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The ruthenium(II) compounds cis-[Ru(bpy) 2 (4-bzpy)(CO)](PF 6 ) 2 (I) and cis-[Ru(bpy) 2 (4-bzpy)(Cl)](PF 6 ) (II) (4-bzpy=4-benzoylpyridine, bpy=2,2'-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The crystal structure of II was determined by X-ray diffraction. The photochemical behavior of I in aqueous solution shows that irradiation with ultraviolet light (365nm) releases both CO and 4-bzpy leading to the formation of the cis-[Ru(bpy) 2 (H 2 O) 2 ] 2+ ion as identified by NMR and electronic spectroscopy. Carbon monoxide release was confirmed with the myoglobin method and by gas chromatographic analysis of the headspace. CO release was not observed when aqueous I was irradiated with blue light (453nm). Changes in the electronic and 1 H NMR spectra indicate that I undergoes photoaquation of 4-bzpy to form cis-[Ru(bpy) 2 (CO)(H 2 O)] 2+ . Blue light irradiation of aqueous II released the coordinated 4-bzpy to give the cis-[Ru(bpy) 2 (H 2 O)(Cl)] 2+ ion. When the latter reaction was carried out in the presence of the nucleobase guanine, Ru-guanine adducts were formed, indicating that the metal containing photoproduct may also participate in biologically relevant reactions. The photochemical behavior of I indicates that it can release either CO or 4-bzpy depending on the wavelength chosen, a feature that may have therapeutic application., (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).

Background and Purpose: The discovery of the pharmacological functions of nitric oxide has led to the development of NO donor compounds as therapeutic agents. A new generation of ruthenium NO donors, cis-[Ru(NO)(bpy)(2)L]X(n), has been developed, and our aim was to show that these complexes are able to lyse Trypanosoma cruzi in vitro and in vivo., Experimental Approach: NO donors were incubated with T. cruzi and their anti-T. cruzi activities evaluated as the percentage of lysed parasites compared to the negative control. In vivo, trypanocidal activity was evaluated by observing the levels of parasitaemia, survival rate and elimination of amastigotes in mouse myocardial tissue. The inhibition of GAPDH was monitored by the biochemical reduction of NAD(+) to NADH., Key Results: The NO donors cis-[Ru(NO)(bpy)(2)L]X(n) presented inhibitory effects on T. cruzi GAPDH (IC(50) ranging from 89 to 153 microM). The crystal structure of the enzyme shows that the inhibitory mechanism is compatible with S-nitrosylation of the active cysteine (cys166) site. Compounds cis-[Ru(NO)(bpy)(2)imN](PF(6))(3) and cis-[Ru(NO)(bpy)(2)SO(3)]PF(6), at a dose of 385 nmol.kg(-1), yielded survival rates of 80 and 60%, respectively, in infected mice, and eradicated any amastigotes from their myocardial tissue., Conclusions and Implications: The ruthenium compounds exhibited potent in vitro and in vivo trypanocidal activities at doses up to 1000-fold lower than the clinical dose for benznidazole. Furthermore, one mechanism of action of these compounds is via the S-nitrosylation of Cys166 of T. cruzi GAPDH. Thus, these compounds show huge potential as candidates for the development of new drugs for the treatment of Chagas's disease.

