Thermally Induced Spin Transitions in Nitroxide-Copper(II)-Nitroxide Spin Triads Studied by EPR

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• 作者：Matvey Fedin ; Sergey Veber ; Igor Gromov ; Ksenia Maryunina ; Sergey Fokin ; Galina Romanenko ; Renad Sagdeev ; Victor Ovcharenko ; Elena Bagryanskaya
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：December 24, 2007
• 年：2007
• 卷：46
• 期：26
• 页码：11405 - 11415
• 全文大小：225K
• 年卷期：v.46,no.26(December 24, 2007)
• ISSN：1520-510X

文摘

Thermally induced spin transitions in a family of heterospin polymer chain complexes of Cu²⁺ hexafluoroacetylacetonatewith two pyrazole-substituted nitronyl nitroxides are studied using electron paramagnetic resonance (EPR)spectroscopy. The structural rearrangements at low temperatures induce spin transitions in exchange-coupled spintriads of nitroxide-copper(II)-nitroxide. The values of exchange interactions in spin triads of studied systems aretypically on the order of tens to hundreds of inverse centimeters. The large magnitude of exchange interactiondetermines the specific and very informative peculiarities in EPR spectra due to the predominant population of theground state of a spin triad and spin exchange processes. The variety of these manifestations depending onstructure and magnetic properties of spin triads are described. EPR is demonstrated as an efficient tool for thecharacterization of spin transitions and for obtaining information on the temperature-dependent sign and value ofthe exchange interaction in strongly coupled spin triads.