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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. [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]

Several ruthenium complexes have been investigated regarding anti- Mycobacterium tuberculosis (anti-MTb) activity, with some diphosphine-containing ruthenium complexes comparable to first and second line drugs. However, to the best of our knowledge, there is no P N P-containing ruthenium complexes applied as metallodrugs. Thus, this study focused on the synthesis, characterization and anti-MTb activity of a new series of coordination compounds with general formula [RuCl(η 6 - p -cymene)(P N R P)]X (R = CH 2 Py (Py = pyridine) − [1a] , CH 2 Ph (Ph = phenyl) − [1b] , Ph − [1c] and p -tol ( p -tol = p -tolyl) − [1d] ; X = PF 6 − or BF 4 − ). The complexes were fully characterized by NMR ( 1 H, 31 P{ 1 H}), vibrational spectroscopy (FTIR), ESI-MS, molar conductance, elemental analysis and X-ray diffraction studies. The molecular structures of [1a] PF 6 , [1c] BF 4 and [1d] PF 6 were determined and confirm the spectroscopic and ESI-MS data. The complexes were used in anti-MTb trials, and the preliminary results are presented. The complexes are promising anti-MTb agents with MIC 90 (Minimum Inhibitory Concentration of compounds required to inhibit the growth of 90% of MTb) values comparable with the Ethambutol, the reference drug used in this work, and complex [1a] BF 4 presented the highest selectivity index. [ABSTRACT FROM AUTHOR]

Reaction of fac- [RuCl 3 (NO)(P–N)] (1) with the triarylphosphines PR 3 in MeOH allows for isolation of the monocationic Ru(II) complexes [RuCl 2 (NO)(P–N)(PR 3 )]PF 6 ; P–N = o -diphenylphosphino- N , N -dimethylaniline, and R = p -MeO-C 6 H 4 (complex 2 ), p -Me-C 6 H 4 ( 3 ), Ph ( 4 ), and p -F-C 6 H 4 ( 5 ). The complexes were characterized by elemental analysis, 31 P{ 1 H}, 1 H NMR and IR spectroscopies, ESI-MS, CV, and X-ray structural data for complexes 3 – 5 . The 31 P{ 1 H} spectra display two doublets with 2 J pp values consistent with cis P-atoms. The ESI-MS spectra reveal the molecular ion [RuCl 2 (NO)(P–N)(PR 3 )] + and the fragmentation ions [M−PR 3 ] + , [M−PR 3 −Cl] + , and [M−PR 3 −2Cl] + . CV data show a one-electron, quasi-reversible reduction process centred at the Ru–NO unit that depends on the p K a of the PR 3 . The IR spectra reveal ν NO bands for coordinated NO + . A known, empirical inverse correlation between the δ P value and the Ru–P bond length of the P–N ligand that exists for a series of cis - and trans -RuX 2 (L)(P–N)(PR 3 ) complexes (X = Cl or Br), where L is a range of small molecules, is extended with L = NO + and now covers the respective ranges of about 30–80 ppm and 2.39–2.17 Å. [ABSTRACT FROM AUTHOR]

In this work, two novel ruthenium-based compounds containing mercaptothiazolinate ligands were synthesized. A methanol (MeOH) solution containing [RuCl 2 (PPh 3 ) 3 ], 2-mercaptothiazoline (Hmctz) or 2-mercaptobenzothiazoline (Hmcbtz) (ligand/Ru = 2) and triethylamine (NEt 3 ) was refluxed leading to the formation of neutral complexes with the general formula cis -[Ru(N–S) 2 (PPh 3 ) 2 ] (N–S = mctz − – complex 1 ; N–S = mcbtz − – complex 2 ). We used NMR ( 1 H and 31 P{ 1 H}), vibrational spectroscopy (FTIR), and elemental analysis to analyze these two complexes. Cyclic voltammetry revealed that complexes 1 and 2 underwent a reversible one-electron process due to the Ru(III)/Ru(II) pair. Reactivity of the complexes 1 and 2 with dmso leading to the substitution of one PPh 3 by dmso was observed (complexes 3 and 4 ). Complex 1 showed higher antimicrobial activity against Gram (+) and Gram (−) bacteria ( Bacillus subtilis and Escherichia coli , respectively). The formation of complex [Ru(mctz) 2 (dmso)(PPh 3 )] ( 3 ) was faster than complex [Ru(mcbtz) 2 (dmso)(PPh 3 )] ( 4 ) and this may account for the higher antibacterial activity of complex 1 . Single-crystal X-ray diffraction furnished the molecular structures of complex 1 and of the product of its reaction with dmso, [Ru(mctz) 2 (dmso)(PPh 3 )] ( 3 ). [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]

