Single Crystal EPR Study of the Dinuclear Cu(II) Complex [Cu(tda)(phen)]2·H2tda (tda = Thiodiacetate, phen = Phenanthroline): Influence of Weak Interdimeric Magnetic Interac

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• 作者：Nicols I. Neuman ; Mireille Perec ; Pablo J. Gonzlez ; Mario C. G. Passeggi ; Alberto C. Rizzi ; Carlos D. Brondino
• 刊名：Journal of Physical Chemistry A
• 出版年：2010
• 出版时间：December 23, 2010
• 年：2010
• 卷：114
• 期：50
• 页码：13069-13075
• 全文大小：233K
• 年卷期：v.114,no.50(December 23, 2010)
• ISSN：1520-5215

文摘

We report powder and single crystal EPR measurements of [Cu(tda)(phen)]₂·H₂tda (tda = thiodiacetate, phen = phenanthroline) at 9.7 GHz. This compound consists of centrosymmetric copper(II) ion dimers, weakly ferromagnetically exchange-coupled (J = +3.2 cm⁻¹), in which the dimeric units are linked by hydrophobic chemical paths involving the phen molecules. EPR revealed that the triplet spectra are collapsed by interdimeric exchange interactions mediated by that chemical path. Analysis and simulation of the single crystal EPR spectra were performed using Anderson’s exchange narrowing model, together with statistical arguments. This approach allowed us to interpret the spectra modulated by the interdimeric interactions in situations of weak, intermediate, and strong exchange. We evaluated an interdimeric exchange constant J′ = 0.0070(3) cm⁻¹, indicating that hydrophobic paths can transmit weak exchange interactions between centers at relatively long distances of the order of 10 Å.