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Sample records for metalated ruthenium complexes

  1. Metal-metal interactions in linear tri-, penta-, hepta-, and nona-nuclear ruthenium string complexes.

    PubMed

    Niskanen, Mika; Hirva, Pipsa; Haukka, Matti

    2012-05-01

    Density functional theory (DFT) methodology was used to examine the structural properties of linear metal string complexes: [Ru(3)(dpa)(4)X(2)] (X = Cl(-), CN(-), NCS(-), dpa = dipyridylamine(-)), [Ru(5)(tpda)(4)Cl(2)], and hypothetical, not yet synthesized complexes [Ru(7)(tpta)(4)Cl(2)] and [Ru(9)(ppta)(4)Cl(2)] (tpda = tri-α-pyridyldiamine(2-), tpta = tetra-α-pyridyltriamine(3-), ppta = penta-α-pyridyltetraamine(4-)). Our specific focus was on the two longest structures and on comparison of the string complexes and unsupported ruthenium backboned chain complexes, which have weaker ruthenium-ruthenium interactions. The electronic structures were studied with the aid of visualized frontier molecular orbitals, and Bader's quantum theory of atoms in molecules (QTAIM) was used to study the interactions between ruthenium atoms. The electron density was found to be highest and distributed most evenly between the ruthenium atoms in the hypothetical [Ru(7)(tpta)(4)Cl(2)] and [Ru(9)(ppta)(4)Cl(2)] string complexes.

  2. Metals fact sheet: Ruthenium

    SciTech Connect

    1996-06-01

    Ruthenium, named after Ruthenia, a province in Western Russia, was discovered in 1827 by Osann in placer ores from Russia`s Ural mountains. A minor platinum group metal (PGM), Ruthenium was the last of the PGMs to be isolated. In 1844, Klaus prepared the first 6 grams of pure ruthenium metal.

  3. Agostic interaction and intramolecular proton transfer from the protonation of dihydrogen ortho metalated ruthenium complexes

    PubMed Central

    Toner, Andrew; Matthes, Jochen; Gründemann, Stephan; Limbach, Hans-Heinrich; Chaudret, Bruno; Clot, Eric; Sabo-Etienne, Sylviane

    2007-01-01

    Protonation of the ortho-metalated ruthenium complexes RuH(H2)(X)(PiPr3)2 [X = 2-phenylpyridine (ph-py) (1), benzoquinoline (bq) (2)] and RuH(CO)(ph-py)(PiPr3)2 (3) with [H(OEt2)2]+[BAr′4]− (BAr′4 = [(3,5-(CF3)2C6H3)4B]) under H2 atmosphere yields the corresponding cationic hydrido dihydrogen ruthenium complexes [RuH(H2)(H-X)(PiPr3)2][BAr′4] [X = phenylpyridine (ph-py) (1-H); benzoquinoline (bq) (2-H)] and the carbonyl complex [RuH(CO)(H-ph-py)(PiPr3)2][BAr′4] (3-H). The complexes accommodate an agostic CH interaction characterized by NMR and in the case of 1-H by x-ray diffraction. Fluxional processes involve the hydride and dihydrogen ligands in 1-H and 2-H and the rotation of the phenyl ring displaying the agostic interaction in 1-H and 3-H. NMR studies (lineshape analysis of the temperature-dependent NMR spectra) and density functional theory calculations are used to understand these processes. Under vacuum, one equivalent of dihydrogen can be removed from 1-H and 2-H leading to the formation of the corresponding cationic ortho-metalated complexes [Ru(H2)(THF)(X)(PiPr3)2]+ [X = ph-py (1-THF), bq (2-THF)]. The reaction is fully reversible. Density functional theory calculations and NMR data give information about the reversible mechanism of CH activation in these ortho-metalated ruthenium complexes. Our study highlights the subtle interplay between key ligands such as hydrides, σ-dihydrogen, and agostic bonds, in CH activation processes. PMID:17360384

  4. Agostic interaction and intramolecular proton transfer from the protonation of dihydrogen ortho metalated ruthenium complexes.

    PubMed

    Toner, Andrew; Matthes, Jochen; Gründemann, Stephan; Limbach, Hans-Heinrich; Chaudret, Bruno; Clot, Eric; Sabo-Etienne, Sylviane

    2007-04-24

    Protonation of the ortho-metalated ruthenium complexes RuH(H(2))(X)(P(i)Pr(3))(2) [X = 2-phenylpyridine (ph-py) (1), benzoquinoline (bq) (2)] and RuH(CO)(ph-py)(P(i)Pr(3))(2) (3) with [H(OEt(2))(2)](+)[BAr'(4)](-) (BAr'(4) = [(3,5-(CF(3))(2)C(6)H(3))(4)B]) under H(2) atmosphere yields the corresponding cationic hydrido dihydrogen ruthenium complexes [RuH(H(2))(H-X)(P(i)Pr(3))(2)][BAr'(4)] [X = phenylpyridine (ph-py) (1-H); benzoquinoline (bq) (2-H)] and the carbonyl complex [RuH(CO)(H-ph-py)(P(i)Pr(3))(2)][BAr'(4)] (3-H). The complexes accommodate an agostic C H interaction characterized by NMR and in the case of 1-H by x-ray diffraction. Fluxional processes involve the hydride and dihydrogen ligands in 1-H and 2-H and the rotation of the phenyl ring displaying the agostic interaction in 1-H and 3-H. NMR studies (lineshape analysis of the temperature-dependent NMR spectra) and density functional theory calculations are used to understand these processes. Under vacuum, one equivalent of dihydrogen can be removed from 1-H and 2-H leading to the formation of the corresponding cationic ortho-metalated complexes [Ru(H(2))(THF)(X)(P(i)Pr(3))(2)](+) [X = ph-py (1-THF), bq (2-THF)]. The reaction is fully reversible. Density functional theory calculations and NMR data give information about the reversible mechanism of C H activation in these ortho-metalated ruthenium complexes. Our study highlights the subtle interplay between key ligands such as hydrides, sigma-dihydrogen, and agostic bonds, in C H activation processes. PMID:17360384

  5. Photophysical studies of bioconjugated ruthenium metal-ligand complexes incorporated in phospholipid membrane bilayers.

    PubMed

    Sharmin, Ayesha; Salassa, Luca; Rosenberg, Edward; Ross, J B Alexander; Abbott, Geoffrey; Black, Labe; Terwilliger, Michelle; Brooks, Robert

    2013-10-01

    The luminescent, mono-diimine ruthenium complexes [(H)Ru(CO)(PPh3)2(dcbpy)][PF6] (1) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridyl) and [(H)Ru(CO)(dppene)(5-amino-1,10-phen)][PF6] (2) (dppene = bis(diphenylphosphino)ethylene; phen = phenanthroline) were conjugated with 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (DPPE) and with cholesterol in the case of complex 2. Using standard conjugation techniques, compound 1 gives the bis-lipid derivative [(H)Ru(CO)(PPh3)2(dcbpy-N-DPPE2)][PF6] (3), while 2 provides the monolipid conjugate [(H)Ru(CO)(dppene)(1,10-phen-5-NHC(S)-N-DPPE)][PF6] (4) and the cholesterol derivative [(H)Ru(CO)(dppene)(1,10-phen-5-NHC(O)Ocholesteryl)][PF6] (5). These compounds were characterized by spectroscopic methods, and their photophysical properties were measured in organic solvents. The luminescence of lipid conjugates 3 and 4 is quenched in organic solvents while compound 4 shows a weak, short-lived, blue-shifted emission in aqueous solution. The cholesterol conjugate 5 shows the long-lived, microsecond-time scale emission associated with triplet metal-to-ligand charge-transfer excited states. Incorporation of conjugate 3 in lipid bilayer vesicles restores the luminescence, but with blue shifts (~80 nm) accompanied by nanosecond-time scale lifetimes. In the vesicles conjugate 4 shows a short-lived and blue-shifted emission similar to that observed in solution but with increased intensity. Conjugation of the complex [(H)Ru(CO)(PhP2C2H4C(O)O-N-succinimidyl)2(bpy)][PF6] (6") (bpy = 2,2'-bipyridyl) with DPPE gives the phosphine-conjugated complex [(H)Ru(CO)(PhP2C2H4C(O)-N-DPPE)2(bpy)][PF6] (7). Complex 7 also exhibits a short-lived and blue-shifted emission in solution and in vesicles as observed for complexes 3 and 4. We have also conjugated the complex [Ru(bpy)2(5-amino-1,10-phen)][PF6]2 (8) with both cholesterol (9) and DPPE (10). Neither complex 9 nor the previously reported complex 10 exhibited the blue shifts observed for complexes 3 and 4

  6. Photophysical Studies of Bioconjugated Ruthenium Metal-Ligand Complexes Incorporated in Phospholipid Membrane Bilayers

    PubMed Central

    Sharmin, Ayesha; Salassa, Luca; Rosenberg, Edward; Ross, J. B. Alexander; Abbott, Geoffrey; Black, Labe; Terwilliger, Michelle; Brooks, Robert

    2013-01-01

    Luminescent, mono-diimine, ruthenium complexes, [(H)Ru(CO)(PPh3)2(dcbpy)][PF6] (1, dcbpy = 4,4′-dicarboxy bipyridyl) and [(H)Ru(CO)(dppene)(5-amino-1,10-phen)][PF6] (2, dppene = bis diphenylphosphino-ethylene, phen = 9,10-phenanthroline), have been conjugated with 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (DPPE) and with cholesterol in the case of 2. Compound 1 gives the bis-lipid derivative [(H)Ru(CO)(PPh3)2(dcbpy-N-DPPE2)][PF6] (3), while 2 provides the mono-lipid conjugate [(H)Ru(CO)(dppene)(1,10-phen-5-NHC(S)-N-DPPE)][ PF6] (4), and the cholesterol derivative [(H)Ru(CO)(dppene)(1,10-phen-5-NHC(O)OChol)][PF6] (5, Chol = cholesteryl), using standard conjugation techniques. These compounds were characterized by spectroscopic methods, and their photophysical properties were measured in organic solvents. The luminescence of lipid conjugates 3 and is quenched in organic solvents while compound 4 a weak, short-lived, blue-shifted emission in solution. The cholesterol conjugate shows the long-lived, microsecond-timescale emission associated with triplet metal-to-ligand charge-transfer (3MLCT) excited states. Incorporation of conjugate 3 in lipid bilayer vesicles restores the luminescence, but with blue shifts (~80 nm) accompanied by nanosecond-timescale lifetimes. In the vesicles conjugate 4 shows a similar short-lived and blue-shifted emission to that observed in solution but with increased intensity. Conjugation of the complex [(H)Ru(CO)(PhP2C2H4C(O)O-N-succinimidyl)2(bpy)][PF6] (6”) with DPPE gives the phosphine-conjugated complex [(H)Ru(CO)(PhP2C2H4C(O)-N-DPPE)2(bpy)][PF6] (7). Complex 7 also exhibits a short-lived and blue-shifted emission in solution and in vesicles as observed for 3 and 4. We have also conjugated the complex [Ru(bpy)2(5-amino-1,10-phenanthroline)][PF6]2 (8) with both cholesterol (9) and DPPE (10). Neither 9 nor the previously reported 10 exhibited the blue shifts observed for 3 and 4 when incorporated into LUVs. The anisotropies of

  7. Electrochemical Instability of Phosphonate-Derivatized, Ruthenium(III) Polypyridyl Complexes on Metal Oxide Surfaces.

    PubMed

    Hyde, Jacob T; Hanson, Kenneth; Vannucci, Aaron K; Lapides, Alexander M; Alibabaei, Leila; Norris, Michael R; Meyer, Thomas J; Harrison, Daniel P

    2015-05-13

    The oxidative stability of the molecular components of dye-sensitized photoelectrosynthesis cells for solar water splitting remains to be explored systematically. We report here the results of an electrochemical study on the oxidative stability of ruthenium(II) polypyridyl complexes surface-bound to fluorine-doped tin oxide electrodes in acidic solutions and, to a lesser extent, as a function of pH and solvent with electrochemical monitoring. Desorption occurs for the Ru(II) forms of the surface-bound complexes with oxidation to Ru(III) enhancing both desorption and decomposition. Based on the results of long-term potential hold experiments with cyclic voltammetry monitoring, electrochemical oxidation to Ru(III) results in slow decomposition of the complex by 2,2'-bipyridine ligand loss and aquation and/or anation. A similar pattern of ligand loss was also observed for a known chromophore-catalyst assembly for both electrochemical water oxidation and photoelectrochemical water splitting. Our results are significant in identifying the importance of enhancing chromophore stability, or at least transient stability, in oxidized forms in order to achieve stable performance in aqueous environments in photoelectrochemical devices. PMID:25871342

  8. Preliminary anti-cancer photodynamic therapeutic in vitro studies with mixed-metal binuclear ruthenium(II)-vanadium(IV) complexes.

    PubMed

    Holder, Alvin A; Taylor, Patrick; Magnusen, Anthony R; Moffett, Erick T; Meyer, Kyle; Hong, Yiling; Ramsdale, Stuart E; Gordon, Michelle; Stubbs, Javelyn; Seymour, Luke A; Acharya, Dhiraj; Weber, Ralph T; Smith, Paul F; Dismukes, G Charles; Ji, Ping; Menocal, Laura; Bai, Fengwei; Williams, Jennie L; Cropek, Donald M; Jarrett, William L

    2013-09-01

    We report the synthesis and characterisation of mixed-metal binuclear ruthenium(II)-vanadium(IV) complexes, which were used as potential photodynamic therapeutic agents for melanoma cell growth inhibition. The novel complexes, [Ru(pbt)2(phen2DTT)](PF6)2·1.5H2O 1 (where phen2DTT = 1,4-bis(1,10-phenanthrolin-5-ylsulfanyl)butane-2,3-diol and pbt = 2-(2'-pyridyl)benzothiazole) and [Ru(pbt)2(tpphz)](PF6)2·3H2O 2 (where tpphz = tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine) were synthesised and characterised. Compound 1 was reacted with [VO(sal-L-tryp)(H2O)] (where sal-L-tryp = N-salicylidene-L-tryptophanate) to produce [Ru(pbt)2(phen2DTT)VO(sal-L-tryp)](PF6)2·5H2O 4; while [VO(sal-L-tryp)(H2O)] was reacted with compound 2 to produce [Ru(pbt)2(tpphz)VO(sal-L-tryp)](PF6)2·6H2O 3. All complexes were characterised by elemental analysis, HRMS, ESI MS, UV-visible absorption, ESR spectroscopy, and cyclic voltammetry, where appropriate. In vitro cell toxicity studies (with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay) via dark and light reaction conditions were carried out with sodium diaqua-4,4',4'',4''' tetrasulfophthalocyaninecobaltate(II) (Na4[Co(tspc)(H2O)2]), [VO(sal-L-tryp)(phen)]·H2O, and the chloride salts of complexes 3 and 4. Such studies involved A431, human epidermoid carcinoma cells; human amelanotic malignant melanoma cells; and HFF, non-cancerous human skin fibroblast cells. Both chloride salts of complexes 3 and 4 were found to be more toxic to melanoma cells than to non-cancerous fibroblast cells, and preferentially led to apoptosis of the melanoma cells over non-cancerous skin cells. The anti-cancer property of the chloride salts of complexes 3 and 4 was further enhanced when treated cells were exposed to light, while no such effect was observed on non-cancerous skin fibroblast cells. ESR and (51)V NMR spectroscopic studies were also used to assess the stability of the chloride salts of complexes 3

  9. Control and utilization of ruthenium and rhodium metal complex excited states for photoactivated cancer therapy

    PubMed Central

    Knoll, Jessica D.; Turro, Claudia

    2015-01-01

    The use of visible light to produce highly selective and potent drugs through photodynamic therapy (PDT) holds much potential in the treatment of cancer. PDT agents can be designed to follow an O2-dependent mechanism by producing highly reactive species such as 1O2 and/or an O2 independent mechanism through processes such as excited state electron transfer, covalent binding to DNA or photoinduced drug delivery. Ru(II)-polypyridyl and Rh2(II,II) complexes represent an important class of compounds that can be tailored to exhibit desired photophysical properties and photochemical reactivity by judicious selection of the ligand set. Complexes with relatively long-lived excited states and planar, intercalating ligands localize on the DNA strand and photocleave DNA through 1O2 production or guanine oxidation by the excited state of the chromophore. Photoinduced ligand substitution occurs through the population of triplet metal centered (3MC) excited states and facilitates covalent binding of the metal complex to DNA in a mode similar to cisplatin. Ligand photodissociation also provides a route to selective drug delivery. The ability to construct metal complexes with desired light absorbing and excited state properties by ligand variation enables the design of PDT agents that can potentially provide combination therapy from a single metal complex. PMID:25729089

  10. Essentially Molecular Metal Complexes Anchored to Zeolite: Synthesis and Characterization of Rhodium Complexes and Ruthenium Complexes Prepared from Rh(acac)(2-C2H4)2 and cis-Ru(acac)2( -C2H4)2

    SciTech Connect

    Ogino, I.; Gates, B

    2010-01-01

    Mononuclear complexes of rhodium and of ruthenium, Rh(acac)({eta}{sup 2}-C{sub 2}H{sub 4}){sub 2} and cis-Ru(acac)2({eta}{sup 2}-C{sub 2}H{sub 4}){sub 2} (acac = C{sub 5}H{sub 7}O{sub 2}{sup -}), were used as precursors to synthesize metal complexes bonded to zeolite {beta}. Infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectra show that the species formed from Rh(acac)({eta}{sup 2}-C{sub 2}H{sub 4}){sub 2} was Rh({eta}{sup 2}-C{sub 2}H{sub 4}){sub 2}{sup +}, which was bonded to the zeolite at aluminum sites via two Rh-O bonds. Reaction of this supported rhodium complex with CO gave the supported rhodium gem-dicarbonyl Rh(CO){sub 2}{sup +}, which was characterized by two {nu}{sub CO} bands in the IR spectrum, at 2048 and 2115 cm{sup -1}, that were sharp (fwhm of 2115-cm{sup -1} band = 5 cm{sup -1}), indicating a high degree of uniformity of the supported species. Nearly the same result was observed (Liang, A. et al. J. Am. Chem. Soc. 2009, 131, 8460) for the isostructural rhodium complex supported on dealuminated HY zeolite, which was characterized by frequencies of the {nu}{sub CO} bands that were 4 and 2 cm{sup -1}, respectively, greater than those characterizing the zeolite {beta}-supported complex. This comparison indicates that the Rh atoms in Rh({eta}{sup 2}-C{sub 2}H{sub 4}){sub 2}{sup +} anchored on zeolite {beta} were slightly more electron-rich than those on zeolite Y. This inference is supported by EXAFS results showing shorter Rh-C bonds in the zeolite {beta}-supported rhodium ethene complex than in the zeolite Y-supported rhodium ethene complex. In contrast to these supported rhodium complexes, the zeolite {beta}-supported ruthenium samples were shown by IR and EXAFS spectroscopies to consist of mixtures of mononuclear ruthenium complexes with various numbers of acac ligands; when CO reacted with the supported ruthenium complexes, the resultant ruthenium carbonyls were characterized by {nu}{sub CO} spectra characteristic of both

  11. Antimicrobial ruthenium complex coating on the surface of titanium alloy. High efficiency anticorrosion protection of ruthenium complex.

