| 金川 慎治（かねがわ しんじ） | データ更新日：2024.04.04 |
助教 ／
先導物質化学研究所
物質基盤化学部門
| 1. | P. Sadhukhan, S. Q. Wu, S. Kanegawa, S. Q. Su, X. P. Zhang, T. Nakanishi, J. I. Long, K. G. Gao, R. Shimada, H. Okajima, A. Sakamoto, J. G. Chiappella, M. S. Huzan,T. Kroll, D. Sokaras, M. L. Baker, O. Sato, Energy conversion and storage via photoinduced polarization change in non-ferroelectric molecular [CoGa] crystals, NATURE COMMUNICATIONS, 10.1038/s41467-023-39127-8, 14, 1, 3394, 2023.06, To alleviate the energy and environmental crisis, in the last decades, energy harvesting by utilizing optical control has emerged as a promising solution. Here we report a polar crystal that exhibits photoenergy conversion and energy storage upon light irradiation. The polar crystal consists of dinuclear [CoGa] molecules, which are oriented in a uniform direction inside the crystal lattice. Irradiation with green light induces a directional intramolecular electron transfer from the ligand to a low-spin Co-III centre, and the resultant light-induced high-spin Co-II excited state is trapped at low temperature, realizing energy storage. Additionally, electric current release is observed during relaxation from the trapped light-induced metastable state to the ground state, because the intramolecular electron transfer in the relaxation process is accompanied with macroscopic polarization switching at the single-crystal level. It demonstrates that energy storage and conversion to electrical energy is realized in the [CoGa] crystals, which is different from typical polar pyroelectric compounds that exhibit the conversion of thermal energy into electricity. Energy harvesting by utilizing optical control has emerged as a promising solution to alleviate energy and environmental crisis. However, it is challenging to realise nano-scale energy storage and conversion in the same material. Here the authors report a nonferroelectric molecular [CoGa] crystal that uses light as an external stimulus to exhibit photoenergy conversion and energy storage properties.. |
| 2. | Su, Sheng-Qun; Wu, Shu-Qi; Huang, Yu-Bo; Xu, Wen-Huang; Gao, Kai-Ge; Okazawa, Atsushi; Okajima, Hajime; Sakamoto, Akira; Kanegawa, Shinji; Sato, Osamu, Photoinduced Persistent Polarization Change in a Spin Transition Crystal, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.202208771, 61, 39, 2022.09. |
| 3. | Cheng, Feng; Wu, Shuqi; Zheng, Wenwei; Su, Shengqun; Nakanishi, Takumi; Xu, Wenhuang; Sadhukhan, Pritam;Sejima, Hibiki; Ikenaga, Shimon; Yamamoto, Kaoru; Gao, Kaige; Kanegawa, Shinji; Sato, Osamu, Macroscopic Polarization Change of Mononuclear Valence Tautomeric Cobalt Complexes Through the Use of Enantiopure Ligand, CHEMISTRY-A EUROPEAN JOURNAL, 10.1002/chem.202202161, 28, 59, 2022.10. |
| 4. | Sadhukhan, Pritam; Wu, Shu-Qi; Long, Jeremy Ian; Nakanishi, Takumi; Kanegawa, Shinji; Gao, Kaige; Yamamoto, Kaoru; Okajima, Hajime; Sakamoto, Akira; Baker, Michael L.; Kroll, Thomas; Sokaras, Dimosthenis; Okazawa, Atsushi; Kojima, Norimichi; Shiota, Yoshihito; Yoshizawa, Kazunari; Sato, Osamu, Manipulating electron redistribution to achieve electronic pyroelectricity in molecular [FeCo] crystals, NATURE COMMUNICATIONS, 10.1038/s41467-021-25041-4, 12, 1, 2021.08. |
| 5. | Sheng Qun Su, Shu Qi Wu, Michael L. Baker, Peter Bencok, Nobuaki Azuma, Yuji Miyazaki, Motohiro Nakano, Soonchul Kang, Yoshihito Shiota, Kazunari Yoshizawa, Shinji Kanegawa, Osamu Sato, Quenching and Restoration of Orbital Angular Momentum through a Dynamic Bond in a Cobalt(II) Complex, Journal of the American Chemical Society, 10.1021/jacs.0c02257, 142, 26, 11434-11441, 2020.07, [URL], Orbital angular momentum plays a vital role in various applications, especially magnetic and spintronic properties. Therefore, controlling orbital angular momentum is of paramount importance to both fundamental science and new technological applications. Many attempts have been made to modulate the ligand-field-induced quenching effects of orbital angular momentum to manipulate magnetic properties. However, to date, reported changes in the magnitude of orbital angular momentum are small in both molecular and solid-state magnetic materials. Moreover, no effective methods currently exist to modulate orbital angular momentum. Here we report a dynamic bond approach to realize a large change in orbital angular momentum. We have developed a Co(II) complex that exhibits coordination number switching between six and seven. This cooperative dynamic bond switching induces considerable modulation of the ligand field, thereby leading to substantial quenching and restoration of the orbital angular momentum. This switching mechanism is entirely different from those of spin-crossover and valence tautomeric compounds, which exhibit switching in spin multiplicity.. |
