Structural characterization of α-amino acid complexes of molybdates: a spectroscopic and DFT study

Abstract

The reactions of L-enantiopure α-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.