Unstable intermediates. Part 178. The structure of intermediates formed in the radiolysis of thiols
Unstable intermediates. Part 178. The structure of intermediates formed in the radiolysis of thiols
复制标题
不稳定的中间体。
DOI：
10.1039/p29770002005
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
M. Symons
中科院分区：
文献类型：
--
作者：
D. Nelson;R. L. Petersen;M. Symons
在77 K下，对多种硫醇进行了60 Co γ射线辐照，包括纯态和稀甲醇玻璃或水玻璃。归属于RS·自由基的光谱具有随环境而变化的gz值（z为沿着C-S键），但在甲醇中均接近2.158。在硫原子上的解离电子俘获（RSH + e-→ R·+ SH-）仅在甲醇玻璃或水玻璃中观察到，推测被喷射出的SH-离子的溶剂化起着重要作用。讨论了含有两个硫原子的物种（X）的结构，g值接近2.058，2.025和2.001。两个竞争对手的结构，RS·-SR 2和RSS·被认为是深入的，并得出结论，前者是最有可能的，除非这两个物种有非常相似的性质。电子损失产生RSH+，然后反应产生R（H）S·-S（H）R+阳离子，这一假设解释了e.s.r.中的某些特征。光谱，作为质子损失的替代方案，得到RS·自由基。
A wide range of thiols have been exposed to 60Co γ-rays at 77 K both in the pure state and in dilute methanolic or aqueous glasses. Spectra assigned to RS· radicals had gz values (z is along the C–S bond) which varied with the environment, but which were all close to 2.158 in methanol. Dissociative electron capture at sulphur (RSH + e–→ R·+ SH–) was only observed in methanolic or aqueous glasses, and it is postulated that solvation of the ejected SH– ion plays an important role. The structure of a species (X) containing two sulphur atoms and having g values close to 2.058, 2.025, and 2.001 is discussed. Two rival structures, RS·–SR2 and RSS· are considered in depth and it is concluded that the former is most probable unless both species have very similar properties. Electron loss to give RSH+ followed by reaction to give R(H)S·–S(H)R+ cations is postulated to explain certain features in the e.s.r. spectra, as an alternative to proton loss to give RS· radicals.