Co(II), Ni(II), Cu(II), and Zn(II) complexes of 4-aminoantipyrine-derived Schiff base. Synthesis,structural elucidation,thermal, biological studies,and photocatalytic activity

The Schiff base ligand was prepared from 4-aminoantipyrine, acetamide, and m-phenylenediamine. Metal salts used for the synthesis of these complexes are Co(II), Ni(II), Cu(II), and Zn(II) acetates. The elemental analysis results are in accordance with proposed formula assigned to these complexes. In the IR spectra, the imine band is shifted to a lower wave number in the complexes. UV spectra and magnetic susceptibility measurements proposed square planar geometry for Co(II), Ni(II), and Cu(II) complexes and tetrahedral geometry for Zn(II) complex. The grain size of the metal complexes was estimated by the Scherrer formula using powder XRD. In the present study, the ligand and its metal complexes are found to be nanocrystalline. Thermal decomposition pattern is in agreement with the proposed formula of the complexes. Irreversible redox behavior of the complex was identified by cyclic voltammetric analysis. The photocatalytic activity of the synthesized complexes are high under UV-spectra using methylene blue dye. DNA studies reveal that the synthesized complexes exhibit both DNA cleavage and DNA binding properties. Antibacterial and antifungal activities were done by the minimum inhibitory concentration (MIC) method. Anticancer activity shows that Cu(II) complex has the highest cytotoxic effect in SK-MEL-28 cell line.