The apicophilicity of thio-substituents in trigonal bipyramidal phosphoranes

Abstract

The variable temperature n.m.r. spectra of a number of five-co-ordinate spirophosphoranes having P-phenoxy- and P-phenylthio-groups have given data on the energetics of the pseudorotation processes available to these systems. It is concluded that the apicophilicities of phenoxy- and phenylthio-groups are similar, with the balance varying according to the nature of the other ligands. Further evidence is given for the high apicophilicity of the hydrogen atom. The concept of multiple turnstile rotation processes is discussed with particular reference to spirophosphoranes.