Synthesis,characterization, and cytotoxicity of mixed-ligand complexes of palladium(II) with 1,10-phenanthroline and N-carbonyl-L-isoleucine dianion

Three novel palladium(II) complexes Pd(Phen)(Bzile)] (I), Pd(Phen)(p-mBzile)] (II), and Pd(Phen)(p-NBzile)] · H₂O (III), where Bzile = N-benzoyl-L-isolecine), p-MBzile = N-(p-methylbenzoyl)-L-isolecine), p-NBzile = N-(p-nitrobenzoyl)-L-isolecine), have been synthesized and characterized by elemental analysis, ES-MS, and IR. The crystal and molecular structure of the complex II has been determined by single crystal X-ray diffraction. The cytotoxicity was tested against carcinoma cell lines: KB, BGC-823, Bel-7402 and HL-60 by MTT assay. The results indicated that these complexes exerted cytotoxicity, but none of them showed higher cytotoxicity than cisplatin. The cytotoxicity against HL-60, BGC-823, Bel-7402 and KB cell lines decreases in the sequence: p-MBzile > Bzile > p-NBzile. It suggests that the acylated groups have important impact on the cytotoxicity of complexes.