    PubMed

    El-Gamel, Nadia E A; Fekry, Amany M

    2015-08-01

    A ruthenium complex was prepared and structurally characterized using various techniques. Antibacterial and antifungal activities of ruthenium complex were evaluated. High significant antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans was recorded. Minor cytotoxicity records were reported at the highest concentration level using MTT assay. The influence of Cu(II), Cr(III), Fe(III) and Ru(III) metal ions of salen Schiff base on the corrosion resistance of Ti-alloy in 0.5M HCl was studied. In vitro corrosion resistance was investigated using electrochemical impedance spectroscopy (EIS) measurements and confirmed by surface examination via scanning electron microscope (SEM) technique. Both impedance and phase angle maximum (θ(max)) values were at maximum in the case of the ruthenium complex with promising antibacterial and antifungal activities. The surface film created by the ruthenium complex was highly resistant against attack or deterioration by bacteria. The EIS study showed high impedance values for the ruthenium complex with increasing exposure time up to 8 days. SEM images showed uniform distribution and adsorption of Ru(III) ions on Ti-alloy surface. The ruthenium complex, as a model of organic-inorganic hybrid complex, offered new prospects with desired properties in industrial and medical applications.

  12. Efficient Energy Transfer and Metal Coupling in Cyanide-Bridged Heterodinuclear Complexes Based on (Bipyridine)(terpyridine)ruthenium(II) and (Phenylpyridine)iridium(III) Complexes.

    PubMed

    Barthelmes, Kevin; Jäger, Michael; Kübel, Joachim; Friebe, Christian; Winter, Andreas; Wächtler, Maria; Dietzek, Benjamin; Schubert, Ulrich S

    2016-06-01

    We report a series of cyanide-bridged, heterodinuclear iridium(III)-ruthenium(II) complexes with the generalized formula [Ir((R2)2-ppy)2(CN)(μ-CN)Ru(bpy)(tpy-R1)]PF6 (ppy = 2-phenylpyridine, bpy = 2,2'-bipyridine, and tpy = 2,2':6',2″-terpyridine). The structural, spectroscopic, and electrochemical properties were analyzed in the context of variation of the electron-withdrawing (e.g., -F, -Br, -CHO) and -donating (e.g., -Me) and extended π-conjugated groups at several positions. In total, ten dinuclear complexes and the appropriate model complexes have been prepared. The iridium(III)-based emission is almost fully quenched in these complexes, and only the ruthenium(II)-based emission is observed, which indicates an efficient energy transfer toward the Ru center. Upon oxidation of the Ru center, the fluorinated complexes 2 exhibit a broad intervalence charge-transfer transition in the near-infrared region. The complexes are assigned to a weakly coupled class II system according to the Robin-Day classification. The electronic structure was evaluated by density functional theory (DFT) and time-dependent DFT calculations to corroborate the experimental data. PMID:27214264

  13. Photoisomerization Mechanism of Ruthenium Sulfoxide Complexes: Role of the Metal-Centered Excited State in the Bond Rupture and Bond Construction Processes.

    PubMed

    Li, Huifang; Zhang, Lisheng; Zheng, Lvyin; Li, Xun; Fan, Xiaolin; Zhao, Yi

    2016-09-26

    Phototriggered intramolecular isomerization in a series of ruthenium sulfoxide complexes, [Ru(L)(tpy)(DMSO)](n+) (where tpy=2,2':6',2''-terpyridine; DMSO=dimethyl sulfoxide; L=2,2'-bipyridine (bpy), n=2; N,N,N',N'-tetramethylethylenediamine (tmen) n=2; picolinate (pic), n=1; acetylacetonate (acac), n=1; oxalate (ox), n=0; malonate (mal), n=0), was investigated theoretically. It is observed that the metal-centered ligand field ((3) MC) state plays an important role in the excited state S→O isomerization of the coordinated DMSO ligand. If the population of (3) MCS state is thermally accessible and no (3) MCO can be populated from this state, photoisomerization will be turned off because the (3) MCS excited state is expected to lead to fast radiationless decay back to the original (1) GSS ground state or photodecomposition along the Ru(2+) -S stretching coordinate. On the contrary, if the population of (3) MCS (or (3) MCO ) state is inaccessible, photoinduced S→O isomerization can proceed adiabatically on the potential energy surface of the metal-to-ligand charge transfer excited states ((3) MLCTS →(3) MLCTO ). It is hoped that these results can provide valuable information for the excited state isomerization in photochromic d(6) transition-metal complexes, which is both experimentally and intellectually challenging as a field of study. PMID:27553700

  14. Photoisomerization Mechanism of Ruthenium Sulfoxide Complexes: Role of the Metal-Centered Excited State in the Bond Rupture and Bond Construction Processes.

    PubMed

    Li, Huifang; Zhang, Lisheng; Zheng, Lvyin; Li, Xun; Fan, Xiaolin; Zhao, Yi

    2016-09-26

    Phototriggered intramolecular isomerization in a series of ruthenium sulfoxide complexes, [Ru(L)(tpy)(DMSO)](n+) (where tpy=2,2':6',2''-terpyridine; DMSO=dimethyl sulfoxide; L=2,2'-bipyridine (bpy), n=2; N,N,N',N'-tetramethylethylenediamine (tmen) n=2; picolinate (pic), n=1; acetylacetonate (acac), n=1; oxalate (ox), n=0; malonate (mal), n=0), was investigated theoretically. It is observed that the metal-centered ligand field ((3) MC) state plays an important role in the excited state S→O isomerization of the coordinated DMSO ligand. If the population of (3) MCS state is thermally accessible and no (3) MCO can be populated from this state, photoisomerization will be turned off because the (3) MCS excited state is expected to lead to fast radiationless decay back to the original (1) GSS ground state or photodecomposition along the Ru(2+) -S stretching coordinate. On the contrary, if the population of (3) MCS (or (3) MCO ) state is inaccessible, photoinduced S→O isomerization can proceed adiabatically on the potential energy surface of the metal-to-ligand charge transfer excited states ((3) MLCTS →(3) MLCTO ). It is hoped that these results can provide valuable information for the excited state isomerization in photochromic d(6) transition-metal complexes, which is both experimentally and intellectually challenging as a field of study.

  15. Complex of transferrin with ruthenium for medical applications

    DOEpatents

    Richards, P.; Srivastava, S.C.; Meinken, G.E.

    1984-05-15

    A novel ruthenium-transferrin complex is disclosed which is prepared by reacting iron-free human transferrin dissolved in a sodium acetate solution at pH 7 with ruthenium by heating at about 40 C for about 2 hours. The complex is purified by means of gel chromotography with pH 7 sodium acetate as eluent. The mono- or di-metal complex produced can be used in nuclear medicine in the diagnosis and/or treatment of tumors and abscesses. Comparative results with Ga-67-citrate, which is the most widely used tumor-localizing agent in nuclear medicine, indicate increased sensitivity of detection and greater tumor uptake with the Ru-transferrin complex. No Drawings

  16. Complex of transferrin with ruthenium for medical applications

    DOEpatents

    Richards, Powell; Srivastava, Suresh C.; Meinken, George E.

    1984-05-15

    A novel Ruthenium-transferrin complex, prepared by reacting iron-free human transferrin dissolved in a sodium acetate solution at pH 7 with ruthenium by heating at about 40.degree. C. for about 2 hours, and purifying said complex by means of gel chromotography with pH 7 sodium acetate as eluent. The mono- or di-metal complex produced can be used in nuclear medicine in the diagnosis and/or treatment of tumors and abscesses. Comparative results with Ga-67-citrate, which is the most widely used tumor-localizing agent in nuclear medicine, indicate increased sensitivity of detection and greater tumor uptake with the Ru-transferrin complex.

  17. (BB)-Carboryne Complex of Ruthenium: Synthesis by Double B-H Activation at a Single Metal Center.

    PubMed

    Eleazer, Bennett J; Smith, Mark D; Popov, Alexey A; Peryshkov, Dmitry V

    2016-08-24

    The first example of a transition metal (BB)-carboryne complex containing two boron atoms of the icosahedral cage connected to a single exohedral metal center (POBBOP)Ru(CO)2 (POBBOP = 1,7-OP(i-Pr)2-2,6-dehydro-m-carborane) was synthesized by double B-H activation within the strained m-carboranyl pincer framework. Theoretical calculations revealed that the unique three-membered (BB)>Ru metalacycle is formed by two bent B-Ru σ-bonds with the concomitant increase of the bond order between the two metalated boron atoms. The reactivity of the highly strained electron-rich (BB)-carboryne fragment with small molecules was probed by reactions with electrophiles. The carboryne-carboranyl transformations reported herein represent a new mode of cooperative metal-ligand reactivity of boron-based complexes. PMID:27526855

  18. (BB)-Carboryne Complex of Ruthenium: Synthesis by Double B–H Activation at a Single Metal Center

    PubMed Central

    2016-01-01

    The first example of a transition metal (BB)-carboryne complex containing two boron atoms of the icosahedral cage connected to a single exohedral metal center (POBBOP)Ru(CO)2 (POBBOP = 1,7-OP(i-Pr)2-2,6-dehydro-m-carborane) was synthesized by double B–H activation within the strained m-carboranyl pincer framework. Theoretical calculations revealed that the unique three-membered (BB)>Ru metalacycle is formed by two bent B–Ru σ-bonds with the concomitant increase of the bond order between the two metalated boron atoms. The reactivity of the highly strained electron-rich (BB)-carboryne fragment with small molecules was probed by reactions with electrophiles. The carboryne–carboranyl transformations reported herein represent a new mode of cooperative metal–ligand reactivity of boron-based complexes. PMID:27526855

  19. Sensitization of NO-Releasing Ruthenium Complexes to Visible Light.

    PubMed

    Becker, Tobias; Kupfer, Stephan; Wolfram, Martin; Görls, Helmar; Schubert, Ulrich S; Anslyn, Eric V; Dietzek, Benjamin; Gräfe, Stefanie; Schiller, Alexander

    2015-10-26

    We report a combined spectroscopical-theoretical investigation on the photosensitization of transition metal nitrosyl complexes. For this purpose, ruthenium nitrosyl complexes based on tetradentate biscarboxamide ligands were synthesized. A crystal structure analysis of a lithium-based ligand intermediate is described. The Ru complexes have been characterized regarding their photophysical and nitric oxide (NO) releasing properties. Quantum chemical calculations have been performed to unravel the influence of the biscarboxamide ligand frame with respect to the molecular electronic properties of the NO-releasing pathway. A quantitative measure for the ligand design within photosensitized Ru complexes is introduced and evaluated spectroscopically and theoretically by using time-dependent density functional theory.

  20. Preparation, stability, and photoreactivity of thiolato ruthenium polypyridyl complexes: Can cysteine derivatives protect ruthenium-based anticancer complexes?

    PubMed

    van Rixel, Vincent H S; Busemann, Anja; Göttle, Adrien J; Bonnet, Sylvestre

    2015-09-01

    Ruthenium polypyridyl complexes may act as light-activatable anticancer prodrugs provided that they are protected by well-coordinated ligands that i) prevent coordination of other biomolecules to the metal center in the dark and ii) can be removed by visible light irradiation. In this paper, the use of monodentate thiol ligands RSH as light-cleavable protecting groups for the ruthenium complex [Ru(tpy)(bpy)(OH2)](PF6)2 ([1](PF6)2; tpy=2,2';6',2″-terpyridine, bpy=2,2'-bypyridine), is investigated. The reaction of [1](2+) with RSH=H2Cys (L-cysteine), H2Acys (N-acetyl-L-cysteine), and HAcysMe (N-acetyl-L-cysteine methyl ester), is studied by UV-visible spectroscopy, NMR spectroscopy, and mass spectrometry. Coordination of the monodentate thiol ligands to the ruthenium complex takes place upon heating to 353 K, but full conversion to the protected complex [Ru(tpy)(bpy)(SR)]PF6 is only possible when a large excess of ligand is used. Isolation and characterization of the two new thiolato complexes [Ru(tpy)(bpy)(κS-HCys)]PF6 ([2]PF6) and [Ru(tpy)(bpy)(κS-HAcys)]PF6 ([3]PF6) is reported. [3]PF6 shows a metal-to-ligand charge-transfer absorption band that is red shifted (λmax=492 nm in water) compared to its methionine analogue [Ru(tpy)(bpy)(κS-HAmet)](Cl)2 ([5](Cl)2, λmax=452 nm; HAmet=N-acetyl-methionine). In the dark the thiolate ligand coordinated to ruthenium is oxidized even by traces of oxygen, which first leads to the sulfenato, sulfinato, and disulfide ruthenium complexes, and finally to the formation of the aqua complex [1](2+). [3]PF6 showed slow photosubstitution of the thiolate ligand by water under blue light irradiation, together with faster photooxidation of the thiolate ligand compared to dark conditions. The use of thiol vs. thioether monodentate ligands is discussed for the protection of anticancer ruthenium-based prodrugs.

  1. Arene-ruthenium(II) complexes with hydrophilic P-donor ligands: versatile catalysts in aqueous media.

    PubMed

    Crochet, Pascale; Cadierno, Victorio

    2014-09-01

    In the last few years there has been increasing interest in the use of water as a reaction medium for catalysis, and therefore in designing water-soluble transition-metal catalysts. Half-sandwich (η(6)-arene)-ruthenium(ii) complexes are a versatile and well-known family of ruthenium compounds that exhibit a rich catalytic and coordination chemistry. This Perspective article focuses on the catalytic applications in aqueous media of (η(6)-arene)-ruthenium(ii) complexes containing water-soluble phosphines, and related hydrophilic P-donor ligands.

  2. Kinetics and mechanism of electron transfer to transition-metal complexes by photochemically produced tris(bipyridyl)ruthenium(1+)ion

    SciTech Connect

    Connolly, P.; Espenson, J.H.; Bakac, A.

    1986-06-18

    Rate constants were determined for the one-electron reduction of Cr(H/sub 2/O)/sub 6//sup 3 +/, several organochromium cations of the family (H/sub 2/O)/sub 5/CrR/sup 2 +/, several substituted pyridine complexes in the series (H/sub 2/O)/sub 5/CrNC/sub 5/H/sub 4/X/sup 3 +/, cobalt(III) amine complexes, and miscellaneous species including Yb/sub aq//sup 3 +/ and (1R,4R,8S,11S)-Ni(tmc)/sub 2//sup +/ (where tmc = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclo-tetradecane). The results are considered in light of the Marcus equation. The data for the pyridine complexes are correlated by the Hammett equation; the reaction constant in comparison with those of other complexes indicates that electron transfer occurs directly to the metal and not, as in certain other instances, by initial reduction of the pyridine ligand bound to chromium. The qualitative differences in rates can be rationalized by a simple MO scheme.

  3. DFT Study of Acceptorless Alcohol Dehydrogenation Mediated by Ruthenium Pincer Complexes: Ligand Tautomerization Governing Metal Ligand Cooperation.

    PubMed

    Hou, Cheng; Zhang, Zhihan; Zhao, Cunyuan; Ke, Zhuofeng

    2016-07-01

    Metal ligand cooperation (MLC) catalysis is a popular strategy to design highly efficient transition metal catalysts. In this presented theoretical study, we describe the key governing factor in the MLC mechanism, with the Szymczak's NNN-Ru and the Milstein's PNN-Ru complexes as two representative catalysts. Both the outer-sphere and inner-sphere mechanisms were investigated and compared. Our calculated result indicates that the PNN-Ru pincer catalyst will be restored to aromatic state during the catalytic cycle, which can be considered as the driving force to promote the MLC process. On the contrary, for the NNN-Ru catalyst, the MLC mechanism leads to an unfavored tautomerization in the pincer ligand, which explains the failure of the MLC mechanism in this system. Therefore, the strength of the driving force provided by the pincer ligand actually represents a prerequisite factor for MLC. Spectator ligands such as CO, PPh3, and hydride are important to ensure the catalyst follow a certain mechanism as well. We also evaluate the driving force of various bifunctional ligands by computational methods. Some proposed pincer ligands may have the potential to be the new pincer catalysts candidates. The presented study is expected to offer new insights for MLC catalysis and provide useful guideline for future catalyst design. PMID:27322755

  4. Similar Biological Activities of Two Isostructural Ruthenium and Osmium Complexes

    SciTech Connect

    Maksimoska,J.; Williams, D.; Atilla-Gokcumen, G.; Smalley, K.; Carroll, P.; Webster, R.; Filippakopoulos, P.; Knapp, S.; Herlyn, M.; Meggers, E.

    2008-01-01

    In this study, we probe and verify the concept of designing unreactive bioactive metal complexes, in which the metal possesses a purely structural function, by investigating the consequences of replacing ruthenium in a bioactive half-sandwich kinase inhibitor scaffold by its heavier congener osmium. The two isostructural complexes are compared with respect to their anticancer properties in 1205?Lu melanoma cells, activation of the Wnt signaling pathway, IC50 values against the protein kinases GSK-3? and Pim-1, and binding modes to the protein kinase Pim-1 by protein crystallography. It was found that the two congeners display almost indistinguishable biological activities, which can be explained by their nearly identical three-dimensional structures and their identical mode of action as protein kinase inhibitors. This is a unique example in which the replacement of a metal in an anticancer scaffold by its heavier homologue does not alter its biological activity.