Abstract: Ruthenium(II) carbonyl complexes containing triarylphosphines and hybrid ligands PPh2-X (X= o-dimethylaniline – P–N, o-pyridine – P-Py, or o-anisole – P–O) were synthesized and characterized. Six new complexes with the formula cis,trans-[RuCl2(CO)(PPh2-X)(PR3)] (X= o-dimethylaniline, R=Ph 1a; X= o-pyridine, R=Ph 2a; X= o-anisole, R=Ph 3a; X= o-dimethylaniline, R= p-tol 1b; X= o-pyridine, R= p-tol 2b; and X= o-anisole, R= p-tol 3b) were obtained by starting from the appropriate precursors, [RuCl2(CO)(DMF)(PPh3)2] or [RuCl2(CO)(DMF)(P{p-tol}3)2]. The two chlorine atoms are in cis position to each other, and the monophosphine (PPh3 or P{p-tol}3) is in trans position to the nitrogen or oxygen of the PPh2-X ligand. The synthesized complexes were characterized by 1D–1H, 31P{1H} and 2D-correlations HMBC 31P–1H NMR, vibrational spectroscopy, elemental analysis, and X-ray diffraction structural determination (for complexes 1a, 2a·CH2Cl2 , 3a, and 3b·CH2Cl2 ). Only the complexes containing the P–O ligand (3a and 3b) reacted with carbon monoxide (at 1atm and room temperature). The NMR (31P{1H}, 1H) data was compatible with carbon monoxide coordination at the OCH3 position, which led to the formation of dicarbonyl complexes [RuCl2(CO)2(P–O)(PR3)] (R=Ph 4a or p-tol 4b), and proved the hemilabile behavior of the P–O ligand. In addition, the complexes underwent isomerization in solution when exposed to ambient light, and the products were analyzed by 31P{1H} NMR. The X-ray structures and the chemical shift in the 31P NMR spectra were correlated and discussed. [Copyright &y& Elsevier]

Abstract: Complex fac-[RuCl3(NO)(P–N)] (1) was synthesized from the reaction of [RuCl3(H2O)2(NO)] and the P–N ligand, o-[(N,N-dimethylamino)phenyl]diphenylphosphine) in refluxing methanol solution, while complex mer,trans-[RuCl3(NO)(P–N)] (2) was obtained by photochemical isomerization of (1) in dichloromethane solution. The third possible isomer mer,cis-[RuCl3(NO)(P–N)] (3) was never observed in direct synthesis as well as in photo- or thermal-isomerization reactions. When refluxing a methanol solution of complex (2) a thermally induced isomerization occurs and complex (1) is regenerated. The complexes were characterized by NMR (31P{1H}, 15N{1H} and 1H), cyclic voltammetry, FTIR, UV–Vis, elemental analysis and X-ray diffraction structure determination. The 31P{1H} NMR revealed the presence of singlet at 35.6 for (1) and 28.3ppm for (2). The 1H NMR spectrum for (1) presented two singlets for the methyl hydrogens at 3.81 and 3.13ppm, while for (2) was observed only one singlet at 3.29ppm. FTIR Ru–NO stretching in KBr pellets or CH2Cl2 solution presented 1866 and 1872cm−1 for (1) and 1841 and 1860cm−1 for (2). Electrochemical analysis revealed a irreversible reduction attributed to RuII–NO+ →RuII–NO0 at −0.81V and −0.62V, for (1) and (2), respectively; the process RuII →RuIII, as expected, is only observed around 2.0V, for both complexes. Studies were conducted using 15NO and both complexes were isolated with 15N-enriched NO. Upon irradiation, the complex fac-[RuCl3(NO)(P–N)] (1) does not exchange 14NO by 15NO, while complex mer,trans-[RuCl3(NO)(P–N)] (2) does. Complex mer,trans-[RuCl3(15NO)(P–N)] (2′) was obtained by direct reaction of mer,trans-[RuCl3(NO)(P–N)] (2) with 15NO and the complex fac-[RuCl3(15NO)(P–N)] (1′) was obtained by thermal-isomerization of mer,trans-[RuCl3(15NO)(P–N)] (2′). DFT calculation on isomer energies, electronic spectra and electronic configuration were done. For complex (1) the HOMO orbital is essentially Ru (46.6%) and Cl (42.5%), for (2) Ru (57.4%) and Cl (39.0%) while LUMO orbital for (1) is based on NO (52.9%) and is less extent on Ru (38.4%), for (2) NO (58.2%) and Ru (31.5%). [Copyright &y& Elsevier]

Abstract: The “Ru(P–P)” unit (P–P=diphosphine) is recognized to be an important core in catalytic species for hydrogenation of unsaturated organic substrates. Thus, in this study we synthesized six new complexes containing this core, including the binuclear complex [(dppb)(CO)Cl2Ru-pz-RuCl2(CO)(dppb)] (pz=pyrazine) which can be used as a precursor for the synthesis of cationic carbonyl species of general formula [RuCl(CO)(dppb)(N–N)]PF6 (N–N=diimine). Complexes with the formula [RuCl(py)(dppb)(N–N)]PF6 were synthesized by exhaustive electrolysis of these carbonyl compounds or from the precursors [RuCl2(dppb)(N–N)]. The new complexes were characterized by microanalysis, conductivity measurements, IR and 31P{1H} NMR spectroscopy, cyclic voltammetry and X-ray crystallography. [Copyright &y& Elsevier]

Abstract: The synthesis and characterization of trans/cis-[RuCl2(dppf)(diimines)], dppf=1,1′-bis(diphenylphosphino)ferrocene; diimines=2,2′-bipyridine (trans/cis-(1)), the new complexes with 4,4′-dimethyl-2,2′-bipyridine (trans/cis-(2)) and 1,10-phenanthroline (cis-(3)) are presented. The complexes were synthesized using two routes and the trans/cis-isomer formation is dependent upon conditions and the precursor applied. The trans-isomer (kinetic) readily isomerizes to the cis-isomer (thermodynamic) when exposed to light (fluorescent) and this process was followed by cyclic voltammetry and UV–vis. The electrochemical studies on these complexes reveal that Fe(III)/Fe(II) couples are insensitive to the isomer (trans/cis) formed, but the Ru(III)/Ru(II) couples are dependent on the isomer. Transfer-hydrogenation reactions for reduction of acetophenone were conducted using complexes cis-(1) and cis-(2) and the results are compared with that obtained for similar complexes. X-ray structure for cis-(3) are presented and discussed. [Copyright &y& Elsevier]