ON THE ELECTRONIC HYPERSURFACE OF THE METHYLENEPHOSPHENIUM CATION

The electronic hypersurface of the methylenephosphenium cation is expl ored on the basis of ab initio calculations of double-zeta quality. Th e findings are compared with corresponding investigations on the nitro gen analogue (iminomethylene cation), methylenesilylene and methylenec arbene. For the phosphorus case, PCH2 is the most stable species on th e potential energy surface, while for the nitrogen case the acetylenic structure, HNCH+ (C(infinity v) symmetry) is the most stable species. For the substituted cases a bridged geometry comes to the fore for PC HR+ (R = NH2, PH2, C6H5). These substituents strongly pronounce cation stability for PCHR+, as evaluated by corresponding group transfer rea ctions.