The ruthenium(II) compounds cis-[Ru(bpy)2(4-bzpy)(CO)](PF6)2 (I) and cis-[Ru(bpy)2(4-bzpy)(Cl)](PF6) (II) (4-bzpy=4-benzoylpyridine, bpy=2,2'-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The crystal structure of II was determined by X-ray diffraction. The photochemical behavior of I in aqueous solution shows that irradiation with ultraviolet light (365nm) releases both CO and 4-bzpy leading to the formation of the cis-[Ru(bpy)2(H2O)2]2+ ion as identified by NMR and electronic spectroscopy. Carbon monoxide release was confirmed with the myoglobin method and by gas chromatographic analysis of the headspace. CO release was not observed when aqueous I was irradiated with blue light (453nm). Changes in the electronic and 1H NMR spectra indicate that I undergoes photoaquation of 4-bzpy to form cis-[Ru(bpy)2(CO)(H2O)]2+. Blue light irradiation of aqueous II released the coordinated 4-bzpy to give the cis-[Ru(bpy)2(H2O)(Cl)]2+ ion. When the latter reaction was carried out in the presence of the nucleobase guanine, Ru-guanine adducts were formed, indicating that the metal containing photoproduct may also participate in biologically relevant reactions. The photochemical behavior of I indicates that it can release either CO or 4-bzpy depending on the wavelength chosen, a feature that may have therapeutic application.

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype. The high rate of metastasis associated to the fact that these cells frequently display multidrug resistance, make the treatment of metastatic disease difficult. Development of antitumor metal-based drugs was started with the discovery of cisplatin, however, the severe side effects represent a limitation for its clinical use. Ruthenium (Ru) complexes with different ligands have been successfully studied as prospective antitumor drugs. In this work, we demonstrated the activity of a series of biphosphine bipyridine Ru complexes (1) [Ru(SO4)(dppb)(bipy)], (2) [Ru(CO3)(dppb)(bipy)], (3) [Ru(C2O4)(dppb)(bipy)] and (4) [Ru(CH3CO2)(dppb)(bipy)]PF6 [where dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2’-bipyridine], on proliferation of TNBC (MDA-MB-231), estrogen-dependent breast tumor cells (MCF-7) and a non-tumor breast cell line (MCF-10A). Complex (4) was most effective among the complexes and was selected to be further investigated on effects on tumor cell adhesion, migration, invasion and in apoptosis. Moreover, DNA and HSA binding properties of this complex were also investigated. Results show that complex (4) was more efficient inhibiting proliferation of MDA-MB-231 cells over non-tumor cells. In addition, complex (4) was able to inhibit MDA-MB231 cells adhesion, migration and invasion and to induce apoptosis and inhibit MMP-9 secretion in TNBC cells. Complex (4) should be further investigated in vivo in order to stablish its potential to improve breast cancer treatment. [ABSTRACT FROM AUTHOR]

We herein report the synthesis and characterization of Ru(II)/amino acid complexes with general formula [Ru(AA-H)(dppb)(4-mebipy)](PF6), where AA-H means the deprotonated amino acids Gly, Ala, Val, Met, Trp, Tyr, and Ser; dppb is 1,4-bis(diphenylphosphino)butane and 4-mebipy = 4,4′-dimethyl-2,2′-bipyridine. The complexes were characterized by31P{1H},13C, and1H NMR spectroscopy, as well as X-ray crystallographic analysis of [Ru(DL-Ala-H)(dppb)(4-mebipy)]+, suggesting the presence of diastereoisomers. The complexes exhibit IC50values against breast tumor cells (MDA-MB-231) comparable with cisplatin. In addition, the Ru(II)-based complex with tryptophan inhibited tumor cell adhesion to collagen type I. Therefore, the use of ruthenium complexes containing amino acids can be an interesting tool for development of new therapeutic agents. [ABSTRACT FROM AUTHOR]

