Palladium(II) complexes with R2edda-derived ligands. Part II. Synthesis, characterization and in vitro antitumoral studies of R2eddip esters and palladium(II) complexes

New R2eddip-type esters (R = cyclopentyl, L3·2HCl 1.5H2O; cyclohexyl, L4·2HCl·H2O) and corresponding palladium(II) complexes, [PdCl2L3] (3) and [PdCl2L4]·H2O (4), as well as [PdCl2L2] (2; L2 diisobutyl ester of eddip) were synthesized and characterized by IR, 1H and 13C NMR spectroscopies and elemental analysis. The crystal structure of L3·2HCl·2CHCl3 was resolved and is given herein. The NMR spectroscopy confirmed the presence of two isomers (from three possible) for each palladium(II) complex. DFT calculations support the formation of two diastereoisomers. In addition, antitumoral investigations were performed and these investigations also included the diisopropyl ester of eddip (L1) and corresponding palladium(II) complex, [PdCl2L1] (1). In vitro antiproliferative activity was determined against several tumor cell lines HeLa, Fem-x, K562 and rested and stimulated normal immunocompetent cells (human peripheral blood mononuclear cells -PBMCs) using MTT test.

Graphical abstractCompounds R2eddip·2HCl esters (L2·2HCl–L4·2HCl) and corresponding palladium(II) complexes (1–4) were tested against HeLa, Fem-x, K562 and rested and stimulated PBMCs. The order of activity is related to R substituent in R2eddip (R = Cy > cPe > iBu > iPr) in both esters and palladium(II) complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide