJIWARA Takashi, 日本化学会第94春季年会, Pybox誘導体を用いたLn(III)錯体の合成と発光特性, Mar. 2014, False
  • KAJIWARA Takashi, 日本化学会第94春季年会, Ln(III) crown-ether錯体の合成とSMM特性, Mar. 2014, False
  • KAJIWARA Takashi, 日本化学会第94春季年会, Ce(III) crown-ether錯体の合成とSMM特性, Mar. 2014, False
  • KAJIWARA Takashi, 第1回東北大学リーディング大学院研究会プログラム 「金属錯体の固体物性最前線‐金属錯体と固体物性物理と生物物性の連携新領域をめざし\nて‐」, 希土類単分子磁石の設計と遅い磁化緩和の観測, Feb. 2014, False
  • KAJIWARA Takashi, アルファ放射体実験室・基盤研究(S)(価数不安定性をもつアクチノイド化合物)合同研究会, 希土類錯体の特異な磁気特性, Feb. 2014, False
  • KAJIWARA Takashi, 錯体化学会第63回討論会, 単分子磁石Zn(II)-Dy(III)-Zn(II)直線状三核錯体における非常に遅い磁化緩和, Nov. 2013, False
  • KAJIWARA Takashi, 錯体化学会第63回討論会, Ce(III)単分子磁石の合成と磁気特性の詳細, Nov. 2013, False
  • KAJIWARA Takashi, 錯体化学会第63回討論会, 直線状Zn(II)-Dy(III)-Zn(II)三核錯体の合成とSMM特性の比較, Nov. 2013, False
  • KAJIWARA Takashi, 錯体化学会第63回討論会, 水溶液中で発光性を示すTripod型配位子を有する希土類錯体の錯体形成挙動と発光特性, Nov. 2013, False
  • KAJIWARA Takashi; Chika Takehara; Shiori Hino; Then Poh Ling; Takashi Kajiwara; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura, The 2nd Japan-France Coordination Chemistry Symposium 2013, Syntheses and magnetic properties of Ce(III)-SMMs, Nov. 2013, True
  • KAJIWARA Takashi; Then Poh Ling; Chika Takehara; Kei Yamashita; Takashi Kajiwara; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura, The 2nd Japan-France Coordination Chemistry Symposium 2013, Syntheses and SMM Behaviours of Linear Zn(II)-Dy(III)-Zn(II) Trinuclear Complexes, Nov. 2013, True
  • KAJIWARA Takashi, 第93春季年会, 直線状Zn(Ⅱ)-Ce(Ⅲ)-Zn(Ⅱ)三核錯体の合成、構造とSMM挙動の発現, Mar. 2013
  • KAJIWARA Takashi, 第93春季年会, Zn(II)-Tb(III)-Zn(II)単分子磁石の構造制御と磁気特性の相関, Mar. 2013, False
  • KAJIWARA Takashi, 日本物理学会 第68回年次大会, 中性子散乱による希土類単分子磁石のスピンダイナミクスの研究III, Mar. 2013
  • KAJIWARA Takashi; Takashi Kajiwara; Akiko Watanabe; Aika Yamashita; Kei Yamashita; Yumiko Kataoka; Motohiro Nakano; Tomoo Yamamura, 40th International Conference on Coordination Chemistry, LnZn, LnZn2, and LnZ3 Complexes as Single-Molecule Magnets, Sep. 2012, Valencia, Spain
  • KAJIWARA Takashi; Kei Yamashita; Rie Miyazaki; Yumiko Kataoka; Takashi Kajiwara; Motohiro Nakano; Tomoo Yamamura, 40th International Conference on Coordination Chemistry, Single-Molecule-Magnet behaviors of linear Zn(II)-Ln(III)-Zn(II) complexes, Sep. 2012, Valencia, Spain
  • KAJIWARA Takashi; Yumiko Kataoka; Naoko Kusunoki; Aika Yamashita; Takayuki Nakanishi; Yasuchika Hasegawa; Takashi Kajiwara, 40th International Conference on Coordination Chemistry, Molecular Design of Zn (II)n ?Ln(III) Multinuclear Complexes and Their Luminescence Properties, Sep. 2012, Valencia, Spain
  • KAJIWARA Takashi, 第62回錯体化学討論会, 直線状Zn(II)-Tb(III)-Zn(II)三核錯体の磁気特性の詳細の解明, Sep. 2012, False
  • KAJIWARA Takashi, 第62回錯体化学討論会, Zn(II)n-Ln(III)複核錯体によるアニオン応答性の希土類発光挙動, Sep. 2012, False
  • KAJIWARA Takashi, 第62回錯体化学討論会, 直線状Zn(II)-Ln(III)-Zn(II)三核骨格を基盤とする単分子磁石合成の軽希土類への展開, Sep. 2012, False
  • KAJIWARA Takashi; Takashi Kajiwara, 62nd Fujihara Seminar, Structural Control of the Magnetic Anisotropy of Lanthanide-based SMMs, May 2012, The Fujihara Foundation of Science, Sendai, Japan, False
  • 渡邉 千遥; 堀井 洋司; 梶原 孝志, 日本化学会 第104春季年会 (2024), フタロシアニンからなる導電性弾性結晶の構築, 20 Mar. 2024, 18 Mar. 2024, 21 Mar. 2024
  • 山田 実季; 溝口 茜子; 堀井 洋司; 梶原 孝志, 日本化学会 第104春季年会 (2024), カルボキシ基導入単分子磁石の合成と気液界面を利用した薄膜の構築, 19 Mar. 2024, 18 Mar. 2024, 21 Mar. 2024
  • 梶原孝志, 第39回希土類討論会, 希土類を基盤とする単分子磁石の構築~異方性の設計と今後の課題, 30 May 2023, 30 May 2023, 31 May 2023

Works

  • f金属錯体における特異な磁気特性の詳細の解明, Apr. 2013, Mar. 2016
  • f金属錯体の磁気異方性制御, Apr. 2010, Mar. 2013

Awards

  • Best Poster Award, 43rd International Conference on Coordination Chemitry, K. Kobayashi, Aug. 2018

Research Projects

  • 01 Apr. 2020, 31 Mar. 2023, 20K05540, Principal investigator
  • 希土類系単分子磁石の磁気特性設計,合成と評価, 0, 0, 0, Competitive research funding
  • 01 Apr. 2020, 31 Mar. 2023, 20K05540, Principal investigator
  • 01 Apr. 2020, 31 Mar. 2023, 20K05540, Principal investigator
  • Grant-in-Aid for Scientific Research (C), 01 Apr. 2017, 31 Mar. 2020, 17K05811, Symmetry-controled magnetization dynamics of single-molecule magnets, Kajiwara Takashi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara Women's University, 4810000, 3700000, 1110000, Several lanthanide complexes show slow magnetic relaxation phenomena under appropriate conditions and they are known as single-molecule magnets. For such complexes, we have examined to synthesize new complexes on the basis of the new molecular design, and to investigate the dynamic magnetic properties employing new instrument for angle-resolved ac susceptibility measurements. We synthesized mixed metal tri-nuclear complexes with the combination of lanthanide and diamagnetic divalent metal ions such as Zn(II) and Mg(II), and also the mono-lanthanide complexes. We found that the strong axial-crystal field enhances the slow magnetic relaxation phenomena, however, we also found that several axial symmetry around magnetic principal axis, which was parallel to molecular axis, accelerates the relaxation due to slight mixing of the ground doublet states., kaken
  • 特定領域研究, 2007, 2008, 19018004, 有機-希土類複合系における単分子磁性の光制御を指向した研究, 梶原 孝志, 日本学術振興会, 科学研究費助成事業, 東北大学, 1800000, 1800000, 単分子磁石とは一つの分子が磁石として振る舞う化合物であり,この20年間に分子磁性の分野では最も注目を集めている化合物群である.その合成に際し,大きな基底スピン多重度と容易軸型の磁気異方性の導入・制御が重要であるが,その実現のためには重希土類金属イオン,特にテルビウムやジスプロシウムの利用が有効である.2004年にTb-Cu二核錯体系として初めての単分子磁石が報告されて依頼,今日まで10例ほどの希土類系単分子磁石が報告されている.このような化合物群を対象とし,本課題研究では希土類金属イオンと周囲の金属イオンとの相互作用の解明,光による分子磁性の制御を目指した物質系の創成と、その詳細な物性・機能性の解明を目指し,研究を行った.光による分子磁性の制御を行うためには,希土類系の単分子磁石合成の設計指針の確立,つまり,確実に単分子磁石となりうる条件・ならない条件を明らかにする必要性がある.本研究では構造的にほとんど違いがないのにもかかわらず,単分子磁石として振る舞う錯体・振る舞わない錯体の1対について詳細な磁気挙動の測定を行い,このような違いが希土類金属イオン周りの配位構造の違いに起因する磁気異方性の違いに帰着できることを見出した.その結果,テルビウム(III)イオンは一般に容易軸型の磁気異方性を有すると考えられていたが,配位構造によっては困難軸型ともなりうること,また,容易軸型の異方性についても,結晶場構造の設計によりその特性を強化することが可能なことを見出した.以上の結果より,分子構造の設計に基づいて単分子磁石挙動を制御するための設計指針を示すことに成功した., kaken
