Synthesis, characterization, and biological evaluation of 4-[(4-hydroxy-7-methyl-1,3-benzothiazol-2-yl) diazenyl]-5-methyl-2-phenyl-2,4-dihydro-3-pyrazol-3-one and its metal complexes

Abstract

New mononuclear Cu(II), Co(II) and Ni(II) complexes of novel azo-dye ligand 4-[(4-hydroxy-7-methyl-1,3-benzothiazol-2-yl)diazenyl]-5-methyl-2-phenyl-2,4-dihydro-3-pyrazol-3-one (L) with O,N-donor site were synthesized and are characterized by various spectroscopic techniques. The quantum chemical parameters were evaluated for all the compounds by ZINDO/1 semi-empirical method and are compared with the experimental data. Spectral investigations suggested the octahedral geometry for Co(II) and Ni(II) complexes and distorted tetrahedral geometry for Cu(II) complex. The antibacterial activity of the compounds was screened against different microbial strains and the results indicated that all the metal complexes exhibited higher activity than the free ligand. The interaction of pUC18 DNA with the synthesized compounds was explored by gel electrophoresis technique. All metal complexes exhibited significant cleavage activity against supercoiled pUC18 DNA. The anticancer activity of the compounds was studied against K562, A549, and MDA-MB-231 by MTT assay and all the metal chelates exhibited good anticancer properties.

GRAPHICAL ABSTRACT

Keywords:

• Azo dyes
• Benzothiazole
• metal complexes
• TG-DTA
• DNA cleavage

Acknowledgements

Authors are thankful to the Department of Chemistry, Kuvempu University, Shankaraghatta, Shimoga for providing the laboratory facilities. We are grateful to the SAIF Panjab University, STIC Cochin University, SAIF IIT Madras for providing spectral and analytical data.

Disclosure statement

No potential conflict of interest was reported by the authors.