Showing papers by "Dino Villagrán published in 2014"
TL;DR: Variable temperature crystallographic and magnetic data as well as density functional theory calculations unequivocally demonstrate the occurrence of π interactions between the p orbitals of the chlorine ligand and the π* orbitals in the Ru2(5+) units.
Abstract: Variable-temperature magnetic and structural data of two pairs of diruthenium isomers, one pair having an axial ligand and the formula Ru2(DArF)4Cl (where DArF is the anion of a diarylformamidine isomer and Ar = p-anisyl or m-anisyl) and the other one being essentially identical but devoid of axial ligands and having the formula [Ru2(DArF)4]BF4, show that the axial ligand has a significant effect on the electronic structure of the diruthenium unit. Variable temperature crystallographic and magnetic data as well as density functional theory calculations unequivocally demonstrate the occurrence of π interactions between the p orbitals of the chlorine ligand and the π* orbitals in the Ru25+ units. The magnetic and structural data are consistent with the existence of combined ligand σ/metal σ and ligand pπ/metal-dπ interactions. Electron paramagnetic resonance data show unambiguously that the unpaired electrons are in metal-based molecular orbitals.
20 citations
TL;DR: Results indicate that in vivo, the pyridineamine ligands are likely to dissociate from the complex, forming a platinum DNA adduct with anti-proliferative activity, and suggest that complexes 13 and 14 hold promise as potential anti-cancer agents.
Abstract: Although cisplatin is considered as an effective anti-cancer agent, it has shown limitations and may produce toxicity in patients. Therefore, we synthesized two cis-dichlorideplatinum(II) compounds (13 and 14) composed of meta- and para-N,N-diphenyl pyridineamine ligands through a reaction of the amine precursors and PtCl2 with respective yields of 16 and 47 %. We hypothesized that compounds 13 and 14, with lipophilic ligands, should transport efficiently in cancer cells and demonstrate more effectiveness than cisplatin. When tested for biological activity, compounds 13 and 14 were found to inhibit the growth of MCF 7 and MDA-MB-231 cells (IC50s 1 ± 0.4 µM and 1 ± 0.2 µM for 13 and 14, respectively, and IC50 7.5 ± 1.3 µM for compound 13 and 1 ± 0.3 µM for compound 14). Incidentally, these doses were found to be lower than cisplatin doses (IC50 5 ± 0.7 µM for MCF 7 and 10 ± 1.1 µM for MDA-MB-231). Similar to cisplatin, 13 and 14 interacted with DNA and induced apoptosis. However, unlike cisplatin, they blocked the migration of MDA-MB-231 cells suggesting that in addition to apoptotic and DNA-binding capabilities, these compounds are useful in blocking the metastatic migration of breast cancer cells. To delineate the mechanism of action, computer-aided analyses (DFT calculations) were conducted for compound 13. Results indicate that in vivo, the pyridineamine ligands are likely to dissociate from the complex, forming a platinum DNA adduct with anti-proliferative activity. These results suggest that complexes 13 and 14 hold promise as potential anti-cancer agents.
10 citations