| 6. | Hikaru Kuramochi, Genki Aoyama, Hajime Okajima, Akira Sakamoto, Shinji Kanegawa, Osamu Sato, Satoshi Takeuchi, Tahei Tahara, Femtosecond Polarization Switching in the Crystal of a [CrCo] Dinuclear Complex, Angewandte Chemie - International Edition, 10.1002/anie.202004583, 59, 37, 15865-15869, 2020.09, [URL], Capability to control macroscopic molecular properties with external stimuli offers the possibility to exploit molecules as switching devices of various types. However, application of such molecular-level switching has often been limited by its speed and thus efficiency. Herein, we demonstrate ultrafast, photoinduced polarization switching in the crystal of a [CrCo] dinuclear complex by ultrafast pump–probe spectroscopy in the visible and mid-infrared regions. The photoinduced polarization switching was found to have a time constant of 280 fs, which makes the [CrCo] complex crystal the fastest polarization-switching material realized using the metastable state. Moreover, the pump–probe data in the visible region reveal the pronounced appearance of coherent nuclear wavepacket motion with a frequency as low as 22 cm−1, which we attribute to a lattice vibrational mode. The pronounced non-Condon effect for its resonance Raman enhancement implies that this mode couples the relevant electronic states, thereby facilitating the ultrafast polarization switching.. |
| 7. | Shu Qi Wu, Meijiao Liu, Kaige Gao, Shinji Kanegawa, Yusuke Horie, Genki Aoyama, Hajime Okajima, Akira Sakamoto, Michael L. Baker, Myron S. Huzan, Peter Bencok, Tsukasa Abe, Yoshihito Shiota, Kazunari Yoshizawa, Wenhuang Xu, Hui Zhong Kou, Osamu Sato, Macroscopic Polarization Change via Electron Transfer in a Valence Tautomeric Cobalt Complex, Nature communications, 10.1038/s41467-020-15988-1, 11, 1, 2020.12, [URL], Polarization change induced by directional electron transfer attracts considerable attention owing to its fast switching rate and potential light control. Here, we investigate electronic pyroelectricity in the crystal of a mononuclear complex, [Co(phendiox)(rac-cth)](ClO<sub>4</sub>)·0.5EtOH (1·0.5EtOH, H<sub>2</sub>phendiox = 9, 10-dihydroxyphenanthrene, rac-cth = racemic 5, 5, 7, 12, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane), which undergoes a two-step valence tautomerism (VT). Correspondingly, pyroelectric current exhibits double peaks in the same temperature domain with the polarization change consistent with the change in dipole moments during the VT process. Time-resolved Infrared (IR) spectroscopy shows that the photo-induced metastable state can be generated within 150 ps at 190 K. Such state can be trapped for tens of minutes at 7 K, showing that photo-induced polarization change can be realized in this system. These results directly demonstrate that a change in the molecular dipole moments induced by intramolecular electron transfer can introduce a macroscopic polarization change in VT compounds.. |
| 8. | Junqiu Li, Shuqi Wu, Shengqun Su, Shinji Kanegawa, Osamu Sato, Manipulating Slow Magnetic Relaxation by Light in a Charge Transfer {Fe2Co} Complex, Chemistry - A European Journal, 10.1002/chem.202000154, 26, 15, 3259-3263, 2020.03, [URL], Some cyanide-bridged complexes are known for exhibiting slow magnetic relaxation behavior in a light-induced metastable state. Herein, an unexpected reverse effect is observed for the first time in the S= (Formula presented.) {FeII LS-CoIII LS-FeIII LS} (HS=high spin, LS=low spin) ground state of a novel V-shaped trinuclear cyanide-bridged {Fe2Co} complex. In this complex, light-switchable iron-cobalt charge transfer with repeatable off/on switching of slow magnetic relaxation is discovered upon alternating laser irradiation at 785 and 560 nm. An important characteristic of the present compound is that the S= (Formula presented.) ground state exhibits slow magnetic relaxation before irradiation, whereas this is accelerated after irradiation. This is different from the typical behavior, where the light-induced metastable state exhibits slow magnetic relaxation.. |