  5. Ruthenium metalation of proteins: the X-ray structure of the complex formed between NAMI-A and hen egg white lysozyme.

    PubMed

    Messori, Luigi; Merlino, Antonello

    2014-04-28

    A crystallographic study of the adduct formed between hen egg white lysozyme (HEWL) and NAMI-A, an established ruthenium(III) anticancer agent in clinical trials, is presented here. The X-ray structure reveals that NAMI-A coordinates the protein, as a naked ruthenium ion, at two distinct sites (namely Asp101 or Asp119) after releasing all its original ligands (DMSO, imidazole and Cl(-)). Structural data of the HEWL/NAMI-A adduct are compared with those previously obtained for the HEWL adduct of AziRu, a NAMI-A analogue bearing a pyridine in place of imidazole. The present results further support the view that NAMI-A exerts its biological effects acting as a classical "prodrug" first undergoing activation and then causing extensive metalation of relevant protein targets. It is also proposed that the original Ru-ligands, although absent in the final adduct, play a major role in directing the ruthenium center to its ultimate anchoring site on the protein surface. PMID:24553967

  6. Water-soluble ruthenium complexes bearing activity against protozoan parasites.

    PubMed

    Sarniguet, Cynthia; Toloza, Jeannette; Cipriani, Micaella; Lapier, Michel; Vieites, Marisol; Toledano-Magaña, Yanis; García-Ramos, Juan Carlos; Ruiz-Azuara, Lena; Moreno, Virtudes; Maya, Juan Diego; Azar, Claudio Olea; Gambino, Dinorah; Otero, Lucía

    2014-06-01

    Parasitic illnesses are major causes of human disease and misery worldwide. Among them, both amebiasis and Chagas disease, caused by the protozoan parasites, Entamoeba histolytica and Trypanosoma cruzi, are responsible for thousands of annual deaths. The lack of safe and effective chemotherapy and/or the appearance of current drug resistance make the development of novel pharmacological tools for their treatment relevant. In this sense, within the framework of the medicinal inorganic chemistry, metal-based drugs appear to be a good alternative to find a pharmacological answer to parasitic diseases. In this work, novel ruthenium complexes [RuCl2(HL)(HPTA)2]Cl2 with HL=bioactive 5-nitrofuryl containing thiosemicarbazones and PTA=1,3,5-triaza-7-phosphaadamantane have been synthesized and fully characterized. PTA was included as co-ligand in order to modulate complexes aqueous solubility. In fact, obtained complexes were water soluble. Their activity against T. cruzi and E. histolytica was evaluated in vitro. [RuCl2(HL4)(HPTA)2]Cl2 complex, with HL4=N-phenyl-5-nitrofuryl-thiosemicarbazone, was the most active compound against both parasites. In particular, it showed an excellent activity against E. histolytica (half maximal inhibitory concentration (IC50)=5.2 μM), even higher than that of the reference drug metronidazole. In addition, this complex turns out to be selective for E. histolytica (selectivity index (SI)>38). The potential mechanism of antiparasitic action of the obtained ruthenium complexes could involve oxidative stress for both parasites. Additionally, complexes could interact with DNA as second potential target by an intercalative-like mode. Obtained results could be considered a contribution in the search for metal compounds that could be active against multiple parasites. PMID:24740394

  7. Water-soluble ruthenium complexes bearing activity against protozoan parasites.

    PubMed

    Sarniguet, Cynthia; Toloza, Jeannette; Cipriani, Micaella; Lapier, Michel; Vieites, Marisol; Toledano-Magaña, Yanis; García-Ramos, Juan Carlos; Ruiz-Azuara, Lena; Moreno, Virtudes; Maya, Juan Diego; Azar, Claudio Olea; Gambino, Dinorah; Otero, Lucía

    2014-06-01

    Parasitic illnesses are major causes of human disease and misery worldwide. Among them, both amebiasis and Chagas disease, caused by the protozoan parasites, Entamoeba histolytica and Trypanosoma cruzi, are responsible for thousands of annual deaths. The lack of safe and effective chemotherapy and/or the appearance of current drug resistance make the development of novel pharmacological tools for their treatment relevant. In this sense, within the framework of the medicinal inorganic chemistry, metal-based drugs appear to be a good alternative to find a pharmacological answer to parasitic diseases. In this work, novel ruthenium complexes [RuCl2(HL)(HPTA)2]Cl2 with HL=bioactive 5-nitrofuryl containing thiosemicarbazones and PTA=1,3,5-triaza-7-phosphaadamantane have been synthesized and fully characterized. PTA was included as co-ligand in order to modulate complexes aqueous solubility. In fact, obtained complexes were water soluble. Their activity against T. cruzi and E. histolytica was evaluated in vitro. [RuCl2(HL4)(HPTA)2]Cl2 complex, with HL4=N-phenyl-5-nitrofuryl-thiosemicarbazone, was the most active compound against both parasites. In particular, it showed an excellent activity against E. histolytica (half maximal inhibitory concentration (IC50)=5.2 μM), even higher than that of the reference drug metronidazole. In addition, this complex turns out to be selective for E. histolytica (selectivity index (SI)>38). The potential mechanism of antiparasitic action of the obtained ruthenium complexes could involve oxidative stress for both parasites. Additionally, complexes could interact with DNA as second potential target by an intercalative-like mode. Obtained results could be considered a contribution in the search for metal compounds that could be active against multiple parasites.

  8. Trimethylsilyl-Substituted Hydroxycyclopentadienyl Ruthenium Hydrides as Benchmarks to Probe Ligand and Metal Effects on the Reactivity of Shvo Type Complexes

    PubMed Central

    Guan, Hairong

    2011-01-01

    The bis(trimethylsilyl)-substituted hydroxycyclopentadienyl ruthenium hydride [2,5-(SiMe3)2-3,4-(CH2OCH2)(η5-C4COH)]Ru(CO)2H (10) is an efficient catalyst for hydrogenation of aldehydes and ketones. Because 10 transfers hydrogen rapidly to aldehydes and ketones and because it does not form an inactive bridging hydride during reaction, hydrogenation of aldehydes and ketones can be performed at room temperature under relatively low hydrogen pressure (3 atm); this is a significant improvement compared with previously developed Shvo type catalysts. Kinetic and 2H NMR spectroscopic studies of the stoichiometric reduction of aldehydes and ketones by 10 established a two-step process for the hydrogen transfer: (1) rapid and reversible hydrogen bond formation between OH of 10 and the oxygen of the aldehyde or ketone, (2) followed by slow transfer of both proton and hydride from 10 to the aldehyde or ketone. The stoichiometric and catalytic activities of complex 10 are compared to those of other Shvo type ruthenium hydrides and related iron hydrides. PMID:23087535

  9. Trimethylsilyl-Substituted Hydroxycyclopentadienyl Ruthenium Hydrides as Benchmarks to Probe Ligand and Metal Effects on the Reactivity of Shvo Type Complexes.

    PubMed

    Casey, Charles P; Guan, Hairong

    2012-01-01

    The bis(trimethylsilyl)-substituted hydroxycyclopentadienyl ruthenium hydride [2,5-(SiMe(3))(2)-3,4-(CH(2)OCH(2))(η(5)-C(4)COH)]Ru(CO)(2)H (10) is an efficient catalyst for hydrogenation of aldehydes and ketones. Because 10 transfers hydrogen rapidly to aldehydes and ketones and because it does not form an inactive bridging hydride during reaction, hydrogenation of aldehydes and ketones can be performed at room temperature under relatively low hydrogen pressure (3 atm); this is a significant improvement compared with previously developed Shvo type catalysts. Kinetic and (2)H NMR spectroscopic studies of the stoichiometric reduction of aldehydes and ketones by 10 established a two-step process for the hydrogen transfer: (1) rapid and reversible hydrogen bond formation between OH of 10 and the oxygen of the aldehyde or ketone, (2) followed by slow transfer of both proton and hydride from 10 to the aldehyde or ketone. The stoichiometric and catalytic activities of complex 10 are compared to those of other Shvo type ruthenium hydrides and related iron hydrides. PMID:23087535

  10. Thermochemistry and Molecular Structure of a Remarkable Agostic Interaction in a Heterobifunctional Ruthenium-Boron Complex

    PubMed Central

    Conley, Brian L.; Williams, Travis J.

    2010-01-01

    A boron-pendant ruthenium species forms a unique agostic methyl bridge between the boron and ruthenium atoms in the presence of a ligating solvent, acetonitrile. NMR inversion-recovery experiments enable measurement of the activation and equilibrium thermochemistry for formation of the agostic bridge. The mechanism for bridge formation involves displacement of an acetonitrile ligand; thus, this is a rare example of a case where an agostic C—H ligand competitively displaces another tight-binding ligand from a coordinatively saturated complex. Characterization of this complex gives unique insights into development of C—H activation catalysis based on this ligand-metal bifunctional motif. PMID:20088526

  11. Sweetening ruthenium and osmium: organometallic arene complexes containing aspartame.

    PubMed

    Gray, Jennifer C; Habtemariam, Abraha; Winnig, Marcel; Meyerhof, Wolfgang; Sadler, Peter J

    2008-09-01

    The novel organometallic sandwich complexes [(eta(6)-p-cymene)Ru(eta(6)-aspartame)](OTf)(2) (1) (OTf = trifluoromethanesulfonate) and [(eta(6)-p-cymene)Os(eta(6)-aspartame)](OTf)(2) (2) incorporating the artificial sweetener aspartame have been synthesised and characterised. A number of properties of aspartame were found to be altered on binding to either metal. The pK(a) values of both the carboxyl and the amino groups of aspartame are lowered by between 0.35 and 0.57 pH units, causing partial deprotonation of the amino group at pH 7.4 (physiological pH). The rate of degradation of aspartame to 3,6-dioxo-5-phenylmethylpiperazine acetic acid (diketopiperazine) increased over threefold from 0.12 to 0.36 h(-1) for 1, and to 0.43 h(-1) for 2. Furthermore, the reduction potential of the ligand shifted from -1.133 to -0.619 V for 2. For the ruthenium complex 1 the process occurred in two steps, the first (at -0.38 V) within a biologically accessible range. This facilitates reactions with biological reductants such as ascorbate. Binding to and activation of the sweet taste receptor was not observed for these metal complexes up to concentrations of 1 mM. The factors which affect the ability of metal-bound aspartame to interact with the receptor site are discussed.

  12. Biological properties of novel ruthenium- and osmium-nitrosyl complexes with azole heterocycles.

    PubMed

    Novak, Maria S; Büchel, Gabriel E; Keppler, Bernhard K; Jakupec, Michael A

    2016-06-01

    Since the discovery that nitric oxide (NO) is a physiologically relevant molecule, there has been great interest in the use of metal nitrosyl compounds as antitumor pharmaceuticals. Particularly interesting are those complexes which can deliver NO to biological targets. Ruthenium- and osmium-based compounds offer lower toxicity compared to other metals and show different mechanisms of action as well as different spectra of activity compared to platinum-based drugs. Novel ruthenium- and osmium-nitrosyl complexes with azole heterocycles were studied to elucidate their cytotoxicity and possible interactions with DNA. Apoptosis induction, changes of mitochondrial transmembrane potential and possible formation of reactive oxygen species were investigated as indicators of NO-mediated damage by flow cytometry. Results suggest that ruthenium- and osmium-nitrosyl complexes with the general formula (indazolium)[cis/trans-MCl4(NO)(1H-indazole)] have pronounced cytotoxic potency in cancer cell lines. Especially the more potent ruthenium complexes strongly induce apoptosis associated with depolarization of mitochondrial membranes, and elevated reactive oxygen species levels. Furthermore, a slight yet not unequivocal trend to accumulation of intracellular cyclic guanosine monophosphate attributable to NO-mediated effects was observed. PMID:26961253

  13. Molecular dinitrogen complexes of ruthenium(II) porphyrins

    SciTech Connect

    Camenzind, M.J.; James, B.R.; Dolphin, D.; Sparapany, J.W.; Ibers, J.A.

    1988-08-24

    The existence of both mono- and bis(nitrogen) complexes of ruthenium have been previously established. Details on a series of complexes are presented herein, and results of an x-ray crystallographic study of Ru(TMP) (THF) (N/sub 2/) are reported. 30 references, 4 tables.

  14. Combining Ruthenium(II) Complexes with Metal-Organic Frameworks to Realize Effective Two-Photon Absorption for Singlet Oxygen Generation.

    PubMed

    Zhang, Wenxiang; Li, Bin; Ma, Heping; Zhang, Liming; Guan, Yunlong; Zhang, Yihe; Zhang, Xindan; Jing, Pengtao; Yue, Shumei

    2016-08-24

    Singlet oxygen ((1)O2), as a reactive oxygen species, has garnered serious attention in physical, chemical, and biological studies. In this paper, we designed and synthesized a new type of singlet-oxygen generation system by exchanging cationic ruthenium complexes (RCs) into anionic bio-MOF-1. The resulting bio-MOF-1&RCs can be used as effective photocatalysts for generation of singlet oxygen under both single-photon and two-photon excitation. Especially, the excellent two-photon absorption (TPA) behavior of bio-MOF-1&RCs aroused our interest greatly because their two-photon absorption band lies in the optical window of biological tissue. Here, we measured the ability of bio-MOF-1&RCs to generate (1)O2 by irradiation under both 490 and 800 nm wavelength light in DMF. 1,3-Diphenylisobenzofuran (DPBF) and 2',7'-dichlorofluorescein (DCFH) were used as typical (1)O2 traps to detect and evaluate the efficiency of generation of (1)O2 under single-photon and two-photon excitation, respectively. Results indicated that bio-MOF-1&[Ru(phen)3](2+) was able to effectively generate (1)O2 under both conditions. Our work creates a novel synergistic TPA system with the excellent photophysical properties of RCs and the unique microporous structure benefit of MOFs, which may open a new avenue for creation of a cancer treatment system with both photodynamic therapy and chemotherapy. PMID:27483010

  15. Photodissociation Spectroscopy of Ruthenium Polypyridyl Complexes in Vacuo

    NASA Astrophysics Data System (ADS)

    Xu, Shuang; Smith, James; Weber, J. Mathias

    Photoelectrochemical water oxidation is a direct way to produce solar fuels from renewable sources. Since this reaction has a high reaction barrier, a cost-effective catalyst is necessary. Ruthenium polypyridyl complexes are promising catalysts for water oxidation. However, the mechanism of catalytic action is not well understood. One major difficulty of a mechanistic understanding is the complexity of reactive solutions under turnover conditions. To circumvent this problem, we applied electronic photodissociation spectroscopy in the UV and visible spectral range to a series of mass selected ruthenium polypyridyl complex ions in vacuo. The ions in this work are of the form [RuII-L]2+, where RuII represents ruthenium(II)-bipyridine-terpyridine, a prototype catalyst belonging to the ruthenium-polypyridyl family. By varying the ligand L, we were able to study the ligand influence on the photophysical properties of the complex. The cases where L = (H2O)1 , 2 , 3 are of particular interest because they are directly related to an intermediate in the catalytic cycle for water oxidation. Our experiment in vacuo is an essential complement to experiments in solution and provides unique information for understanding the photophysics and photochemistry of these complexes on a molecular level.

  16. Efficient energy conversion in photochromic ruthenium DMSO complexes.

    PubMed

    Rachford, Aaron A; Petersen, Jeffrey L; Rack, Jeffrey J

    2006-07-24

    The photochromic compounds trans- and cis-[Ru(tpy)(Mepic)(dmso)](OSO2CF3) (2 and 3, respectively; tpy is 2,2':6',2"-terpyridine; Mepic is 6-methyl-2-pyridinecarboxylate; dmso is dimethyl sulfoxide) and cis-[Ru(tpy)(Brpic)(dmso)](PF6) (4; Brpic is 6-bromo-2-pyridinecarboxylate) were prepared and characterized by single-crystal X-ray crystallography, electrochemistry, NMR, IR, and UV-vis spectroscopy. The geometry labels refer to the relationship between the carboxylate oxygen of the picolinate ligand and dmso. Electrochemical studies reveal that only the trans isomer shows S-to-O isomerization following oxidation of Ru(II) and O-to-S isomerization following reduction of Ru(III). The cis isomers of both complexes feature reversible one-electron Ru(III/II) couples. All complexes undergo phototriggered S-to-O isomerization following MLCT (metal-to-ligand charge transfer) excitation with quantum yields (Phi(S-->O)) of 0.79 (2), 0.011 (3), and 0.014 (4). The methyl group in 2 promotes isomerization by hindering rotation of the dmso ligand about the Ru-S bond. Computational results support this role for the methyl group. Relative energy calculations show that the barrier to rotation is approximately 8 kcal mol(-1). These results suggest that rotation is an important vibration for isomerization in photochromic ruthenium-dmso complexes. PMID:16842000

  17. Molecular Models of Ruthenium(II) Organometallic Complexes

    ERIC Educational Resources Information Center

    Coleman, William F.

    2007-01-01

    This article presents the featured molecules for the month of March, which appear in the paper by Ozerov, Fafard, and Hoffman, and which are related to the study of the reactions of a number of "piano stool" complexes of ruthenium(II). The synthesis of compound 2a offers students an alternative to the preparation of ferrocene if they are only…

  18. Carriers for metal complexes on tumour cells: the effect of cyclodextrins vs CNTs on the model guest phenanthroline-5,6-dione trithiacyclononane ruthenium(II) chloride.

