MOLECULAR AND ELECTRONIC-STRUCTURE OF HALOGEN-SUBSTITUTED PHOSPHAALKENES

Peculiarities of the molecular and electronic structure of P- and C-ha logen-substituted phosphaalkenes have been considered on the basis of results of X-ray diffraction studies and quantum-chemical calculations . Introduction of an electronegative halogen atom is shown to have an insignificant effect on the intramolecular bond angle distribution, wh ereas the influence on the P=C bond length is noticeable. Thus, in P-s ubstituted phosphaalkenes it substantially increases the polarization of the P=C bond (which causes its noticeable shortening), In C-substit uted phosphaalkenes the effect of halogen atoms is less pronounced: de creasing the P=C bond polarization leads only to its slight elongation . In addition, a considerable elongation of the phosphorus-halogen bon d in comparison with three-coordination phosphorus compounds is a pecu liarity of the molecular structure of P-halogen-substituted phosphaalk enes.