| 9. | Wei Huang, Shuqi Wu, Xiangwei Gu, Yao Li, Atsushi Okazawa, Norimichi Kojima, Shinya Hayami, Michael L. Baker, Peter Bencok, Mariko Noguchi, Yuji Miyazaki, Motohiro Nakano, Takumi Nakanishi, Shinji Kanegawa, Yuji Inagaki, Tatsuya Kawae, Gui Lin Zhuang, Yoshihito Shiota, Kazunari Yoshizawa, Dayu Wu, Osamu Sato, Temperature dependence of spherical electron transfer in a nanosized [Fe14] complex, Nature communications, 10.1038/s41467-019-13279-y, 10, 1, 2019.12, [URL], The study of transition metal clusters exhibiting fast electron hopping or delocalization remains challenging, because intermetallic communications mediated through bridging ligands are normally weak. Herein, we report the synthesis of a nanosized complex, [Fe(Tp)(CN)3]8[Fe(H2O)(DMSO)]6 (abbreviated as [Fe14], Tp−, hydrotris(pyrazolyl)borate; DMSO, dimethyl sulfoxide), which has a fluctuating valence due to two mobile d-electrons in its atomic layer shell. The rate of electron transfer of [Fe14] complex demonstrates the Arrhenius-type temperature dependence in the nanosized spheric surface, wherein high-spin centers are ferromagnetically coupled, producing an S = 14 ground state. The electron-hopping rate at room temperature is faster than the time scale of Mössbauer measurements (−8 s). Partial reduction of N-terminal high spin FeIII sites and electron mediation ability of CN ligands lead to the observation of both an extensive electron transfer and magnetic coupling properties in a precisely atomic layered shell structure of a nanosized [Fe14] complex.. |
| 10. | Narita Masahiro, Teraoka Takaaki, Murafuji Toshihiro, Shiota Yoshihito, Yoshizawa Kazunari, Mori Shigeki, Uno Hidemitsu, Kanegawa Shinji, Sato Osamu, Goto, Kenta, Tani Fumito, An Azulene-Based Chiral Helicene and Its Air-Stable Cation Radical, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 10.1246/bcsj.20190219, 92, 11, 1867-1873, 2019.11. |
| 11. | Takahiro Inatomi, Yukino Fukahori, Yuji Yamada, Ryuta Ishikawa, Shinji Kanegawa, Yuji Koga, Kouki Matsubara, Ni(i)-Ni(iii) cycle in Buchwald-Hartwig amination of aryl bromide mediated by NHC-ligated Ni(i) complexes, Catalysis Science and Technology, 10.1039/c8cy02427h, 9, 8, 1784-1793, 2019.01, [URL], Intermediate amide complexes of NHC-ligated monovalent nickel in Buchwald-Hartwig amination of aryl halides were isolated and structurally characterized. The amide complexes reacted with aryl bromide to form a cross-coupling product. Lowerature observation of the oxidative addition product of the Ni(i) amide complex with aryl bromide indicated the presence of a Ni(iii) intermediate. The results showed that a well-defined mononuclear NHC-Ni(i) complex can act as a key intermediate in homogeneous catalysis.. |
| 12. | Yao, Zi-Shuo, Wu, Shu-Qi, Kitagawa, Yasutaka, Ni, Zhong-Hai, Nojiri, Hiroyuki, 塩田 淑仁, 吉澤 一成, KANG SOONCHUL, 金川 慎治, 佐藤 治, Anisotropic Change in the Magnetic Susceptibility of a Dynamic Single Crystal of a Cobalt(II) Complex, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.201606165, 56, 3, 717-721, 2017.01. |
| 13. | 金川 慎治, 塩田 淑仁, KANG SOONCHUL, Takahashi, Kazuyuki, Okajima, Hajime, Sakamoto, Akira, Iwata, Tatsuya, Kandori, Hideki, 吉澤 一成, 佐藤 治, Directional Electron Transfer in Crystals of [CrCo] Dinuclear Complexes Achieved by Chirality-Assisted Preparative Method, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/jacs.6b05089, 138, 43, 14170-14173, 2016.11. |
| 14. | Huang, You-Gui, 塩田 淑仁, Su, Sheng-Qun, Wu, Shu-Qi, Yao, Zi-Shuo, Li, Guo-Ling, 金川 慎治, KANG SOONCHUL, 蒲池 高志, 吉澤 一成, 佐藤 治, Thermally Induced Intra-Carboxyl Proton Shuttle in a Molecular Rack-and-Pinion Cascade Achieving Macroscopic Crystal Deformation, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.201607886, 55, 47, 14628-14632, 2016.11. |
| 15. | Li, Guo-Ling, 金川 慎治, Yao, Zi-Shuo, Su, Sheng-Qun, Wu, Shu-Qi, Huang, You-Gui, KANG SOONCHUL, 佐藤 治, Influence of Intermolecular Interactions on Valence Tautomeric Behaviors in Two Polymorphic Dinuclear Cobalt Complexes, CHEMISTRY-A EUROPEAN JOURNAL, 10.1002/chem.201603817, 22, 48, 17130-17135, 2016.11. |
| 16. | Kouki Matsubara, Yukino Fukahori, Takahiro Inatomi, Saeko Tazaki, Yuji Yamada, Yuji Koga, Shinji Kanegawa, Toshikazu Nakamura, Monomeric three-coordinate N-heterocyclic carbene nickel(I) complexes Synthesis, structures, and catalytic applications in cross-coupling reactions, Organometallics, 10.1021/acs.organomet.6b00419, 35, 19, 3281-3287, 2016.10, [URL], A series of three-coordinate monovalent nickel halide complexes bearing N-heterocyclic carbene (NHC) ligands, i.e., NiCl(IPr)(L) [L = pyridine, P(OPh)3, bis(diphenylphosphino)butane (dppb), IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene], NiX(IMes)(PPh3) (X = Cl and Br, IMes = 1,3-bis(mesityl)imidazol-2-ylidene), were prepared. The complexes were identified using NMR spectroscopy, superconducting quantum interference device (SQUID), and X-ray crystallography. Additionally, ESR spectra of NiCl(IPr)(pyridine) were taken in toluene. These complexes had three-coordinate Y-shaped geometries in both the solid and solution states. The compounds containing IPr showed equilibrium between the monomeric and dimeric forms, with liberation of ligands. Addition of 1,2-bis(diphenylphosphino)ethane and 1,3-bis(diphenylphosphino)propane to the dinickel(I) IPr complex instead of dppb resulted in heterolytic cleavage to nickel(0) and nickel(II) species. Catalysis of Suzuki cross-coupling and Buchwald-Hartwig amination of aryl bromide using the complexes was investigated. The efficiencies in the amination of aryl bromide depended strongly on the additional donor ligands.. |
