Hsieh Andrew Y, Haines Ronald S, Harper Jason B
School of Chemistry, University of New South Wales, UNSW Sydney, Sydney 2052, Australia.
J Org Chem. 2024 Oct 18;89(20):14929-14939. doi: 10.1021/acs.joc.4c01685. Epub 2024 Oct 10.
The nucleofugality of dimethyl sulfide was measured in solvent mixtures containing ionic liquids. The first-order rate constants of the solvolysis of sulfonium salts were determined in mixtures containing different proportions of 1-butyl-3-methylimidazolium (trifluoromethanesulfonyl)imide in ethanol, representing the first report on the solvolysis of a charged species in an ionic liquid. Temperature-dependent kinetic studies allowed determination of activation parameters and rationalization of observed solvent effects in different ionic liquid mixtures. From the solvolysis data, the nucleofugality of dimethyl sulfide in different proportions of this ionic liquid in ethanol was determined. Further, the nucleofugality of dimethyl sulfide was determined in mixtures containing high proportions of each of seven other ionic liquids in ethanol. These data allowed quantification of the effects of varying both the amount of ionic liquid present and on changing the components of the ionic liquid on the nucleofugality of dimethyl sulfide. The ionic liquid mixtures were shown to affect the nucleofugality of this nucleofuge in a different manner to the previously studied monatomic charged nucleofuges, owing to different microscopic interactions in solution. This work highlighted the necessity of considering electrofuges with an appropriate range of electrofugality values along with the importance of the nucleofuge-specific sensitivity parameter.
在含有离子液体的溶剂混合物中测定了二甲基硫醚的离去倾向。在含有不同比例1-丁基-3-甲基咪唑鎓（三氟甲磺酰）亚胺的乙醇混合物中，测定了锍盐溶剂解的一级速率常数，这是关于离子液体中带电物种溶剂解的首次报道。温度相关的动力学研究有助于确定活化参数，并合理解释在不同离子液体混合物中观察到的溶剂效应。根据溶剂解数据，确定了二甲基硫醚在乙醇中不同比例的这种离子液体中的离去倾向。此外，还测定了二甲基硫醚在含有高比例其他七种离子液体中每种离子液体的乙醇混合物中的离去倾向。这些数据能够量化离子液体含量的变化以及离子液体成分的改变对二甲基硫醚离去倾向的影响。由于溶液中不同的微观相互作用，离子液体混合物对这种离去基团离去倾向的影响方式与之前研究的单原子带电离去基团不同。这项工作强调了考虑具有适当离去倾向值范围的亲电体的必要性以及离去基团特异性敏感参数的重要性。
