Bojana B. Zmejkovski

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

New R(2)eddip-type esters (R = cyclopentyl, L3 x 2 HCl 1.5 H(2)O; cyclohexyl, L4 x 2 HCl x H(2)O) and corresponding palladium(II) complexes, [PdCl(2)L3] (3) and [PdCl(2)L4] x H(2)O (4), as well as [PdCl(2)L2] (2; L2 diisobutyl ester of eddip) were synthesized and characterized by IR, (1)H and (13)C NMR spectroscopies and elemental analysis. The crystal structure of L3 x 2 HCl x 2 CHCl(3) 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, [PdCl(2)L1] (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.

Palladium(II) complexes with R2edda-derived ligands

Abstract Four palladium(II) complexes with R2edda ligands, dichlorido(O,O′-dialkylethylenediamine-N,N′-diacetate)palladium(II) monohydrates, [PdCl2(R2edda)]∙H2O, R = Me, Et, n-Pr, i-Bu, and the new ligand precursor i-Bu2edda∙2HCl∙H2O, O,O′-diisobutylethylenediamine-N,N′-diacetate dihydrochloride monohydrate, were synthesized and characterized by IR, 1H and 13C NMR spectroscopy, and elemental analysis. DFT calculations were performed for the palladium(II) complexes and a high possibility for isomer formation due to stereogenic N ligand atoms was confirmed. Moreover, DFT simulations revealed energetic profile of isomer formation. Computational outcomes are in agreement with spectroscopic instrumental findings, both strongly indicating a non-stereoselective reaction between selected esters and K2[PdCl4], forming isomers.

Antiproliferative Activity of Gold(III) Complexes with Esters of Cyclohexyl-Functionalized Ethylenediamine-N,N’-Diacetate

Abstract Six gold(III) complexes with esters of cyclohexyl-functionalized ethylenediamine-N,N’-diacetate, general formula [AuCl2{(S,S)-R2eddch}]PF6, [(S,S)-eddch = (S,S)-ethylenediamine-N,N’-di-2-(3-cyclohexyl)propanoate, R = Me, Et, n-Pr, n-Bu, i-Bu, i-Am, 1–6, respectively], were tested against cancer cell lines such as human melanoma Fem-x, human colon carcinoma LS174T and non-small cell lung carcinoma A549 as well as a non-cancerous human embryonic lung fibroblasts MRC-5 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with the aim of assessing in vitro antitumoral activity and selectivity. All investigated complexes showed lower cytotoxicity and better or similar selectivity in comparison to cisplatin, used as reference compound. Complex [AuCl2{(S,S)-(i-Am)2eddch}]PF6 (6) demonstrated the highest activity against Fem-x (IC50 = 14.98 ± 0.34 μM). Additionally, the same complex expressed 4.5 times higher selectivity than cisplatin.

(S,S)-N,N′-Bis(1-carb­oxy-2-methyl­prop­yl)ethyl­enediammonium dihalide cyclo­penta­nol tetra­solvate (halide = bromide/chloride ≃ 1:12)

In the crystal structure of the title compound, C12H26N2O4 2+·2(Br0.085Cl0.915)−·4C5H9OH, the complete cation is generated by crystallographic twofold symmetry. Contamination of the chloride counter-anion with bromide occured during the preparation, due to the use of 1,2-dibromoethane. One of the solvent molecules is disordered, with occupancies 0.53 (3):0.47 (3). The crystal packing is stabilized by an infinite two dimensional ⋯X⋯H—N—H⋯X⋯ hydrogen-bonding network (X: Br−/Cl− ≃ 1:12). In addition, O—H⋯X and O—H⋯O hydrogen bonds involving solvent molecules are observed.