| 17. | Huang, You-Gui, 塩田 淑仁, Wu, Ming-Yan, Su, Sheng-Qun, Yao, Zi-Shuo, KANG SOONCHUL, 金川 慎治, Li, Guo-Ling, Wu, Shu-Qi, 蒲池 高志, 吉澤 一成, Ariga, Katsuhiko, Hong, Mao-Chun, 佐藤 治, Superior thermoelasticity and shape-memory nanopores in a porous supramolecular organic framework, NATURE COMMUNICATIONS, 10.1038/ncomms11564, 7, 2016.05, Flexible porous materials generally switch their structures in response to guest removal or incorporation. However, the design of porous materials with empty shape-switchable pores remains a formidable challenge. Here, we demonstrate that the structural transition between an empty orthorhombic phase and an empty tetragonal phase in a flexible porous dodecatuple intercatenated supramolecular organic framework can be controlled cooperatively through guest incorporation and thermal treatment, thus inducing empty shape-memory nanopores. Moreover, the empty orthorhombic phase was observed to exhibit superior thermoelasticity, and the molecular-scale structural mobility could be transmitted to a macroscopic crystal shape change. The driving force of the shape-memory behaviour was elucidated in terms of potential energy. These two interconvertible empty phases with different pore shapes, that is, the orthorhombic phase with rectangular pores and the tetragonal phase with square pores, completely reject or weakly adsorb N-2 at 77 K, respectively.. |
| 18. | Zhang, Kuirun, KANG SOONCHUL, Yao, Zi-shuo, Nakamura, Kazusa, Yamamoto, Takashi, Einaga, Yasuaki, Azuma, Nobuaki, Miyazaki, Yuji, Nakano, Motohiro, 金川 慎治, 佐藤 治, Charge-Transfer Phase Transition of a Cyanide-Bridged Fe-II/Fe-III Coordination Polymer, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 10.1002/anie.201601526, 55, 20, 6047-6050, 2016.05, Heterometallic Prussian blue analogues are known to exhibit thermally induced charge transfer, resulting in switching of optical and magnetic properties. However, charge-transfer phase transitions have not been reported for the simplest FeFe cyanide-bridged systems. A mixed-valence Fe-II/Fe-III cyanide-bridged coordination polymer, {[Fe(Tp)(CN)(3)](2)Fe(bpe)5H(2)O}(n), which demonstrates a thermally induced charge-transfer phase transition, is described. As a result of the charge transfer during this phase transition, the high-spin state of the whole system does not change to a low-spin state. This result is in contrast to FeCo cyanide-bridged systems that exhibit charge-transfer-induced spin transitions. キーワード. |
| 19. | 砂田 祐輔, Ishida, Shintaro, Hirakawa, Fumiya, 塩田 淑仁, 吉澤 一成, 金川 慎治, 佐藤 治, 永島 英夫, Iwamoto, Takeaki, Persistent four-coordinate iron-centered radical stabilized by pi-donation, CHEMICAL SCIENCE, 10.1039/c5sc02601f, 7, 1, 191-198, 2016.01, Dinuclear iron carbonyl complex 2, which contains an elongated unsupported Fe-Fe bond, was synthesized by the reaction between Fe-2(CO)(9) and phosphinyl radical 1. Thermal Fe-Fe bond homolysis led to the generation of a four-coordinate carbonyl-based iron-centered radical, 3, which is stabilized by pi-donation. Complex 3 exhibited high reactivity toward organic radicals to form diamagnetic five-coordinate Fe(II) complexes.. |
| 20. | KANG SOONCHUL, 塩田 淑仁, Kariyazaki, Akira, 金川 慎治, 吉澤 一成, 佐藤 治, Heterometallic Fe-III/K Coordination Polymer with a Wide Thermal Hysteretic Spin Transition at Room Temperature, CHEMISTRY-A EUROPEAN JOURNAL, 10.1002/chem.201503392, 22, 2, 532-538, 2016.01, The anionic Fe-III complex exhibiting cooperative spin transition with a wide thermal hysteresis near room temperature, K[Fe(5-Brthsa)(2)] (5-Brthsa-H-2=5-bromosalicylaldehyde thiosemicarbazone), is reported. The hysteresis (Delta=69 K in the first cycle) shows a one-step transition in heating mode and a two-step transition in cooling mode. X-ray structure analysis showed that the coexistence of hydrogen bond and cation-pi interactions, as well as alkali metal coordination bonds, to give 2D coordination polymer structure. This result is contrary to previous reports of broad thermal hysteresis induced by coordination bonds of FeII spin crossover coordination polymers (with 1D/3D structures), and by strong intermolecular interactions in the molecular packing through pi-pi stacking or hydrogen-bond networks. As a consequence, the importance, or the very good suitability of alkali metal-based coordination bonds and cation-pi interactions for communicating cooperative interactions in spin-crossover (SCO) compounds must be reconsidered.. |
