Amine Garci

Synthesis, molecular structure, computational study and in vitro anticancer activity of dinuclear thiolato-bridged pentamethylcyclopentadienyl Rh(III) and Ir(III) complexes

Neutral dinuclear dithiolato-bridged pentamethylcyclopentadienyl Rh(III) complexes of the type (C5Me5)2Rh2(μ-SR)2Cl2 (R = CH2Ph, 1; R = CH2CH2Ph, 2) and cationic dinuclear trithiolato-bridged pentamethylcyclopentadienyl Rh(III) and Ir(III) complexes of the type [(C5Me5)2M2(μ-SR)3](+) (M = Rh, R = CH2Ph, 3; M = Rh, R = CH2CH2Ph, 5; M = Rh, R = CH2C6H4-p-(t)Bu, 7: M = Ir, R = CH2Ph, 4; M = Ir, R = CH2CH2Ph, 6; M = Ir, R = CH2C6H4-p-(t)Bu, 8) have been synthesized from the chloro-bridged pentamethylcyclopentadienyl Rh(III) and Ir(III) dimers (C5Me5)2M2(μ-Cl)2Cl2 by reaction with the corresponding thiol derivative (RSH). Complexes 3-8 were isolated as chloride salts. All complexes were obtained in good yield and were fully characterized by spectroscopic methods. The molecular structures of the neutral complexes (1 and 2) show interesting features: the two rhodium atoms are bridged by two thiolato ligands with no metal-metal bonds and the pentamethylcyclopentadienyl and chlorido ligands are oriented syn to each other, an uncommon conformation for such dinuclear complexes. These structural features were rationalized using DFT calculations. Additionally, the antiproliferative activity of the complexes was evaluated against the cancerous A2780 (cisplatin sensitive) and A2780cisR (cisplatin resistant) human ovarian cell lines and on the noncancerous HEK293 human embryonic kidney cells. All complexes were found to be active and the cationic iridium complexes , and are particularly cytotoxic, with IC50 values in the nanomolar range (IC50 < 0.1 μM). The catalytic activity of the complexes for the oxidation of glutathione (GSH) to GSSG was evaluated by NMR spectroscopy.

Synthesis, characterisation and in vitro anticancer activity of hexanuclear thiolato-bridged arene ruthenium metalla-prisms.

Hexanuclear thiolato-bridged arene ruthenium metalla-prisms of the general formula [(p-cymene)(6)Ru(6)(SR)(6)(tpt)(2) ](6+) (R=CH(2)Ph, CH(2)C(6)H(4)-p-tBu, CH(2)CH(2)Ph; tpt=2,4,6-tris(4-pyridyl)-1,3,5-triazine), obtained from the dinuclear precursors [(p-cymene)(2)Ru(2)(SR)(2)Cl(2)], AgCF(3)SO(3) and tpt, have been isolated and fully characterised as triflate salts. The metalla-prisms are highly cytotoxic against human ovarian cancer cells, especially towards the cisplatin-resistant cell line A2780cisR (IC(50) <0.25 μM).

Insight into the dynamic ligand exchange process involved in bipyridyl linked arene ruthenium metalla-rectangles

The dynamic ligand exchange behavior of cationic arene ruthenium metalla-rectangles of the type [(p-cymene)4Ru4(OO∩OO)2(N∩N)2]4+ (OO∩OO = oxalato, 2,5-dioxydo-1,4-benzoquinonato, 5,8-dioxydo-1,4-naphthoquinonato; N∩N = 4,4′-bipyridine-H8, 4,4′-bipyridine-D8) has been studied in solution. The robustness of the rectangular architecture has been evidenced by NMR and ESI mass spectrometry. Thermodynamic and kinetic aspects of the ligand exchange process have been explored using 1H/2D isotope labeling of the 4,4′-bipyridine connectors. This study shows that ligand exchange does not proceed spontaneously for these metalla-assemblies, even at high temperature, unless an external stimulus is applied.

2,5-Di­bromo-3,6-dimeth­oxycyclo­hexa-2,5-diene-1,4-dione

In the structure of the title compound, C8H6Br2O4, the complete molecule is generated by the application of a centre of inversion. The molecule is planar (r.m.s. deviation for all non-H atoms but methyl C = 0.0358 Å), with only the methyl groups being deviated from the plane [by ±0.321 (4) Å]. In the crystal packing, Br⋯O(methoxy) halogen bonds [3.2407 (19) Å] connect molecules into supramolecular layers parallel to (101).

Dichlorido(furfuryl­amine-κN)(η6-hexa­methyl­benzene)­ruthenium(II)

The single-crystal X-ray structure analysis of [RuCl2(C12H18)(C5H7NO)] reveals a distorted piano-stool geometry around the RuII atom, with a hexamethylbenzene ligand, two chloride ligands and a furfurylamine ligand, the latter coordinating through the amine group. In the crystal, a dimeric structure is observed as a result of N—H⋯Cl interactions between two symmetry-related molecules.