Synthesis and spectral characterizations of vanadyl(ii) and chromium(iii) mixed ligand complexes containing metformin drug and glycine amino acid

Metformin is one of the most effective drugs for the treatment of type II diabetes. Two new mixed ligand complexes of vanadyl(ii) and chromium(iii) ions with the general formula [VOL1L2]SO4 and [CrL1L2(Cl)2]Cl, respectively, where L1 is the metformin and L2 is the glycine amino acid, have been synthesized in MeOH solvent with 1:1:1 stoichiometry and characterized by several spectroscopic techniques. The spectroscopic data suggested that the [VOL1L2]SO4 complex possesses a square pyramidal geometry, where the [CrL1L2(Cl)2]Cl complex possesses an octahedral geometry. The L1 ligand coordinated to the VO(ii) and Cr(iii) ions via the N atoms of the imino (‒C═NH) groups, where the L2 ligand coordinated via the O atom of the carboxylate group (COO) and the N atom of the amino group (NH2). The interaction of ligands L1 and L2 with the metal ions leads to complexes that have organized nanoscale structures with a main diameter of ∼14 nm for the [CrL1L2(Cl)2]Cl complex and ∼40 nm for the [VOL1L2]SO4 complex.