Synthesis, spectral characterization, and antimicrobial evaluation of new imine derived from 3-methylthiophene-2-carboxaldehyde and its Co(II), Ni(II), Cu(II), and Zn(II) metal complexes

Some new 1:1 (ML) and 1:2 (ML2) metal complexes of Co(II), Ni(II), Cu(II), and Zn(II) have been synthesized with novel ligand, that is, 4-(3-methylthiophene-2-ylmethyleneamino)-3-mercapto-6-methyl-5-oxo-1,2,4-triazine. Ligand and its metal complexes were characterized on the basis of various physicochemical techniques like elemental analysis, magnetic moment, molar conductance, cyclic voltammetry, and spectroscopic (H-1-NMR, infrared [IR], electronic, fluorescence, and electron spin resonance [ESR]) data. On the basis of these studies, octahedral and square planar geometries have been proposed for Co(II), Ni(II), Zn(II), and Cu(II) metal complexes, respectively. Thermogravimetric analysis (TGA) was carried out to study the thermal decomposition and stability of metal complexes. Electrochemical behavior of Cu(II) complexes have also been explored by cyclic voltammetry. The complexes have shown promising antimicrobial activity when checked by in vitro method against some bacterial and fungal strains. In addition to these studies, quantum mechanical approach was also performed in order to find some structural information of newly synthesized compounds.

Automated summary

Novel metal complexes of Co(II), Ni(II), Cu(II), and Zn(II) with a new ligand were synthesized and characterized using various physicochemical techniques. The complexes exhibited different geometries, thermal stability, electrochemical behavior, antimicrobial activity, and structural information was obtained through quantum mechanical approach.