Synthesis, Spectroscopic Characterization, Crystal Structures and Antibacterial Activity of Vanadium(V) Complexes of Fluoro- and Chloro-Substituted Benzohydrazone Ligands.

A new vanadium(V) complex, [VOL(OMe)(MeOH)]·MeOH (1·MeOH), was prepared by the reaction of VO(acac)2 with 2-chloro-N'-(5-fluoro-2-hydroxybenzylidene)benzohydrazide (H2L) in methanol. By addition of salicylhydroxamic acid (HSHA) to the methanolic solution of 1, a new salicylhydroxamate-coordinated vanadium(V) complex, [VOL(SHA)]·H2O (2·H2O), was obtained. Both complexes were characterized by elemental analysis, infrared spectroscopy, thermal analysis and single crystal X-ray diffraction. Complex 1 crystallizes with methanol molecule as a solvate, and complex 2 as a monohydrate. The V atoms in the complexes are in octahedral coordination. In the crystal structure of 1·MeOH, the vanadium complexes are linked by methanol solvate molecules through intermolecular O-H∙∙∙N and O-H∙∙∙O hydrogen bonds to form chains along the c axis. In the crystal structure of 2·H2O, the vanadium complexes are linked by water molecules through intermolecular O-H∙∙∙O hydrogen bonds, to form 1D chains along the a axis. The chains are further linked through intermolecular O-H∙∙∙N and O-H∙∙∙O hydrogen bonds in the c direction to form 2D layers. The antimicrobial activities of the complexes against K. pneumoniae, S. aureus, P. aeroginosa, E. coli, and B. subtilis were investigated.

Synthesis and crystal structures of ethanol-coordinated molybdenum(VI) oxo complexes with tridentate hydrazone ligands.

Reaction of [MoO2(acac)2] (where acac = acetylacetonate) with two similar hydrazone ligands in ethanol yielded two ethanol-coordinated mononuclear molybdenum(VI) oxo complexes with general formula [MoO2L(EtOH)], where L = L1 = (N'-(3,5-dibromo-2-hydroxybenzylidene)-4-nitrobenzohydrazide (H2L1), and L = L2 = (N'-(3,5-dibromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide (H2L2). Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method. All of the investigated compounds were further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazone ligands coordinate to the MoO2 cores through enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atoms in both complexes are in octahedral coordination. Thermal stability of the complexes has also been studied.

Synthesis, biological evaluation, and molecular docking studies of 2,5-substituted-1,4-benzoquinone as novel urease inhibitors.

A series of 2,5-substituted-1,4-benzoquinone (1-6) were prepared and structurally characterized by elemental analysis, IR spectra, (1)H and (13)C NMR spectra, and single crystal X-ray determination. The urease inhibitory activities of the compounds against H. pylori urease were studied. Among the compounds, 2,5-bis(2-morpholin-4-ylethylamino)-[1,4]benzoquinone (2) shows the most effective activity with IC(50) value of 27.30 ± 2.17 µM. Docking simulation was performed to insert compound 2 into the crystal structure of H. pylori urease at the active site to determine the probable binding mode. As a result, compound 2 may be used as a potential urease inhibitor.