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We report herein synthesis and characterization of four new organoruthenium(II) complexes of the type [RuH(CO)(PPh3)2(L1,2)]Cl (1,3) and [Ru(CO)(Cl)2(AsPh3)(L1,2)] (2,4) derived from the reaction of [RuHCl(CO)(EPh3)3] (E = P or As) with 2-(pyridine-2yl)benzoxazole (L1) and 2-(pyridine-2yl)benzthiazole (L2). Single-crystal X-ray diffraction data of2proved octahedral geometry of the complexes with a 1 : 1 ratio between the metal and the coordinated ligands. The binding affinities of1–4toward calf-thymus DNA (CT-DNA) and BSA were thoroughly studied by various spectroscopic techniques. Furthermore, the coordination compounds exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the correspondingo-quinone and phosphatase-like activities in the hydrolysis of 4-nitrophenyl phosphate to 4-nitrophenolate ion. The kinetic parameters have been determined using Michaelis–Menten approach. The highestkcatvalues suggested that coordination compounds exhibit higher rates of catalytic efficacy. [ABSTRACT FROM PUBLISHER]

Helical twisting powers of a series of ruthenium complexes with screw-like Δ, Λ chirality were investigated inN-(4-Methoxybenzylidene)-4-butylaniline (MBBA). Λ-[Ru(acac)2(trop)] (acac = acetylacetonate, trop = tropolonate) shows a fairly low HTP of 18 µm−1, while we found that the HTP increased almost double by connecting with an achiral bulky unit [Ru(Cp)(dppe)] (Cp = cyclopentadienyl, dppe = 1,2-bis(diphenyl)phosphinoethane) that was found to behave as a molecular “picket fence” to force the orientation of surrounding MBBA molecules. [ABSTRACT FROM AUTHOR]

A ligand ipdp (ipdp = indeno[1′,2′ : 5,6]pyrazino[2,3-i]dipyrido[3,2-a : 2′,3′-c]phenazine-8-one) and its ruthenium complexes, [Ru(L)2(ipdp)]2+ (L = bpy (2,2′-bipyridine), phen (1,10-phenanthroline)), have been synthesized and characterized by elemental analysis, electrospray mass spectra, and 1H NMR. The interaction between the complexes and calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods and viscosity measurements. The results indicate that the complexes can bind to CT-DNA in an intercalative mode. In addition, both complexes promote the photocleavage of plasmid pBR322 DNA under irradiation. The mechanistic studies reveal that singlet oxygen 1O2 plays a significant role in DNA photocleavage. [ABSTRACT FROM AUTHOR]

[RuCl2(NCCH3)2(cod)], an alternative starting material to [RuCl2(cod)] n for the preparation of ruthenium(II) complexes, has been prepared from the polymer compound and isolated in yields up to 87% using a new work-up procedure. The compound has been obtained as a yellow solid without water of crystallization. The complexes [RuCl2(NCR)2(cod)] spontaneously transform into dimers [Ru2Cl(μ-Cl)3(cod)2(NCR)] (R = Me, Ph). 1H NMR kinetic experiments for these transformations evidenced first-order behavior. [RuCl2(NCPh)2(cod)] dimerizes slower by a factor of ten than [RuCl2(NCCH3)2(cod)]. The following activation parameters, ΔH # = 114 ± 3 kJ mol−1 and ΔS # = 66 ± 9 J K−1 mol−1 for R = CH3CN (ΔG # = 94 ± 5 kJ mol−1, 298.15 K) and ΔH # = 122 ± 2 kJ mol−1 and ΔS # = 75 ± 6 J K−1 mol−1 for R = Ph (ΔG # = 100 ± 4 kJ mol−1, 298.15 K), have been calculated from the first-order rate constants in the temperature range 294–323 K. The kinetic parameters are in agreement with a two-step mechanism with dissociation of acetonitrile as the rate-determining step. The molecular structures of [Ru2Cl(μ-Cl)3(cod)2(NCR)] (R = Me, Ph) have been determined by X-ray diffraction. [ABSTRACT FROM AUTHOR]

