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Complexes with general formula [RuCl(η6-p-cymene)(P-NR-P)]X (R = CH2Py (Py = pyridine) - [1a]+, CH2Ph (Ph = phenyl) - [1b]+, Ph - [1c] and p-tol (p-tol = p-tolyl) - [1d]+; X = PF6- or BF4-) were evaluated as cytotoxic agents against two cancer cell lines (HeLa and MDA-MB-231). All metal complexes are active in the range of concentrations tested (up to 100 μmol L-1). The IC50 (μmol L-1) values for the metal complexes are lower than that found for cisplatin. The activities are up to 6- and 15-fold higher than cisplatin for HeLa and MDA-MB-231 cancer cell lines, respectively. Studies of DNA binding and DNA cleavage were performed. DNA binding studies revealed a modest hypochromic shift in the metal complexes electronic spectra, indicating a weak interaction with Kb values in the range of 1.7 × 103-1.6 × 104. Although the cleavage tests revealed that in the dark DNA is not a biological target for these metal complexes, upon blue light irradiation they are activated causing DNA cleavage. Electrochemical studies showed the presence of two independent redox processes, one attributed to the oxidation process of Ru2+ → Ru3+ (EC process) and the other one to the reduction of Ru2+ → Ru1+, which is further reduced to Ru0 (ECE mechanism). In both processes, coupled chemical reactions were observed. DFT calculations were performed to support the electrochemical/chemical behavior of the complexes. The reactivity of complex [1b]BF4 with CH3CN was evaluated and two complexes were isolated [2b]BF4 and [3b]BF4. The complex mer-[RuCl(CH3CN)3(P-NCH2Ph-P)]BF4 ([2b]BF4) was isolated after refluxing the precursor [1b]BF4 in CH3CN. Isomerization of [2b]BF4 in CH3CN resulted in the formation of fac-[RuCl(CH3CN)3(P-NCH2Ph-P)]BF4. An attempt to isolate the fac-isomer by adding diethyl ether was unsuccessful, and the complex [3b]BF4 was observed as the major component. The complex [Ru2(μ-Cl3)(CH3CN)2(P-NCH2Ph-P)2]BF4 ([3b]BF4) proved to be very stable and can be obtained from both the mer- and the fac-isomers. The molecular structures of [1b]BF4 and [3b]BF4 were solved by single-crystal X-ray diffraction.

The complexes trans/cis-[RuCl2(DPEphos)(ampy)] (trans – 1a; cis – 1b) and trans/cis-[RuCl2(DPEphos)(en)] (trans – 2a; cis – 2b) were obtained from the reactions of mer-[RuCl2(DPEphos)(PPh3)] (PPh3 = triphenylphosphine) with the corresponding amine in CH2Cl2. The isomer 1a was observed in situ when the reaction was carried out at r.t.; isolation leads to mixtures with 1b, while the latter was isolated when the reaction was performed under reflux. On the other hand, trans-[RuCl2(DPEphos)(en)] (2a) was obtained at r.t., in good yield and the cis-isomer 2b was observed when the reaction was carried out under reflux or when a CH2Cl2 solution of 2a is exposed to ambient light, but 2b was not isolated in pure form even under reflux for one week. Cyclic voltammetry studies revealed the presence of one reversible process with E1/2 0.57 and 0.40 V for 1b and 2a, respectively. Both 1b and 2a were used as pre-catalysts for reduction of acetophenone and p-substituted acetophenones (F–, Me– and MeO–) in transfer-hydrogenation conditions (isopropanol, 82 °C, and pre-catalyst:KOH:acetophenones in molar ratio 1:20:500 and/or 1:20:1000) showing conversions of 93–99% and TOF values up to 4.2 104 h−1. [ABSTRACT FROM AUTHOR]

Complexes with general formulap,t-[Ru(CO)(PR3)(tren)]X2[R = Ph (1) orp-tol (2); tren = tris(2-aminoethyl)amine; X = Cl−or] were prepared from [RuCl2(CO)(dmf)(PR3)] by direct reaction with tren. The complexes were fully characterized by NMR (1H,31P{1H}, HMBC1H–31P), FTIR and ESI-MS spectroscopy, elemental analysis, and the structures ofp,t-[Ru(CO)(PPh3)(tren)](PF6)2(1•PF6) andp,t-[Ru(CO)(P{p-tol}3)(tren)]Cl2(2•Cl) were determined by X-ray diffraction. The water soluble complexes1•Cland2•Clwere tested as antimicrobial agents against Gram (+) and Gram (−) bacteria with the latter showing superior activity than the approved antimicrobial agent chloramphenicol in one of the strains. [ABSTRACT FROM AUTHOR]

Abstract: We synthesized complexes with the general formula trans-[RuCl2(CO)(PR3)(N–N)] (N–N=diimines and/or amines; PR3 =triphenylphosphine or tri-p-tolylphosphine) by reacting trans-[RuCl2(CO)(dmf)(PR3)2] (dmf= N,N-dimethylformamide) and the appropriate N–N donor ligands. We characterized the complexes by NMR (31P, 1H, nOe, HMBC, and HSQC), FTIR, and elemental analyses; we also analyzed trans-[RuCl2(CO)(PPh3)(bipy)], trans, trans-[RuCl2(CO)(P{p-tol3})(ampy)] and trans, trans-[RuCl2(CO)(PPh3)(ampy)] by X-ray diffraction. We tested the complexes as pre-catalyst for the reduction of acetophenone in transfer-hydrogenation conditions, using isopropanol as the hydrogen source. The catalyst/base/substrate molar proportion of 1:20:1000 yielded conversions up to 83% in 24h, whereas the proportion 1:20:500 furnished conversions up to 96% in 4h. In addition, p-substituted acetophenone were reduced with conversions up to 95% within 135min of reaction time. The complexes containing the ligands ampy and en were the most active–the “RuH-NH” unit promoted reactions via the outer-sphere mechanism. [Copyright &y& Elsevier]