Structure and bonding in diphosphinocarbenes. An ab initio investigation

Abstract

Self consistent field calculations, supplemented by MOller-Plesset second-order estimates of correlation effects, are presented for the compounds R 2 PCPR 2 , R=NH 2 and R=N(iPr) 2 , as well as for species resulting from protonation or addition of H 2 and HF. The relative stability of possible isomers is computed and discussed. Diphosphanylcarbenes always prefer an asymmetric PC multiple-bond structure such as >P-C ⊖ =P ⊗ <, incorporating alkylidynephosphorane and vinyl ylide characteristics