    PubMed

    Braga, Susana S; Marques, Joana; Heister, Elena; Diogo, Cátia V; Oliveira, Paulo J; Paz, Filipe A Almeida; Santos, Teresa M; Marques, Maria Paula M

    2014-06-01

    The complex [Ru[9]aneS3(pdon)Cl]Cl (pdon = 1,10-phenanthroline-5,6-dione) was readily obtained from the stoichiometric reaction of Ru[9]aneS3(dmso)Cl2 with pdon. Recrystallisation in ethanol using salicylic acid as a co-crystallisation helper afforded single-crystals suitable for the collection of X-ray diffraction data which afforded a reasonable structural description. Two different kinds of molecular carriers were tested as vehicles for this complex: carbon nanotubes (CNTs) and cyclodextrins. CNTs had an insufficient loading rate for the ruthenium complex at CNT concentrations deemed non-cytotoxic on cultured cells. The cyclodextrin (CD) carriers, β-CD and TRIMEB (standing for permethylated β-CD), were able to form two adducts, studied by powder X-ray diffraction, thermogravimetric analysis (TGA), (13)C{(1)H} CP/MAS NMR and FT-IR spectroscopies. The DNA thermal denaturation studies showed that the complex 1 is able to intercalate with DNA. The in vitro cytotoxicity of the free complex [Ru[9]aneS3(pdon)Cl]Cl (1) and of its two CD adducts (2 and 3) was assessed on both rodent and human cell lines. By using the mouse K1735-M2 melanoma cell line and the non-tumour rat H9c2 cardiomyoblasts, the results showed that 1 and 2 significantly inhibited the growth of the tumour cell line while displaying a good safety profile on cardiomyoblasts. Compound 3 at 100 μM inhibited the proliferation of both cell lines, with a higher activity towards the melanoma cell line. The cytotoxicity of the compounds 1-3 was further assessed on human breast cancer cell lines. Against the MDA-MB-231 line, growth inhibition occurred only with 1 and 3 at the incubation time of 96 h, both with approximate inhibition rates of 50 %; against the MCF-7 line, mild cytotoxicity was observed at 48 h of incubation, with IC50 values calculated above 100 μM for 1, 2 and 3.

  19. Complex of transferrin with ruthenium for medical applications. [Ru 97, Ru 103

    DOEpatents

    Richards, P.; Srivastava, S.C.; Meinken, G.E.

    1980-11-03

    A novel Ruthenium-transferrin complex, prepared by reacting iron-free human transferrin dissolved in a sodium acetate solution at pH 7 with ruthenium by heating at about 40/sup 0/C for about 2 hours, and purifying said complex by means of gel chromatography with pH 7 sodium acetate as eluent. The mono- or di-metal complex produced can be used in nuclear medicine in the diagnosis and/or treatment of tumors and abscesses. Comparitive results with Ga-67-citrate, which is the most widely used tumor-localizing agent in nuclear medicine, indicate increased sensitivity of detection and greater tumor uptake with the Ru-transferrin complex.

  20. Biological processing of dinuclear ruthenium complexes in eukaryotic cells.

    PubMed

    Li, Xin; Heimann, Kirsten; Dinh, Xuyen Thi; Keene, F Richard; Collins, J Grant

    2016-10-20

    The biological processing - mechanism of cellular uptake, effects on the cytoplasmic and mitochondrial membranes, intracellular sites of localisation and induction of reactive oxygen species - of two dinuclear polypyridylruthenium(ii) complexes has been examined in three eukaryotic cells lines. Flow cytometry was used to determine the uptake of [{Ru(phen)2}2{μ-bb12}](4+) (Rubb12) and [Ru(phen)2(μ-bb7)Ru(tpy)Cl](3+) {Rubb7-Cl, where phen = 1,10-phenanthroline, tpy = 2,2':6',2''-terpyridine and bbn = bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane} in baby hamster kidney (BHK), human embryonic kidney (HEK-293) and liver carcinoma (HepG2) cell lines. The results demonstrated that the major uptake mechanism for Rubb12 and Rubb7-Cl was active transport, although with a significant contribution from carrier-assisted diffusion for Rubb12 and passive diffusion for Rubb7-Cl. Flow cytometry coupled with Annexin V/TO-PRO-3 double-staining was used to compare cell death by membrane damage or apoptosis. Rubb12 induced significant direct membrane damage, particularly with HepG2 cells, while Rubb7-Cl caused considerably less membrane damage but induced greater levels of apoptosis. Confocal microscopy, coupled with JC-1 assays, demonstrated that Rubb12 depolarises the mitochondrial membrane, whereas Rubb7-Cl had a much smaller affect. Cellular localisation experiments indicated that Rubb12 did not accumulate in the mitochondria, whereas significant mitochondrial accumulation was observed for Rubb7-Cl. The effect of Rubb12 and Rubb7-Cl on intracellular superoxide dismutase activity showed that the ruthenium complexes could induce cell death via a reactive oxygen species-mediated pathway. The results of this study demonstrate that Rubb12 predominantly kills eukaryotic cells by damaging the cytoplasmic membrane. As this dinuclear ruthenium complex has been previously shown to exhibit greater toxicity towards bacteria than eukaryotic cells, the results of the present study suggest that

  1. Biological processing of dinuclear ruthenium complexes in eukaryotic cells.

    PubMed

    Li, Xin; Heimann, Kirsten; Dinh, Xuyen Thi; Keene, F Richard; Collins, J Grant

    2016-10-20

    The biological processing - mechanism of cellular uptake, effects on the cytoplasmic and mitochondrial membranes, intracellular sites of localisation and induction of reactive oxygen species - of two dinuclear polypyridylruthenium(ii) complexes has been examined in three eukaryotic cells lines. Flow cytometry was used to determine the uptake of [{Ru(phen)2}2{μ-bb12}](4+) (Rubb12) and [Ru(phen)2(μ-bb7)Ru(tpy)Cl](3+) {Rubb7-Cl, where phen = 1,10-phenanthroline, tpy = 2,2':6',2''-terpyridine and bbn = bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane} in baby hamster kidney (BHK), human embryonic kidney (HEK-293) and liver carcinoma (HepG2) cell lines. The results demonstrated that the major uptake mechanism for Rubb12 and Rubb7-Cl was active transport, although with a significant contribution from carrier-assisted diffusion for Rubb12 and passive diffusion for Rubb7-Cl. Flow cytometry coupled with Annexin V/TO-PRO-3 double-staining was used to compare cell death by membrane damage or apoptosis. Rubb12 induced significant direct membrane damage, particularly with HepG2 cells, while Rubb7-Cl caused considerably less membrane damage but induced greater levels of apoptosis. Confocal microscopy, coupled with JC-1 assays, demonstrated that Rubb12 depolarises the mitochondrial membrane, whereas Rubb7-Cl had a much smaller affect. Cellular localisation experiments indicated that Rubb12 did not accumulate in the mitochondria, whereas significant mitochondrial accumulation was observed for Rubb7-Cl. The effect of Rubb12 and Rubb7-Cl on intracellular superoxide dismutase activity showed that the ruthenium complexes could induce cell death via a reactive oxygen species-mediated pathway. The results of this study demonstrate that Rubb12 predominantly kills eukaryotic cells by damaging the cytoplasmic membrane. As this dinuclear ruthenium complex has been previously shown to exhibit greater toxicity towards bacteria than eukaryotic cells, the results of the present study suggest that

  2. The Development and Study of Surface Bound Ruthenium Organometallic Complexes

    NASA Astrophysics Data System (ADS)

    Abbott, Geoffrey Reuben

    The focus of this project has been on the use of mono-diimine ruthenium organometallic complexes, of the general structure [H(Ru)(CO)(L)2(L') 2][PF6] (L=PPh3, DPPENE and L'=Bpy, DcBpy, MBpyC, Phen, AminoPhen) bound to surfaces as luminescent probes. Both biological and inorganic/organic hybrid surfaces have been studied. The complexes were characterized both bound and unbound using standard analytical techniques such as NMR, IR and X-ray crystallography, as well as through several photophysical methods as well. Initially the study focused on how the photophyscial properties of the complexes were affected by incorporation into biological membranes. It was found that by conjugating the probes to a more rigid cholesterol moiety that luminescence was conserved, compared to conjugation with a far more flexible lipid moiety, where luminescence was either lost or reduced. Both the cholesterol and lipid conjugates were able to insert into a lipid membrane, and in the more rigid environment some of the lipid conjugates regained some of their luminescence, but often blue shifted and reduced, depending on the conjugation site. Silica Polyamine Composites (SPCs) were a hybrid material developed in the Rosenberg Lab as useful metal separation materials, that could be easily modified, and had several benefits over current commercially available polymers, or inorganic materials. These SPCs also provided an opportunity for the development of a heterogeneous platform for luminescent complexes as either catalysts or sensors. Upon binding of the luminescent Ru complexes to the surface no loss, or major change in luminescence was seen, however, when bound to the rigid surface a significant increase in excited state lifetime was measured. It is likely that through binding and interacting with the surface that the complexes lost non-radiative decay pathways, resulting in the increase in lifetime, however, these interactions do not seem to affect the energy level of the MLCT band in a

  3. Photoinduced interactions of supramolecular ruthenium(II) complexes with plasmid DNA: synthesis and spectroscopic, electrochemical, and DNA photocleavage studies.

    PubMed

    Swavey, Shawn; DeBeer, Madeleine; Li, Kaiyu

    2015-04-01

    Two new bridging ligands have been synthesized by combining substituted benzaldehydes with phenanthrolinopyrrole (php), resulting in new polyazine bridging ligands. The ligands have been characterized by (1)H NMR, mass spectroscopy, and elemental analysis. These new ligands display π-π* transitions above 500 nm with modest molar absorptivities. Upon excitation at the ligand-centered charge-transfer transition, weak emission with a maximum wavelength of 612 nm is observed. When coordinated to two ruthenium(II) bis(bipyridyl) groups, the new bimetallic complexes generated give an overall 4+ charge. The electronic transitions of the bimetallic ruthenium(II) complexes display traditional π-π* transitions at 287 nm and metal-to-ligand charge-transfer transitions at 452 nm with molar absorptivities greater than 30000 M(-1) cm(-1). Oxidation of the ruthenium(II) metal centers to ruthenium(III) occurs at potentials above 1.4 V versus the Ag/AgCl reference electrode. Spectroscopic and electrochemical measurements indicate that the ruthenium(II) moieties behave independently. Both complexes are water-soluble and show the ability to photonick plasmid DNA when irradiated with low-energy light above 550 nm. In addition, one of the complexes, [Ru(bpy)2php]2Van(4+), shows the ability to linearize plasmid DNA and gives evidence, by gel electrophoresis, of photoinduced binding to plasmid DNA. PMID:25798576

  4. Excited state dynamics and isomerization in ruthenium sulfoxide complexes.

    PubMed

    King, Albert W; Wang, Lei; Rack, Jeffrey J

    2015-04-21

    Molecular photochromic compounds are those that interconvert between two isomeric forms with light. The two isomeric forms display distinct electronic and molecular structures and must not be in equilibrium with one another. These light-activated molecular switch compounds have found wide application in areas of study ranging from chemical biology to materials science, where conversion from one isomeric form to another by light prompts a response in the environment (e.g., protein or polymeric material). Certain ruthenium and osmium polypyridine sulfoxide complexes are photochromic. The mode of action is a phototriggered isomerization of the sulfoxide from S- to O-bonded. The change in ligation drastically alters both the spectroscopic and electrochemical properties of the metal complex. Our laboratory has pioneered the preparation and study of these complexes. In particular, we have applied femtosecond pump-probe spectroscopy to reveal excited state details of the isomerization mechanism. The data from numerous complexes allowed us to predict that the isomerization was nonadiabatic in nature, defined as occurring from a S-bonded triplet excited state (primarily metal-to-ligand charge transfer in character) to an O-bonded singlet ground state potential energy surface. This prediction was corroborated by high-level density functional theory calculations. An intriguing aspect of this reactivity is the coupling of nuclear motion to the electronic wave function and how this coupling affects motions productive for isomerization. In an effort to learn more about this coupling, we designed a project to examine phototriggered isomerization in bis-sulfoxide complexes. The goal of these studies was to determine whether certain complexes could be designed in which a single photon excitation event would prompt two sulfoxide isomerizations. We employed chelating sulfoxides in this study and found that both the nature of the chelate ring and the R group on the sulfoxide affect

  5. Probing excited state charge transfer dynamics in a heteroleptic ruthenium complex.

    PubMed

    Ghosh, Rajib; Palit, Dipak K

    2014-01-01

    Dynamics of metal to ligand charge transfer in the excited states of ruthenium polypyridyl complexes, which have shown promise as materials for artificial solar energy harvesting, has been of immense interest recently. Mixed ligand complexes are especially important for broader absorption in the visible region. Dynamics of ultrafast vibrational energy relaxation and inter-ligand charge transfer processes in the excited states of a heteroleptic ruthenium complex, [Ru(bpy)2(pap)](ClO4)2 (where bpy is 2,2'-bipyridine and pap is 2-(phenylazo)pyridine) have been investigated using femtosecond to nanosecond time-resolved transient absorption spectroscopic techniques. A good agreement between the TA spectrum of the lowest excited (3)MLCT state of [Ru(bpy)2(pap)](ClO4)2 complex and the anion radical spectrum of the pap ligand, which has been generated using the pulse radiolysis technique, confirmed the charge localization at the pap ligand. While the lifetime of the inter-ligand charge transfer from the bpy to the pap ligand in the (3)MLCT state is about 2.5 ps, vibrational cooling of the pap-localized(3)MLCT state occurs over a much longer time scale with a lifetime of about 35 ps. Ultrafast charge localization dynamics observed here may have important consequences in artificial solar energy harvesting systems, which employ heteroleptic ruthenium complexes. PMID:24247908

  6. In Situ Catalyst Modification in Atom Transfer Radical Reactions with Ruthenium Benzylidene Complexes.

    PubMed

    Lee, Juneyoung; Grandner, Jessica M; Engle, Keary M; Houk, K N; Grubbs, Robert H

    2016-06-01

    Ruthenium benzylidene complexes are well-known as olefin metathesis catalysts. Several reports have demonstrated the ability of these catalysts to also facilitate atom transfer radical (ATR) reactions, such as atom transfer radical addition (ATRA) and atom transfer radical polymerization (ATRP). However, while the mechanism of olefin metathesis with ruthenium benzylidenes has been well-studied, the mechanism by which ruthenium benzylidenes promote ATR reactions remains unknown. To probe this question, we have analyzed seven different ruthenium benzylidene complexes for ATR reactivity. Kinetic studies by (1)H NMR revealed that ruthenium benzylidene complexes are rapidly converted into new ATRA-active, metathesis-inactive species under typical ATRA conditions. When ruthenium benzylidene complexes were activated prior to substrate addition, the resulting activated species exhibited enhanced kinetic reactivity in ATRA with no significant difference in overall product yield compared to the original complexes. Even at low temperature, where the original intact complexes did not catalyze the reaction, preactivated catalysts successfully reacted. Only the ruthenium benzylidene complexes that could be rapidly transformed into ATRA-active species could successfully catalyze ATRP, whereas other complexes preferred redox-initiated free radical polymerization. Kinetic measurements along with additional mechanistic and computational studies show that a metathesis-inactive ruthenium species, generated in situ from the ruthenium benzylidene complexes, is the active catalyst in ATR reactions. Based on data from (1) H, (13)C, and (31)P NMR spectroscopy and X-ray crystallography, we suspect that this ATRA-active species is a RuxCly(PCy3)z complex.

  7. Metal-to-Ligand Charge-Transfer Emissions of Ruthenium(II) Pentaammine Complexes with Monodentate Aromatic Acceptor Ligands and Distortion Patterns of their Lowest Energy Triplet Excited States.

    PubMed

    Tsai, Chia Nung; Mazumder, Shivnath; Zhang, Xiu Zhu; Schlegel, H Bernhard; Chen, Yuan Jang; Endicott, John F

    2015-09-01

    This is the first report of the 77 K triplet metal-to-ligand charge-transfer ((3)MLCT) emission spectra of pentaammine-MDA-ruthenium(II) ([Ru(NH3)5(MDA)](2+)) complexes, where MDA is a monodentate aromatic ligand. The emission spectra of these complexes and of the related trans-[Ru(NH3)4(MDA) (MDA')](2+) complexes are closely related, and their emission intensities are very weak. Density functional theory (DFT) calculations indicate that the energies of the lowest (3)MLCT excited states of Ru-MDA complexes are either similar to or lower than those of the lowest energy metal-centered excited states ((3)MC(X(Y))), that the barrier to internal conversion at 77 K is large compared to kBT, and that the (3)MC(X(Y)) excited states are weakly bound. The [Ru(NH3)5py](2+) complex is an exception to the general pattern: emission has been observed for the [Ru(ND3)5(d5-py)](2+) complex, but its lifetime is apparently very short. DFT modeling indicates that the excited state distortions of the different (3)MC excited states are very large and are in both Ru-ligand bonds along a single Cartesian axis for each different (3)MC excited state, nominally resulting in (3)MC(X(Y)), (3)MC((X)Y), and (3)MC(Z) lowest energy metal-centered states. The (3)MC(X(Y)) and (3)MC((X)Y) states appear to be the pseudo-Jahn-Teller distorted components of a (3)MC((XY)) state. The (3)MC(X(Y)) states are distorted up to 0.5 Å in each H3N-Ru-NH3 bond along a single Cartesian axis in the pentaammine and trans-tetraammine complexes, whereas the (3)MC(Z) states are found to be dissociative. DFT modeling of the (3)MLCT excited state of [Ru(NH3)5(py)](2+) indicates that the Ru center has a spin density of 1.24 at the (3)MLCT energy minimum and that the (3)MLCT → (3)MC(Z) crossing is smooth with a very small barrier (<0.5 kcal/mol) along the D3N-Ru-py distortion coordinate, implying strong (3)MLCT/(3)MC excited state configurational mixing. Furthermore, the DFT modeling indicates that the long

  8. The synthesis and antiparasitic activity of aryl- and ferrocenyl-derived thiosemicarbazone ruthenium(II)-arene complexes.

