Structure and bonding of the vanadium(III) hexa-aqua cation. 2. Manifestation of dynamical Jahn-Teller coupling in axially distorted vanadium(III) complexes.
Ground-state spin-Hamiltonian parameters, magnetic data, and electronic Raman spectra of hexacoordinate vanadium(III) complexes are calculated with consideration to the ((3)A (3)E) e vibronic interaction and compared to experimental data. It is shown that the zero-field-splitting of the (3)A(g) (S(6)) ground term may be reduced significantly by the dynamical Jahn-Teller effect, particularly when the pi-anisotropy of the metal-ligand bonding interaction is significant, and the energy of the Jahn-Teller active vibration is comparable to the diagonal axial field. The dynamical Jahn-Teller effect may also give rise to a significant enhancement in the Raman intensity of overtones and higher harmonics of Jahn-Teller active vibrations, when the energies of these transitions fall in the proximity of intra-(3)T(1g) (O(h)) electronic Raman transitions. A simple method of conducting vibronic coupling calculations is described, employing ligand field matrices generated by angular overlap model calculations, which may in principle be applied to any transition metal complex.
Tregenna-Piggott
Philip L W
PL
Department of Chemistry, University of Bern, Freiestrasse 3, CH-3000, Bern 9 Switzerland. tregenna@iac.unibe.ch
Carver
Graham
G