Synthesis, spectral characterization, X-ray crystal structure and antimicrobial activities of two cis dioxido-vanadium(V) complexes incorporating unsymmetrical dimalonitrile-based (NNO) Schiff base ligands

Abstract

Two tridentate NNO Schiff base ligands 2-amino-3-((E)-(2-hydroxybenzylidene)amino)maleonitrile (H2L1), 2-amino-3-((E)-(2-hydroxy-3-methoxybenzylidene)amino)maleonitrile (H2L2), and their cis dioxido-vanadium(V) complexes, [NH(CH2CH3)3][VO2(L1)] (1), [NH(CH2CH3)3][VO2(L2)] (2) have been synthesized and fully characterized using spectroscopic and physicochemical methods including FT-IR, molar conductivity, elemental analysis, 1H NMR, 13C NMR, and UV–Vis spectroscopy techniques. The structures of the V(V) complexes have been also accomplished using single-crystal X-ray diffraction. In both complexes, the coordination polyhedron around the vanadium ion is best described as a distorted square pyramid. In these structures, the donor atoms (NNO) of the monobasic Schiff base ligands and one of the oxo groups form the basal plane while the other oxo group occupies the apical position. Also, the antimicrobial activities of these compounds have been evaluated against Pseudomonas aeruginosa ATCC 27853; Staphylococcus aureus PTCC 1112, Micrococcus luteus PTCC 1110, Bacillus cereus PTCC 1015, Escherichia coli PTCC 1330, Listeria monocytogenes; Klebsiella pneumoniae, Enterococcus faecalis and Candida albicans PTCC 5027.