    PubMed

    Adams, Muneebah; Li, Yiqun; Khot, Heena; De Kock, Carmen; Smith, Peter J; Land, Kirkwood; Chibale, Kelly; Smith, Gregory S

    2013-04-01

    A series of aryl-functionalized and ferrocenyl monothiosemicarbazone compounds (L1-L4) were synthesized in moderate yields via a general Schiff-base condensation reaction. The thiosemicarbazone (TSC) ligands were reacted with the ruthenium dimer [Ru(Ar)(μ-Cl)Cl](2) (Ar = benzene; p-cymene) to yield a series of cationic mononuclear ruthenium(II)-arene thiosemicarbazone complexes of the general type [Ru(Cl)(TSC)(Ar)]Cl (1-8). The thiosemicarbazone ligands act as bidentate chelating ligands that coordinate to the ruthenium(ii) ion via the imine nitrogen and the thione sulfur atoms. The thiosemicarbazone ligands, as well as their metal complexes, were characterized by NMR, IR spectroscopy and ESI(+)-mass spectrometry. The molecular structure of the mononuclear ruthenium(II)-arene thiosemicarbazone complex (6) was determined by single-crystal X-ray diffraction analysis. The ruthenium(II)-arene thiosemicarbazone complexes were further evaluated for their in vitro antiparasitic activities against the Plasmodium falciparum chloroquine-sensitive (NF54) and chloroquine-resistant (Dd2) strains, as well as the G3 strain of Trichomonas vaginalis.

  9. Spectroscopic investigation on the interaction of ruthenium complexes with tumor specific lectin, jacalin

    NASA Astrophysics Data System (ADS)

    Ayaz Ahmed, Khan Behlol; Reshma, Elamvazhuthi; Mariappan, Mariappan; Anbazhagan, Veerappan

    2015-02-01

    Several ruthenium complexes are regarded as anticancer agents and considered as an alternative to the widely used platinum complexes. Owing to the preferential interaction of jacalin with tumor-associated T-antigen, we report the interaction of jacalin with four ruthenium complex namely, tris(1,10-phenanthroline)ruthenium(II)chloride, bis(1,10-phenanthroline)(N-[1,10]phenanthrolin-5-yl-pyrenylmethanimine)ruthenium(II)chloride, bis(1,10-phenanthroline)(dipyrido[3,2-a:2‧,3‧-c]-phenazine)ruthenium(II)chloride, bis(1,10-phenanthroline)(11-(9-acridinyl)dipyrido[3,2-a:2‧,3‧-c]phenazine)ruthenium(II) chloride. Fluorescence spectroscopic analysis revealed that the ruthenium complexes strongly quenched the intrinsic fluorescence of jacalin through a static quenching procedure, and a non-radiative energy transfer occurred within the molecules. Association constants obtained for the interaction of different ruthenium complexes with jacalin are in the order of 105 M-1, which is in the same range as those obtained for the interaction of lectin with carbohydrate and hydrophobic ligand. Each subunit of the tetrameric jacalin binds one ruthenium complex, and the stoichiometry is found to be unaffected by the presence of the specific sugar, galactose. In addition, agglutination activity of jacalin is largely unaffected by the presence of the ruthenium complexes, indicating that the binding sites for the carbohydrate and the ruthenium complexes are different. These results suggest that the development of lectin-ruthenium complex conjugate would be feasible to target malignant cells in chemo-therapeutics.

  10. Spectroscopic investigation on the interaction of ruthenium complexes with tumor specific lectin, jacalin.

    PubMed

    Ayaz Ahmed, Khan Behlol; Reshma, Elamvazhuthi; Mariappan, Mariappan; Anbazhagan, Veerappan

    2015-02-25

    Several ruthenium complexes are regarded as anticancer agents and considered as an alternative to the widely used platinum complexes. Owing to the preferential interaction of jacalin with tumor-associated T-antigen, we report the interaction of jacalin with four ruthenium complex namely, tris(1,10-phenanthroline)ruthenium(II)chloride, bis(1,10-phenanthroline)(N-[1,10]phenanthrolin-5-yl-pyrenylmethanimine)ruthenium(II)chloride, bis(1,10-phenanthroline)(dipyrido[3,2-a:2',3'-c]-phenazine)ruthenium(II)chloride, bis(1,10-phenanthroline)(11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine)ruthenium(II) chloride. Fluorescence spectroscopic analysis revealed that the ruthenium complexes strongly quenched the intrinsic fluorescence of jacalin through a static quenching procedure, and a non-radiative energy transfer occurred within the molecules. Association constants obtained for the interaction of different ruthenium complexes with jacalin are in the order of 10(5) M(-1), which is in the same range as those obtained for the interaction of lectin with carbohydrate and hydrophobic ligand. Each subunit of the tetrameric jacalin binds one ruthenium complex, and the stoichiometry is found to be unaffected by the presence of the specific sugar, galactose. In addition, agglutination activity of jacalin is largely unaffected by the presence of the ruthenium complexes, indicating that the binding sites for the carbohydrate and the ruthenium complexes are different. These results suggest that the development of lectin-ruthenium complex conjugate would be feasible to target malignant cells in chemo-therapeutics. PMID:25306128

  11. Spectroscopic investigation on the interaction of ruthenium complexes with tumor specific lectin, jacalin.

    PubMed

    Ayaz Ahmed, Khan Behlol; Reshma, Elamvazhuthi; Mariappan, Mariappan; Anbazhagan, Veerappan

    2015-02-25

    Several ruthenium complexes are regarded as anticancer agents and considered as an alternative to the widely used platinum complexes. Owing to the preferential interaction of jacalin with tumor-associated T-antigen, we report the interaction of jacalin with four ruthenium complex namely, tris(1,10-phenanthroline)ruthenium(II)chloride, bis(1,10-phenanthroline)(N-[1,10]phenanthrolin-5-yl-pyrenylmethanimine)ruthenium(II)chloride, bis(1,10-phenanthroline)(dipyrido[3,2-a:2',3'-c]-phenazine)ruthenium(II)chloride, bis(1,10-phenanthroline)(11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine)ruthenium(II) chloride. Fluorescence spectroscopic analysis revealed that the ruthenium complexes strongly quenched the intrinsic fluorescence of jacalin through a static quenching procedure, and a non-radiative energy transfer occurred within the molecules. Association constants obtained for the interaction of different ruthenium complexes with jacalin are in the order of 10(5) M(-1), which is in the same range as those obtained for the interaction of lectin with carbohydrate and hydrophobic ligand. Each subunit of the tetrameric jacalin binds one ruthenium complex, and the stoichiometry is found to be unaffected by the presence of the specific sugar, galactose. In addition, agglutination activity of jacalin is largely unaffected by the presence of the ruthenium complexes, indicating that the binding sites for the carbohydrate and the ruthenium complexes are different. These results suggest that the development of lectin-ruthenium complex conjugate would be feasible to target malignant cells in chemo-therapeutics.

  12. Gas-phase chemistry of ruthenium and rhodium carbonyl complexes.

    PubMed

    Cao, Shiwei; Wang, Yang; Qin, Zhi; Fan, Fangli; Haba, Hiromitsu; Komori, Yukiko; Wu, Xiaolei; Tan, Cunmin; Zhang, Xin

    2016-01-01

    Short-lived ruthenium and rhodium isotopes were produced from a (252)Cf spontaneous fission (SF) source. Their volatile carbonyl complexes were formed in gas-phase reactions in situ with the carbon-monoxide containing gas. A gas-jet system was employed to transport the volatile carbonyls from the recoil chamber to the chemical separation apparatus. The gas-phase chemical behaviors of these carbonyl complexes were studied using an online low temperature isothermal chromatography (IC) technique. Long IC columns made up of FEP Teflon were used to obtain the chemical information of the high-volatile Ru and Rh carbonyls. By excluding the influence of precursor effects, short-lived isotopes of (109-110)Ru and (111-112)Rh were used to represent the chemical behaviours of Ru and Rh carbonyls. Relative chemical yields of about 75% and 20% were measured for Ru(CO)5 and Rh(CO)4, respectively, relative to the yields of KCl aerosols transported in Ar gas. The adsorption enthalpies of ruthenium and rhodium carbonyl complexes on a Teflon surface were determined to be around ΔHads = -33(+1)(-2) kJ mol(-1) and -36(+2)(-1) kJ mol(-1), respectively, by fitting the breakthrough curves of the corresponding carbonyl complexes with a Monte Carlo simulation program. Different from Mo and Tc carbonyls, a small amount of oxygen gas was found to be not effective for the chemical yields of ruthenium and rhodium carbonyl complexes. The general chemical behaviors of short-lived carbonyl complexes of group VI-IX elements were discussed, which can be used in the future study on the gas-phase chemistry of superheavy elements - Bh, Hs, and Mt carbonyls. PMID:26573993

  13. PHOTOCHEMICAL CO2 REDUCTION BY RHENUIM AND RUTHENIUM COMPLEXES.

    SciTech Connect

    FUJITA,E.; MUCKERMAN, J.T.; TANAKA, K.

    2007-11-30

    Photochemical conversion of CO{sub 2} to fuels or useful chemicals using renewable solar energy is an attractive solution to both the world's need for fuels and the reduction of greenhouse gases. Rhenium(I) and ruthenium(II) diimine complexes have been shown to act as photocatalysts and/or electrocatalysts for CO{sub 2} reduction to CO. We have studied these photochemical systems focusing on the identification of intermediates and the bond formation/cleavage reactions between the metal center and CO{sub 2}. For example, we have produced the one-electron-reduced monomer (i.e. Re(dmb)(CO){sub 3}S where dmb = 4,4'-dimethy-2,2'-bipyridine and S = solvent) either by reductive quenching of the excited states of fac-[Re(dmb)(CO){sub 3}(CH{sub 3}CN)]PF{sub 6} or by photo-induced homolysis of [Re(dmb)(CO){sub 3}]{sub 2}. We previously found that: (1) the remarkably slow dimerization of Re(dmb)(CO){sub 3}S is due to the absence of a vacant coordination site for Re-Re bond formation, and the extra electron is located on the dmb ligand; (2) the reaction of Re(dmb)(CO){sub 3}S with CO{sub 2} forms a CO{sub 2}-bridged binuclear species (CO){sub 3}(dmb)Re-CO(O)-Re(dmb)(CO){sub 3} as an intermediate in CO formation; and (3) the kinetics and mechanism of reactions are consistent with the interaction of the CO{sub 2}-bridged binuclear species with CO{sub 2} to form CO and CO{sub 3}{sup 2-}.

  14. Radiosensitisation of human colorectal cancer cells by ruthenium(II) arene anticancer complexes

    PubMed Central

    Carter, R; Westhorpe, A; Romero, MJ; Habtemariam, A; Gallevo, CR; Bark, Y; Menezes, N; Sadler, PJ; Sharma, RA

    2016-01-01

    Some of the largest improvements in clinical outcomes for patients with solid cancers observed over the past 3 decades have been from concurrent treatment with chemotherapy and radiotherapy (RT). The lethal effects of RT on cancer cells arise primarily from damage to DNA. Ruthenium (Ru) is a transition metal of the platinum group, with potentially less toxicity than platinum drugs. We postulated that ruthenium-arene complexes are radiosensitisers when used in combination with RT. We screened 14 ruthenium-arene complexes and identified AH54 and AH63 as supra-additive radiosensitisers by clonogenic survival assays and isobologram analyses. Both complexes displayed facial chirality. At clinically relevant doses of RT, radiosensitisation of cancer cells by AH54 and AH63 was p53-dependent. Radiation enhancement ratios for 5–10 micromolar drug concentrations ranged from 1.19 to 1.82. In p53-wildtype cells, both drugs induced significant G2 cell cycle arrest and apoptosis. Colorectal cancer cells deficient in DNA damage repair proteins, EME1 and MUS81, were significantly more sensitive to both agents. Both drugs were active in cancer cell lines displaying acquired resistance to oxaliplatin or cisplatin. Our findings broaden the potential scope for these drugs for use in cancer therapy, including combination with radiotherapy to treat colorectal cancer. PMID:26867983

  15. Carboxylate-assisted C(sp³)-H activation in olefin metathesis-relevant ruthenium complexes.

    PubMed

    Cannon, Jeffrey S; Zou, Lufeng; Liu, Peng; Lan, Yu; O'Leary, Daniel J; Houk, K N; Grubbs, Robert H

    2014-05-01

    The mechanism of C-H activation at metathesis-relevant ruthenium(II) benzylidene complexes was studied both experimentally and computationally. Synthesis of a ruthenium dicarboxylate at a low temperature allowed for direct observation of the C-H activation step, independent of the initial anionic ligand-exchange reactions. A first-order reaction supports an intramolecular concerted metalation-deprotonation mechanism with ΔG(‡)(298K) = 22.2 ± 0.1 kcal·mol(-1) for the parent N-adamantyl-N'-mesityl complex. An experimentally determined ΔS(‡) = -5.2 ± 2.6 eu supports a highly ordered transition state for carboxylate-assisted C(sp(3))-H activation. Experimental results, including measurement of a large primary kinetic isotope effect (k(H)/k(D) = 8.1 ± 1.7), agree closely with a computed six-membered carboxylate-assisted C-H activation mechanism where the deprotonating carboxylate adopts a pseudo-apical geometry, displacing the aryl ether chelate. The rate of cyclometalation was found to be influenced by both the electronics of the assisting carboxylate and the ruthenium ligand environment. PMID:24731019

  16. Carboxylate-assisted C(sp³)-H activation in olefin metathesis-relevant ruthenium complexes.

    PubMed

    Cannon, Jeffrey S; Zou, Lufeng; Liu, Peng; Lan, Yu; O'Leary, Daniel J; Houk, K N; Grubbs, Robert H

    2014-05-01

    The mechanism of C-H activation at metathesis-relevant ruthenium(II) benzylidene complexes was studied both experimentally and computationally. Synthesis of a ruthenium dicarboxylate at a low temperature allowed for direct observation of the C-H activation step, independent of the initial anionic ligand-exchange reactions. A first-order reaction supports an intramolecular concerted metalation-deprotonation mechanism with ΔG(‡)(298K) = 22.2 ± 0.1 kcal·mol(-1) for the parent N-adamantyl-N'-mesityl complex. An experimentally determined ΔS(‡) = -5.2 ± 2.6 eu supports a highly ordered transition state for carboxylate-assisted C(sp(3))-H activation. Experimental results, including measurement of a large primary kinetic isotope effect (k(H)/k(D) = 8.1 ± 1.7), agree closely with a computed six-membered carboxylate-assisted C-H activation mechanism where the deprotonating carboxylate adopts a pseudo-apical geometry, displacing the aryl ether chelate. The rate of cyclometalation was found to be influenced by both the electronics of the assisting carboxylate and the ruthenium ligand environment.

  17. Dicarba-closo-dodecarborane-containing half-sandwich complexes of ruthenium, osmium, rhodium and iridium: biological relevance and synthetic strategies.

    PubMed

    Barry, Nicolas P E; Sadler, Peter J

    2012-04-21

    This review describes how the incorporation of dicarba-closo-dodecarboranes into half-sandwich complexes of ruthenium, osmium, rhodium and iridium might lead to the development of a new class of compounds with applications in medicine. Such a combination not only has unexplored potential in traditional areas such as Boron Neutron Capture Therapy agents, but also as pharmacophores for the targeting of biologically important proteins and the development of targeted drugs. The synthetic pathways used for the syntheses of dicarba-closo-dodecarboranes-containing half-sandwich complexes of ruthenium, osmium, rhodium and iridium are also reviewed. Complexes with a wide variety of geometries and characteristics can be prepared. Examples of addition reactions on the metal centre, B-H activation, transmetalation reactions and/or direct formation of metal-metal bonds are discussed (103 references).

  18. Threading of Binuclear Ruthenium Complex Through DNA Bases

    NASA Astrophysics Data System (ADS)

    Paramanathan, Thayaparan; Westerlund, Fredrik; McCauley, Micah; Lincoln, Per; Rouzina, Ioulia; Williams, Mark

    2009-03-01

    Due to steric constraints the dumb-bell shaped binuclear ruthenium complex can only intercalate DNA by threading, which requires local melting of the DNA to occur. By mechanically manipulating a single DNA molecule held with optical tweezers, we lower the barrier to threading compared to bulk experiments. Stretching single DNA molecules with different drug concentrations and holding a constant force allows the binding to reach equilibrium. We can obtain the equilibrium fractional ligand binding and length of DNA at saturation. Fitting these results yields quantitative measurements of the binding thermodynamics and kinetics. In addition, we obtain the minimum binding site size, which may be determined by either electrostatic repulsion or steric constraints.

  19. Enantioselective olefin metathesis with cyclometalated ruthenium complexes.

    PubMed

    Hartung, John; Dornan, Peter K; Grubbs, Robert H

    2014-09-17

    The success of enantioselective olefin metathesis relies on the design of enantioenriched alkylidene complexes capable of transferring stereochemical information from the catalyst structure to the reactants. Cyclometalation of the NHC ligand has proven to be a successful strategy to incorporate stereogenic atoms into the catalyst structure. Enantioenriched complexes incorporating this design element catalyze highly Z- and enantioselective asymmetric ring opening/cross metathesis (AROCM) of norbornenes and cyclobutenes, and the difference in ring strain between these two substrates leads to different propagating species in the catalytic cycle. Asymmetric ring closing metathesis (ARCM) of a challenging class of prochiral trienes has also been achieved. The extent of reversibility and effect of reaction setup was also explored. Finally, promising levels of enantioselectivity in an unprecedented Z-selective asymmetric cross metathesis (ACM) of a prochiral 1,4-diene was demonstrated. PMID:25137310

  20. Enantioselective olefin metathesis with cyclometalated ruthenium complexes.

    PubMed

    Hartung, John; Dornan, Peter K; Grubbs, Robert H

    2014-09-17

    The success of enantioselective olefin metathesis relies on the design of enantioenriched alkylidene complexes capable of transferring stereochemical information from the catalyst structure to the reactants. Cyclometalation of the NHC ligand has proven to be a successful strategy to incorporate stereogenic atoms into the catalyst structure. Enantioenriched complexes incorporating this design element catalyze highly Z- and enantioselective asymmetric ring opening/cross metathesis (AROCM) of norbornenes and cyclobutenes, and the difference in ring strain between these two substrates leads to different propagating species in the catalytic cycle. Asymmetric ring closing metathesis (ARCM) of a challenging class of prochiral trienes has also been achieved. The extent of reversibility and effect of reaction setup was also explored. Finally, promising levels of enantioselectivity in an unprecedented Z-selective asymmetric cross metathesis (ACM) of a prochiral 1,4-diene was demonstrated.