• Three new Ru(II) complexes were prepared. • Full characterization is reported. • Single-crystal X-ray diffraction confirm the molecular structures. • DFT are in agreement with experimental data. Reactions of cis -[RuCl 2 (P-P)(bipy)] precursors with the SpymMe 2 ligand (4,6-dimethyl-2-pyrimidinethiol) yielded complexes of the [Ru(SpymMe 2)(P-P)(bipy)]PF 6 type, where P-P = 1,2-bis(diphenylphosphino)ethane (dppe - for complex 1), 1,3-bis(diphenylphosphino)propane (dppp - for complex 2) and 1,1'-bis(diphenylphosphino)ferrocene (dppf - for complex 3) and bipy = 2,2'-bipyridine. The new compounds were obtained by displacing the chlorido ligands from the precursors and coordination of one monoanionic 4,6-dimethyl-2-pyrimidinethiol ligand. All complexes were characterized by spectroscopic, electrochemical and elemental analysis techniques, as well as single-crystal X-ray diffraction, where the structures of complexes 1, 2 and 3 showed that the SpymMe 2 ligand coordinates to the ruthenium(II) center as bidentated, yielding complexes with the sulfur atom trans positioned to the nitrogen atom from the bipy ligand. A theoretical study of the structures of the complexes was performed using the DFT/B3LYP method. Distances and angles of optimized structures agree with X-ray experimental data. Furthermore, the calculated IR and UV-Vis spectra are compatible with experimental data. Charge decomposition analysis (CDA) and NBO (natural bond orbitals) charges showed that there was an overall charge transfer from bipy and P-P ligands to the ruthenium centers. Higher electrochemical stability and 1H and 31P{1H} NMR shifts of 1, 2 and 3 compared with precursors could be explained by the lower values of calculated molecular orbital energies, NBO charge on atoms and CDA data. Finally, the structure of the isomers of complexes 1, 2 and 3, considering the sulfur atom trans positioned to the phosphorus atom, were optimized, showing that they are slightly less stable, presenting total energy higher, 10.4, 31.5 and 60.5 kJ/mol than 1, 2 and 3 , where nitrogen is trans to the phosphorus atom. [ABSTRACT FROM AUTHOR]

Thirteen new ruthenium amino acid complexes were synthesized and characterized. They were obtained by the reaction of α-amino acids (AA) with [RuCl 2 (P-P)(N-N)], where P-P = 1,4-bis(diphenylphosphino)butane (dppb) or 1,3-bis(diphenylphosphino)propane (dppp) and N-N = 4,4′-dimethyl-2,2′-bipyridine (4′-Mebipy), 5,5′-dimethyl-2,2′-bipyridine (5′-Mebipy) or 4,4′-Methoxy-2-2′-bipyridine (4′-MeObipy). This afforded a family of complexes formulated as [Ru(AA-H)(P-P)(N-N)]PF 6 , where AA = glycine (Gly), L-alanine (Ala), L-valine (Val), L-tyrosine (Tyr), L-tryptophan (Trp), L-histidine (His) and L-methionine (Met). All compounds were characterized by elemental analysis, spectroscopic and electrochemical techniques. The [Ru(AA-H)(P-P)(N-N)]PF 6 complexes are octahedral (the AA-H ligand binding involves N-amine and O-carboxylate), diamagnetic (low-spin d 6 , S = 0) and present bands due to electronic transitions in the visible region. 1 H, 13 C{ 1 H} and 31 P{ 1 H} NMR spectra of the complexes indicate the presence of C 2 symmetry, and the identification of diastereoisomers. In vitro cytotoxicity assays of the compounds and cisplatin were carried out using MDA-MB-231 (human breast) tumor cell line and a non-tumor breast cell line (MCF-10A). Most complexes present promising results with IC 50 values comparable with the reference drug cisplatin and high selectivity indexes were found for the complexes containing L-Trp. The binding of two Ru-precursors of the type [RuCl 2 (dppb)(N N)] (N-N = 4′-MeObipy or 4′-Mebipy) to the blood transporter protein human serum albumin (HSA) was evaluated by fluorescence and circular dichroism spectroscopy. Both complexes bind HSA, probably in the hydrophobic pocket near Trp214, and the Ru-complex containing 4′-MeObipy shows higher affinity for HSA than the 4′-Mebipy one. [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]

