作者:Vladimir T. Varlamov、Evguenii T. Denisov、Chryssostomos Chatgilialoglu
DOI:10.1021/jo010408u
日期:2001.9.1
Absolute rate constants for the reaction of tri-tert-butylphenoxyl radical (ArO*) with (TMS)(3)SiH were measured spectrophotometrically in the temperature range 321-383 K. Rate constants for the hydrogen abstraction from (TMS)(3)SiH by diarylaminyl radicals of type (4-X-C(6)H(4))(2)N* were determined by using a method in which the corresponding amines catalyze the reaction of ArO* with (TMS)(3)SiH
三叔丁基苯氧基自由基(ArO *)与(TMS)(3)SiH反应的绝对速率常数是在321-383 K的温度范围内用分光光度法测量的。从(TMS)(3)析氢的速率常数通过使用其中相应的胺催化ArO *与(TMS)(3)SiH的反应的方法确定(4-XC(6)H(4))(2)N *型二芳基自由基的SiH。在364.2 K下,对于X = H,CH(3),CH(3)O和Br,速率常数在2-50 M(-)(1)s(-)(1)的范围内ArO *的值低3个数量级。这些反应的共同特征是较低的前指数因子[ArO *和Ph(2)N *的log(A / M(-1)s(-1))分别为4.4和5.2],这反映了较高的空间需求在过渡状态。