  1. Enantioselective Olefin Metathesis with Cyclometalated Ruthenium Complexes

    PubMed Central

    2015-01-01

    The success of enantioselective olefin metathesis relies on the design of enantioenriched alkylidene complexes capable of transferring stereochemical information from the catalyst structure to the reactants. Cyclometalation of the NHC ligand has proven to be a successful strategy to incorporate stereogenic atoms into the catalyst structure. Enantioenriched complexes incorporating this design element catalyze highly Z- and enantioselective asymmetric ring opening/cross metathesis (AROCM) of norbornenes and cyclobutenes, and the difference in ring strain between these two substrates leads to different propagating species in the catalytic cycle. Asymmetric ring closing metathesis (ARCM) of a challenging class of prochiral trienes has also been achieved. The extent of reversibility and effect of reaction setup was also explored. Finally, promising levels of enantioselectivity in an unprecedented Z-selective asymmetric cross metathesis (ACM) of a prochiral 1,4-diene was demonstrated. PMID:25137310

  2. Unusual dimer formation of cyclometalated ruthenium NHC p-cymene complexes.

    PubMed

    Schleicher, David; Tronnier, Alexander; Leopold, Hendrik; Borrmann, Horst; Strassner, Thomas

    2016-02-28

    We present the synthesis and structural characterization of novel ruthenium complexes containing C^C* cyclometalated N-heterocyclic carbene ligands, η(6)-arene (p-cymene) ligands and one bridging chlorine ion. Complexes of the general formula [Ru(p-cymene)(C^C*)Cl] were prepared via a one-pot synthesis using in situ transmetalation from the correspondent silver NHC complexes. These complexes react with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBAr(F)4) to form dinuclear complexes of the general structure [Ru(p-cymene)(C^C*)-μ-Cl-(p-cymene)(C^C*)Ru](+)[BAr(F)4](-). Solid-state structures confirm that the pseudo-tetrahedral coordination around the metal center with the η(6)-ligand aligned perpendicularly to the C^C* ligand and the i-Pr group "atop" is retained in the bimetallic complexes.

  3. Ruthenium(II)-PNN pincer complex catalyzed dehydrogenation of benzyl alcohol to ester: A DFT study

    NASA Astrophysics Data System (ADS)

    Tao, Jingcong; Wen, Li; Lv, Xiaobo; Qi, Yong; Yin, Hailiang

    2016-04-01

    The molecular mechanism of the dehydrogenation of primary alcohol to ester catalyzed by the ruthenium(II)-PNN pincer complex Ru(H)(η2-BH4)(PNN), [PNN: (2-(di-tert-butylphosphinomethyl)-6-(diethlaminomethyl)-pyridine)] has been investigated using density functional theory calculations. The catalytic cycle includes three stages: (stage I) alcohol dehydrogenation to form aldehyde, (stage II) coupling of aldehyde with alcohol to give hemiacetal or ester, and (stage III) hemiacetal dehydrogenation to form ester. Two dehydrogenation reactions occur via the β-H elimination mechanism rather than the bifunctional double hydrogen transfer mechanism, which could be rationalized as the fluxional behavior of the BH4- ligand. At the second stage, the coupling reaction requires alcohol or the ruthenium catalyst as mediator. The formation of hemiacetal through the alcohol-mediated pathway is kinetically favorable than the ruthenium catalyst-mediated one, which may be attributed to the smaller steric hindrance when the aldehyde approaches the alcohol moiety in the reaction system. Our results would be helpful for experimental chemists to design more effective transition metal catalysts for dehydrogenation of alcohols.

  4. Controlling the binding of dihydrogen using ruthenium complexes containing N-mono-functionalised 1,4,7-triazacyclononane ligand systems.

    PubMed

    Gott, Andrew L; McGowan, Patrick C; Podesta, Thomas J

    2008-07-28

    Pendant arm macrocycles derived from 1,4,7-triazacyclononane were reacted with RuHCl(CO)(PPh(3))(3) and RuHCl(PPh(3))(3) to yield air-stable cationic ruthenium hydrides that were characterised by a variety of techniques, including X-ray crystallography. Protonation of the metal hydride complexes with a proton source yielded eta(2)-dihydrogen complexes. The lifetime of the dihydrogen ligand was effected by a judicious choice of ancillary ligands.

  5. Controlling the binding of dihydrogen using ruthenium complexes containing N-mono-functionalised 1,4,7-triazacyclononane ligand systems.

    PubMed

    Gott, Andrew L; McGowan, Patrick C; Podesta, Thomas J

    2008-07-28

    Pendant arm macrocycles derived from 1,4,7-triazacyclononane were reacted with RuHCl(CO)(PPh(3))(3) and RuHCl(PPh(3))(3) to yield air-stable cationic ruthenium hydrides that were characterised by a variety of techniques, including X-ray crystallography. Protonation of the metal hydride complexes with a proton source yielded eta(2)-dihydrogen complexes. The lifetime of the dihydrogen ligand was effected by a judicious choice of ancillary ligands. PMID:18615220

  6. Synthesis and Single-Molecule Conductance Study of Redox-Active Ruthenium Complexes with Pyridyl and Dihydrobenzo[b]thiophene Anchoring Groups.

    PubMed

    Ozawa, Hiroaki; Baghernejad, Masoud; Al-Owaedi, Oday A; Kaliginedi, Veerabhadrarao; Nagashima, Takumi; Ferrer, Jaime; Wandlowski, Thomas; García-Suárez, Víctor M; Broekmann, Peter; Lambert, Colin J; Haga, Masa-Aki

    2016-08-26

    The ancillary ligands 4'-(4-pyridyl)-2,2':6',2''-terpyridine and 4'-(2,3-dihydrobenzo[b]thiophene)-2,2'-6',2"-terpyridine were used to synthesize two series of mono- and dinuclear ruthenium complexes differing in their lengths and anchoring groups. The electrochemical and single-molecular conductance properties of these two series of ruthenium complexes were studied experimentally by means of cyclic voltammetry and the scanning tunneling microscopy-break junction technique (STM-BJ) and theoretically by means of density functional theory (DFT). Cyclic voltammetry data showed clear redox peaks corresponding to both the metal- and ligand-related redox reactions. Single-molecular conductance demonstrated an exponential decay of the molecular conductance with the increase in molecular length for both the series of ruthenium complexes, with decay constants of βPY =2.07±0.1 nm(-1) and βBT =2.16±0.1 nm(-1) , respectively. The contact resistance of complexes with 2,3-dihydrobenzo[b]thiophene (BT) anchoring groups is found to be smaller than the contact resistance of ruthenium complexes with pyridine (PY) anchors. DFT calculations support the experimental results and provided additional information on the electronic structure and charge transport properties in those metal|ruthenium complex|metal junctions. PMID:27472889

  7. Synthesis and Single-Molecule Conductance Study of Redox-Active Ruthenium Complexes with Pyridyl and Dihydrobenzo[b]thiophene Anchoring Groups.

    PubMed

    Ozawa, Hiroaki; Baghernejad, Masoud; Al-Owaedi, Oday A; Kaliginedi, Veerabhadrarao; Nagashima, Takumi; Ferrer, Jaime; Wandlowski, Thomas; García-Suárez, Víctor M; Broekmann, Peter; Lambert, Colin J; Haga, Masa-Aki

    2016-08-26

    The ancillary ligands 4'-(4-pyridyl)-2,2':6',2''-terpyridine and 4'-(2,3-dihydrobenzo[b]thiophene)-2,2'-6',2"-terpyridine were used to synthesize two series of mono- and dinuclear ruthenium complexes differing in their lengths and anchoring groups. The electrochemical and single-molecular conductance properties of these two series of ruthenium complexes were studied experimentally by means of cyclic voltammetry and the scanning tunneling microscopy-break junction technique (STM-BJ) and theoretically by means of density functional theory (DFT). Cyclic voltammetry data showed clear redox peaks corresponding to both the metal- and ligand-related redox reactions. Single-molecular conductance demonstrated an exponential decay of the molecular conductance with the increase in molecular length for both the series of ruthenium complexes, with decay constants of βPY =2.07±0.1 nm(-1) and βBT =2.16±0.1 nm(-1) , respectively. The contact resistance of complexes with 2,3-dihydrobenzo[b]thiophene (BT) anchoring groups is found to be smaller than the contact resistance of ruthenium complexes with pyridine (PY) anchors. DFT calculations support the experimental results and provided additional information on the electronic structure and charge transport properties in those metal|ruthenium complex|metal junctions.

  8. Design and synthesis of DNA-tethered ruthenium complexes that self-assemble into linear arrays.

    PubMed

    Stewart, Kristen M; McLaughlin, Larry W

    2003-12-01

    Ruthenium(II) bis(terpyridine) complexes have been prepared with two triethylene glycol linkers to which DNA sequences have been attached; hybridization at various complex ratios results in linear arrays of varying lengths.

  9. In Situ Catalyst Modification in Atom Transfer Radical Reactions with Ruthenium Benzylidene Complexes.

    PubMed

    Lee, Juneyoung; Grandner, Jessica M; Engle, Keary M; Houk, K N; Grubbs, Robert H

    2016-06-01

    Ruthenium benzylidene complexes are well-known as olefin metathesis catalysts. Several reports have demonstrated the ability of these catalysts to also facilitate atom transfer radical (ATR) reactions, such as atom transfer radical addition (ATRA) and atom transfer radical polymerization (ATRP). However, while the mechanism of olefin metathesis with ruthenium benzylidenes has been well-studied, the mechanism by which ruthenium benzylidenes promote ATR reactions remains unknown. To probe this question, we have analyzed seven different ruthenium benzylidene complexes for ATR reactivity. Kinetic studies by (1)H NMR revealed that ruthenium benzylidene complexes are rapidly converted into new ATRA-active, metathesis-inactive species under typical ATRA conditions. When ruthenium benzylidene complexes were activated prior to substrate addition, the resulting activated species exhibited enhanced kinetic reactivity in ATRA with no significant difference in overall product yield compared to the original complexes. Even at low temperature, where the original intact complexes did not catalyze the reaction, preactivated catalysts successfully reacted. Only the ruthenium benzylidene complexes that could be rapidly transformed into ATRA-active species could successfully catalyze ATRP, whereas other complexes preferred redox-initiated free radical polymerization. Kinetic measurements along with additional mechanistic and computational studies show that a metathesis-inactive ruthenium species, generated in situ from the ruthenium benzylidene complexes, is the active catalyst in ATR reactions. Based on data from (1) H, (13)C, and (31)P NMR spectroscopy and X-ray crystallography, we suspect that this ATRA-active species is a RuxCly(PCy3)z complex. PMID:27186790

  10. Osmium, ruthenium, iridium and uranium in silicates and chromite from the eastern Bushveld Complex, South Africa

    USGS Publications Warehouse

    Gijbels, R.h.; Millard, H.T.; Desborough, G.A.; Bartel, A.J.

    1974-01-01

    Osmium, ruthenium, iridium and uranium contents were determined in eight ortho pyroxene, seven plagioclase, and three chromite mineral separates from the eastern Bushveld Complex. Neutron activation analysis was used to measure the platinum metals, and uranium was determined by a fission track technique. The platinum metals were found to be present within each mine??ral in the proportions Os:Ru:Ir = 1:7:1, while the concentrations of these metals in the minerals are in the ratios orthopyroxene:plagioclase:chromite = 1:16:700. The concentration of uranium was found to range from 11 to 66 ppb (parts per billion) and not to vary significantly from mineral to mineral. The data for the platinum metals are consistent with a model in which the eastern Bushveld Complex was formed by the fractional crystallization of two separately injected magmas. A computer fit of this model to these data indicates that the initial concentrations of Os, Ru and Ir in the first magma were 0.24, 2.0 and 0.21 ppb and in the second magma were 0.16, 1.1 and 0.18 ppb, respectively. The fit also yields the distribution coefficients for the partitioning between the liquid and cumulus orthopyroxene, cumulus plagioclase and cumulus chromite. These coefficients (mineral/liquid) for osmium are 4.5, 66 and 2700; for ruthenium, they are 5, 65 and 2700; and for iridium, they are 4, 60 and 1600. To make this fit, it was necessary to hypothesize the existence of two types of chromite: one type with a large distribution coefficient, presumably formed as a cumulus phase at high temperature, and another, more prevalent type with a smaller distribution coefficient, which may have been formed by postcumulus growth at a lower temperature. This hypothesis is supported by data for coexisting chromite-silicate pairs, which indicate that the chromite grains expelled these platinum metals as they cooled. ?? 1974.

  11. Chiral Ruthenium(II) Polypyridyl Complexes: Stabilization of G-Quadruplex DNA, Inhibition of Telomerase Activity and Cellular Uptake

    PubMed Central

    Yu, Qianqian; Liu, Yanan; Wang, Chuan; Sun, Dongdong; Yang, Xingcheng; Liu, Yanyu; Liu, Jie

    2012-01-01

    Two ruthenium(II) complexes, Λ-[Ru(phen)2(p-HPIP)]2+ and Δ-[Ru(phen)2(p-HPIP)]2+, were synthesized and characterized via proton nuclear magnetic resonance spectroscopy, electrospray ionization-mass spectrometry, and circular dichroism spectroscopy. This study aims to clarify the anticancer effect of metal complexes as novel and potent telomerase inhibitors and cellular nucleus target drug. First, the chiral selectivity of the compounds and their ability to stabilize quadruplex DNA were studied via absorption and emission analyses, circular dichroism spectroscopy, fluorescence-resonance energy transfer melting assay, electrophoretic mobility shift assay, and polymerase chain reaction stop assay. The two chiral compounds selectively induced and stabilized the G-quadruplex of telomeric DNA with or without metal cations. These results provide new insights into the development of chiral anticancer agents for G-quadruplex DNA targeting. Telomerase repeat amplification protocol reveals the higher inhibitory activity of Λ-[Ru(phen)2(p-HPIP)]2+ against telomerase, suggesting that Λ-[Ru(phen)2(p-HPIP)]2+ may be a potential telomerase inhibitor for cancer chemotherapy. MTT assay results show that these chiral complexes have significant antitumor activities in HepG2 cells. More interestingly, cellular uptake and laser-scanning confocal microscopic studies reveal the efficient uptake of Λ-[Ru(phen)2(p-HPIP)]2+ by HepG2 cells. This complex then enters the cytoplasm and tends to accumulate in the nucleus. This nuclear penetration of the ruthenium complexes and their subsequent accumulation are associated with the chirality of the isomers as well as with the subtle environment of the ruthenium complexes. Therefore, the nucleus can be the cellular target of chiral ruthenium complexes for anticancer therapy. PMID:23236402

  12. Homobimetallic Ruthenium-N-Heterocyclic Carbene Complexes For Olefin Metathesis

    NASA Astrophysics Data System (ADS)

    Sauvage, Xavier; Demonceau, Albert; Delaude, Lionel

    In this chapter, the synthesis and catalytic activity towards olefin metathesis of homobimetallic ruthenium (Ru)-alkylidene, -cyclodiene or -arene complexes bearing phosphine or N-heterocyclic carbene (NHC) ligands are reviewed. Emphasis is placed on the last category of bimetallic compounds. Three representatives of this new type of molecular scaffold were investigated. Thus, [(p-cymene)Ru(m-Cl)3RuCl (h2-C2H4)(L)] complexes with L = PCy3 (15a), IMes (16a), or IMesCl2 (16b) were prepared. They served as catalyst precursors for cross-metathesis (CM) of various styrene derivatives. These experiments revealed the outstanding aptitude of complex 16a (and to a lesser extent of 16b) to catalyze olefin metathesis reactions. Contrary to monometallic Ru-arene complexes of the [RuCl2(p-cymene)(L)] type, the new homobimetallic species did not require the addition of a diazo compound nor visible light illumination to initiate the ring-opening metathesis of norbornene or cyclooctene. When diethyl 2,2-diallylmalonate and N,N-diallyltosylamide were exposed to 16a,b, a mixture of cycloisomerization and ring-closing metathesis (RCM) products was obtained in a nonselective way. Addition of phenylacetylene enhanced the metathetical activity while completely repressing the cycloisomerization process.

  13. Water Oxidation by Ruthenium Complexes Incorporating Multifunctional Bipyridyl Diphosphonate Ligands.

    PubMed

    Xie, Yan; Shaffer, David W; Lewandowska-Andralojc, Anna; Szalda, David J; Concepcion, Javier J

    2016-07-01

    We describe herein the synthesis and characterization of ruthenium complexes with multifunctional bipyridyl diphosphonate ligands as well as initial water oxidation studies. In these complexes, the phosphonate groups provide redox-potential leveling through charge compensation and σ donation to allow facile access to high oxidation states. These complexes display unique pH-dependent electrochemistry associated with deprotonation of the phosphonic acid groups. The position of these groups allows them to shuttle protons in and out of the catalytic site and reduce activation barriers. A mechanism for water oxidation by these catalysts is proposed on the basis of experimental results and DFT calculations. The unprecedented attack of water at a neutral six-coordinate [Ru(IV) ] center to yield an anionic seven-coordinate [Ru(IV) -OH](-) intermediate is one of the key steps of a single-site mechanism in which all species are anionic or neutral. These complexes are among the fastest single-site catalysts reported to date. PMID:27166584

  14. Ruthenium or osmium complexes and their uses as catalysts for water oxidation

    DOEpatents

    Concepcion Corbea, Javier Jesus; Chen, Zuofeng; Jurss, Jonah Wesley; Templeton, Joseph L; Hoertz, Paul; Meyer, Thomas J

    2014-10-28

    The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

  15. Ruthenium or osmium complexes and their uses as catalysts for water oxidation

    DOEpatents

    Corbea, Javier Jesus Concepcion; Chen, Zoufeng; Jurss, Jonah Wesley; Templeton, Joseph L.; Hoertz, Paul; Meyer, Thomas J.

    2016-06-07

    The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

  16. Ruthenium or osmium complexes and their uses as catalysts for water oxidation

    SciTech Connect

    Corbea, Javier Jesus Concepcion; Chen, Zuofeng; Jurss, Jonah Wesley; Templeton, Joseph L.; Hoertz, Paul; Meyer, Thomas J.

