Investigation of the EPR parameters and local structures for Cu²⁺ in Bis(l-asparaginato) M(II) catalysts (M=Zn, Cd, Mg)

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• 作者：Zhang Hua-Ming^a ; ^b ; ^{huamingzhang66@gmail.com} ; Wu Shao-Yi^a ; Kuang Min-Quan^a ; Zhang Zhi-Hong^a
• 关键词：D. Electron paramagnetic resonance (EPR) ; D. crystal fields ; D. defects
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2012
• 期刊代码：69_00223697
• 类别：ch
• 出版时间：July, 2012
• 卷：73
• 期：7
• 页码：846-850
• 文件大小：181 K

摘要

The electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants) for Cu²⁺ in Bis(l-asparaginato) M(II) catalysts (M=Zn, Cd, Mg) are theoretically investigated using the high order perturbation formulas of these parameters for 3d⁹ ions in orthorhombically elongated octahedra. Ligand orbital and spin-orbit coupling contributions are included from the cluster approach in view of strong covalency. The ligand octahedra (i.e., [CuO₄N₂]^{12鈭?/sup> clusters) are found to experience axial and perpendicular local bond length variations 螖 (鈮?.19-0.25 脜) and 未 (鈮?.12-0.14 脜) due to the Jahn-Teller effect and size mismatch, which are dissimilar to those of host M2+ sites in pure compounds. The theoretical EPR parameters based on the above local structures show good agreement with the observed values, and some improvements are achieved as compared with those in the previous work. The local structures of these centers are discussed.}