A theoretical study of the Jorgensen’s nephelauxetic effect in some simple transition metal halo-complexes from a molecular orbital computation

Abstract

A theoretical study of Jorgensen's nephelauxetic effect in some simple high spin transition metal halo-complexes has been made with an unrestricted Hartree-Fock-SCF-INDO MO calculation. The nephelauxetic spectroscopic parameters—the Racah integralB and the covalency factor β- have been theoretically evaluated from the above MO analysis results. For this a pseudo-atom model and an eigen-MO model have been employed. The results allow a comparison to be made between the experimental and theoretical results, which indicate the relative success of the pseudo-atom model over the other. It has also been pointed out that the results from both models would have improved considerably if the use of metal valence basis orbitals corresponding to its final oxidation state had been resorted to. The concept of differential covalency and its effect on nephelauxetic parameters are also discussed.