New complexes with the general formula [RuCl(NIC)(dppb)(X-bipy)]PF 6 were prepared by exchanging the Cl- trans ligand to the phosphorus atom by Nicotinamide (NIC). DNA and human serum albumin interactions were evaluated. Compound C3 showed high activity and selectiveness in WM1366 tumor lines, SK-MEL-147 and mainly CHL-1. Which were correlated to the generation of species that react to oxygen (ROS). [Display omitted] A set of new ruthenium complexes, [RuCl(NIC)(dppb)(4,4′-Me-bipy)]PF 6 (C1) , [RuCl(NIC)(dppb)(4,4′-Methoxy-bipy)]PF 6 (C2), and [RuCl(NIC)(dppb)(5,5′-Me-bipy)]PF 6 (C3), where NIC = 3-pyridinecarboxamide, 4,4′-Me-bipy = 4,4′-dimethyl-2,2′-bipyridine, 4,4′-Methoxy-bipy = 4,4′-dimethoxy-2,2′-bipyridine, and 5,5′-Me-bipy = 5,5′-dimethyl-2,2′-bipyridine were synthesized and characterized by elemental analysis, UV/Vis and infrared spectroscopy, 31P{1H},1H, 13C{1H} nuclear magnetic resonance (NMR), and cyclic voltammetry. In addition, the structure of [RuCl(NIC)(dppb)(4,4′-Me-bipy)]PF 6 was confirmed by single crystal X-ray diffraction (XRD). The solution stability study of C1-C3 showed the formation of pyridine which was coordinated due to solvent protic attacked to nicotinamide, and an elimination reaction of a carbamate group was observed. C1 - C3 interacted with DNA through intercalation, electrostatic forces of attraction, or hydrogen bonding. The complexes interacted, moderately and spontaneously, with HSA, mainly through Van der Waals and hydrogen bond interactions. An in vitro evaluation of the (C1-C3) complexes revealed a cytotoxicity against MCF-7, HepG2, A549, SK-MEL-147, WM1366, and CHL-1. A higher cytotoxicity was observed for compound (C3) against melanoma cell cancer (CHL-1). Moreover, the (C3) complex inhibited the clonogenic capacity and cell cycle progression of CHL-1 cells and induced apoptosis involving the production of reactive oxygen species (ROS). [RuCl(py)(dppb)(5,5′-Me-bipy)]PF 6 presented a very close C3 cytotoxicity against melanoma cell cancer (CHL-1). [ABSTRACT FROM AUTHOR]

In this work we present the synthesis and characterization of six new ruthenium compounds with general formulae [Ru(L)(dppb)(bipy)]PF 6 and [Ru(L)(dppe) 2 ]PF 6 where L = salicylic acid (Sal), 4-aminosalicylic acid (AmSal) or 2,4-dihydroxybenzoic acid (DiSal), dppb = 1,4- bis (diphenylphosphino)butane, dppe = 1,2- bis (diphenylphosphino)ethane and bipy = 2,2′-bipyridine. The complexes were characterized by elemental analysis, molar conductivity, cyclic voltammetry, NMR, UV–vis and IR spectroscopies, and two by X-ray crystallography. The 31P{1H} NMR spectra of the complexes with the general formula [Ru(L)(dppe) 2 ]PF 6 showed that the phosphorus signals are solvent-dependent. Aprotic solvents, which form strong hydrogen bonds with the complexes, inhibit the free rotation of the salicylic acid-based, modifying the diphosphine cone angles, leading to distortion of the phosphorus signals in the NMR spectra. The cytotoxicity of the complexes was evaluated in MCF-7, MDA-MB-231, SKBR3 human breast tumor cells, and MCF-10 non-tumor cell lines. The complexes with the structural formula [Ru(L)(dppe) 2 ]PF 6 were the most cytotoxic, and the complex [Ru(AmSal)(dppe) 2 ]PF 6 with L = 4-aminosalicylic acid ligand was the most selective for the MDA-MB-231 cell line. This complex interacts with the transferrin and induces apoptosis through the intrinsic pathway, as demonstrated by increased levels of proteins involved in apoptotic cell death. [Display omitted] • Six Ru(II) complexes of salicylic acid and derivatives were synthesized. • Complex [Ru(AmSal)(dppe) 2 ]PF 6 – Ru(5) was the most selective against TNBC. • Ru(5) inhibited colony formation by acting as a cytotoxic and cytostatic agent. • Ru(5) induced tumor cells apoptosis, altering the mitochondrial membrane potential. • Ru (5) induced cell death through intrinsic apoptotic pathway signaling. [ABSTRACT FROM AUTHOR]

