A computational investigation of phosphaalkynes: a new building block

Abstract

The electronic properties of CP, CP and C-P bonds and their aza analogues, CN, CN and C-N bonds, were investigated using an ab initio self-consistent field molecular orbital approach at the 4-31G ∗ level. The cyclodimerization and cyclotetramerization of the monomer, methylphosphaacetylene (CH 3-CP) were analyzed by the molecular electrostatic potential (MEP) method. Based on the MEP maps, two reactive sites attractive towards an incoming electrophile were identified for phosphaacetylene, but its aza analogue, acetonitrile, showed only a single reactive site. The -CP group, in contrast to the -CN group, tends to form ‘side-on’ bonds with transition metals, and this has been reinforced by MEP maps of phosphaacetylene, indicating a larger negative region near the π-bonds.