NUCLEOPHILE AND ARYL RADICAL REACTIVITY IN SRN1 AROMATIC NUCLEOPHILIC-SUBSTITUTION REACTIONS - ABSOLUTE AND RELATIVE ELECTROCHEMICAL DETERMINATION
NUCLEOPHILE AND ARYL RADICAL REACTIVITY IN SRN1 AROMATIC NUCLEOPHILIC-SUBSTITUTION REACTIONS - ABSOLUTE AND RELATIVE ELECTROCHEMICAL DETERMINATION
复制标题
DOI：
10.1021/ja00298a009
复制
发表时间：
1985-01-01
影响因子：
15
通讯作者：
THIEBAULT, A
中科院分区：
文献类型：
--
作者：
AMATORE, C;OTURAN, MA;THIEBAULT, A
用三种电化学方法测定了Ar·+ Nu ~+反应的速率常数。在直接循环伏安法中，数据来自于加入亲核试剂后底物峰电流的降低，而在相对方法中，数据来自于在两种亲核试剂存在下底物溶液重复循环时观察到的两种取代产物的峰高。在氧化还原催化法中，底物的还原是由外源可逆电对催化的，数据来自于加入亲核试剂后催化电流的降低。结合这三种方法测定了一系列26个芳基-亲核试剂对的反应活性。在大多数情况下，速率常数接近扩散极限。例外的是2-喹啉基和2-吡啶基！根的讨论了反应驱动力中a ~* 和v ~* 轨道的能量差与特征标准势和键能的关系。
Three electrochemical methods are used to obtain the rate constants of the Ar·+ Nu" reaction. In the direct cyclic voltammetric method, the data are derived from the decrease of the substrate peak current upon additionof the nucleophile while in the relative method they are obtained from the peak heights of the two substitution products observed upon repetitive cycling of the substrate solution in the presence of two nucleophiles. In theredox catalysis method, the reduction of the substrate is catalyzed by an exogeneous reversible couple and the data are derived from the decrease of the catalytic current upon addition of the nucleophile. All three methods were combined to determine the reactivitiesof a series of 26 aryl radical-nucleophile couples. In most cases, the rate constant is close to the diffusion limit. The exceptions concern the 2-quinolyl and 2-pyridy! radicals. The results are discussed in terms of energy difference between the a* and v* orbitalsin the driving force of the reaction as related to characteristic standard potentials and bond energies.