Abstract In this study, a detailed quantum chemical investigation of the contribution of phenyl thiol derivatives in thiol-ene reaction mechanism has been carried out for the first time. DFT calculations have been used to investigate the role of substitution in thiol-ene reactions. It is well known that the reaction mechanism is strongly controlled by the kP/kCT ratio, where kP is the propagation rate constant of the thiyl radical’s addition to the alkene and kCT is the rate constant of chain transfer to a thiol. The electrophilic nature of the phenylthio radicals and the singlet-triplet (S-T) gap of alkenes are mainly responsible for the variation of the activation barriers for the propagation reaction, this demonstrates the importance of the ene functionality on the propagation reaction. A correlation between the radical stabilization energy of the carbon centered radical intermediate and the chain transfer activation energy could not be established. The transition structures of the chain transfer reactions were shown to be stabilized by intramolecular interactions, which have lowered the activation barriers. In this study, we underlie the kP/kCT ratio which is highly dependent not only on the alkene functionality, but also on the thiol functionality. Tailor-made polymers can be obtained by altering the substituents or their positions, and the computational procedure described herein is expected to guide the synthesis.

中文翻译：

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硫醇-烯点击反应的理论研究：DFT 视角

摘要 本研究首次对苯硫醇衍生物在硫醇-烯反应机理中的贡献进行了详细的量子化学研究。DFT 计算已用于研究取代在硫醇-烯反应中的作用。众所周知，反应机理受 kP/kCT 比的强烈控制，其中 kP 是硫基自由基加成到烯烃的传播速率常数，kCT 是链转移到硫醇的速率常数。苯硫基的亲电性质和烯烃的单线态-三线态（ST）间隙是传播反应活化势垒变化的主要原因，这证明了烯官能团对传播反应的重要性。无法建立碳中心自由基中间体的自由基稳定能与链转移活化能之间的相关性。链转移反应的过渡结构被证明通过分子内相互作用稳定，这降低了激活障碍。在这项研究中，我们建立了 kP/kCT 比率的基础，该比率不仅高度依赖于烯烃官能度，还高度依赖于硫醇官能度。可以通过改变取代基或它们的位置来获得定制的聚合物，本文描述的计算程序有望指导合成。链转移反应的过渡结构被证明通过分子内相互作用稳定，这降低了激活障碍。在这项研究中，我们建立了 kP/kCT 比率的基础，该比率不仅高度依赖于烯烃官能度，还高度依赖于硫醇官能度。可以通过改变取代基或它们的位置来获得定制的聚合物，本文描述的计算程序有望指导合成。链转移反应的过渡结构被证明通过分子内相互作用稳定，这降低了激活障碍。在这项研究中，我们建立了 kP/kCT 比率的基础，该比率不仅高度依赖于烯烃官能度，还高度依赖于硫醇官能度。可以通过改变取代基或它们的位置来获得定制的聚合物，本文描述的计算程序有望指导合成。