Novel palladium(II) complexes of N-(5-nitro-salicylidene)-Schiff bases: Synthesis, spectroscopic characterization and cytotoxicity investigation

Abstract

A series of palladium(II) complexes (1e–3e) with the general formulae [Pd(L)(H2O)]·xH2O were newly synthesized by the interaction of palladium(II) chloride and the monosodium salts of N-(5-nitro-salicylidene)-Schiff base ligands (1a–3a) in aqueous DMF solution. The identities of all the complexes were proven by elemental analysis, FTIR, 1H, 13C NMR, LC–MS, UV–vis, XPS, powder XRD spectra, thermal analysis, conductivity and magnetic susceptibility measurements. The obtained analytical and physicochemical results exhibited a square-planar coordination of the palladium(II) ion having a double deprotonated ligand and a coordinated water molecule. In vitro cytotoxicity of these Pd(II) complexes was screened against tumor cell lines (HeLa and MCF-7), and a normal human cell line (HEK-293). The complexes 1e and 2e exhibited a moderate antitumor activity against HeLa cell lines, while 3e had better activity than standard anticancer drug, doxorubicin. All three complexes showed the best active cytotoxicity than doxorubicin against MCF-7 cancer lines. For HEK-293 lines, a decrease in concentration of the complexes significantly decreased their toxicity.