Three promising antimycobacterium tuberculosis ruthenium(II) complexes with the deprotonated ligands 2-hydroxynicotinic acid (2-OHnicH), 6-hydroxynicotinic acid (6-OHnicH) and 3-hydroxypicolinic acid (3-OHpicH) were synthesized and characterized. Structural analysis revealed three different coordination modes depending of the hydroxypyridinecarboxylate ligand. In the complex [Ru(2-OHnic)(dppb)(bipy)]PF 6 ( 1 ), the 2-OHnic anion is coordinated by the O,O-chelating mode (via carboxylate group and phenolate oxygen), in the [Ru(6-OHnic)(dppb)(bipy)]PF 6 ( 2 ) a O–O chelation by the carboxylate group is observed for the 6-OHnic ligand and for the complex [Ru(3-OHpic)(dppb)(bipy)]PF 6 ( 3 ) a N,O-chelating mode (via carboxylate) occurs to the 3-OHpic anion. The compounds were evaluated for activity against Mycobacterium tuberculosis H 37 Rv ATCC 27294 using Resazurin Microtitre Assay (REMA) plate method and cytotoxicity in VERO CCL-81 cell line. All the synthesized compounds exhibited good antimycobacterial activity and a completely lack of cytotoxicity activity, indicating a good selectivity index. [ABSTRACT FROM AUTHOR]

Amino acid/diphosphine ruthenium complexes, of general formula [Ru(AA-H)(dppb)(bipy)]PF 6 [AA = amino acid: glycine (gly), l -alanine (ala), l -tyrosine (tyr), l -methionine (met), l -leucine (leu), l -valine (val), l -serine (ser), l -tryptophan (trp), and l -lysine(lys); dppb = 1,4-bis(diphenylphosphino)butane; bipy = 2,2′-bipyridine], were synthesized and characterized. The X-ray structures of the glycine and leucine complexes showed that the amino acids are coordinated to the metal center through the carboxylate and amine groups. The complexes, except for the glycine ligand, form two different conformational isomers, as suggested by X-ray structure determination of the complex with leucine, and shown by 31 P{ 1 H} NMR analysis. The cyclic and differential pulse voltammograms of the complexes exhibited an oxidation potential (Ru II /Ru III ) close to 1.0 V, against Ag/AgCl. Toxicity tests against the MDA-MB-231 and DU 145 human tumor cell lines and the Ehrlich mouse cell line indicated a high degree of cytotoxicity for the amino acid complexes. The intrinsic binding constants ( K b ) for the amino acid complexes were determined and found to be in the range of 1.40 × 10 4 –1.80 × 10 4 M −1 , suggesting weak interactions of the complexes with DNA. [ABSTRACT FROM AUTHOR]