The precursor Ru([9]aneS3)(DMSO)Cl2 (1), where [9]aneS3 represents 1,4,7-trithiacyclononane, was dissolved in acetonitrile at 50°C and stirred for several hours to assess the solvent's ability to coordinate to 1. A bis(acetonitrile) Ru(III) compound (2) crystallized as solid yellow needles upon slow evaporation of the reaction solution at room temperature. The structure of 2 was investigated in the solid state by FT-IR and single-crystal diffraction, showing it to be [Ru(III)([9]aneS3)(NCMe)2Cl]Cl2 · 2H2O (2). To assess the biological action of 2, growth-inhibition tests were carried by the MTT assay on a human tumor cell line of interest to our group, the osteosarcoma MG-63 line. Results have shown that the complex requires concentrations above 200 µmol L−1 at 72 h of incubation to display cytotoxic action on this cell line. [ABSTRACT FROM PUBLISHER]

Two new ruthenium(II) complexes, [Ru(dmp)2(BHIP)]2+ (1) and [Ru(dmb)2(BHIP)]2+ (2), were synthesized and characterized by elemental analysis, ESI-MS, and 1H NMR. DNA-binding constants of these complexes with calf-thymus DNA (ct-DNA) were determined to be 2.09 (±0.18) × 104 (mol L−1)−1 (s = 2.58) and 1.48 (±0.17) × 105 (mol L−1)−1 (s = 1.57), respectively. Viscosity measurements show that 1 and 2 interact with ct-DNA by intercalation. Upon irradiation at 365 nm, 1 and 2 induce cleavage of pBR322 DNA. The cytotoxicity of these complexes was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptosis induced by the complexes was studied by flow cytometry. The results of the cell cycle arrest show that 2 can inhibit the proliferation of BEL-7402 cells in the G0/G1 phase. [ABSTRACT FROM PUBLISHER]

This work presents two potential metallo-drugs, the ionic (C17H19FN3O3)3[RuCl6] · 3H2O (1) and the coordination [Ru(C17H17FN3O3)3] · 4H2O (2) compounds, obtained by the combination of ruthenium(III) and ciprofloxacin in different synthetic conditions. The ESI MS spectrum of 1 displayed a main peak at m/z = 994.6, assigned to the gaseous phase adduct (ciprofloxacin)3 · H+, while 2 featured peaks at m/z 1093.3 and 547.1 ascribed to [Ru(C17H17FN3O3)3 · H+–4H2O]+ and [Ru(C17H17FN3O3)3 · 2H+–4H2O]2+. Thermal analysis corroborated the proposed water content for both complexes. Absorption spectra of the compounds in aqueous medium are dominated by ciprofloxacin transitions in the UV region but displayed weak bands in the visible region, assigned to ligand field transitions. The cyclic voltammograms of 2 exhibited a quasi-reversible process ascribed to the Ru(II)/(III) redox pair at −0.25 V (vs. SHE) while 1 displayed this process at −0.11 V, showing that the central ruthenium ion is stabilized in the (III) oxidation state by the coordination to the hard oxygen atoms of ciprofloxacin. The solubility of 1 is pH dependent (as well as free ciprofloxacin) while 2 is fully water soluble and stable under physiological pH for at least 48 h. The compounds are also stable under incubation conditions (stomach pH and 37°C) without significant pH lowering. An interaction study of 2 with ct-DNA showed a value of K b = 2.47 (±0.89) × 104 mol−1 L for the intrinsic binding constant. [ABSTRACT FROM PUBLISHER]

The reaction of cis-[RuCl2(dmso)4] with [6-(2-pyridinyl)-5,6-dihydrobenzimidazo[1,2-c]quinazoline] (L) afforded in pure form a blue ruthenium(II) complex, [Ru(L1)2] (1), where the original L changed to [2-(1H-benzoimidazol-2-yl)-phenyl]-pyridin-2-ylmethylene-amine (HL1 ). Treatment of RuCl3 · 3H2O with L in dry tetrahydrofuran in inert atmosphere led to a green ruthenium(II) complex, trans-[RuCl2(L2)2] (2), where L was oxidized in situ to the neutral species 6-pyridin-yl-benzo[4,5]imidazo[1,2-c]quinazoline (L2 ). Complex 2 was also obtained from the reaction of RuCl3 · 3H2O with L2 in dry ethanol. Complexes 1 and 2 have been characterized by physico-chemical and spectroscopic tools, and 1 has been structurally characterized by single-crystal X-ray crystallography. The electrochemical behavior of the complexes shows the Ru(III)/Ru(II) couple at different potentials with quasi-reversible voltammograms. The interaction of these complexes with calf thymus DNA by using absorption and emission spectral studies allowed determination of the binding constant K b and the linear Stern–Volmer quenching constant K SV. [ABSTRACT FROM AUTHOR]

