Palladium(ii) and platinum(ii) complexes with ONN donor pincer ligand: synthesis, characterization and in vitro cytotoxicity study

Abstract

New Pd(II) and Pt(II) complexes, [Pd(HL)Cl₂] (C1) and [Pt(L)Cl] (C2) with ONN donor pincer ligand, 5-(diethylamino)-2-((Z)-((E)-(phenyl(pyridin-2-yl)methylene)hydrazono)methyl)phenol (HL) were synthesized and thoroughly characterized using spectroscopic techniques. X-ray structures of the complexes revealed that HL acts as bidentate N,N and tridentate O,N,N chelator in Pd(II) and Pt(II) complexes, respectively. The antiproliferative activity of the complexes was explored against four different human cancer (MCF-7, HCT116, A549, HepG2) cell lines. However, the maximum cytotoxicity was seen in the HepG2 cell line [IC₅₀ = 6–12 μM] for both the complexes. IC₅₀ for both complexes, C1 and C2, toward human peripheral blood mononuclear cells (hPBMC) cells were found to be >200 μM. The cytotoxicity of platinum complex (C2) was comparable to that of the cisplatin in HepG2 cell lines.