A novel azo metal complexes of 5, 5, 7-trimethyl-4, 5, 6, 7-tetrahydro-1, 3-benzothiazol as potential pharmacological agents: Synthesis and spectroscopic characterization.

Abstract A series of bioactive Cu (II), Co (II), Ni (II) and Fe (III) complexes of the novel disperse azo dye ligand was obtained from the reaction between 5, 5, 7-trimethyl-4, 5, 6, 7-tetrahydro-1, 3-benzothiazol-2-amine and 2-thioxodihydropyrimidine-4, 6 (1 H , 5 H)-dione by the conventional diazo-coupling reaction at 0–5 °C. The structural characterization of the synthesized compounds were elucidated by using various physicochemical and spectroscopic techniques. The observed lower molar conductivity values for all the metal complexes suggested their non-electrolytic nature. From the spectral investigations, it is evident that the newly synthesized azo dye behaves as a tridentate ligand and its complexes with the various metal ions found to form a six-membered chelate ring with octahedral geometry except for the Cu (II) complex which has distorted octahedral geometrical environment. Thermal behaviour of the metal complexes was studied by TG-DTA technique and exhibited good thermal stabilities and also confirmed the presence of coordinated water molecules in Ni (II) complex. Electrochemical behaviour of the Cu (II) complex was studied by cyclic voltammetry in DMF solution and the results indicated well-established quasi-reversible behaviour at a scan rate of 0.05 V-1. The results of the anti-mycobacterial and anti-inflammatory activity indicated that, the metal chelates are relatively more potent than the parent ligand. The cytotoxic effect of the synthesized compounds was studied against two cancerous cell lines HeLa and A549 by MTT assay and the Cu (II) and Fe (III) complexes were proved to be potential anticancer agents. Highlights • Synthesis of novel bioactive metal chelates derived from 5, 5, 7-trimethyl-4, 5, 6, 7-tetrahydro-1, 3-benzothiazol. • ESR spectra suggested the mononuclear nature of the complexes and all of them are having octahedral geometry except the Cu (II) complex which has distorted octahedral environment around the copper ion. • The cyclic voltammogram of the Cu (II) complex exhibited a well-established quasi-reversible behaviour in DMF solution at a scan rate of 0.05 V-1. • All the metal complexes showed enhanced pharmacological properties than the free ligand. [ABSTRACT FROM AUTHOR]