A new Ru(II) complex, [Ru(bpy)2L](ClO4)2 (bpy = 2,2′-bipyridine, L = 1,10-phenanthrolineselenazole), has been synthesized and structurally characterized by elemental analysis, ESI-MS, and 1H NMR. The interaction of human telomeric oligomer 5′-AG3(T2AG3)3-3′ with the Ru(II) complex was explored by competition FRET experiment, fluorescence titration, circular dichroism spectroscopy, thermal denaturation, polymerase chain reaction stop assay, and TRAP assay. The Ru(II) complex can selectively bind to G-quadruplex DNA. The results indicated that the complex not only induces a remarkable conformational change of human telomeric DNA, but also has the ability to stabilize the G-quadruplex. [ABSTRACT FROM PUBLISHER]

Bis(2,2′-bipyridine) complexes of ruthenium(II) with 2-, 3-, and 4-acetylpyridine derivatives were synthesized and structurally characterized. The effect of changing the location of the pyridine's acetyl substituent was studied experimentally and theoretically to clarify the effect of substituent position on the chemical behavior and photochemical properties of the complex. The substituent position on the heterocyclic-pyridine was found to strongly affect the chemical and photochemical properties of the complex. Variation of the position of the substituent, and thus ligand modification brought by as a consequence of this variation, offers possibilities to design complexes of desired structural and photochemical properties. [ABSTRACT FROM AUTHOR]

This article presents recent progress in our laboratory on the interactions of Ru(II) polypyridyl complexes with calf thymus DNA (CT-DNA). Mixed polypyridyl Ru(II) complexes [Ru(L)4(AIP)]2+ and [Ru(L)4PyIP]2+, where L is 4-amino pyridine and pyridine (AIP = 2-(9-anthryl)-1H-imidazo[4,5-f][1,10]phenanthroline; PyIP = 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), have been synthesized and characterized by elemental analysis, and physicochemical methods such as ESI-MS, UV-Vis, IR, and NMR spectroscopic techniques. Electronic absorption titrations, fluorescence spectroscopy, viscosity measurements, and salt-dependent studies of CT-DNA in the presence of incremental amounts of all four Ru(II) complexes clearly demonstrate that all four complexes bind to DNA by intercalation. The DNA-binding affinities of these complexes follow the order [Ru(4-APy)4(PyIP)]2+ > [Ru(Py)4PyIP]2+ > [Ru(4-APy)4(AIP)]2+ > [Ru(Py)4AIP]2+. Irradiation of pBR 322 DNA with these complexes results in nicking of the plasmid DNA. All four complexes were screened for antimicrobial activity. All complexes also exhibited DNA “light switch” properties. These results suggest that both ancillary ligand and intercalative ligand influence the binding of these complexes to DNA. [ABSTRACT FROM AUTHOR]

A series of four tripodal ligands L1–4 were prepared by the reaction of 9-(2-hydroxy)phenylimino-4,5-diazafluorene with 1,3,5-tris(bromomethyl)benzene, 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene, tris(2-chloroethyl)amine hydrochloride, and pentaerythrityl tetratosylate, respectively, in DMF solution under nitrogen. For each ligand, Ru(II) complexes were prepared by refluxing Ru(bipy)2Cl2 · 2H2O and ligand in 2-methoxyethanol. Photophysical behaviors of these Ru(II) complexes have been investigated by UV-Vis absorption and luminescence spectrometry. They display metal-to-ligand charge transfer absorption at 442 nm in MeCN solution at room temperature and emission at 574 nm in EtOH–MeOH (4 : 1, v/v) glassy matrix at 77 K. Electrochemical studies of the Ru(II) complexes show one Ru(II)-centered oxidation at 1.33 V and three ligand-centered reductions. [ABSTRACT FROM PUBLISHER]

