Synthesis, characterization and biological evaluation of methyl dithiocarbonate-acenaphthenequinone (MDTCZ-ACQ) schiff base ligand and its coordination complexes with copper, nickel, zinc, and cobalt

Abstract

This study presents the characterization of a novel Schiff base ligand, methyl dithiocarbonate with acenaphthenequinone (MDTCZ-ACQ), and its coordination complexes with copper (Cu), nickel (Ni), zinc (Zn), and cobalt (Co). The ligand and its metal complexes were synthesized and characterized through techniques such as UV-vis spectroscopy, FTIR, and NMR. Structural analysis indicated a tetrahedral geometry for the metal complexes. The electronic spectrum of the ligand showed a characteristic azomethine group absorption around 282 nm, along with a C--S stretch at 1148 cm-1, and an N-N group at 1045 cm-1. The Schiff base ligand exhibited a strong peak at 1603 cm-1, attributed to the nu(C--N) bond, suggesting that the dithiocarbazate acenaphthenequinone moiety acts as a bidentate ligand coordinating through azomethine nitrogen and an oxygen atom. Biological investigations demonstrated that the Schiff base complexes showed enhanced activity against Escherichia coli, with a resistance zone of 19 mm, while the copper and zinc complexes exhibited superior antibacterial efficacy compared to nickel and cobalt complexes.