Gustavo Von Poelhsitz

We describe the synthesis, physicochemical characterization, and in vitro antitumor assays of four novel analogous ruthenium(II) complexes with general formula cis-[Ru^II(N-L)(P-P)₂]PF₆, where P-P = bis(diphenylphosphine)methane (dppm, in complexes 1 and 2) or bis(diphenylphosphine)ethane (dppe, in complexes 3 and 4) and N-L = 5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione (Btsc, in complexes 1 and 3) or 5,6-diphenyltriazine-3-one (Bsc, in complexes 2 and 4). The data were consistent with cis arrangement of the biphosphine ligands. For the Btsc and Bsc ligands, the data pointed to monoanionic bidentate coordination to ruthenium(II) through N,S and N,O, respectively. Single-crystal X-ray diffraction showed that complex 1 crystallized in the monoclinic system, space group P2₁/c. Determination of the cytotoxicity profiles of complexes 1–4 gave SI values ranging from 1.19 to 3.50 against the human lung adenocarcinoma cell line A549 and the non-tumor lung cell line MRC-5. Although the molecular docking studies suggested that the interaction between DNA and complex 4 was energetically favorable, the experimental results showed that they interacted weakly. Overall, our results demonstrated that these novel ruthenium(II) complexes have interesting in vitro antitumor potential and this study may contribute to further studies in medicinal inorganic chemistry.

The title complex cis-[Ru(dppm)₂(bta)]PF₆, dppm = 1,1-bis(diphenylphosphino)methane; bta^– = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate, was prepared from the cis-[RuCl₂(dppm)₂] precursor in mild conditions. Elemental analysis, spectroscopy (FTIR, ¹H, ³¹P{¹H} and ¹⁹F{¹H} NMR) as well as single-crystal X-ray diffraction were used to characterize the new complex. Electronic structure of the complex was described utilizing TD-DFT analysis. All data indicate a good degree of purity, a cis arrangement for the diphosphines and a distorted geometry for the ruthenium center.

The title complex cis-[Ru(dppm)2(bta)]PF6, dppm = 1,1-bis(diphenylphosphino)methane; bta– = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate, was prepared from the cis-[RuCl2(dppm)2] precursor in mild conditions. Elemental analysis, spectroscopy (FTIR, 1H, 31P{1H} and 19F{1H} NMR) as well as single-crystal X-ray diffraction were used to characterize the new complex. Electronic structure of the complex was described utilizing TD-DFT analysis. All data indicate a good degree of purity, a cis arrangement for the diphosphines and a distorted geometry for the ruthenium center.

Reaction of the precursor cis,fac-[RuCl₂(dmso-S)₃(dmso-O)] with three carbazate ligands led to new compounds of the type cis,fac-[RuCl₂(dmso-S)₃(L)] (L = benzylcarbazate (bc), 1; 4-methoxybenzylcarbazate (mc), 2; or 3,5-dimethoxy-α,α-dimethylbenzylcarbazate (mmc), 3). Complexes 1–3 have been characterized by elemental analysis (CHN), FTIR, UV–vis, and ¹H and ¹³C{¹H} NMR spectroscopy. Complex 1 was also analyzed by single-crystal X-ray diffraction and theoretical calculations were performed in order to better understand its spectroscopic data and electronic structure. All collected data were consistent with substitution of one dmso ligand by a monodentate carbazate ligand. Preliminary biological assays against breast and prostate human cancer cell lines were performed in order to evaluate the cytotoxic activity of these three new complexes.