Abstract: This work links aspects of non-covalent interaction among gold nanoparticles (AuNPs) and ruthenium complexes, which were used to modify the surface of the glassy carbon electrode (GCE), without the necessity of a sulfur substrate with a covalent bond between gold–sulfur (Au–S), to keep the AuNPs onto the surface of the electrode. The AuNPs were synthesized by the method of encapsulation by citrate conferring on them a negative charge. The ruthenium complex [RuCl(dppb)(bipy)(4-vpy]+ was synthesized by ligand exchange in its coordination sphere, giving it a positive charge. A thin film of [RuCl(dppb)(bipy)(4-vpy)]+ was generated onto the surface of glassy carbon electrode (GCE), using cyclic voltammetry, under potential cycling between −0.9 and −2.4V, to produce the CGE–Ru+ electrode. Afterward, the GCE–Ru+ electrode was kept in a colloidal suspension of AuNPs for 1h to incorporate them onto the surface of GCE–Ru+ by electrostatic interaction. The resulting electrode GCE–Ru–AuNPs was finally washed with water to remove the excess of AuNPs and it was used to acetaminophen detection by cyclic voltammetry. To find the optimum analysis conditions of the modified electrode, studies were conducted to understand; which were: the number of cyclic voltammograms to produce the film, dip-coating time in AuNPs, pH, scan rate and repeatability. The Ru–AuNPs aggregates were analyzed by UV–Vis spectroscopy (UV–Vis), Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR–ATR), nuclear magnetic resonance of phosphorus (31P{1H} NMR), cyclic voltammetry (CV); scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS) and transmission electron microscopy with energy dispersive spectroscopy (TEM–EDS). The X-ray structure of [RuCl(dppb)(5,5′-Me-bipy)(4-vpy)](PF6) was determinate. [Copyright &y& Elsevier]

Highlights: [•] Two solvate forms of fac-[RuCl3(NO)(dppb)] were obtained. [•] Guest acetone and chloroform were identified by XRD and FT-IR analysis. [•] Solvent inclusion affects the molecular structure of the complex. [•] Weak intermolecular interactions kept the solvent caged. [ABSTRACT FROM AUTHOR]

Abstract: The arene–ruthenium complex [Ru(η6-C10H14)(dppf)Cl]PF6 (1) was used as a precursor for the syntheses of the [Ru(η6-C10H14)(dppf)Br]PF6 (2), [Ru(η6-C10H14)(dppf)I]PF6 (3), [Ru(η6-C10H14)(dppf)SnF3]PF6 (4) and [Ru(η6-C10H14)(dppf)Cl][SnCl3]·0.45CH2Cl2 (5) complexes by its reactions with KBr, KI, SnF2 and SnCl2, respectively. All of the compounds were characterized by NMR, IR, 57Fe and 119Sn-Mössbauer spectroscopy, and cyclic voltammetry. The single-crystal X-ray structure analysis of the [Ru(η6-C10H14)(dppf)Cl][SnCl3]·0.45CH2Cl2 complex revealed the expected piano-stool geometry. Cyclic voltammograms of the complexes showed only one quasi-reversible electrochemical process, involving the oxidation of Fe(II) and Ru(II) at the same potential, which was confirmed by exhaustive electrolysis experiments. 57Fe-Mössbauer parameters obtained for the complexes (1–5) were fitted with one doublet corresponding to a site of one iron(II). The 119Sn-Mössbauer parameters of the complex (4) indicate that tin is tetra covalent. [Copyright &y& Elsevier]

Abstract: Phosphine ruthenate complexes containing the non-innocent ligands 4-chloro-1,2-phenylenediamine (opda-Cl) and 3,3′,4,4′-tetraamminebiphenyl (diopda) were synthesized and characterized by means of X-ray diffraction, electrochemistry, 31P{1H} NMR and electronic spectroscopies. Crystals of cis-[RuCl2(dppb)(bqdi-Cl)] complex were isolated as a mixture of two conformational isomers due to different positions of the chlorine atoms of the o-phenylene ligand in relation to the P1 atom of the phosphine moiety. [Copyright &y& Elsevier]

