All-Valence Electron CNDO Calculations on Transition Metal Complexes

Abstract

The CNDO‐II approximate SCF molecular orbital method is extended to include molecules containing atoms of the first transition series. Valence orbitals explicitly considered in the transition atoms are 3d, 4s, and 4p. Calculations are reported for the monoxides of Sc, Ti, V, and Cu, using three sets of orbital exponents. The results are compared, where possible, with those obtained by ab initio methods, and appropriate values for off‐diagonal core parameters are proposed. The method is used to evaluate the orbital levels for a number of hexafluorometallate complex ions. Fair agreement is found between the calculated and experimentally observed metal‐fluorine equilibrium bond lengths. The eigenfunctions are used to obtain the transferred spin densities to the fluorine ligands and in general these compare favourably with the values derived from electron spin and nuclear magnetic resonance measurements.