量子ヘテロスピン分子集合系の分子磁性と純有機フェリ磁性体の分子設計

2000 Fiscal Year Annual Research Report

• Project/Area Number: 12740385
• Research Institution: Osaka City University
• Principal Investigator: 塩見 大輔 大阪市立大学, 理学部, 助教授 (40260799)
• Keywords: 有機磁性 / 分子磁性 / フェリ磁性 / 有機塩 / ニトロニルニトロキシド / 量子モンテカルロ法 / 電子スピン共鳴 / 磁化率

Research Abstract

有機フェリ磁性体を構築するための新奇な分子設計アプローチを提案した.それに基づいてモデル分子を合成し,固体集合系の磁気的性質を詳細に調べた.さらに,モデルスピンハミルトニアンを用いた数値計算を行ない,従来の原子ベースの磁性の常識を変える可能性のある新たなスピン整列様式を明らかにした.
1.ハイゼンベルグモデルに基づいた数値計算(厳密対角化法と量子モンテカルロ法)の結果,基底一重項(S=0)のビラジカルがモノラジカル(S=1/2)と相互作用した場合,古典的な予想とは異なり,フェリ磁性が発現する可能性があることを明らかにした.これは,従来の磁性研究分野にはなかった,新しいスピン整列の概念(「スピン0有機フェリ磁性」)である.
2.基底3重項(S=1)のπビラジカルとπモノラジカル(S=1/2)の弱結合系トリラジカルを合成した.X線結晶構造解析によって,1次元フェリ磁性鎖の存在を明らかにした.さらにmKオーダーの極低温領域まで磁化率を測定した結果,純有機物としては初めて,フェリ磁性特有の磁化の発散現象を観測した.
3.スピン多重度の異なる2種類の分子にイオン電荷を持たせ,クーロン力により共結晶化する「有機塩フェリ磁性体」アプローチを提案した.このアプローチのモデル系として,メタフェニレン置換ビラジカルのフェノール誘導体と,そのアニオン(アルカリ金属塩)を合成した.磁化率とESRスペクトルを測定した結果,アニオン化により,基底スピン多重度が3重項(S=1)から1重項(S=0)に反転することを見出した.電荷が付与された有機スピン系では,メタフェニレンリンカーが高スピン状態を生成するという単純なトポロジー則が成立しないことを明らかにした.この基底1重項(S=0)アニオン分子は,次年度に,上記の「スピン0有機フェリ磁性」を実験的に検証するためのモデル系として調べる予定である.

