Syntheses, crystal structures, and magnetic properties of a series of cyanide-bridged trinuclear chromate(III)?nickel(II)?chromate(III) complexes based on dicyanidechromate(III) building blocks

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• 作者：Hui Chen ; Bao-Xi Miao ; Li-Fang Zhang ; ^{zhanglifang@cumt.edu.cn} ; Guo-Ling Li ; Zhong-Hai Ni ; ^{nizhonghai@cumt.edu.cn}
• 关键词：Heterometallic complex ; Crystal structure ; Cyanide-bridged ; Magnetic property ; Magneto-structural correlation
• 刊名：Inorganica Chimica Acta
• 出版年：2013
• 出版时间：1 August, 2013
• 年：2013
• 卷：404
• 期：Complete
• 页码：34-39
• 全文大小：1188 K

文摘

Four cyanide-bridged trinuclear Cr^III?Ni^II?Cr^III complexes [Ni(cyclam)][Cr(bpb)(CN)₂]₂¡¤2H₂O (1) (cyclam = 1,4,8,11-tetraazacyclotetradecane, bpb^2- = 1,2-bis(pyridine-2-carboxamido)-benzenate), [Ni(cyclam)][Cr(bpClb)(CN)₂]₂¡¤4H₂O (2) (bpClb^2- = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate), [Ni(cyclam)][Cr(bpmb)(CN)₂]₂¡¤4H₂O (3) (bpmb^2- = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate) and [Ni(cyclam)][Cr(bpdmb)(CN)₂]₂ (4) (bpdmb^2- = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate) have been synthesized by the reaction of [Ni(cyclam)](ClO₄)₂ with a series of dicyanidechromate(III) building blocks. Single crystal X-ray diffraction analyses show that the four complexes have similar trinuclear structures with Cr^III-CN-Ni^II-NC-Cr^III linkages. Magnetic investigations indicate the ferromagnetic coupling between Cr(III) and Ni(II) centers through the cyanide bridge, with J_CrNi = 4.64(3) cm^?1 for 1, 4.33(4) cm^?1 for 2, 3.57(3) cm^?1 for 3 and 5.3(1) cm^?1 for 4. The study on magneto-structural correlation for cyanide-bridged Cr^III?Ni^II systems reveals that the cyanide-bridging bond angle is related to the strength of magnetic exchange coupling: the larger the Ni-NC bond angle, the stronger the Ni?Cr magnetic interaction.