| 21. | Soonchul Kang, Yoshihito Shiota, Akira Kariyazaki, Shinji Kanegawa, Kazunari Yoshizawa, Osamu Sato, Frontispiece Heterometallic FeIII/K Coordination Polymer with a Wide Thermal Hysteretic Spin Transition at Room Temperature, Chemistry - A European Journal, 10.1002/chem.201680262, 22, 2, 2016.01, [URL], The FeIII anionic complex exhibiting cooperative spin transition with a wide thermal hysteresis near room temperature, K[Fe(5-Brthsa)2] (5-Brthsa-H2=5-bromosalicylaldehyde thiosemicarbazone), is reported. The hysteresis shows a one-step transition in heating mode and a two-step transition in cooling mode. X-ray structure analysis shows the coexistence of hydrogen bond and cation-π interactions, along with metal coordination bonds, to give 2D coordination polymer structure.. |
| 22. | Su, Sheng-Qun, 蒲池 高志, Yao, Zi-Shuo, Huang, You-Gui, 塩田 淑仁, 吉澤 一成, Azuma, Nobuaki, Miyazaki, Yuji, Nakano, Motohiro, Maruta, Goro, Takeda, Sadamu, KANG SOONCHUL, 金川 慎治, 佐藤 治, Assembling an alkyl rotor to access abrupt and reversible crystalline deformation of a cobalt(II) complex, NATURE COMMUNICATIONS, 10.1038/ncomms9810, 6, 2015.11, Harnessing molecular motion to reversibly control macroscopic properties, such as shape and size, is a fascinating and challenging subject in materials science. Here we design a crystalline cobalt(II) complex with an n-butyl group on its ligands, which exhibits a reversible crystal deformation at a structural phase transition temperature. In the low-temperature phase, the molecular motion of the n-butyl group freezes. On heating, the n-butyl group rotates ca. 100 degrees around the C-C bond resulting in 6-7% expansion of the crystal size along the molecular packing direction. Importantly, crystal deformation is repeatedly observed without breaking the single-crystal state even though the shape change is considerable. Detailed structural analysis allows us to elucidate the underlying mechanism of this deformation. This work may mark a step towards converting the alkyl rotation to the macroscopic deformation in crystalline solids. |
| 23. | KANG SOONCHUL, 金川 慎治, 塩田 淑仁, 吉澤 一成, 佐藤 治, A ferromagnetically coupled Fe-42 cyanide-bridged nanocage, Nature Communications, 10.1038/ncomms6955, 6, 2015.01. |
| 24. | Zi Shuo Yao, Masaki Mito, Takashi Kamachi, Yoshihito Shiota, Kazunari Yoshizawa, Nobuaki Azuma, Yuji Miyazaki, Kazuyuki Takahashi, Kuirun Zhang, Takumi Nakanishi, Soonchul Kang, Shinji Kanegawa, Osamu Sato, Molecular motor-driven abrupt anisotropic shape change in a single crystal of a Ni complex, Nature Chemistry, 10.1038/nchem.2092, 6, 12, 1079-1083, 2014.01, [URL], Many molecular machines with controllable molecular-scale motors have been developed. However, transmitting molecular movement to the macroscopic scale remains a formidable challenge. Here we report a single crystal of a Ni complex whose shape changes abruptly and reversibly in response to thermal changes at around room temperature. Variableerature single-crystal X-ray diffraction studies show that the crystalline shape change is induced by an unusual 90° rotation of uniaxially aligned oxalate molecules. The oxalate dianions behave as molecular-scale rotors, with their movement propagated through the entire crystalline material via intermolecular hydrogen bonding. Consequently, the subnanometre-scale changes in the oxalate molecules are instantly amplified to a micrometre-scale contraction or expansion of the crystal, accompanied by a thermal hysteresis loop. The shape change in the crystal was clearly detected under an optical microscope. The large directional deformation and prompt response suggest a role for this material in microscale or nanoscale thermal actuators.. |
