Copper/aminoxyl species are proposed as key intermediates in aerobic alcohol oxidation. Several possible electronic structural descriptions of these species are possible, and the present study probes this issue by examining four crystallographically characterized Cu/aminoxyl halide complexes by Cu K-edge, Cu L2,3-edge, and Cl K-edge X-ray absorption spectroscopy. The mixing coefficients between Cu, aminoxyl, and halide orbitals are determined via these techniques with support from density functional theory. The emergent electronic structure picture reveals that Cu coordination confers appreciable oxoammonium character to the aminoxyl ligand. The computational methodology is extended to one of the putative intermediates invoked in catalytic Cu/aminoxyl-driven alcohol oxidation reactions, with similar findings. Collectively, the results have important implications for the mechanism of alcohol oxidation and the underlying basis for cooperativity in this co-catalyst system.

中文翻译：

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铜 (II)-TEMPO/ABNO 配合物的电子结构分析提供了铜 (I)-氧铵特性的证据

铜/氨氧基物种被提议作为有氧醇氧化的关键中间体。这些物种的几种可能的电子结构描述是可能的，本研究通过通过 Cu K-edge、Cu L2,3-edge 和 Cl K-edge X 射线吸收检查四种晶体学表征的 Cu/氨基酰卤络合物来探讨这个问题光谱学。Cu、氨氧基和卤化物轨道之间的混合系数是通过这些技术在密度泛函理论的支持下确定的。电子结构图显示，Cu 配位赋予氨氧基配体明显的氧铵特性。计算方法扩展到在催化铜/氨氧基驱动的醇氧化反应中调用的推定中间体之一，具有类似的发现。总的来说，