Metal based triazole compounds: Their synthesis, computational, antioxidant, enzyme inhibition and antimicrobial properties

The present research work was aimed to synthesize biologically active Schiff base compound, 2-((E)-[(3-{[(Z)-(2-hydroxyphenyl)methylidene]jamino)-1H-1,2,4-triazol-5-yl)imino]methyl}phenol (L) by condensation reaction of 2-hydroxybenzaldehyde with 3,5-diamino-1,2,4-triazole. In order to evaluate the effect of metal ions on the biological properties, ligand (L) was then coordinated to the metal ions such as Fe(II), Co(ll), Ni(II) and Zn(II). Characterization of ligand and its metal complexes was done by physical, spectral and analytical data. The synthesized compounds were screened for antioxidant, enzyme inhibition and antibacterial/antifungal activities. The screening results indicated the ligand to possess bioactivity which significantly enhanced upon chelation/coordination with the metal ions. Computational studies were also carried out on the ligand to check orbital involvement and bonding interactions. The optimized frequency, intensity and geometry of the vibrational bands of ligand (L) were obtained through density functional theory (DFT) using 6-311++G (d.p) basis sets. Molecular stability and bond strength were also studied by carrying out the natural bond orbital analysis (NBO). The calculated HOMO and LUMO energies confirmed the charge transfer in the molecule of ligand. (C) 2018 Elsevier B.V. All rights reserved.