| 25. | Tao Liu, Hui Zheng, KANG SOONCHUL, Yoshihito Shiota, Shinya Hayami, Masaki Mito, Osamu Sato, Kazunari Yoshizawa, Shinji Kanegawa, Chunying Duan, A light-induced spin crossover actuated single-chain magnet, NATURE COMMUNICATIONS, 10.1038/ncomms3826, 4, 2013.11, Both spin-crossover complexes and molecular nanomagnets display bistable magnetic states, potentially behaving as elementary binary units for information storage. It is a challenge to introduce spin-crossover units into molecular nanomagnets to switch the bistable state of the nanomagnets through external stimuli-tuned spin crossover. Here we report an iron(II) spin-crossover unit and paramagnetic iron(III) ions that are incorporated into a well-isolated double-zigzag chain. The chain exhibits thermally induced reversible spin-crossover and light-induced excited spin-state trapping at the iron(II) sites. Single-chain magnet behaviour is actuated accompanying the synergy between light-induced excited spin-state trapping at the iron(II) sites and ferromagnetic interactions between the photoinduced high-spin iron(II) and low-spin iron(III) ions in the chain. The result provides a strategy to switch the bistable state of molecular nanomagnets using external stimuli such as light and heat, with the potential to erase and write information at a molecular level.. |
| 26. | Zhao Yang Li, Jing Wei Dai, Kevin J. Gagnon, Hong Ling Cai, Takashi Yamamoto, Yasuaki Einaga, Han Hua Zhao, Shinji Kanegawa, Osamu Sato, Kim R. Dunbar, Ren Gen Xiong, A neutral Fe(iii) compound exhibiting a two-step spin transition and dielectric anomalies, Dalton Transactions, 10.1039/c3dt51554k, 42, 41, 14685-14688, 2013.11, [URL], The mononuclear ferric compound Fe(H-5-Cl-thsa-Me)(5-Cl-thsa-Me) ·H2O (1) was synthesized and characterized using powder/single-crystal X-ray diffraction, Mössbauer spectroscopy, differential scanning calorimetry (DSC), and magnetic susceptibility measurements. This photo-responsive compound shows reversible, two-step spin-crossover behaviour. Moreover, dielectric anomalies were observed during the spin transitions, demonstrating the multifunctional properties of compound 1.. |
| 27. | Zhao-Yang Li, Jing-Wei Dai, Yoshihito Shiota, Kazunari Yoshizawa, Shinji Kanegawa, Osamu Sato, Multi-Step Spin Crossover Accompanied by Symmetry Breaking in an Fe-III Complex: Crystallographic Evidence and DFT Studies, CHEMISTRY-A EUROPEAN JOURNAL, 10.1002/chem.201302272, 19, 39, 12948-12952, 2013.09. |
| 28. | Dai Jingwei, Shinji Kanegawa, Li Zhaoyang, KANG SOONCHUL, Osamu Sato, A Switchable Complex Ligand Exhibiting Photoinduced Valence Tautomerism, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 10.1002/ejic.201300531, 2013, 24, 4150-4153, 2013.08. |
| 29. | Shinji Kanegawa, KANG SOONCHUL, Osamu Sato, Preparation and Valence Tautomeric Behavior of a Cobalt-Dioxolene Complex with a New TTF-functionalized Phenanthroline Ligand, CHEMISTRY LETTERS, 10.1246/cl.130118, 42, 7, 700-702, 2013.07. |
| 30. | Atsushi Tashiro, Shinji Kanegawa, Osamu Sato, Yoshio Teki, ESR study of light-induced valence tautomerism of a Co mononuclear complex [Co(phen)(3,5-DTBSQ)(3,5-DTBCat)], Polyhedron, 10.1016/j.poly.2013.03.039, 66, 167-170, 2013.04, [URL], Light-induced valence tautomerism (LIVT) and the relaxation process of a mononuclear complex, [Co(phen)(3,5-DTBSQ)(3,5-DTBCat)] (1) (phen = 1,10-phenanthroline, 3,5-DTBSQ = 3,5-di-tert-butyl-semiquinone, 3,5-DTBCat = 3,5-di-tert-butyl-catechol) were investigated by monitoring the ESR signal of the semiquinonate radical both in powder sample and in the sample diluted in butyronitrile or benzene glass matrix. LIVT phenomena were observed in all samples. The ESR signal decay and the relaxation in the glass matrixes were well analyzed by double exponential fitting, indicating the possibility of two-step mechanism in the LIVT process.. |
| 31. | Shinji Kanegawa, KANG SOONCHUL, Osamu Sato, Spin Crossover Behavior of Dinuclear Fe-II Complexes with Bis-Tetradentate Bridging-Type Ligands, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 10.1002/ejic.201201069, 5-6, 725-729, 2013.02. |
| 32. | Zhao Yang Li, Osamu Sato, Zi Shuo Yao, Soonchul Kang, Shinji Kanegawa, Multifunctional Materials Combining Spin-Crossover with Conductivity and Magnetic Ordering, Spin-Crossover Materials: Properties and Applications, 10.1002/9781118519301.ch11, 303-319, 2013.01, [URL], This chapter introduces compounds synthesized to develop new spin-crossover conductors, in which spin-crossover phenomena and conductivity coexist or interact. It also introduces spin-crossover magnets, in which spin-crossover phenomena and magnetic interaction coexist or interact. A possible route for the synthesis of multifunctional materials exhibiting spin-crossover and conductivity is the preparation of double salts, by combining spin-crossover cations/anions and conducting molecular anions/cations through electrostatic interactions. Another route is the preparation of a spin-crossover complex with a potentially conducting ligand. The preparation of spin-crossover conductors in which conductivity and light-induced excited spin state trapping (LIESST) exhibit synergistic effects is desired. Multifunctional materials exhibiting both spin-crossover and magnetic interaction are achieved by combining a spin-crossover cation/anion with an anionic/cationic magnetic framework. Another route is the incorporation of spin-crossover sites into magnetic frameworks. This edition first published 2013. |