Abstract: This paper describes the synthesis and characterization of four new ruthenium complexes containing 1,4 bis(diphenylphosphino)butane (dppb), 2-pyridinecarboxylic acid anion (pic) and the diimines [(2,2′-bipyridine (bipy), 4,4′-dimethyl-2,2′-bipyridine (Me-bipy), 4,4′-dichloro-2,2′-bipyridine (Cl-bipy) and 1,10-phenanthroline (phen) as ligands, with formulae [Ru(pic)(dppb)(bipy)]PF6 (SCAR01), [Ru(pic)(dppb)(Me-bipy)]PF6 (SCAR02), [Ru(pic)(dppb)(Cl-bipy)]PF6 (SCAR03) and [Ru(pic)(dppb)(phen)]PF6 (SCAR04). Additionally, the in vitro anti-Mycobacterium tuberculosis (MTB) activity, cytotoxicity and activity against in vitro infection of these complexes and two more complexes, cis-[Ru(pic)(dppe)2]PF6 (SCAR05) and cis-[RuCl2(dppb)(bipy)] (SCAR06), and their free ligands are described and discussed. All compounds showed excellent MIC against MTB, low cytotoxicity and a selectivity index higher than 10. Also, all compounds showed significant intracellular inhibition and the compound SCAR05 showed a better activity than rifampin and SQ109. This is the first report of activity against in vitro infection of ruthenium compounds. [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 synthesis and characterization of ruthenium compounds of the type [RuCl2(NO)(dppp)(L)]PF6 [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 19.0μM 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=200μM). [Copyright &y& Elsevier]

Abstract: The reaction of cis-[RuCl2(P–P)(N–N)] type complexes (P–P=1,4-bis(diphenylphosphino)butane or (1,1′-diphenylphosphino)ferrocene; N–N=2,2′-bipyridine or 1,10-phenantroline) with monodentate ligands (L), such as 4-methylpyridine, 4-phenylpyridine and benzonitrile forms [RuCl(L)(P–P)(N–N)]+ species. Upon characterization of the isolated compounds by elemental analysis, 31P{1H} NMR and X-ray crystallography it was found out that the type of the L ligand determines its position in relation to the phosphorus atom. While pyridine derivatives like 4-methylpyridine and 4-phenylpyridine coordinate trans to the phosphorus atom, the benzonitrile ligand (bzCN), a good π acceptor, coordinates trans to the nitrogen atom. A 31P{1H} NMR experiment following the reaction of the precursor cis-[RuCl2(dppb)(phen)] with the benzonitrile ligand shows that the final position of the entering ligand in the complex is better defined as a consequence of the competitive effect between the phosphorus atom and the cyano-group from the benzonitrile moiety and not by the trans effect. In this case, the benzonitrile group is stabilized trans to one of the nitrogen atoms of the N–N ligand. A differential pulse voltammetry experiment confirms this statement. In both experiments the [RuCl(bzCN)(dppb)(phen)]PF6 species with the bzCN ligand positioned trans to a phosphorus atom of the dppb ligand was detected as an intermediate complex. [Copyright &y& Elsevier]

Abstract: The chemistry of Ru(III) complexes containing dmso as a ligand has become an interesting area in the cancer treatment field. Because of this, structural knowledge and chemistry of the moiety Ru(III)–dmso have become important to cancer research. The crystal structures of the compounds mer-[RuCl3(dms)3] (1) and mer-[RuCl3(dms)2(dmso)]:mer-[RuCl3(dms)3] (2) were determined by X-ray crystallography and a speciation of the presence of intramolecular hydrogen bond in these structures has been studied. Compound (1) crystallizes in the orthorhombic space group, Pna21; a =16.591(8)Å, b =8.724(2)Å, c =10.547(3)Å; Z =12 and (2) crystallizes in the space group, P21/C; a =11.9930(2)Å, b =7.9390(2) Å, c =15.8700(3)Å, β =93.266(1)°, Z =2. From the X-ray structures solved in this work, were possible to suggest an interpretation for the broad lines observed in the EPR spectra of the Ru(III) compounds explored here. Also, the exchange interactions detected by EPR spectroscopy in solid state and in solution, confirm the presence of van der Waals interactions such as C–H…Cl in the compounds (1), (2) and (3). The use of techniques such as IR, UV–vis, 1H NMR and EPR Spectroscopy and Cyclic Voltammetry were applied in this work to analyze the behavior of these metallocompounds. [Copyright &y& Elsevier]

