Transition metal complexes of a hydrazone–oxime ligand containing the isonicotinoyl moiety: Synthesis, characterization and microbicide activities

• Published in: Applied organometallic chemistry 2018-07, Vol.32 (7), p.n/a
• Main Authors: Shakdofa, Mohamad M.E., El‐Saied, Fathy A., Rasras, Anas J., Al‐Hakimi, Ahmed N.
• Format: Article
• Language: English
• Subjects: Biological activity; Carbonyl groups; Carbonyls; Chemical bonds; Chemistry; Cobalt; Coordination compounds; Copper; E coli; Electron paramagnetic resonance; Electron spin; ESR; Hydrazones; hydrazone–oxime; isonicotinoyl hydrazide; Ligands; Magnetic permeability; metal complexes; Metals; microbicide activities; Planar structures; Spectra; Spectral methods; Spin resonance; Transition metal compounds
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.4376

Complexes of VO2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Ru3+ and UO22+ with (3‐(hydroxyimino)butan‐2‐ylidene)isonicotinohydrazide were synthesized and characterized using physical and spectral methods. Analytical data revealed that the complexes formed in 1:1 or 1:2 metal–ligand ratios. Spectral studies showed that the ligand bonded to the metal ion in neutral tridentate, monobasic tridentate or monobasic bidentate fashion through azomethine nitrogen atom, protonated/deprotonated imine oxime group and/or ketonic/enolic carbonyl group. From the electronic spectral data together with magnetic susceptibility values a square planar, tetrahedral or distorted octahedral structure can be proposed for all complexes. Electron spin resonance spectra for Cu2+ complexes (2–4) revealed axial symmetry with g|| > g⊥ > ge, indicating distorted octahedral or square planar structures and the unpaired electron exists in a dx2−y2 orbital with marked covalent bond feature. The prepared complexes showed good to excellent biological activity, and the most active complexes against Aspergillus niger were 4 and 9 with zone of inhibition of 25 and 23 mm, respectively. Complexes 10 and 11 showed interesting activity against Escherichia coli with zone of inhibition of 44 and 32 mm, respectively. Complexes of (3‐(hydroxyimino)butan‐2‐ylidene)isonicotinohydrazide were synthesized and characterized using physical and spectral methods. Their microbicide activity against Aspergillus niger and Escherichia coli was examined using the well diffusion method.