THE TRANS INFLUENCE IN [RH(PH3)3CL] - A DENSITY-FUNCTIONAL THEORY STUDY

Optimised geometries computed using the local density approximation (LDA) of density functional theory (DFT) have been obtained for the Wilkinson's catalyst model complex [Rh(PH3)3Cl]. The LDA method accurately predicts the 0.09 angstrom shortening of the Rh-P(trans) distance relative to Rh-P(cis) although the Rh-Cl contact is about 0.05 angstrom too short. These geometrical data are significantly better than single determinant Hartree-Fock (HF) results. In contrast, the Mulliken charge density analyses are very similar and give comparable descriptions of the bonding although small differences in the predicted d-orbital sequences suggest that the LDA method describes a stronger in-plane pi-acceptor interaction than does HF theory.