| 33. | KANG SOONCHUL, Shinji Kanegawa, Osamu Sato, Slow magnetic relaxation in a 4,2-ribbon like Fe-III Co-2(II) heterobimetallic chain, DALTON TRANSACTIONS, 10.1039/c2dt31168b, 41, 44, 13575-13577, 2012.09. |
| 34. | Kensuke Murashima, Takeaki Watanabe, Shinji Kanegawa, Daisuke Yoshihara, Yuji Inagaki, Satoru Karasawa, Noboru Koga, Preparations, crystal structures, and magnetic properties of N, N-dipyridylaminoxyl as a new magnetic coupler and its one-dimensional cobalt(II) chains, Inorganic chemistry, 10.1021/ic202397m, 51, 9, 4982-4993, 2012.05, [URL], N,N-Dipyridilaminoxyl, NOpy 2, having a stable aminoxyl, was prepared as a new magnetic coupler for heterospin systems. Solutions of NOpy 2 were mixed with those of bis{1,1,1,5,5,5, hexafluoro-4- (phenylimino)-2-pentanonate}cobalt derivatives, Co(hfpip-X) 2, at a 1:1 ratio to afford the polymeric cobalt(II) complexes, [Co(hfpip-X) 2(NOpy 2)] n; X = H (1), F (2), F 3 (3), F 5 (4), Cl (5), Cl 3 (6), Br (7), and I (8) as single crystals. In all complexes, the local structures of the cobalt-complex units were compressed octahedra and the pyridine ligands in NOpy 2 units coordinated to the cobalt ions in trans configuration to form linear chains for 1-4 and in cis configuration to form helical chains for 5-8. In the chains, the aminoxyl in NOpy 2 ferromagnetically interacted with the cobalt ions to produce the ferromagnetic chains with J intra/k B = 9-14 K. In the magnetic susceptibility experiments of aligned sample of 6, the magnetic easy axis was determined to be the a* axis, which was the direction perpendicular to the b axis of the chain axis. The resulting chains, all except 4, interacted antiferromagnetically among each other, and especially in 1, 5, 7, and 8, the magnetic behaviors characteristic to canted two-dimensional (2D) antiferromagnets with T c = 5.6, 4.0, 4.0, and 6.2 K, respectively, were observed. All complexes showed slow magnetic relaxations affected by the interchain antiferromagnetic interaction. The effective activation barriers, Δ eff/k B, for the reorientation of the magnetism for all complexes except 4 were estimated to be 25-39 K in the presence of a direct current (dc) field.. |
| 35. | Dong, DP; Liu, T; Kanegawa, S; Kang, S; Sato, O; He, C ; Duan, CY, Photoswitchable Dynamic Magnetic Relaxation in a Well-Isolated {Fe2Co} Double-Zigzag Chain, Angewandte Chemie International Edition, 10.1002/anie.201105987, 52, 21, 5119, 2012.04, Charge-transfer-induced spin transition occurs cooperatively and reversibly in the isolated FeIII2CoII chains of {[Fe(pzTp)(CN)3]2Co(4-styrylpyridine)2}⋅2 H2O ⋅2 CH3OH (1). When 1 is irradiated with 532 nm light, it shows single-chain magnetic behavior with no antiferromagnetic ordering after irradiation (see picture; C gray, N blue, B yellow; LS=low spin, HS=high spin).. |
| 36. | Liu, T; Dong, DP; Kanegawa, S; Kang, S; Sato, O; Shiota, Y; Yoshizawa, K; Hayami, S; Wu, S; He, C; Duan, CY , Reversible Electron Transfer in a Linear {Fe2Co} Trinuclear Complex Induced by Thermal Treatment and Photoirraditaion, Angewandte Chemie International Edition, 10.1002/anie.201201305, 51, 18, 4367, 2012.03, A linear cyanido-bridged Fe2Co compound (see picture) exhibits a reversible, thermally induced cooperative charge transfer transition accompanying spin transition and polar–nonpolar transformation in the trinuclear cluster. The change in magnetic properties and polarity could also be induced by irradiation with light.. |
| 37. | Yoshio Teki, Mugen Shirokoshi, Shinji Kanegawa, Osamu Sato, ESR study of light-induced valence tautomerism of a dinuclear Co complex, European Journal of Inorganic Chemistry, 10.1002/ejic.201100467, 25, 3761-3767, 2011.09, [URL], Light-induced valence tautomerism (LIVT) of a dinuclear complex, [{Co(dpqa)}2(dhbq)](PF6)3 (1), was investigated by ESR analysis of dhbq3-. LIVT phenomena were observed in the sample diluted in the glass matrix as well as that in powder form. The signal decay and the relaxation were analyzed by double exponential fitting; the results suggest a two-step mechanism. Quantum mechanical tunneling was clearly observed in the glass matrix. Light-induced valence tautomerism (LIVT) of a dinuclear complex, [{Co(dpqa)}2(dhbq)](PF6)3 (1), was investigated by ESR analysis of dhbq3-. LIVT phenomena were observed in the glass matrix as well as in the powder sample. The signal decay and the relaxation, analyzed by double exponential fitting, suggest a two-step mechanism. Quantum tunneling phenomena were clearly observed in the glass matrix.. |
