Synthesis, characterization, and biological assay of Ni(II), Pd(II), and Pt(IV) complexes based on tridentate imidazole ligand

Three new mononuclear metal complexes of the type ML(M = Ni, Pd, and Pt), with (N,N,O) azo ligand, 2-[2'-(3,4-Dimethyl carboxy phenyl)azo]-4,5-Dichloro imidazole (L1H), have been prepared and characterized using Uv-vis., FT-IR, NMR and elemental (C.H.N) analyses. In addition, all complexes were analyzed by molar conductance, magnetic susceptibility, and thermogravimetric analyses. The spectroscopic techniques showed that the ligand under investigation behaves as a tridentate ligand (N,N,O). Further, the free radical scavenging activity of ligand and metal complexes have been determined by their interaction with the stable DPPH free radical. All the compounds exhibited significant antiproliferative activity against the human breast cancer line, MCF-7, and normal cells HdFn. Results showed higher cytotoxic activity and lower IC50 values, suggesting they can kill cancer cells at very low concentrations.