Synthesis, crystal structures and antimicrobial activity of dioxidomolybdenum(VI) complexes derived from aroylhydrazones.

Two new aroylhydrazone compounds (E)-N'-(3-ethoxy-2-hydroxybenzylidene)-3-(trifluoromethyl)benzohydrazide (H2La) and (E)-2-bromo-N'-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide (H2Lb) were prepared and characterized by 1H NMR spectroscopy. Reaction of the aroylhydrazones with MoO2(acac)2 afforded two new dioxidomolybdenum(VI) complexes with general formula [MoO2L(CH3OH)] (L = La for 1, Lb for 2). The complexes were characterized by IR and UV-Vis spectroscopy. Molecular structures of the aroylhydrazones and two dioxidomolybdenum(VI) complexes were further characterized by single crystal X-ray determination. The aroylhydrazone ligands coordinate to Mo through the phenolate oxygen, imine nitrogen, and enolate oxygen atom. The Mo atom displays a distorted octahedral geometry, with the three donors of the aroylhydrazone ligands and one oxo defining the equatorial plane, and one methanol and the other oxo occupying the axial positions. The effective antimicrobial activity of the compounds against the bacteria strains B. subtilis, S. aureus, E. coli, P. fluorescens and on the fungal strains C. albicans and A. niger was observed.