The Tris(trimethylsilyl)silane/Thiol Reducing System: A Tool for Measuring Rate Constants for Reactions of Carbon-Centered Radicals with Thiols
作者:Chryssostomos Chatgilialoglu
DOI:10.1002/hlca.200690221
日期:2006.10
methodology is described that allows one to determine the rate constants of carbon-centered radicals with a variety of thiols by using the tris(trimethylsilyl)silane/thiol couple as a reducing system. A total of 20 rate constants for the hydrogen abstraction from a variety of alkyl-, silyl-, and aryl-substituted thiols by the primary-alkyl radical 2 in toluene at 80° were determined with the aid of the
描述了对众所周知的“自由基钟”方法的扩展,该方法允许通过使用三(三甲基甲硅烷基)硅烷/硫醇对作为还原系统来确定各种硫醇的碳中心自由基的速率常数。借助5 -exo-trig环化反应,确定了在80°下甲苯中的伯烷基基团2从各种烷基,甲硅烷基和芳基取代的硫醇中提取氢的总共20个速率常数作为计时装置。此外,通过酰基9从各种烷基和甲硅烷基取代的硫醇中提取氢的七个速率常数使用脱羰过程作为计时装置,测量了苯在80°C时的浓度。速率常数从10 6到10 8 M -1 s -1在两个数量级上变化。取代基效应得到合理化。比较了这些还原体系和其他常见氢供体的自由基捕获能力。