  • 若手研究(B), 2006, 2007, 18750041, 外場により制御されるナノ磁石, 梶原 孝志, 日本学術振興会, 科学研究費助成事業, 東北大学, 3700000, 3700000, 磁石と呼ばれる化合物は構造的に二種類に大別され,2次元・3次元構造を持ち転位温度以下で長距離磁気秩序相を示すバルク磁石に対し,1次元ないし孤立した分子構造を有する磁石をナノ磁石と総称する.ナノ磁石が磁石として振る舞うメカニズムは,分子内に形成された双極小ポテンシャルによってスピン反転が妨げられることに起因し,分子構造の設計により磁気特性の制御が可能なことが大きな特徴である.ナノ磁石構築には,容易軸型の磁気異方性を有する金属イオンを強磁性的ないしフェリ磁性的に連結することが一般的な構築手法であるが,筆者は磁化容易面型の金属イオンを構造制御しながら連結することにより,これまでにないタイプのナノ磁石(単一次元鎖磁石)の構築に成功してきた.この系はその分子構造により磁気構造が規制されるため,外場に応答した構造的な変化と磁気挙動の変化が連動するという特徴を有する.構造変化の要因として,結晶溶媒の可逆な吸脱着に着目して研究を遂行した.錯体を形成する有機配位子部分に種々の置換基を導入した錯体を合成し,それぞれについて溶媒の吸脱着と磁気特性の変化について詳細を検討した結果,本系がこのような外場の変化に対して種々の応答を示すこと,例えば磁気特性が強化される系,ほとんど影響を受けない系,あるいはナノ磁石と常磁性の間を往復する系などを見出した.バルク磁石系ではこのような可逆な磁気挙動の変化を示す系は知られていたが,ナノ磁石系では初めての例である., kaken
  • 特定領域研究, 2005, 2006, 17042006, 有機-希土類複合系を基盤とする分子性発光材料の開発, 梶原 孝志, 日本学術振興会, 科学研究費助成事業, 東北大学, 3600000, 3600000, 希土類金属イオンと大環状有機配位子p-tert-ブチルスルポニルカリックスアレーンとにより形成されるナノサイズのクラスター錯体5種について選択的合成法を確立するとともに,その発光挙動の解明を実験化学的・計算化学的に行うことに成功した.この大環状配位子は分子全体に広がったπ共役系を有し,π-π励起は360〜380nmと低エネルギー領域に存在する.本配位子系においては構造的な自由度が高く,また,その高度に広がった共役系におけるエネルギー準位が構造に依存して変化するという極めて斬新な性質を有しており,その結果として構造に依存した希土類金属イオンの発光選択制が実現されている.つまり,配位子の励起三重項エネルギーが希土類金属イオンのf-f*励起エネルギーよりわずかに高いため,配位子励起に引き続くf-f*励起の進行は,配位子の励起三重項状態と希土類金属イオンのf*励起準位のごくわずかなエネルギーマッチングの良し悪しにより劇的な変化を見せる.この現象については分子軌道計算に基づく考察を行い,この機構の正しさが理論的な面からも証明された.また,Tb(III)とEu(III)の混合キュバン錯体系においては,溶媒の違いにより錯体の構造が変化することが種々の分光学的測定より明らかとなっているが,この構造の変化を発光色の違いにより目視により観測することにも成功した., kaken
  • Grant-in-Aid for Scientific Research (B), 2002, 2004, 14340203, Construction of Nano Strucutures Based on Metal Cluster Complexes and Their Chemistry, ITO Tasuku; YAMAGUCHI Tadashi; KAJIWARA Takashi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Tohoku University, 16600000, 16600000, Main results are classified into three groups. A.Oligomers of triruthenium cluster [Ru_3(O)(CH_3COO)_6L_3]^. We found the existence of"Charge Transfer Isomer"in the asymmetric mixrd valence state of the pyrazine bridged cluster dimer, and studied their dynamic behavior in intramolecular elecron transfer by means of IR spectro-electrochemical method. The fact that"charge transfer isomers"exist in a single oxidation statte of mixed valence state is extremely rare. Rate constants of intramolecular electron transfer within each isomer, which results in the interconversion of the charge transfer isomer, were on