Differentiation between metal-metal stretching and ligand-sensitive vibrations in dimetal tetraacetates by ligand deuteration

Abstract

Previously reported studies of the Raman, resonance Raman, and electronic spectra of dirhodium tetracarboxylates have included observations that the wavenumber shifts in the metalcarboxylate modes induced by deuteration of the carboxylate ligand are larger than those caused by oxygen substitution. The method has been applied to the case of Mo/sub 2/(O/sub 2/CCH/sub 3/)/sub 4/ where nu(Mo-Mo) occurs at 404 cm/sup -1/ as previously determined by metal-isotope substitution. Results were obtained that were consistent with those obtained by metal-isotope substitution. Thus, it is concluded that deuteration of the carboxylate group may provide a useful, low-cost alternative to /sup 18/O- and metal-isotope substitution experiments for assignment of metal-metal stretching vibrations in dimeric tetracarboxylates. 13 references, 2 figures, 1 table.