Concerted and Stepwise Dissociative Electron Transfers. Oxidability of the Leaving Group and Strength of the Breaking Bond as Mechanism and Reactivity Governing Factors Illustrated by the Electrochemical Reduction of α-Substituted Acetophenones
作者:Claude P. Andrieux、Jean-Michel Savéant、André Tallec、Robert Tardivel、Caroline Tardy
DOI:10.1021/ja963674b
日期:1997.3.1
of the dissociative electron transfer reaction, and, in the stepwise cases, the determination of the cleavage rate constants and the standard potentials for the formation of the anion radical. Analysis of the data, using thermodynamical parameters derived from experiment and from literature points to three mechanism governing factors, the oxidability of the leaving group, the bond dissociation energy
对一系列 α-取代苯乙酮的循环伏安研究允许鉴定解离电子转移反应的协调和逐步特征,并且在逐步情况下,确定裂解速率常数和标准电位形成阴离子自由基。使用源自实验和文献的热力学参数分析数据指向三个机制控制因素,离去基团的氧化性、键断裂的键解离能和LUMO能量。在许多情况下,这些因素中的第一个似乎在控制协调与逐步二分法方面占主导地位。氟取代基提供了一个相反的例子,其中键强度克服了离去基团氧化性的不利影响。就阴离子自由基裂解反应性而言,这也是一个例外,其中 C-F 键的强度显着有助于减缓...