Ylide及其相应自由基的热力学稳定性研究

本文首次测定了三苯基胂、三丁基磷和二丁基碲系列Ylide的前体化合物中α-C-H键在二甲亚砜(DMSO)溶液中的pKA和气相中的均裂键能(BDE)。通过这些结构相似的Ylide相应性质的类比, 对有关的碳负离子和碳自由基的热力学稳定性以及磷Ylide中P-C键的属性及其对磷Ylide性质的影响从构效关系的更深层次进行了讨论。

Thermodynamic stabilities of ylides and their corresponding radicals

Determinations of the equilibrium acidities in dimethylsulfoxide solution and the α-C-H homolytic bond dissociation energies in the gas phase for structurally different triphenylarsonium, tributylphosphonium and dibutyltellurium ylide precusors are reported. The thermodynamic stabilities of the corresponding carbanions and carbon radicals as well as the nature of the P-C bonds in phosphonium ylides and its influence on the properties of the ylides are discussed in detailes, based on a comparison with other type of ylides of the similar structure and on the structure-property relationship.