VIBRATIONAL SATELLITE STRUCTURES AND PROPERTIES OF ELECTRONIC STATES OF TRANSITION-METAL COMPLEXES

Pd(2-thpy)2, Pt(2-thpY)2, [Ru(bpy-h8)3]2+, [Ru(bpy-h8)2(bpy-d8)]2+, [R u(bpy-d8)3]2+, [Os(bpy-h8)3]2+, [Os(bpy-h8)2(bpy-d8)]2+, and [Os(bpy-d 8)3]2+ were isolated in crystalline matrices in order to obtain highly resolved emission spectra. A detailed analysis of the electronic orig ins and of the vibrational satellite structures reveals trends. which allow the various compounds to be ordered with respect to increasing M LCT character. Interestingly, an increasing MLCT character is connecte d with decreasing shifts of the equilibrium positions of the potential hypersurfaces and with decreasing changes of force constants upon exc itation. Presumably, this behavior is a consequence of an increasing c ovalency in the compounds investigated. Moreover, especially the resol ved vibrational satellite structures of [Ru(bpy)3]2+ and [Os(bpy)3]2allow the conclusion that the electronic excitation in the lowest exci ted states is delocalized over the metal and the three (bpy)-ligands.