the IR time scale. These results have been published in Angew.Chem.Int., 43, 1376-1381 (2004). We prepared linear oligomers of the cluster, pyrazine bridged trimer and tetramer. These oligomers were designed specifically to show multiple one electron reversible redox waves in their cyclic voltammograms. The trimer and tetramer showed, respecively, 11-step/12-electron and 14-step/15=electron reversible redox waves. These results have been published in Bull.Chem.Soc.Jpn.,78,591-598(2005). B.Use of Pt(II)to metal dative bond, Previously we had reported that carbon donor ligands exerted strong ligand field for platinum(II) ion, and that such platinum(II)complexes often form strong platinum to metal dative bonds. Using this idea, we prepared many of nano-sized cluster complexes with the platinum to metal dative bond. Typical examples are a tetranuclear platinum-rhodium-rhodium-platinum cluster complex and a one dimensional linear complex in which silver(I) and platinum(II) are alternately arranged. Manuscript of this study for publication is in preparation. C.Use of metal cluster forming ligand. We found in this study that p-tert-butyl-thiacalix[6]arene and p-tert-butyl-sulfonylcalix[4]arene act as cluster forming ligand. p-tert-butyl-sulfonylcalix[4]arene reacted with an excess of copper acetate to give a nano-sized decacopper cluster complex. And we found that a ferromagnetic interzcton operated in this cluster. This has been published in J.Am.Chem.Soc.,124,11274(2002). p-Tert-butyl-sulfonylcalix[4]arene reacted with lanthanoide ions to afford nano-sized compound with wheel like structure which sonsists of eight lanthanoide ions and four callixarene ligands. This study has been published in Angew.Chem.Int.,43,1382-1385(2004)., kaken
  • 若手研究(B), 2001, 2002, 13740370, 鉄(III)三核クラスター配位子を用いた磁性多核錯体の構築, 梶原 孝志, 日本学術振興会, 科学研究費助成事業, 東北大学, 2100000, 2100000, 本研究は鉄(II)ないし鉄(III)イオンと有機配位子Hbpcaよりなる錯体を一つのユニットとして集積型金属錯体を構築し,その磁気的相互作用について詳細の解明と制御を目的として遂行したものである.表題の鉄(III)三核クラスター配位子(CL^-)は中心にμ_<3>-オキソにより架橋された鉄(III)三核クラスターコアを有し,鉄イオン間を架橋するアルコキソイオン,四つの塩化物イオン,そして配位可能なカルボニル酸素を提供する二つのbpca^-イオンよりなり,一価の負電荷を有する錯体であり、金属イオン集積体の構築素子として極めて有効である。二つのクラスター配位子と二価の第一遷移金属イオンから成る七核錯体における磁気的挙動は極めて複雑であり,その詳細の解明にむけ,bpca^-を介した磁気的相互作用の一般的な性質について明らかにした.特に,bpca^-の特徴的な架橋様式(疑似二回対称を有するκ^2N:κ^3N型配位)に基づき,σスピン間に軌道直交性による強磁性的相互作用が発現することを見いだしたのは大きな成果である.これに基づき,様々な金属イオンに対して"Ferromagnetic Coupler"として働くことのできる錯体配位子[Cu(bptap)_2]の創製に成功した(bptap^-はbpca^-のSchiff塩基誘導体).また,bpca^-を介して鉄(II)-鉄(III)を交互鎖状に配列させた錯体が単一次元鎖状磁石となることを見出した.これらの成果は,bpca-鉄系が磁性多核錯体構築の有効な原料となることを示すものである., kaken
