Sy Piecco Kurt W E, Aboelenen Ahmed M, Pyle Joseph R, Vicente Juvinch R, Gautam Dinesh, Chen Jixin
Department of Chemistry and Biochemistry, Nanoscale and Quantum Phenomena Institute, and Center for Intelligent Chemical Instrumentation, Ohio University, Athens, Ohio 45701, United States.
ACS Omega. 2018 Oct 31;3(10):14327-14332. doi: 10.1021/acsomega.8b01725. Epub 2018 Oct 29.
Thiol-ene click chemistry has become a powerful paradigm in synthesis, materials science, and surface modification in the past decade. In the photoinitiated thiol-ene reaction, an induction period is often observed before the major change in its kinetic curve, for which a possible mechanism is proposed in this report. Briefly, light soaking generates radicals following the zeroth-order reaction kinetics. The radical is the reactant that initializes the chain reaction of thiol-ene coupling, which is a first-order reaction. Combining both and under the light-limited conditions, a surprising kinetics represented by a Gaussian-like model evolves that is different from the exponential model used to describe the first-order reaction of the final product. The experimental data are fitted well with the new model, and the reaction kinetic constants can be pulled out from the fitting.
在过去十年中，硫醇-烯点击化学已成为合成、材料科学和表面改性领域的一种强大范例。在光引发的硫醇-烯反应中，通常会在其动力学曲线发生重大变化之前观察到一个诱导期，本报告针对此提出了一种可能的机制。简而言之，光浸泡按照零级反应动力学生成自由基。该自由基是引发硫醇-烯偶联链反应的反应物，硫醇-烯偶联是一级反应。在光照受限条件下将两者结合，会出现一种由类高斯模型表示的惊人动力学，它不同于用于描述最终产物一级反应的指数模型。实验数据与新模型拟合良好，并且可以从拟合中得出反应动力学常数。
