Solvatomagnetic Studies on Cyano-Bridged Bimetallic Chains Based on [Mn(cyclam)]³⁺ and Hexacyanometallates

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• 作者：Beata Nowicka ; Michał Heczko ; Michał Rams ; Mateusz Reczyński ; Bartłomiej Gaweł ; Wojciech Nitek and Barbara Sieklucka
• 刊名：European Journal of Inorganic Chemistry
• 出版年：2017
• 出版时间：January 3, 2017
• 年：2017
• 卷：2017
• 期：1
• 页码：99-106
• 全文大小：1393K
• ISSN：1099-0682c

文摘

Structures and solvatomagnetic properties of two 1D CN-bridged assemblies based on the complex [Mn(cyclam)]³⁺ (cyclam = 1,4,8,11-tetraazacyclotetradecane) were characterised. The isostructural {[Mn(cyclam)][Cr(CN)₆]·6H₂O}_n (1·6H₂O) and {[Mn(cyclam)][Fe(CN)₆]·6H₂O}_n (2·6H₂O) chains crystallise in the space group C2/m. When dried in air at a slightly elevated temperature the hexahydrates undergo irreversible partial dehydration to stable dihydrates 1·2H₂O and 2·2H₂O. The structure model of 1·2H₂O proposed from the powder XRD data shows lower symmetry of the network, described by the space group P2₁, and a markedly different relative arrangement of the chains. The Mn–Cr chains are characterised by antiferromagnetic (AFM) exchange through the CN bridges (J = –2.8 K for 1·6H₂O and –6.0 K for 1·2H₂O), which was modelled by quantum Monte Carlo simulations. Together with weaker AFM Mn–Cr interactions between the chains, it leads to ferrimagnetic ordering. FM intrachain interactions (J = 4.5 K for 2·6H₂O and 7.1 K for 2·2H₂O) and AFM 3D ordering are observed for the Mn–Fe chains. The dehydration process in both compounds causes an increase in the strength of magnetic exchange, which reflects changes in the CN bridge geometry.