School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
Org Biomol Chem. 2019 Dec 18;18(1):66-75. doi: 10.1039/c9ob02258a.
A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
一系列三唑鎓盐被制备出来，这些盐具有不同的电子和空间性质，它们的 pKa 值是在 25°C 的 DMSO 中使用指示缓冲剂法测定的。考虑了每种系统结构变化对三唑鎓阳离子酸度的影响，特别考察了通过使用哈米特 σ 参数定量地改变电子性质的影响。还报道了第一个生成介离子卡宾的唑鎓盐的第一个 pKa 值。这些新数据允许为这类三唑鎓盐的去质子化选择合适的碱，并有可能将本文中测定的 pKa 值与相应卡宾的亲核性相关联。
