| Project/Area Number |
02453014
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理化学一般
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| Research Institution | Osaka City University |
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Principal Investigator |
ITOH Koichi Osaka City Univ., Dept. of Chem., Prof., 理学部, 教授 (70029403)
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| Co-Investigator(Kenkyū-buntansha) |
TAKUI Takeji Osaka City Univ., Dept. of Chem, Prof., 理学部, 教授 (10117955)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 1992: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | Organic ferrimagnets / Unusually large negative spin polarization / Organic molecular based magnetism / ENDOR / TRIPLE / pi Topoology / Spin multiplet-multiplet interaction / Hetero-spin systems / Spin chemistry / 有機フェリ磁性 / 複合型高スピン分子 / 電子核ー核三重共鳴 / スピン密度分布 / 次世代テクノロジ- / 有機磁性 / 分子性磁性 / 有機強磁性高分子 / 有機フェリ磁性高分子 / トポロジ-的対称性 / 電子一核二重共鳴 / 負のスピン分極 |
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| Research Abstract |
Organic molecular based magnetism has been the focus of current topics in many fields of both pure and applied sciences. It is of crucial importance to substantiate the possible occurrence of various types of purely organic magnetism, particularly purely organic ferrimangetism which is defined as antiferromagnetically coupled organic hetero-spin assemblages with coherence length of long range.
This program deals with the topologically spin-controlled molecular design and spin structure of the first organic hetero-spin system, 4-(diphenylmethylene)-4'-(m-phenylenebis (phenylmethylene)-ether 1, in which non-identical spins (S_i=1 and S_j=2) couple antiferromagnetically via an ether bridge in the ground state. The hetero spin system is a model for purely organic ferrimagnets via through-bond approaches, in which the underlining magnetic coupling is superexchange interaction via the bridge. The concept of the molecular design under study is associated with a counterpart of crystalline ferrimagnets via through-space approaches commonly exploited in magnetic materials. The single-crystal ENDOR spectroscopy has been applied to 1, featuring an unusually large negative spin polarization in the spin density distribution for the ground state (S=1). The finding discloses a physical insight into organic ferrimagnetism. The unusual negative spin polarization strictly arises from a salient feature of organic hetero-spin systems in the electronic ground state, directly showing that one molecular spin moiety with S_i (S_j=1) is inverted against the another with an inequivalent spin S_j (S_j=2) in antiferromagnetically coupled hetero-spin systems. The spin-inversion is responsible for such an unusually large negative spin polarization that chemistry so far has never expected. It is referred to a new aspect of negative spin polarization in chemistry.
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