The reaction of Brønsted acids with cis-[Ru(bpy)2(CO3)] (bpy = 2,2′-bipyridine) under CO results in cleavage of the carbonato ligand and formation of cationic cis-[Ru(bpy)2(CO)L] n + complexes [L = ONO2 (1 +), OH2 (2 2+), Cl (3 +), OCOH (4 +), and OCOCH3 (5 +)]. The structures of 1 + and 2 2+ were confirmed by single-crystal X-ray diffraction. Crystal data for 1(PF6): monoclinic, P21/c, a = 10.5242(3), b = 15.4727(3), c = 14.6571(3) Å, β = 92.3219(9)°, V = 2384.77(9) Å3, Z = 4, D calcd = 1.806 g cm−3, 5460 unique reflections (R int = 0.032), R 1 = 0.0540 [I > 2σ(I)], wR 2 = 0.1642 (all reflections); crystal data for 2(ClO4)2 · H2O: monoclinic, C2/c, a = 20.4247(7), b = 10.0777(3), c = 15.6039(5) Å, β = 127.7569(8)°, V = 2539.31(14) Å3, Z = 4, D calcd = 1.769 g cm−3, 2895 unique reflections (R int = 0.036), R 1 = 0.0343 [I > 2σ(I)], wR 2 = 0.0907 (all reflections). Except for 2(PF6)2 the complexes exhibit oxidation at 1.02–1.30 V versus Fc+/Fc in acetonitrile. Bipyridine-centered reductions are also observed; these redox potentials depend on the nature of L. This convenient synthesis will be useful for producing cis-[Ru(bpy)2(CO)L] n +-type complexes in high yield. [ABSTRACT FROM AUTHOR]

The S‒S bond undergoes a reductive cleavage when 2,2′-dithiobis(5-nitropyridine) is reacted with Ru(bpy)2Cl2 (bpy = 2,2′-bipyridine) and yields the monocationic species [Ru(bpy)2(S-Py-NO2)]+. The synthesized complex Ru(N5S)+ was characterized by UV-visible (UV-Vis), cyclic voltammetry, FT-IR, 1H-NMR, and X-ray. The 1H-NMR spectra show a set of signals according to low complex symmetry. The electrochemistry analysis showed a quasi-reversible RuIII/II wave observed at 0.78 V versus Ag/AgCl. X-ray structural analysis revealed a distorted octahedral coordination sphere around the metal. The octahedral N5S chromophore surrounding the metal ion is formed via two trans N and S atoms and four nitrogen atoms from two bis(2,2′-bipyridiyl) ligands. The distortion provoked by an N,S-schelating short-bite ligand has already been shown in similar derivatives. In the title compound, this effect is more dramatic since the four-membered ring presents more strain, and this effect is similar to the previously analyzed four-membered N,S-chelating short-bite ligand. [ABSTRACT FROM AUTHOR]

Reactions of Ru3(CO)12with novel tetradentate Schiff bases ligands H2L1-5 in benzene under reduced pressure afforded the formation of new Ru(II) complexes of the type [Ru(CO)2(L1-5)] where L = anion of N,N/bis(salicylaldehyde)4,5-dimethyl-1, 2-phenylenediamine (saldmophn), N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (saldcophn), N,N/bis(salicylalde-hyde)2,3-diaminonaphthalene (saldnap), N,N/bis(o-vanillin)4, 5-dimethy-l,2-phenylenediamine (ovaldmophn), and N,N/bis(o-vanillin)4,5-dichloro-1,2-phenylenediamine (ovaldcophn), respectively. All the newly synthesized complexes were investigated using elemental analysis, FT-IR, UV-Vis, mass spectrometry, and magnetic measurements. An octahedral structure has been tentatively proposed for the new complexes. All the new complexes have been found to be efficient catalysts for oxidation of primary and secondary alcohols into corresponding carbonyl compounds in presence of N-methylmorpholine-N-oxide (NMO) as the source of oxygen. In view of the biological activity, the ligands showed moderate bactericidal activities, where upon chelation with ruthenium, the bactericidal activities increased and the results have been compared with some known antibiotics. [ABSTRACT FROM AUTHOR]

