Structural characterization of alpha-amino acid complexes of molybdates: A spectroscopic and DFT study

The reactions of L-enantiopure alpha-amino acids (aaH) with Na2MoO4 led to the high-yield isolation of Mo(VI) complexes of general formula Mo2O4(OH)4(aaH). A similar outcome was achieved by using (NH4)6Mo7O24 in the place of Na2MoO4. Solid-state IR and NMR spectroscopy indicated the presence of cis-MoO2 units linked by a zwitterionic amino acid ligand, via a bidentate bridging coordination through the carboxylate group. Thus possible dinuclear and polynuclear structures are proposed on the basis of DFT calculations.