An ab initio study of the P-C bond rotation in phosphorus(V)-stabilized carbanions: the phosphoryl versus thiophosphoryl group

An ab initio study shows that the activation barrier for P-C bond rotation in P-methylthioxophosphonic diamide anion (8-) is higher than that found in previous oxophosphoryl analog studies on the phosphoryl analog 7-. The result indicates that the stabilizing capabilities of the different chalcogens are different. The study is conducted on structures and energies of different rotamers of 8- compared to 7-. Details of analysis of phosphoryl- and thiophosphoryl-stabilized anions are given.