    2013-09-03

    The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

  17. Promising in Vitro anti-Alzheimer Properties for a Ruthenium(III) Complex

    PubMed Central

    2013-01-01

    Metal complexes represent today an attractive class of experimental anti-Alzheimer agents with the potential of blocking β-amyloid 1–42 aggregation and scavenging its toxicity. Three representative ruthenium(III) complexes, namely NAMI A, KP1019, and PMRU20, were specifically evaluated to this end in an established in vitro model of AD relying on primary cortical neurons. Notably, PMRU20 turned out to be highly effective in protecting cortical neurons against Aβ 1–42 toxicity, while the other tested ruthenium compounds were poorly active or even inactive; we also found that PMRU20 is virtually devoid of any significant toxicity in vitro at the applied concentrations. Interestingly, PMRU20 was neuroprotective even against the toxicity induced by Aβ 25–35. The direct reaction of PMRU20 with Aβ 1–42 was explored through ESI MS analysis and some adduct formation evidenced. In addition, thioflavin T assays revealed that PMRU20 greatly reduces Aβ 1–42 aggregation. The implications of these findings are discussed in relation to emerging treatment strategies for the Alzheimer’s disease. PMID:24900669

  18. Density functional theory study of oxygen-atom insertion into metal-methyl bonds of iron(II), ruthenium(II), and osmium(II) complexes: study of metal-mediated C-O bond formation.

    PubMed

    Pardue, Daniel B; Mei, Jiajun; Cundari, Thomas R; Gunnoe, T Brent

    2014-03-17

    Metal-mediated C-O bond formation is a key step in hydrocarbon oxygenation catalytic cycles; however, few examples of this reaction have been reported for low-oxidation-state complexes. Oxygen insertion into a metal-carbon bond of Cp*M(CO)(OPy)R (Cp* = η(5)-pentamethylcyclopentadienyl; R = Me, Ph; OPy = pyridine-N-oxide; M = Fe, Ru, Os) was analyzed via density functional theory calculations. Oxygen-atom insertions through a concerted single-step organometallic Baeyer-Villiger pathway and a two-step pathway via a metal-oxo intermediate were studied; calculations predict that the former pathway was lower in energy. The results indicated that functionalization of M-R to M-OR (R = Me, Ph) is plausible using iron(II) complexes. Starting from Cp*Fe(CO)(OPy)Ph, the intermediate Fe-oxo showed oxyl character and, thus, is best considered an Fe(III)O(•-) complex. Oxidation of the π-acid ancillary ligand CO was facile. Substitutions of CO with dimethylamide and NH3 were calculated to lower the activation barrier by ∼1-2 kcal/mol for formation of the Fe(III)O(•-) intermediate, whereas a chloride ligand raised the activation barrier to 26 kcal/mol from 22.9 kcal/mol. PMID:24571202

  19. Synthesis, structures and properties of new hybrid solids containing ruthenium complexes and polyoxometalates

    SciTech Connect

    Yan Bangbo; Hodsdon, Samantha A.; Li Yanfen; Carmichael, Christopher N.; Cao Yan; Pan Weiping

    2011-12-15

    Two new organic-inorganic hybrid solids containing Keggin ions and ruthenium complexes have been synthesized and characterized by FT-IR, UV-vis, luminescence, X-ray, and TG analysis. In KNa[Ru(bpy){sub 3}]{sub 2}[H{sub 2}W{sub 12}O{sub 40}]{center_dot}8H{sub 2}O (1), the [Ru(bpy){sub 3}]{sup 2+} (bpy=2,2 Prime -bipyridine) complex ions are located in between the infinite one-dimensional double-chains formed by adjacent Keggin anions [H{sub 2}W{sub 12}O{sub 40}]{sup 6-} linked through {l_brace}KO{sub 7}{r_brace} and {l_brace}NaO{sub 6}{r_brace} polyhedra, while in K{sub 6}[Ru(pzc){sub 3}]{sub 2}[SiW{sub 12}O{sub 40}] Bullet 12H{sub 2}O (2), the [Ru(pzc){sub 3}]{sup -} (pzc=pyrazine-2-carboxylate) complex anions are confined by layered networks of the [SiW{sub 12}O{sub 40}]{sup 4-} clusters connected by potassium ions. Both compounds exhibit three-dimensional frameworks through noncovalent interactions such as hydrogen bonds and anion Midline-Horizontal-Ellipsis {pi} interactions. Additionally, compound 1 shows strong luminescence at 604 nm in solid state at room temperature. - Graphical abstract: Two three-dimensional framework solids are constructed from polyoxoanions and ruthenium-organic complexes through noncovalent interactions. Highlights: Black-Right-Pointing-Triangle Ru complexes form hybrid solids with polyoxometalates. Black-Right-Pointing-Triangle Anion Midline-Horizontal-Ellipsis {pi} interaction between polyoxometalates and metal complexes was observed. Black-Right-Pointing-Triangle Noncovalent interactions play an important role in the assembly of solids. Black-Right-Pointing-Triangle The hybrid solid shows luminescence properties.

  20. Theoretical study on photooxidation mechanism of ruthenium complex [Ru(II)-(bpy)2 (TMBiimH2 )](2+) with molecular oxygen.

    PubMed

    Liu, Li-Hong; Wu, Dan; Xia, Shu-Hua; Cui, Ganglong

    2016-09-15

    Photoinduced reactions of ruthenium complexes with molecular oxygen have attracted a lot of experimental attention; however, the reaction mechanism remains elusive. In this work, we have used the density functional theory method to scrutinize the visible-light induced photooxidation mechanism of the ruthenium complex [Ru(II)-(bpy)2 (TMBiimH2 )](2+) (bpy: 2, 2-bipyridine and TMBiimH2 : 4, 5, 4, 5-tetramethyl-2, 2-biimidazole) initiated by the attack of molecular oxygen. The present computational results not only explain very well recent experiments, also provide new mechanistic insights. We found that: (1) the triplet energy transfer process between the triplet molecular oxygen and the metal-ligand charge transfer triplet state of the ruthenium complex, which leads to singlet molecular oxygen, is thermodynamically favorable; (2) the singlet oxygen addition process to the S0 ruthenium complex is facile in energy; (3) the chemical transformation from endoperoxide to epidioxetane intermediates can be either two- or one-step reaction (the latter is energetically favored). These findings contribute important mechanistic information to photooxidation reactions of ruthenium complexes with molecular oxygen. © 2016 Wiley Periodicals, Inc. PMID:27384925

  1. A selective, long-lived deep-red emissive ruthenium(II) polypyridine complexes for the detection of BSA.

    PubMed

    Babu, Eththilu; Muthu Mareeswaran, Paulpandian; Singaravadivel, Subramanian; Bhuvaneswari, Jayaraman; Rajagopal, Seenivasan

    2014-09-15

    A selective, label free luminescence sensor for bovine serum albumin (BSA) is investigated using ruthenium(II) complexes over the other proteins. Interaction between BSA and ruthenium(II) complexes has been studied using absorption, emission, excited state lifetime and circular dichroism (CD) spectral techniques. The luminescence intensity of ruthenium(II) complexes (I and II), has enhanced at 602 and 613 nm with a large hypsochromic shift of 18 and 5 nm respectively upon addition of BSA. The mode of binding of ruthenium(II) complexes with BSA has analyzed using computational docking studies.

  2. Polynuclear ruthenium, osmium and gold complexes. The quest for innovative anticancer chemotherapeutics.

    PubMed

    Hartinger, Christian G; Phillips, Andrew D; Nazarov, Alexey A

    2011-01-01

    Polynuclear compounds are a relatively new and successful approach in metal-based cancer chemotherapy as typified by the trinuclear Pt compound BBR3464 which was evaluated in clinical trials. In this review, we discuss newer developments of polynuclear ruthenium, osmium and gold complexes, focusing on their anticancer activity. The compounds presented are often supposed to exert their anticancer activity by different modes of action as compared to established drugs, including newly proposed mechanisms such as enzyme inhibition, crosslinking of biomacromolecules or through photo-activation, though many of the examples are also capable of binding to DNA nucleobases. Important metabolization and chemical characteristics of such compounds are discussed, and if the appropriate data is available, molecular modes of action are highlighted.

  3. Proton-coupled electron transfer and multielectron oxidations in complexes of ruthenium and osmium

    SciTech Connect

    Dovletoglou, A.

    1992-01-01

    This doctoral research concerns the mechanism of proton-coupled electron transfer over an extended pH range. These processes between ruthenium and osmium complexes and hydroquinones have been studied using spectrophotometric methods and cyclic voltammetry. Elucidation of the mechanistic details has been attempted by using isotopic labelling, kinetic analysis, and numerical simulation of complex kinetic schemes. The coordination and redox chemistry of polypyridyl-acetylacetonato and -oxalato complexes of ruthenium and the role of ancillary ligands in defining the properties of Ru[sup IV]O complexes were explored. These studies represent the first attempt to probe possible 2e[sup [minus

  4. Radiochemistry of ruthenium

    SciTech Connect

    Schulz, W W; Metcalf, S G; Barney, G S

    1984-06-01

    Information on ruthenium is presented. Topics include the following; isotopes and nuclear properties of ruthenium; review of the chemistry of ruthenium including metal and alloys, compounds of ruthenium, and solution chemistry; separation methods including volatilization of RuO{sub 4}, precipitation and coprecipitation, solvent extraction, chromatographic techniques, and analysis for radioruthenium. 445 refs., 7 figs., 23 tabs.

  5. Immobilization and electrochemical properties of ruthenium and iridium complexes on carbon electrodes

    NASA Astrophysics Data System (ADS)

    Gupta, Ayush; Blakemore, James D.; Brunschwig, Bruce S.; Gray, Harry B.

    2016-03-01

    We report the synthesis and surface immobilization of two new pyrene-appended molecular metal complexes: a ruthenium tris(bipyridyl) complex (1) and a bipyridyl complex of [Cp*Ir] (2) (Cp*  =  pentamethylcyclopentadienyl). X-ray photoelectron spectroscopy confirmed successful immobilization on high surface area carbon electrodes, with the expected elemental ratios for the desired compounds. Electrochemical data collected in acetonitrile solution revealed a reversible reduction of 1 near  -1.4 V, and reduction of 2 near  -0.75 V. The noncovalent immobilization, driven by association of the appended pyrene groups with the surface, was sufficiently stable to enable studies of the molecular electrochemistry. Electroactive surface coverage of 1 was diminished by only 27% over three hours soaking in electrolyte solution as measured by cyclic voltammetry. The electrochemical response of 2 resembled its soluble analogues, and suggested that ligand exchange occurred on the surface. Together, the results demonstrate that noncovalent immobilization routes are suitable for obtaining fundamental understanding of immobilized metal complexes and their reductive electrochemical properties.

  6. Immobilization and electrochemical properties of ruthenium and iridium complexes on carbon electrodes.

    PubMed

    Gupta, Ayush; Blakemore, James D; Brunschwig, Bruce S; Gray, Harry B

    2016-03-01

    We report the synthesis and surface immobilization of two new pyrene-appended molecular metal complexes: a ruthenium tris(bipyridyl) complex (1) and a bipyridyl complex of [Cp*Ir] (2) (Cp*  =  pentamethylcyclopentadienyl). X-ray photoelectron spectroscopy confirmed successful immobilization on high surface area carbon electrodes, with the expected elemental ratios for the desired compounds. Electrochemical data collected in acetonitrile solution revealed a reversible reduction of 1 near  -1.4 V, and reduction of 2 near  -0.75 V. The noncovalent immobilization, driven by association of the appended pyrene groups with the surface, was sufficiently stable to enable studies of the molecular electrochemistry. Electroactive surface coverage of 1 was diminished by only 27% over three hours soaking in electrolyte solution as measured by cyclic voltammetry. The electrochemical response of 2 resembled its soluble analogues, and suggested that ligand exchange occurred on the surface. Together, the results demonstrate that noncovalent immobilization routes are suitable for obtaining fundamental understanding of immobilized metal complexes and their reductive electrochemical properties. PMID:26871865

  7. Cellular delivery of pyrenyl-arene ruthenium complexes by a water-soluble arene ruthenium metalla-cage.

    PubMed

    Furrer, Mona Anca; Schmitt, Frédéric; Wiederkehr, Michaël; Juillerat-Jeanneret, Lucienne; Therrien, Bruno

    2012-06-28

    Three pyrenyl-arene ruthenium complexes (M(1)-M(3)) of the general formula [Ru(η(6)-arene-pyrenyl)Cl(2)(pta)] (pta = 1,3,5-triaza-7-phosphaadamantane) have been synthesised and characterised. Prior to the coordination to ruthenium, pyrene was connected to the arene ligand via an alkane chain containing different functional groups: ester (L(1)), ether (L(2)) and amide (L(3)), respectively. Furthermore, the pyrenyl moieties of the M(n) complexes were encapsulated within the hydrophobic cavity of the water soluble metalla-cage, [Ru(6)(η(6)-p-cymene)(6)(tpt)(2)(donq)(3)](6+) (tpt = 2,4,6-tri-(pyridin-4-yl)-1,3,5-triazine; donq = 5,8-dioxydo-1,4-naphthoquinonato), while the arene ruthenium end was pointing out of the cage, thus giving rise to the corresponding host-guest systems [M(n)⊂Ru(6)(η(6)-p-cymene)(6)(tpt)(2)(donq)(3)](6+) ([M(n)⊂cage](6+)). The antitumor activity of the pyrenyl-arene ruthenium complexes (M(n)) and the corresponding host-guest systems [M(n)⊂cage][CF(3)SO(3)](6) were evaluated in vitro in different types of human cancer cell lines (A549, A2780, A2780cisR, Me300 and HeLa). Complex M(2), which contains an ether group within the alkane chain, demonstrated at least a 10 times higher cytotoxicity than the reference compound [Ru(η(6)-p-cymene)Cl(2)(pta)] (RAPTA-C). All host-guest systems [M(n)⊂cage](6+) showed good anticancer activity with IC(50) values ranging from 2 to 8 μM after 72 h exposure. The fluorescence of the pyrenyl moiety allowed the monitoring of the cellular uptake and revealed an increase of uptake by a factor two of the M(2) complex when encapsulated in the metalla-cage [Ru(6)(η(6)-p-cymene)(6)(tpt)(2)(donq)(3)](6+).

  8. Asymmetric mixed-valence complexes that consist of cyclometalated ruthenium and ferrocene: synthesis, characterization, and electronic-coupling studies.

    PubMed

    Wu, Si-Hai; Shen, Jun-Jian; Yao, Jiannian; Zhong, Yu-Wu

    2013-01-01

    Three bis-tridentate ferrocene-containing cyclometalated ruthenium complexes, [(Fcdpb)Ru(tpy)](+) (1(+)), [(Fctpy)Ru(dpb)](+) (2(+)), and [(Fcdpb)Ru(Fctpy)](+) (3(+)), have been prepared and characterized, where Fcdpb is the 2-deprotonated form of 1,3-di(2-pyridyl)-5-ferrocenylbenzene, tpy is 2,2':6',2"-terpyridine, dpb is the 2-deprotonated form of 1,3-di(2-pyridyl)benzene, and Fctpy is 4'-ferrocenyl-2,2':6',2"-terpyridine. Single crystals of compounds 2(+) and 3(+) have been studied by X-ray analysis. Complexes 1(+) and 2(+) displayed two anodic redox waves, whilst three well-separated redox couples were observed for compound 3(+). A combined experimental and computational study suggested that the ferrocene unit on the Fcdpb moiety in compounds 1(+) and 3(+) was oxidized first. In contrast, the order of the oxidation of ruthenium and ferrocene in complex 2(+) was reversed. Metal-to-metal-charge-transfer transitions (MM'CT) have been observed for the singly oxidized states 1(2+), 2(2+), and 3(2+) in the near-infrared region. Hush analysis showed that the metal-metal electronic couplings in compounds 1(2+) and 3(2+) were much stronger than those in compound 2(2+).

  9. Ruthenium(II) complexes containing quinone based ligands: Synthesis, characterization, catalytic applications and DNA interaction

    NASA Astrophysics Data System (ADS)

    Anitha, P.; Manikandan, R.; Endo, A.; Hashimoto, T.; Viswanathamurthi, P.

    2012-12-01

    1,2-Naphthaquinone reacts with amines such as semicarbazide, isonicotinylhydrazide and thiosemicarbazide in high yield procedure with the formation of tridentate ligands HLn (n = 1-3). By reaction of ruthenium(II) starting complexes and quinone based ligands HLn (n = 1-3), a series of ruthenium complexes were synthesized and characterized by elemental and spectroscopic methods (FT-IR, electronic, 1H, 13C, 31P NMR and ESI-MS). The ligands were coordinated to ruthenium through quinone oxygen, imine nitrogen and enolate oxygen/thiolato sulfur. On the basis of spectral studies an octahedral geometry may be assigned for all the complexes. Further, the catalytic oxidation of primary, secondary alcohol and transfer hydrogenation of ketone was carried out. The DNA cleavage efficiency of new complexes has also been tested.

  10. Ruthenium(II) complexes containing quinone based ligands: synthesis, characterization, catalytic applications and DNA interaction.

    PubMed

    Anitha, P; Manikandan, R; Endo, A; Hashimoto, T; Viswanathamurthi, P

    2012-12-01

    1,2-Naphthaquinone reacts with amines such as semicarbazide, isonicotinylhydrazide and thiosemicarbazide in high yield procedure with the formation of tridentate ligands HL(n) (n=1-3). By reaction of ruthenium(II) starting complexes and quinone based ligands HL(n) (n=1-3), a series of ruthenium complexes were synthesized and characterized by elemental and spectroscopic methods (FT-IR, electronic, (1)H, (13)C, (31)P NMR and ESI-MS). The ligands were coordinated to ruthenium through quinone oxygen, imine nitrogen and enolate oxygen/thiolato sulfur. On the basis of spectral studies an octahedral geometry may be assigned for all the complexes. Further, the catalytic oxidation of primary, secondary alcohol and transfer hydrogenation of ketone was carried out. The DNA cleavage efficiency of new complexes has also been tested. PMID:23063861

  11. Mechanistic Insights into C-H Oxidations by Ruthenium(III)-Pterin Complexes: Impact of Basicity of the Pterin Ligand and Electron Acceptability of the Metal Center on the Transition States.

