Evidences of Electronic Effects in the Vibrational Spectra of Some Rhodium(II) Carboxylate Complexes

Abstract

Abstract - A series of dirhodium tetracarboxylate complexes, containing triphenylphosphine as axial ligand was investigated by electronic and Raman spectroscopy, aiming to detect the influence of electronic effects of the carboxylate substituents on the v₁[v_(RhRh)] and v₂[v_(RhO)] Modes. When pairs of complexes with similar molecular weights are compared, as in the case of the cyclopentanecarboxylate and trifluoroacetate complexes, the striking difference in the inductive character of the two species results in substantial shifts of the v₁ and v₂ modes as a consequence of variations in the corresponding force constants rather than a simple mass effect as previously observed for non-substituted rhodium-carboxylates.

Key Words:

• rhodium carboxylates
• Raman spectrum
• electronic spectrum
• substituent effects.