Quinoline and pyrazolone functionalized cis-dioxomolybdenum(VI) complexes: synthesis, hyphenated experimental-DFT studies and bactericidal implications

Abstract

ABSTRACTA new series of mixed-ligand complexes of dioxomolybdenum(VI) of the general composition [MoO2(L)(8-hq)(H2O)], where 8-hq=8-hydroxyquinoline and LH=4-acylpyrazolones viz., 3-methyl-1-phenyl-4-propionyl-2-pyrazolin-5-one (pmphpH), 4-butyryl-3-methyl-1-phenyl-2-pyrazolin-5-one (bumphpH), 4-iso-butyryl-3-methyl-1-phenyl-2-pyrazolin-5-one (iso-bumphpH) or 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (bmphpH) has been synthesized by the reaction of [MoO2(acac)2] and the target ligands in ethanol medium. The complexes have been characterized by elemental analyses, decomposition temperature, molar conductance, magnetic susceptibility, thermogravimetric studies, FT-IR, UV-vis, 1H NMR, 13C NMR, and FAB mass spectral studies. The thermal decomposition processes of one complex, cis-[MoO2(iso-bumphp)(8-hq)(H2O)] has been discussed with the evaluation of the order of reaction (n) and the activation energy (Ea) calculated from the thermogravimetric (TG) curve. Antibacterial study of one of the synthesized complexes at various dilutions has also been carried in comparison with the ligands and metal precursor using ampicillin as a standard drug. Gaussian09 software package was employed to carry out the theoretical study using density functional theory DFT/B3LYP level of theory under LANL2MB (for Mo)/6-311 + G (for non-metallic elements) basis set for one of the complexes, cis-[MoO2(bmphp)(8-hq)(H2O)]. Based on experimental and theoretical data, suitable pseudo pentagonal bipyramidal structures have been proposed for this class of metal complexes.