Synthesis, computational, spectroscopic, thermal and antimicrobial activity studies on some metal-urate complexes

New sixteen uric acid metal complexes of different stoichiometry, stereo-chemistries and modes of interactions were synthesized using different metals Cr. Mn, Fe, Co, Ni, Cu, Cd, UO2, Na and K. The synthesized complexes were characterized by elemental analysis, spectral (IR. UV Vis and ESR) methods, thermal analysis (TG, DTA and DSC) and magnetic susceptibility studies. Molecular modeling calculations were used to characterize the ligation sites of the free ligand. Furthermore, quantum chemical parameters of uric acid such as the energies of highest occupied molecular orbital (E-HOMO), energies of lowest unoccupied molecular orbital (E-LUMO), the separation energy (Delta E = E-LUMO - E-HOMO), the absolute electronegativity, chi. the chemical potential, P-i, the absolute hardness, eta and the softness (sigma) were obtained for uric acid. Eight different microbial categories were used to study the antimicrobial activity of the free ligand and ten of its complexes. The results indicate that the ligand and its metal complexes possess antimicrobial properties. The stoichiometry of iron uric acid complex was studied by using different spectrophotometric methods. (C) 2012 Elsevier B.V. All rights reserved.