  • 奨励研究(A), 1999, 2000, 11740366, 二重交換相互作用発現を目指した鉄(II,III,II)混合原子価三核錯体の合成, 梶原 孝志, 日本学術振興会, 科学研究費助成事業, 東北大学, 2100000, 2100000, 研究の過程で新規に鉄(III)三核クラスター配位子(CL-)の合成に成功した.CL-は中心にμ_3-オキソにより架橋された鉄(III)三核クラスターコアを有し,鉄イオン間を架橋するアルコキソイオン,四つの塩化物イオン,そして配位可能なカルボニル酸素を提供する二つのbpca-イオンよりなり,一価の負電荷を有する錯体である.CL-は同じ方向を向いた四つの配位可能なカルボニルサイトを有し、金属イオン集積体の構築素子として極めて有効である。二つのクラスター配位子と二価の第一遷移金属イオンから成る七核錯体を複数合成し、その磁気的挙動を調べた。特に鉄(II)イオン、マンガン(II)イオンとCL-よりなる七核錯体は、基底スピンがS=6,12/3と大きなものであり、その磁気的振る舞いは特異なものである。混合原子価鉄七核錯体(前者)においては、まだプレリミナリーな結果ながら磁気異方性が存在することも強磁場中のトルク測定より明らかとなった。基底スピン多重度が大きなものとなるのはクラスター配位子と中心の鉄(II)イオンとの間の強い相互作用によると考えられるが,この相互作用はクラスター配位子内の鉄(III)イオンと中心の鉄(II)イオン間の電荷移動的な相互作用に基づく可能性が高く,本研究課題の二重交換相互作用が働いていることを示唆するものである.単分子磁石となる可能性を含め,今後の発展性のある新たな化合物群の創製に成功したことが本課題研究における成果と言える., kaken
  • 基盤研究(C), 01 Apr. 2020, 31 Mar. 2023, 20K05540, カチオン部位を有する配位子を用いた希土類単分子磁石の創出と磁気異方性の精密解析, 梶原 孝志, 日本学術振興会, 科学研究費助成事業, 奈良女子大学, 4420000, 3400000, 1020000, 本研究課題では希土類金属イオンの磁気異方性に立脚した遅い磁化緩和の発現(単分子磁石挙動の発現)を配位子の構造制御に基づいて制御するとともにその遅い磁化緩和の機構解明を目的としている。 希土類金属イオンは大きな軌道角運動量と磁化を保持し、結晶場の効果により特定の方向に磁化ベクトルの向きを固定するが可能となる。配位子はルイス塩基であり、その電荷と希土類金属イオンのf軌道との電荷反発に基づいて軌道角運動量の向きが特定の方向に固定される。もし配位子にルイス酸的な部位(カチオン性の部位)を導入することができれば、磁気異方性の強化が可能となると考え、そのような配位子の原材料となるピラジン-2,6-ジカルボン酸の合成を試み、グラムオーダーでの合成に成功した。 上記と並行し、ピラジンジカルボン酸と比較の対象となるピリジンジカルボン酸を配位子とする錯体についての研究を進めた。この中で、軌道角運動量を持たないガドリニウム錯体(既知)が40Kという高温まで遅い磁化緩和を示すことが明らかとなったので、その磁化緩和機構の解明を試みた。具体的には、一辺4-5mm程度の大きさの単結晶を育成し、分子の主軸(3回軸)に平行ないし垂直に磁場を印加した状態で交流磁化率を測定し、遅い磁化緩和の異方性について検討を行った。結果として結晶の配向に対する遅い磁化緩和の方向依存性を見出すことに成功した。このような磁化の異方性はほとんど知られておらず、遅い磁化緩和の機構解明に役に立つ事例であると考えている。, kaken
  • Grant-in-Aid for Scientific Research (B), 01 Apr. 2011, 31 Mar. 2016, 23350067, Detailed study of the slow magnetic relaxation phenomena of lanthanide-based single molecule magnets, Kajiwara Takashi; KATAOKA Yumiko, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara Women's University, 18070000, 13900000, 4170000, Paramagnetic complexes which show slow magnetic relaxation phenomena are known as single-molecule magnets (SMMs). In this work, we have proposed the mechanism of the slow relaxation of the magnetization for each lanthanide(III) ion, and synthesized several single-molecular magnets including Ce(III), Nd(III), Tb(III), Dy(III), Er(III), or Yb(III). Due to the characteristic 4f electrons, lanthanide(III) ions have large total angular momentum J and magnetic anisotropy. In the anisotropic ligand field, J ground state splits into Jz sub-states and in some cases, the Jz sub-states which direct along the z-axis were stabilized compared with other sub-state. This situation is known as Ising-type magnetic anisotropy. We have proposed how to design such an Ising-type anisotropy for each Ln(III) ion, and investigated the detail of slow magnetic relaxation features of the synthesized Ln(III) complexes., kaken
