2,2′-Bipyridine-6,6′-diyl bisnitroxide as a paramagnetic host: Encapsulation of a zinc(II) ion |
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Authors: | Kazuya KoideTakayuki Ishida |
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Affiliation: | Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan |
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Abstract: | A chelate complex of zinc(II) and 2,2′-bipyridine-6,6′-diyl bis(tert-butyl nitroxide) (bpybNO) with a metal/ligand ratio of 1/2 was structurally characterized to be [Zn(bpybNO)2][Zn(hfac)3]2, where Hhfac stands for 1,1,1,5,5,5-hexafluoropentane-2,4-dione. The magnetic susceptibility measurement indicates the presence of considerable antiferromagnetic interaction among the four S = 1/2 spins. The exchange parameter J was estimated as 2J/kB = −103(1) K, on the basis of a tetrahedral coupling model. The antiferromagnetic coupling is stronger after complexation than before. The density-functional theory calculation on related model compounds supports the present analysis and clarified the role of the zinc ion as a superexchange coupler. |
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Keywords: | Supramolecular chemistry Magnetic property Organic free radical Zinc Bipyridine |
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