Research Products

• [Publications] 塩見大輔: "Quantum ferrimagnetism based on organic biradicals with a spin-0 ground state : Numerical calculations of molecule-based ferrimagnetic spin chains"Journal of Physical Chemistry B. (印刷中). (2001)
• [Publications] 塩見大輔: "Quantum ferrimagnetic spin chains as studied by numerical calculations of a Heisenberg spin Hamiltonian and ESR experiments"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 塩見大輔: "Molecular design of organic ferrimagnets"Synthetic Metals. (印刷中). (2001)
• [Publications] 長谷修一郎: "Phenol-substituted nitronyl nitroxide biradicals with a triplet (S=1) ground state"Journal of Materials Chemistry. 11. 756-760 (2001)
• [Publications] 塩見大輔: "Spin-spin correlation function and magnetic susceptibility of quantum ferrimagnetic spin chains as models for organic molecule-based ferrimagnetics"Journal of Physical Chemistry B. 104. 1961-1965 (2000)
• [Publications] M.C.B.L.Shohoji: "Electronic quartet and triplet states of polyanionic C60 fullerene and their anomalous spin relaxation as studied by cw-ESR/2D-electron spin transient nutation spectroscopy"Journal of the American Chemical Society. 122. 2962-2963 (2000)
• [Publications] 森田靖: "New persistent radicals : Synthesis and electronic spin structure of 2, 5-di-tert-butyl-6-oxophenalenoxyl derivatives"Journal of the American Chemical Society. 122. 4825-4826 (2000)
• [Publications] 西澤真裕: "Evidence for the breakdown of simple classical pictures of organic molecule-based ferrimagnetics : Low temperature crystal structure and single-crystal ESR studies of an organic heterospin system"Journal of Physical Chemistry B. 104. 503-509 (2000)
• [Publications] 上山幸嗣: "Benzoic acid and phenol derivatives of nitronyl nitroxide biradical as building blocks of organic molecule-based ferrimagnetics"Applied Magnetic Resonance. 19. 45-57 (2000)
• [Publications] 尾田伸之: "Molecular and electronic structures of high-spin polyphenylene-based oligo nitrenes as studied by ESR spectroscopy"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 松岡秀人: "Transition moment spectroscopy-based simulation of 2D electron spin transient nutation spectra of Eu2+ ion in a CaF2 single crystal"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 上山幸嗣: "Intramolecular magnetic interactions and solid state magnetic properties of phenol and benzoic acid derivatives of nitronyl nitroxide biradicals"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 金谷貴保: "Nitroxide triradicals as building blocks of molecule-based ferrimagnetics"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 長谷修一郎: "Magnetic properties of phenol-substituted nitronyl nitroxide biradicals and their anion radical salts"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 福井晃三: "Electronic spin identification of paramagnetic centers in crystalline solids of C60 and its derivatives as studied by ESR/2D electron spin transition nutation spectroscopy"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 田中航也: "Electronic and molecular structures of di(dianthrylcarbene) coupled by 1, 4-diethynylbenzene as studied by cw/pulsed ESR spectroscopy"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 福井晃三: "Electron-nuclear magnetic resonance studies on electronic spin structure of novel persistent neutral radical with 1, 3-diazaphenalene skeleton"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 中澤重顕: "Polyanionic C60-based high-spin molecular clusters as studied by pulsed ESR/2D electron spin transient nutation spectroscopy"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 佐藤和信: "Pulsed ESR/2D-electron spin transient nutation study of stable high-spin polycarbenes"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 西尾尊久: "14N-ENDOR and spin-lattice relaxation study of high-spin ferric iron (III) octaethylporphyrin"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 坂井素子: "Low-dimensional molecule-based magnets ; Structures and magnetic properties of cupper (II) complexes with hydrogen-bonded network"Magnetix Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 中澤重顕: "Spin quartet and triplet states of polyanionic C60 fullerenes and their anomalous spin relaxation as studied by cw-ESR/2D-electron spin transient nutation spectroscopy"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 福井晃三: "ESR/1H-ENDOR (TRIPLE) studies on generation and decay processes of a triangulene derivatives, the first non-Kekule polynuclear aromatic hydrocarbon"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 森田靖: "New stable neutral radicals : Synthesis and electronic spin structure of 2, 5-di-t-butyl-6-oxophenalenoxyl derivatives"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 古川貢: "Dynamic magnetic properties from microstructured ferromagnetic thin films with 1-d periodic lattice structure"Magnetic Resonance and Related Phenomena. (印刷中). (2001)
• [Publications] 金谷貴保: "Single-component ferrimagnetic : Triplet-doublet composite molecules as constituents of purely organic molecule-based ferrimagnets"Polyhedron. (印刷中). (2001)
• [Publications] 長谷修一郎: "Magnetic properties of phenol-substituted nitronyl nitroxide biradicals as building blocks of organic salt ferrimagnets"Polyhedron. (印刷中). (2001)
• [Publications] 佐藤和信: "Spin characterization of lanthanoid ion Eu2+ (8S7/2) in a CaF2 single crystal by two-dimensional electron spin transient nutation spectroscopy in "Two-dimensional correlation spectroscopy""American Institute of Physics. 4 (2000)
• [Publications] 工位武治: "Two-dimensional FT-pulsed electron spin transient nutation spectroscopy in "Two-dimensional correlation spectroscopy""American Institute of Physics. 10 (2000)
• [Publications] M.C.B.L.Shohoji: "Electronic and molecular structures of polyanionic C60 fullerene and high-spin C60n-clusters studied by ESR/2D-electron spin transient nutation spectroscopy "in Two-dimensional correlation spectroscopy"American Institute of Physics. 6 (2000)