Bindungstheoretische Untersuchungen von Bor-Phosphor-Wasserstoff-Verbindungen mit semiempirischen SCF-Verfahren

Abstract

The applicability of theCNDO/2 method for compounds containing boron, phosphorus and hydrogen is tested, comparing the results with ab initio calculations. Good agreement is found for most data; for P−H bonds, however, some methodical artefacts are found, leading to erroneous results, especially in regard to charge densities. An imperfect parametrization of phosphorus is supposed to be responsible for these artefacts.

Calculations were performed for a recently prepared compound, γ-phosphinodiborane, and one possible isomer, in their respectiveCNDO minimum geometries. The energies obtained lead to the same predictions about their relative stability as is found experimentally.

Bonding is discussed by means of localized molecular orbitals, and the hybridization model, frequently used for such species, is tested critically.