Abstract: The reaction of cis-[RuCl2(dppb)(N–N)], dppb=1,4-bis(diphenylphosphino)butane, complexes with the ligand HSpymMe2, 4,6-dimethyl-2-mercaptopyrimidine, yielded the cationic complexes [Ru(SpymMe2)(dppb)(N–N)]PF6, N–N=bipy (1) and Me-bipy (2), bipy=2,2′-bipyridine and Me-bipy=4,4′-dimethyl-2,2′-bipyridine, which were characterized by spectroscopic and electrochemical techniques and X-ray crystallography and elemental analysis. Additionally, preliminary in vitro tests for antimycobacterial activity against Mycobacterium tuberculosis H37Rv ATCC 27264 and antitumor activity against the MDA-MB-231 human breast tumor cell line were carried out on the new complexes and also on the precursors cis-[RuCl2(dppb)(N–N)], N–N=bipy (3) and Me-bipy (4) and the free ligands dppb, bipy, Me-bipy and SpymMe2. The minimal inhibitory concentration (MIC) of compounds needed to kill 90% of mycobacterial cells and the IC50 values for the antitumor activity were determined. Compounds 1–4 exhibited good in vitro activity against M. tuberculosis, with MIC values ranging between 0.78 and 6.25μg/mL, compared to the free ligands (MIC of 25 to >50μg/mL) and the drugs used to treat tuberculosis. Complexes 1 and 2 also showed promising antitumor activity, with IC50 values of 0.46±0.02 and 0.43±0.08μM, respectively, against MDA-MB-231 breast tumor cells. [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]

Abstract: The [Ru(dppb)(mbt)2], mbt=2-mercaptobenzothiazole, complex, isolated from the reaction of the mer-[RuCl3(dppb)(OH2)] complex with the 2,2′-dithiobis(benzothiazole), mbts, was characterized by spectroscopic and electrochemical techniques (E 1/2 =0.78V versus NHE) and its structure was determined by crystal X-ray analysis. The structural analysis suggests that the S–S bond of the mbts ligand is cleaved, thus forming two four-membered chelate rings coordinated to the ruthenium through the N,S-donor atoms of the mbt reduced ligands, with an average bite angle of 67.295(11)°. The 1H and 13C NMR signals observed for mbts ligand coordinated to the metal center, the changes in the vibrational spectra, and the appearance of a MLCT band in the electronic spectrum of the complex point for the reduced state of the ruthenium metal center, RuII. These reducing processes are suggested to be due to the methanol interference, which is observed to be strongly affected by N-methylmorpholine. The cytochrome c electrochemistry was analyzed by using the SAMs formed by the mbts and the [Ru(dppb)(mbt)2] complex on gold, with only the former presenting electroactivity. [Copyright &y& Elsevier]

The fac-[RuCl3(NO)(dppb)] complex I has been prepared from solution of the correspondent mer isomer in refluxing methanol (dppb=1,4-bis(diphenylphosphino)butane). The mer-[RuCl3(NO)(diop)] (II) has been obtained from the mer-[RuCl3(diop)(H2O)] by bubbling NO for 1 h in dichloromethane (diop=2S,3S-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane). The complexes have been characterized by microanalysis, cyclic voltammetry (CV), IR and 31P{1H} NMR spectroscopies. The crystal and molecular structures of these two compounds have been determined from X-ray studies. The mer-[RuCl3(NO)(dppb)] isomer III was characterized in solution by NMR spectra (31P{1H}, 1H{31P}, 31P&z.sbnd;1H HETCORR, COSY 1H&z.sbnd;1H, HMQC 1H&z.sbnd;13C and HMBC 1H&z.sbnd;13C). [Copyright &y& Elsevier]