| 38. | H. Xu, G. Juhász, K. Yoshizawa, M. Takahashi, S. Kanegawa, *O. Sato,, “Mixed-metal complex [Fe(bipe)(Au(CN)2)2MeOH] with gold clusters: a novel two-dimensional polyrotaxane net clipped by aurophilic interaction”, CrystEngComm, 12, 4045-4047, 2011.06. |
| 39. | Haitao Xu, Gergely Juhász, Kazunari Yoshizawa, Masashi Takahashi, Shinji Kanegawa, Osamu Sato, Mixed-metal complex [Fe(bipe)(Au(CN)2)2·MeOH] with gold clusters A novel two-dimensional polyrotaxane net clipped by aurophilic interaction, CrystEngComm, 10.1039/c0ce00376j, 12, 12, 4031-4034, 2010.12, [URL], A novel two-dimensional mixed-metal coordination polymer, [Fe(bipe)(Au(CN)2)2·MeOH], composed of polyrotaxane with Fe2(bipe)2 loops and rigid [Au(CN)2] - rods, forms a 2D → 2D parallel interpenetrating structure. The two networks are clipped by gold clusters via aurophilic interaction.. |
| 40. | T. Liu, Y.-J. Zhang, S. Kanegawa, *O. Sato, Water-Switching of Spin Transitions Induced by Metal-to-Metal Charge Transfer in a Microporous Framework, Angew. Chem. Int. Ed., 10.1002/anie.201002881, 49, 46, 8645-8648, 2010.11. |
| 41. | Liu, T; Zhang, YJ; Kanegawa, S; Sato, O, Photoinduced Metal-to-Metal Charge Transfer toward Single-Chain Magnet, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/ja1027953, 132, 24, 8250, 2010.06. |
| 42. | Zhang Yan-Juan, Liu Tao, Kanegawa Shinji, Sato Osamu, Interconversion between a Nonporous Nanocluster and a Microporous Coordination Polymer Showing Selective Gas Adsorption, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/ja908670u, 132, 3, 912, 2010.01. |
| 43. | Zhang, Yan-Juan, Liu, Tao, Kanegawa, Shinji, Sato, Osamu, Reversible Single-Crystal-to-Single-Crystal Transformation from Achiral Antiferromagnetic Hexanuclears to a Chiral Ferrimagnetic Double Zigzag Chain , Journal of the American Chemical Society, 10.1021/ja901539y, 131, 23, 7942, 2009.06. |
| 44. | Gergely Juhsz, Ryotaro Matsuda, Shinji Kanegawa, Kaori Inoue, Osamu Sato* and Kazunari Yoshizawa, Bistability of Magnetization without Spin-Transition in a High-Spin Cobalt(II) Complex due to Angular Momentum Quenching , Journal of the American Chemical Society, 10.1021/ja808448j, 131, 13, 4560, 2009.04. |
| 45. | Shinji Kanegawa, Satoru Karasawa, Masataka Maeyama, Motohiro Nakano, and Noboru Koga, Crystal Design of Monometallic Single-Molecule Magnets Consisting of Cobalt-Aminoxyl Heterospins, Journal of the American Chemical Society, 10.1021/ja0767579, 130, 10, 3079-3094, 2008.03. |
| 46. | Shinji Kanegawa, Satoru Karasawa, Motohiro Nakano, Noboru Koga, Magnetic properties of 1:4 complexes of CoIIX2(X = NCO -, NCS -, and Br -) with 4-(N-tert- butylaminoxyl)pyridine. Antiferromagnets in crystalline states and single-molecule magnets in frozen solutions, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.79.1372, 79, 9, 1372-1382, 2006.09, [URL], Three cobalt(II) complexes, [Co(X) 2(4NOpy) 4] (X = NCO -, NCS -, and Br -; 4NOpy = 4-(N-tert-butylaminoxyl)-pyridine) were prepared, and their molecular structures were characterized by X-ray structure analysis. The molecular geometry of [Co(X) 2(4NOpy) 4] (X = NCO - and NCS -) is a compressed octahedron, in which the counter ions occupy the apical positions with short bond distances of 2.064-2.098 Å. In the crystalline state, from plots of χ mol vs T and χ′ mol vs T, [Co(NCO) 2(4NOpy) 4] and [Co(NCS) 2(4NOpy) 4] are antiferromagnets with T N = 4.5 and 15 K, respectively. In frozen solution, on the other hand, both complexes and [Co(Br) 2(4NOpy) 4] functioned as single-molecule magnets. The χ″ mol vs T plot for [Co(Br) 2(4NOpy) 4] gave a effective activation barrier (U eff) of 20 K for the reorientation of the spin. From the field dependence of magnetization at various temperatures below 5 K for [Co(X) 2(4NOpy) 4] (X = NCO -, NCS -, and Br -) the values of the zero-field splitting parameters, D/k B, were estimated to be -14, -9.7, and -4.5 K with S = 5/2, respectively. Theoretical studies based on the ligand-field theory model for [Co(NCO) 2(4NOpy) 4] gave an exchange coupling parameter, J/k B, of 29 K and a thermodynamic activation barrier, U, of 60 K.. |
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