Quantum-chemical study of intramolecular electronic effects in phosphaalkenes

The semiempirical CNDO/2 method has been used in a quantum-chemical study of the electronic and spatial structures of a series of phosphaalkenes as influenced by the nature of the substituents on the two-coordinated phosphorus atom and the carbon atom forming the P=C bond, as well as simple models for these. The data are compared with results from nonempirical calculations found in the literature for the latter. The authors discuss the effects of the substituents on the -electron structures of the phosphaalkenes and the character of the outer orbitals. It is found that the d AO of phosphorus plays only a slight part in forming the bonds in these compounds. The electron-density distributions are close to those found for ethylene derivatives. The conclusions agree with spectral and structural studies on the phosphaalkenes.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 5, pp. 545–553, September–October 1986.