Two Cyanide-Bridged MnII–NbIV Coordination Chain Ferrimagnets Promoted by Interchain Ferromagnetic Interactions

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• 作者：Michał Magott ; Hanna Tomkowiak ; Andrzej Katrusiak ; Wojciech Nitek ; Barbara Sieklucka ; Dawid Pinkowicz
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 6, 2016
• 年：2016
• 卷：55
• 期：11
• 页码：5281-5286
• 全文大小：387K
• 年卷期：0
• ISSN：1520-510X

文摘

Two new coordination chain compounds based on octacyanoniobate(IV) are reported: {[Mn^II(bpy)(H₂O)₂]₂[Nb^IV(CN)₈]·5H₂O}_n (1) and {[Mn^II(bpy)(H₂O)₂][Mn^II(bpy)₂][Nb^IV(CN)₈]·5H₂O}_n (2) (bpy = 2,2′-bipyridine). Both have the topology of vertex-sharing CN-bridged squares. The Mn₂Nb₂ units are mutually parallel in 1 and perpendicular in 2. The antiferromagnetic intrachain interactions between the Mn^II and Nb^IV centers in 1 and 2, typical for Mn^II-[Nb^IV(CN)₈] family of compounds, lead to ferrimagnetic ground state of each single chain. Both compounds show bulk ferrimagnetic ordering below their critical temperatures (T_c) of 6.4 K in 1 and 4.7 K in 2. Such a behavior is due to the ferromagnetic interchain interactions, assured by the π–π contacts between the 2,2′-bipyridine rings and by the hydrogen bonds between the terminal cyanide ligands of the [Nb^IV(CN)₈]-building blocks and coordination/crystallization water molecules. 1 and 2 are rare examples of ferrimagnets promoted by interchain ferromagnetic exchange, and the T_c of 1 is one of the highest among similar 1-D coordination polymers.