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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 PNP-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)(PN 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 - P{ 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., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The synthesis and characterization of ruthenium compounds of the type [RuCl(2)(NO)(dppp)(L)]PF(6) [dppp=1,3-bis(diphenylphosphino)propane; L=pyridine, 4-methylpyridine, 4-phenylpyridine and dimethyl sulfoxide] are described. The complexes were characterized by elemental analysis, UV/Vis and infrared spectroscopy, cyclic voltammetry, and X-ray crystallography for the complexes with the pyridine and 4-methylpyridine ligands. In vitro evaluation of these nitrosyl complexes revealed cytotoxic activity from 7.1 to 19.0 microM against the MDA-MB-231 breast tumor cells and showed that, in this case, they are more active than the reference metallodrug cisplatin. The 1,3-bis(diphenylphosphino)propane and the N-heterocyclic ligands alone failed to show cytotoxic activities at the concentrations tested (maximum concentration utilized=200 microM).

An arene-ruthenium (II) complex - [Ru(η6-p-cymene)(ampy)Cl]PF6, where ampy is 2-(aminomethyl)pyridine - was synthesized and used in the construction of a modified carbon ceramic electrode (Ru-CCE) for determining paracetamol (PCT) by square wave voltammetry (SWV). The modified electrode, constructed by sol-gel methods, provides a considerable enhancement of PCT oxidation. Under the optimized working conditions, the peak current is linear to the PCT concentration in the ranges of 1.99 x 10-6-3.10 x 10-5 mol L-1 with a detection limit of 5.83 x 10-7 mol L-1. The Ru-CCE showed good repeatability and reproducibility (RSD < 4%), long-term stability (>12 months). Lastly, the proposed sensor was used for the determination of PCT in pharmaceutical formulations, offering a promising tool for quality control. [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]

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: 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: Complex fac-[RuCl3(NO)(P–N)] was synthesized from [RuCl3(H2O)2(NO)] in methanol solution under reflux. The orange solid obtained was characterized by NMR (31P{1H}, 1H, 13C) and, cyclic voltammetry, ESI-MS, IR, elemental analysis and X-ray diffraction structure determination. The 31P{1H} reveals the presence of singlet at 36ppm. IR N–O stretching as KBr pellets or CH2Cl2 solution presented 1866cm−1 and 1872cm−1, respectively. [Copyright &y& Elsevier]