Structures of model phosphinoamide anions

Analysis of the parent phosphinoamide/iminophosphide anion, H2PNH- and its fluoro derivatives, involved ab initio computations. A saddle point connects the pair of real minima observed for the geometries, optimized at the SCF level. The pair of minima match cis and trans conformations. The saddle point, in a majority of instances, matches the rotational barrier about the P-N bond.