Unusual Conformation of a Dinuclear Paddle Wheel Copper(II) Complex. Synthesis, Structural Characterization and EPR Studies

详细信息    查看全文

• 作者：Ver贸nica Paredes-Garc铆a ; Ricardo C. Santana ; Rosa Madrid ; Andr茅s Vega ; Evgenia Spodine ; Diego Venegas-Yazigi
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：August 5, 2013
• 年：2013
• 卷：52
• 期：15
• 页码：8369-8377
• 全文大小：469K
• 年卷期：v.52,no.15(August 5, 2013)
• ISSN：1520-510X

文摘

An unusual and unique conformation of a paddle wheel type binuclear copper(II) complex containing acetate and acetamido ligands, {Cu₂(渭₂-O₂CCH₃)₄}(OCNH₂CH₃) (1), was obtained by solvothermal synthesis. The structural characterization of this compound shows that the apical (acetamido) ligands are disposed at a 62掳 dihedral angle, generating a special conformation as a consequence of the synthetic method used. This conformation has not been reported in other paddle wheel copper(II) tetraacetate compounds. Electron paramagnetic resonance (EPR) spectra of powder samples of (1) were obtained at 9.5 and 33.8 GHz, while single crystal spectra were obtained at 33.8 GHz with a B₀ applied in three orthogonal planes. The fit of the single crystal experimental data allowed gave g = 2.345 卤 0.003, and g = 2.057 卤 0.005. The angular variation of the EPR line allows evaluation of the fine structure of (1), giving D = 鈭?.337 卤 0.002 cm^鈥? and E = 鈭?.005 卤 0.001 cm^鈥?. The line width angular dependence, used together with the Anderson model and Kubo鈥揟omita theory, permitted the interdimer interaction to be evaluated as |J鈥瞸 = (0.051 卤 0.002) cm^鈥?. Using the powder spectral temperature dependence it was possible to evaluate the intradinuclear exchange coupling constan J₀ as 鈭?01 卤 2 cm^鈥?, which is considerably lower than that reported for other analogous copper(II) tetraacetate paddle wheel compounds (Cu^II鈥揚W), showing the remarkable effect of the conformation of the terminal ligands on the magnetic interaction.