State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
Inorg Chem. 2010 Oct 18;49(20):9392-9. doi: 10.1021/ic100996b.
Density functional theory (DFT) calculations have been performed to investigate the alcohol oxidation to acetaldehyde catalyzed by [CuBr(2)(2,2'-bipy)]-TEMPO (TEMPO stands for 2,2,6,6-tetramethylpiperidinyloxy; bipy stands for bipyridine). The total charge for the studied catalytic system is +1. The catalytic cycle consists of two parts, namely, alcohol oxidation and TEMPO regeneration. In alcohol oxidation, the reaction follows the Sheldon's mechanism for the proposed two mechanisms, i.e., Semmelhack's mechanism and Sheldon's mechanism. The water participation plays minor role in the H atom abstraction step. In TEMPO regeneration, the proposed three paths are competitive in energy. By comparing with experimental observation, it is found that the path, in which alcohol provides the proton to TEMPO(-) to produce TEMPOH followed by the oxidation of TEMPOH directly to TEMPO by O(2), is favored. In TEMPO regeneration, CH(3)CN acts as the ligand to stabilize the Cu(I) species during the catalytic cycle.
密度泛函理论（DFT）计算已被用于研究[CuBr(2)(2,2'-bipy)]-TEMPO（TEMPO 代表 2,2,6,6-四甲基哌啶氧基；bipy 代表联吡啶）催化的醇氧化为乙醛。研究催化体系的总电荷为+1。催化循环由两部分组成，即醇氧化和 TEMPO 再生。在醇氧化中，反应遵循 Sheldon 机制，而不是 Semmelhack 机制和 Sheldon 机制。水的参与在 H 原子的攫取步骤中作用较小。在 TEMPO 再生中，提出的三条路径在能量上是竞争的。通过与实验观察结果进行比较，发现由醇向 TEMPO(-)提供质子以产生 TEMPOH，然后由 O(2)直接将 TEMPOH 氧化为 TEMPO 的路径是有利的。在 TEMPO 再生中，CH(3)CN 在催化循环中作为配体稳定 Cu(I)物种。