In this study we investigated the photochemical production of hydrogen from water using three heterogeneous microporous ruthenium coordination polymers [Ru2(p-BDC)2X]n (p-BDC = 1,4-benzenedicarboxylate, X = Cl, Br and BF4) in the presence of multi-component systems. The order of catalytic performances is [Ru2(p-BDC)2Br]n>[Ru2(p-BDC)2BF4]n>[Ru2(p-BDC)2Cl]n. The most active catalyst, [Ru2(p-BDC)2Br]n, caused the evolution of 46.7 μmol hydrogen molecules with a turn-over number of 18.7 based on [Ru2(p-BDC)2Br]n under visible light irradiation for 4 h. We ascertained that the differences in catalytic activities originated from (1) the efficiency of the quenching of methyl-viologen radicals by [Ru2(p-BDC)2X]n and (2) the durability of the structure in the reaction. In order to examine the catalytic reaction mechanism, we performed theoretical calculations for neutral model structures [Ru2(HCOO)4X(H2O)] (X = Cl, Br), one-electron reduction model complexes [Ru2(HCOO)4X(H2O)]- and deduced intermediate model structures [H-Ru2(HCOO)4X] using broken-symmetry hybrid density functional theory methods. [ABSTRACT FROM AUTHOR]

Ruthenium(III) complexes of the type trans-[Ru(L)2(AsPh3)2]Cl (L = mono anions of 4-hydroxy-3-(p-X-phenylazo)-benzopyrane-2-one derivatives (For L1, X = H; L2, X = CH3; L3, X = Cl; and L4, X = NO2; AsPh3 = triphenylarsine) have been synthesized and characterized by elemental analysis, spectroscopic (IR, UV-VIS and ESR), magnetic and cyclic voltammetric techniques. The mechanism and the catalytic oxidation of benzyl alcohol, cyclohexanol and cinnamyl alcohol by trans-[Ru(L1)2(AsPh3)2]Cl with hydrogen peroxide as co-oxidant were described. [ABSTRACT FROM AUTHOR]

This paper outlines organoruthenium with dppf (dppf=1,1′‐bis(diphenylphosphino)ferrocene) ligand. The structures, reactivity, catalysis and electrochemistry features of dppf‐containing (Cp/Cp*)Ru(II) and (arene)Ru(II) {Cp=η5‐C5H5; Cp*=η5‐C5Me5; arene=p‐cymene, 1,2,3,5‐Me4C6H2, 1,3,5‐Me3C6H3, 1,2,3‐Me3C6H3Me4‐C6H2, C6Me6; dppf=1,1′‐bis(diphenylphosphino)ferrocene} complexes are presented in this review, as well as some from our research. This review mainly covered the differences observed in their structures, reactivity and their catalytic and electrochemical properties published over 2000 to 2005. [ABSTRACT FROM AUTHOR]

Reactions of 1,2,3-triphenyl-1,2,3-triphosphaindan ( I ), C 6 H 4 (PPh) 3 , with [Ru 3 (CO) 12 ] under various conditions result in the rupture of the P 3 C 2 -ring framework in the ligand and the cleavage of the M--M bonds in the parent cluster, leading to the formation of a series of phosphido bridged and phosphinidene capped trinuclear or polyhedral ruthenium clusters: a tetra-nuclear butterfly-like cluster [Ru 4 (CO) 10 (μ 3 -PPh)] 1 , a tri-nuclear bent-chain skeleton cluster [Ru 3 (CO) 9 {μ 3 -η 3 -PPhC 6 H 4 (PPh) 2 }] 2 , and a nonplanar six-atom-raft rhombic geometry cluster [Ru 6 (CO) 12 (μ 3 -PPh)(μ 4 -PPh) 2 (μ 3 -η 2 -C 6 H 4 )] 3 . All compounds have been fully characterized by spectroscopic methods, while the molecular structures of the new compounds 2 and 3 are established by X-ray crystallographic techniques. [ABSTRACT FROM AUTHOR]