  • Grant-in-Aid for Challenging Exploratory Research, 01 Apr. 2012, 31 Mar. 2015, 24655127, Detailed study of the magnetic-structure of lanthanide-based single molecule magnets by neutron scattering method, KAJIWARA Takashi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara Women's University, 3900000, 3000000, 900000, Lanthanide(III) complexes which show a slow magnetic relaxation phenomenon are called as lanthanide-based single molecule magnets, SMMs. In this work, we have investigated the detail of the spin-flipping process of SMMs by means of the inelastic neutron scattering method. The application of neutron scattering on the soft materials such as SMMs was rather rare, and we have first explored the complexes which show SMM behavior being suitable for such a measurement. After detailed study of magnetic properties of candidates, we have synthesized two samples of which all hydrogen atoms were exchanged with deuterium (C40D39N8O11S2Zn2Ln、>98% atom D), and neutron scattering experiments were carried out at Cold-Neutron Disk-Chopper Spectrometer : AMATERAS, J-PARC, Tokai-mura. The analyses of the scattering data are now ongoing., kaken
  • Grant-in-Aid for Scientific Research (C), 2010, 2012, 22550053, Materials chemistry of uranium complexes with one-axis symmetry, SATOH Isamu; YAMAMURA Tomoo; LI Dexin; KAJIWARA Takashi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Tohoku University, 4680000, 3600000, 1080000, Many of the uranium complexes at their oxidation states of +5 (5f1 electron configuration), +4 (5f2 configuration), and +3 (5f3 configuration) have ligand field of Cn with an-axis symmetry. Our experimental investigation were achieved by synthesis of uranium complexes with such variety of oxidation state and electronic configuration and discussed on the ligand field states on ground state., kaken
  • Grant-in-Aid for Scientific Research (C), 2008, 2010, 20550054, Tuning of the Physical Properties of Fe(II/III) Single-Chain Magnet, KAJIWARA Takashi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Tohoku University, 4680000, 3600000, 1080000, A family of single-chain magnets, of which the SCM character originated from the spatial arrangement of high spin Fe^ ions with easy-plane anisotropy, was synthesized and their magnetic properties were investigated., kaken
  • 2008, 2008, 20900108, Synthetic and magnetic studies of Lanthanide based Single-molecule Magnets, KAJIWARA Takashi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Tohoku University, 個々の分子が磁石として振る舞う単分子磁石(single molecule magnet, SMM)の合成に際し, 重希土類金属イオンを用いる手法が注目を集めている. 本研究ではTb(III), Dy(III), Ho(III)等の希土類イオンに着目し, 磁気異方性発現のメカニズムと強化について結晶場の設計という観点から詳細の解明を試み, 分子設計によって磁気異方性と単分子磁石挙動をコントロールするための新たな手法について提示した., kaken


Copyright © MEDIA FUSION Co.,Ltd. All rights reserved.