Synthesis, crystal structures, and antimicrobial activities of hydrazone complexes of vanadium(V)

Abstract

Two hydrazone ligands, (E)-N′-(3-bromo-2-hydroxybenzylidene)-2-methoxybenzohydrazide (HL a ) and (E)-N′-(2-hydroxy-3-methylbenzylidene)-2-methoxybenzohydrazide (HL b ), were prepared and characterized by IR, UV-vis, and 1 H NMR spectroscopy. The corresponding vanadium(V) complexes, 2[VOL a L]·CH 3 OH (1) and [VOL b L] (2), where L is the monoanionic form of benzohydroxamic acid (HL), were prepared and characterized by IR and UV-vis spectroscopy, and single-crystal X-ray diffraction. Complex 1 crystallizes as the monoclinic space group P2 1 /c, with unit cell dimensions a = 14.4161(16) Å, b = 14.0745(16) Å, c = 24.069(2) Å, β = 96.247(2), V = 4854.5(9) Å 3 , Z = 4, R 1 = 0.0541, wR 2 = 0.1423, Goof = 1.032. Complex 2 crystallizes in the orthorhombic space group Pbca, with unit cell dimensions a = 13.5906(6) Å, b = 18.1865(11) Å, c = 18.4068(11) Å, V = 4549.5(4) Å 3 , Z = 8, R 1 = 0.0549, wR 2 = 0.1397, Goof = 1.054. X-ray analysis indicates that the complexes are mononuclear octahedral vanadium(V) complexes. The thermal behavior of the complexes was investigated. The hydrazone ligands and their complexes were also evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities using the MTT (3-(4,5-*Corresponding author. dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The two complexes have moderate to good activities against B. subtilis and S. aureus, and 1 has moderate activity against E. coli.

The crystal structure of (E)-N′-(pyridin-2-ylmethylene)pyrazine-2-carbohydrazide, C11H9N5O

“…The reason is, that they show excellent properties in many aspects, for example catalysis [6], magnetism [7], antitumor [8], antibacterial [9], antituberculosis [10]. Recently, we have synthesized and characterized some hydrazone compounds and their metal complexes [11,12].…”