Two Vanadium(V) Complexes Derived from Bromo and Chloro-Substituted Hydrazone Ligands: Syntheses, Crystal Structures and Antimicrobial Property

Zi-Qiang Sun,Xiao-Yang Qiu,Shun-Feng Yu,Xin-Lan Xu,Shu-Juan Liu

doi:10.17344/acsi.2020.6236

Abstract

Two vanadium(V) complexes derived from the bromo and chloro-substituted hydrazones N'-(4-bromo-2-hydroxybenzylidene)- 2-chlorobenzohydrazide (H2L1) and N'-(3-bromo-5-chloro-2-hydroxybenzylidene)-3-methylbenzohydrazide (H2L2) with the formula [VOL1(OCH3)(CH3OH)] (1) and [VOL2(OCH3)(CH3OH)] (2) were newly synthesized and characterized by IR, UV-Vis and 1H NMR spectroscopy. The structures of H2L1 and the complexes were further confirmed by single crystal X-ray diffraction. Both vanadium complexes are mononuclear, with the metal atoms coordinated by the hydrazone ligands, methanol ligands, and methanolate ligands, and the oxo groups, forming octahedral geometry. The hydrazones and the vanadium complexes were assayed for the antimicrobial activities on Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence, and the fungi Candida albicans and Aspergillus niger. The existence of the bromo and chloro groups in the hydrazone ligands may improve the antimicrobial property.

Highlights

Hydrazone compounds and their metal complexes have received particular attention due to their interesting biological aspects like antibacterial,[1] antifungal,[2] and antitumor.[3]
The antibacterial activities of the hydrazone compounds and the vanadium complexes were tested against B. subtilis, S. aureus, E. coli, and P. fluorescence using MH (Mueller–Hinton) medium
The hydrazones H2L1 and H2L2 were readily prepared by the condensation reaction of a 1:1 molar ratio of 4-bromosalicylaldehyde with 2-chlorobenzohydrazide, and 3-bromo-5-chlorosalcylaldehyde with 3-methylbenzohydrazide, respectively in methanol

Summary

Introduction

Hydrazone compounds and their metal complexes have received particular attention due to their interesting biological aspects like antibacterial,[1] antifungal,[2] and antitumor.[3]. Single crystals of the compound H2L1 were obtained by slow evaporation of the methanolic solution in air for a week. The antibacterial activities of the hydrazone compounds and the vanadium complexes were tested against B. subtilis, S. aureus, E. coli, and P. fluorescence using MH (Mueller–Hinton) medium.

Results

Conclusion