Cis鈥揟rans Isomeric and Polymorphic Effects on the Magnetic Properties of Water-Bridged Copper Coordination Chains

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• 作者：Bojan Kozlev膷ar ; Nives Kitanovski ; Zvonko Jagli膷i膰 ; Nuno A. G. Bandeira ; Vincent Robert ; Boris Le Guennic ; Patrick Gamez
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：March 5, 2012
• 年：2012
• 卷：51
• 期：5
• 页码：3094-3102
• 全文大小：619K
• 年卷期：v.51,no.5(March 5, 2012)
• ISSN：1520-510X

文摘

The synthesis and magnetic characterization of vanillin-based Cu(II) mononuclear complexes of formula [Cu(van)₂(H₂O)₂](H₂O)_x (van = vanillinate; x = 0, compound 1; x = 2, compounds 2 and 3) were performed. Despite the presence of very similar [Cu(van)₂(H₂O)₂] moieties, the crystal structures exhibit distinct Cu路路路Cu contacts and display three different through-H-bond exchange-coupling pathways. As a result of the relative positions of the water molecules, the experimental (MAGSUS) exchange-coupling constants are dissimilar, i.e., J(1) = 鈭?.0 cm^鈥? (the data have been fitted to the Bleaney鈥揃owers equation considering a dimer; 2J = 鈭?.0 cm^鈥?), J(2) = 鈭?.0 cm^鈥? (the data have been fitted to the Bonner鈥揊ischer equation for a chain of monomeric copper(II) units), whereas compound 3 is paramagnetic. Subsequently, the theoretical density functional theory (DFT) and wave function theory-based (DDCI) calculations were carried out to better understand the role of the water molecule as a mediator of the magnetic coupling. The use of localized orbitals allows one to elucidate the role of the H-bonds in generating exchange interactions. Since the exchange-coupling constants are strongly dependent on the mechanisms selectively introduced, the role of the H-bond is demonstrated.