Metal based bio-active 1,2,4 triazole derivatives: Preparation, spectral, thermal and antimicrobial studies
We report the synthesis and characterization of a series of metal complexes of bivalent Cobalt, Nickel, Copper, Zinc and Palladium with novel Schiff base ligand 4-((4-isopropoxybenzylidene)amino)-5-propyl-4H-3-thiol-1,2,4-triazole (IBPT). The ligand (IBPT) was derived by the condensation reaction of 4-isopropoxybenzaldehyde and 4-amino-5-propyl-3-thiol-1,2,4-triazole and characterised by IR and proton(1H) NMR spectroscopic techniques. The complexes have been investigated using characterised Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron spin resonance (ESR), UV−visible and fluorescence spectroscopies. Based on the comparative analysis of IR and NMR data of ligand and metal complexes, it has been suggested that the ligand chelates with metal ions in a bidentate fashion via N (azomethine) and S (thiol) atoms. Elemental analysis, molar conductance, magnetic moments and redox behaviour of complexes have also been studied. In addition, Tauc’s formula has been employed to determine the optical bandgap of complexes using the electronic spectral data. Thermogravimetric analysis revealed the number of coordinated water molecules and thermal stability of metal complexes. Various thermodynamic and kinetic parameters have been evaluated with the help of thermal data using Coats- Redfern method. The octahedral environment of divalent Cobalt, Nickel and Zinc complexes while square planner structure of Copper and Palladium complexes was elucidated with the help of spectroscopic data. Moreover, in-vitro antimicrobial activities of Schiff base ligand and its complexes were estimated against four pathogenic bacterial (two Gram Positive, two Gram negative) and three fungal strains (C. Albicans, A. Niger and A. Clavatus). The biological outcomes ensure the convenient utility of these novel complex as antimicrobial agents.
Chemical Biology Letters