    PubMed

    Mitome, Hiroumi; Ishizuka, Tomoya; Kotani, Hiroaki; Shiota, Yoshihito; Yoshizawa, Kazunari; Kojima, Takahiko

    2016-08-01

    A ruthenium(II) complex, [Ru(dmdmp)Cl(MeBPA)] (2) (Hdmdmp = N,N-dimethyl-6,7-dimethylpterin, MeBPA = N-methyl-N,N-bis(pyridylmethyl)amine), having a pterin derivative as a proton-accepting ligand, was synthesized and characterized. Complex 2 shows higher basicity than that of a previously reported Ru(II)-pterin complex, [Ru(dmdmp) (TPA)](+) (1) (TPA = tris(2-pyridylmethyl)amine). On the other hand, 1e(-)-oxidized species of 1 (1OX) exhibits higher electron-acceptability than that of 1e(-)-oxidized 2 (2OX). Bond dissociation enthalpies (BDE) of the two Ru(II) complexes having Hdmdmp as a ligand in proton-coupled electron transfer (PCET) to generate 1OX and 2OX were calculated to be 85 kcal mol(-1) for 1OX and 78 kcal mol(-1) for 2OX. The BDE values are large enough to perform H atom transfer from C-H bonds of organic molecules to the 1e(-)-oxidized complexes through PCET. The second-order rate constants (k) of PCET oxidation reactions were determined for 1OX and 2OX. The logarithms of normalized k values were proportional to the BDE values of C-H bonds of the substrates with slopes of -0.27 for 1OX and -0.44 for 2OX. The difference between 1OX and 2OX in the slopes suggests that the transition states in PCET oxidations of substrates by the two complexes bear different polarization, as reflection of difference in the electron acceptability and basicity of 1OX and 2OX. The more basic 2OX attracts a proton from a C-H bond via a more polarized transition state than that of 1OX; on the contrary, the more electron-deficient 1OX forms less polarized transition states in PCET oxidation reactions of C-H bonds.

  12. Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

    PubMed Central

    Sainna, Mala A.; de Visser, Sam P.

    2015-01-01

    Industrial Fischer-Tropsch processes involve the synthesis of hydrocarbons usually on metal surface catalysts. On the other hand, very few homogeneous catalysts are known to perform a Fischer-Tropsch style of reaction. In recent work, we established the catalytic properties of a diruthenium-platinum carbene complex, [(CpRu)2(μ2-H)(μ2-NHCH3)(μ3-C)PtCH3(P(CH3)3)2](CO)n+ with n = 0, 2 and Cp = η5-C5(CH3)5, and showed it to react efficiently by initial hydrogen atom transfer followed by methyl transfer to form an alkyl chain on the Ru-center. In particular, the catalytic efficiency was shown to increase after the addition of two CO molecules. As such, this system could be viewed as a potential homogeneous Fischer-Tropsch catalyst. Herein, we have engineered the catalytic center of the catalyst and investigated the reactivity of trimetal carbene complexes of the same type using iron, ruthenium and osmium at the central metal scaffold. The work shows that the reactivity should increase from diosmium to diruthenium to diiron; however, a non-linear trend is observed due to multiple factors contributing to the individual barrier heights. We identified all individual components of these reaction steps in detail and established the difference in reactivity of the various complexes. PMID:26426009

  13. Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

    PubMed

    Sainna, Mala A; de Visser, Sam P

    2015-09-28

    Industrial Fischer-Tropsch processes involve the synthesis of hydrocarbons usually on metal surface catalysts. On the other hand, very few homogeneous catalysts are known to perform a Fischer-Tropsch style of reaction. In recent work, we established the catalytic properties of a diruthenium-platinum carbene complex, [(CpRu)₂(μ²-H) (μ²-NHCH₃)(μ³-C)PtCH₃(P(CH₃)₃)₂](CO)n⁺ with n=0, 2 and Cp=η⁵-C₅(CH₃)₅, and showed it to react efficiently by initial hydrogen atom transfer followed by methyl transfer to form an alkyl chain on the Ru-center. In particular, the catalytic efficiency was shown to increase after the addition of two CO molecules. As such, this system could be viewed as a potential homogeneous Fischer-Tropsch catalyst. Herein, we have engineered the catalytic center of the catalyst and investigated the reactivity of trimetal carbene complexes of the same type using iron, ruthenium and osmium at the central metal scaffold. The work shows that the reactivity should increase from diosmium to diruthenium to diiron; however, a non-linear trend is observed due to multiple factors contributing to the individual barrier heights. We identified all individual components of these reaction steps in detail and established the difference in reactivity of the various complexes.

  14. Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

    PubMed

    Sainna, Mala A; de Visser, Sam P

    2015-01-01

    Industrial Fischer-Tropsch processes involve the synthesis of hydrocarbons usually on metal surface catalysts. On the other hand, very few homogeneous catalysts are known to perform a Fischer-Tropsch style of reaction. In recent work, we established the catalytic properties of a diruthenium-platinum carbene complex, [(CpRu)₂(μ²-H) (μ²-NHCH₃)(μ³-C)PtCH₃(P(CH₃)₃)₂](CO)n⁺ with n=0, 2 and Cp=η⁵-C₅(CH₃)₅, and showed it to react efficiently by initial hydrogen atom transfer followed by methyl transfer to form an alkyl chain on the Ru-center. In particular, the catalytic efficiency was shown to increase after the addition of two CO molecules. As such, this system could be viewed as a potential homogeneous Fischer-Tropsch catalyst. Herein, we have engineered the catalytic center of the catalyst and investigated the reactivity of trimetal carbene complexes of the same type using iron, ruthenium and osmium at the central metal scaffold. The work shows that the reactivity should increase from diosmium to diruthenium to diiron; however, a non-linear trend is observed due to multiple factors contributing to the individual barrier heights. We identified all individual components of these reaction steps in detail and established the difference in reactivity of the various complexes. PMID:26426009

  15. Filamentation of Escherichia coli K12 elicited by some monomeric, dimeric and trimeric complexes of ruthenium in various oxidation states.

    PubMed

    Gibson, J F; Hughes, M N; Poole, R K; Rees, J F

    1985-05-01

    A number of ruthenium complexes were tested for their ability to induce filamentation in Escherichia coli. These included monomeric and dimeric complexes with ruthenium in the II or III oxidation states, as well as mixed-valence complexes with ruthenium in the (II,III) oxidation states. In general, dimeric mixed-valence Ru(II,III) complexes were the most active class of compound, although some complexes of this type were relatively inactive. These were pyrazine- or bipyridyl-bridged complexes which are known to involve strong metal-ligand interaction, which stabilizes the Ru(II) oxidation state. Some Ru(III) complexes were also significantly active in induction of filamentous growth in E. coli. One of these was [Ru(NH3)5Cl]Cl2, which did not inhibit electron transport, Mg2+-ATPase activity or DNA synthesis in E. coli, but like [Ru2(NH3)6Br3]Br2 X H2O was a potent inhibitor of respiration-driven calcium transport in the organism. Filament-inducing activity of the complex was reduced in the presence of NaCl, but not in the presence of added Ca2+, ethanol, calcium pantothenate, or E. coli 'division promoting extract'. This behaviour is also similar to that of [Ru2(NH3)6Br3]Br2 X H2O. It is suggested that both complexes may induce filamentation in E. coli by a common mechanism, which may involve interference with calcium metabolism, or a wall or membrane target, rather than interaction with DNA. PMID:3159489

  16. Carbon nanotubes dispersed in aqueous solution by ruthenium(ii) polypyridyl complexes

    NASA Astrophysics Data System (ADS)

    Huang, Kewei; Saha, Avishek; Dirian, Konstantin; Jiang, Chengmin; Chu, Pin-Lei E.; Tour, James M.; Guldi, Dirk M.; Martí, Angel A.

    2016-07-01

    Cationic ruthenium(ii) polypyridyl complexes with appended pyrene groups have been synthesized and used to disperse single-walled carbon nanotubes (SWCNT) in aqueous solutions. To this end, planar pyrene groups enable association by means of π-stacking onto carbon nanotubes and, in turn, the attachment of the cationic ruthenium complexes. Importantly, the ionic nature of the ruthenium complexes allows the formation of stable dispersions featuring individualized SWCNTs in water as confirmed in a number of spectroscopic and microscopic assays. In addition, steady-state photoluminescence spectroscopy was used to probe the excited state interactions between the ruthenium complexes and SWCNTs. These studies show that the photoluminescence of both, that is, of the ruthenium complexes and of SWCNTs, are quenched when they interact with each other. Pump-probe transient absorption experiments were performed to shed light onto the nature of the photoluminescence quenching, showing carbon nanotube-based bands with picosecond lifetimes, but no new bands which could be unambigously assigned to photoinduced charge transfer process. Thus, from the spectroscopic data, we conclude that quenching of the photoluminescence of the ruthenium complexes is due to energy transfer to proximal SWCNTs.Cationic ruthenium(ii) polypyridyl complexes with appended pyrene groups have been synthesized and used to disperse single-walled carbon nanotubes (SWCNT) in aqueous solutions. To this end, planar pyrene groups enable association by means of π-stacking onto carbon nanotubes and, in turn, the attachment of the cationic ruthenium complexes. Importantly, the ionic nature of the ruthenium complexes allows the formation of stable dispersions featuring individualized SWCNTs in water as confirmed in a number of spectroscopic and microscopic assays. In addition, steady-state photoluminescence spectroscopy was used to probe the excited state interactions between the ruthenium complexes and SWCNTs

  17. A new di-ruthenium complex with an intense near-infrared electronic band

    SciTech Connect

    Spreer, L.O.; Allen, C.B.; MacQueen, D.B.; Calvin, M.; Otvos, J.W.

    1993-12-31

    A new di-ruthenium complex prepared by the aerobic oxidation of trans Ru(1,4,7,11-tetraazacyclo-tetradecane) Cl{sub 2} has been investigated. The FAB mass spectrum shows mass peaks centered at m/z 732 and the isotopic ion distribution pattern gives the composition C{sub 20}H{sub 36}N{sub 8}Cl{sub 4}Ru{sub 2}. This paper gives evidence supporting characterization of this species as the ruthenium analogue of a di-iron complex with a delocalized pi system (Inorg. Chem. 1992, 31, 717) bridging two tetraazamacrocycles. The di-ruthenium complex, like the di-iron has a very intense electronic transition in the near-infrared.

  18. A SAR study of novel antiproliferative ruthenium and osmium complexes with quinoxalinone ligands in human cancer cell lines.

    PubMed

    Ginzinger, Werner; Mühlgassner, Gerhard; Arion, Vladimir B; Jakupec, Michael A; Roller, Alexander; Galanski, Markus; Reithofer, Michael; Berger, Walter; Keppler, Bernhard K

    2012-04-12

    A series of ruthenium(II) arene complexes with 3-(1H-benzimidazol-2-yl)-1H-quinoxalin-2-one, bearing pharmacophoric groups of known protein kinase inhibitors, and related benzoxazole and benzothiazole derivatives have been synthesized. In addition, the corresponding osmium complexes of the unsubstituted ligands have also been prepared. The compounds have been characterized by NMR, UV-vis, and IR spectroscopy, ESI mass spectrometry, elemental analysis, and by X-ray crystallography. Antiproliferative activity in three human cancer cell lines (A549, CH1, SW480) was determined by MTT assays, yielding IC(50) values of 6-60 μM for three unsubstituted metal-free ligands, whereas values for the metal complexes vary in a broad range from 0.3 to 140 μM. Complexation with osmium of quinoxalinone derivatives with benzimidazole or benzothiazole results in a more consistent increase in cytotoxicity than complexation with ruthenium. For selected compounds, the capacity to induce apoptosis was confirmed by fluorescence microscopy and flow-cytometric analysis, whereas cell cycle effects are only moderate.

  19. ONO-pincer ruthenium complex-bound norvaline for efficient catalytic oxidation of methoxybenzenes with hydrogen peroxide.

    PubMed

    Yoshida, Ryota; Isozaki, Katsuhiro; Yokoi, Tomoya; Yasuda, Nobuhiro; Sadakane, Koichiro; Iwamoto, Takahiro; Takaya, Hikaru; Nakamura, Masaharu

    2016-08-21

    The enhanced catalytic activity of ruthenium complex-bound norvaline Boc-l-[Ru]Nva-OMe 1, in which the ONO-pincer ruthenium complex Ru(pydc)(terpy) 2 is tethered to the α-side chain of norvaline, has been demonstrated for the oxidation of methoxybenzenes to p-benzoquinones with a wide scope of substrates and unique chemoselectivity. PMID:27314504

  20. Syntheses and Characterization of Ruthenium(II) Tetrakis(pyridine)complexes: An Advanced Coordination Chemistry Experiment or Mini-Project

    ERIC Educational Resources Information Center

    Coe, Benjamin J.

    2004-01-01

    An experiment for third-year undergraduate a student is designed which provides synthetic experience and qualitative interpretation of the spectroscopic properties of the ruthenium complexes. It involves the syntheses and characterization of several coordination complexes of ruthenium, the element found directly beneath iron in the middle of the…

  1. Transient Spectroscopic Characterization of the Genesis of a Ruthenium Complex Catalyst Supported on Zeolite Y

    SciTech Connect

    Ogino, Isao; Gates, Bruce C.

    2010-01-12

    A mononuclear ruthenium complex anchored to dealuminated zeolite HY, Ru(acac)(C{sub 2}H{sub 4}){sup 2+} (acac = acetylacetonate, C{sub 5}H{sub 7}O{sup 2}{sup -}), was characterized in flow reactors by transient infrared (IR) spectroscopy and Ru K edge X-ray absorption spectroscopy. The combined results show how the supported complex was converted into a form that catalyzes ethene conversion to butene. The formation of these species resulted from the removal of acac ligands from the ruthenium (as shown by IR and extended X-ray absorption fine structure (EXAFS) spectra) and the simultaneous decrease in the symmetry of the ruthenium complex, with the ruthenium remaining mononuclear and its oxidation state remaining essentially unchanged (as shown by EXAFS and X-ray absorption near-edge structure spectra). The removal of anionic acac ligands from the ruthenium was evidently compensated by the bonding of other anionic ligands, such as hydride from H2 in the feed stream, to form species suggested to be Ru(H)(C{sub 2}H{sub 4}){sub 2}{sup +}, which is coordinatively unsaturated and inferred to react with ethene, leading to the observed formation of butene in a catalytic process.

  2. Striking difference in antiproliferative activity of ruthenium- and osmium-nitrosyl complexes with azole heterocycles.

    PubMed

    Büchel, Gabriel E; Gavriluta, Anatolie; Novak, Maria; Meier, Samuel M; Jakupec, Michael A; Cuzan, Olesea; Turta, Constantin; Tommasino, Jean-Bernard; Jeanneau, Erwann; Novitchi, Ghenadie; Luneau, Dominique; Arion, Vladimir B

    2013-06-01

    Ruthenium nitrosyl complexes of the general formulas (cation)(+)[cis-RuCl4(NO)(Hazole)](-), where (cation)(+) = (H2ind)(+), Hazole = 1H-indazole (Hind) (1c), (cation)(+) = (H2pz)(+), Hazole = 1H-pyrazole (Hpz) (2c), (cation)(+) = (H2bzim)(+), Hazole = 1H-benzimidazole (Hbzim) (3c), (cation)(+) = (H2im)(+), Hazole = 1H-imidazole (Him) (4c) and (cation)(+)[trans-RuCl4(NO)(Hazole)](-), where (cation)(+) = (H2ind)(+), Hazole = 1H-indazole (1t), (cation)(+) = (H2pz)(+), Hazole = 1H-pyrazole (2t), as well as osmium analogues of the general formulas (cation)(+)[cis-OsCl4(NO)(Hazole)](-), where (cation)(+) = (n-Bu4N)(+), Hazole =1H-indazole (5c), 1H-pyrazole (6c), 1H-benzimidazole (7c), 1H-imidazole (8c), (cation)(+) = Na(+); Hazole =1H-indazole (9c), 1H-benzimidazole (10c), (cation)(+) = (H2ind)(+), Hazole = 1H-indazole (11c), (cation)(+) = H2pz(+), Hazole = 1H-pyrazole (12c), (cation)(+) = (H2im)(+), Hazole = 1H-imidazole (13c), and (cation)(+)[trans-OsCl4(NO)(Hazole)](-), where (cation)(+) = n-Bu4N(+), Hazole = 1H-indazole (5t), 1H-pyrazole (6t), (cation)(+) = Na(+), Hazole = 1H-indazole (9t), (cation)(+) = (H2ind)(+), Hazole = 1H-indazole (11t), (cation)(+) = (H2pz)(+), Hazole = 1H-pyrazole (12t), have been synthesized. The compounds have been comprehensively characterized by elemental analysis, ESI mass spectrometry, spectroscopic techniques (IR, UV-vis, 1D and 2D NMR) and X-ray crystallography (1c·CHCl3, 1t·CHCl3, 2t, 3c, 6c, 6t, 8c). The antiproliferative activity of water-soluble compounds (1c, 1t, 3c, 4c and 9c, 9t, 10c, 11c, 11t, 12c, 12t, 13c) in the human cancer cell lines A549 (nonsmall cell lung carcinoma), CH1 (ovarian carcinoma), and SW480 (colon adenocarcinoma) has been assayed. The effects of metal (Ru vs Os), cis/trans isomerism, and azole heterocycle identity on cytotoxic potency and cell line selectivity have been elucidated. Ruthenium complexes (1c, 1t, 3c, and 4c) yielded IC50 values in the low micromolar concentration range. In contrast to most

  3. Synthesis and characterisation of nonclassical ruthenium hydride complexes containing chelating bidentate and tridentate phosphine ligands.

    PubMed

    Prechtl, Martin H G; Ben-David, Yehoshoa; Giunta, Daniela; Busch, Stefan; Taniguchi, Yuki; Wisniewski, Wolfgang; Görls, Helmar; Mynott, Richard J; Theyssen, Nils; Milstein, David; Leitner, Walter

    2007-01-01

    The synthesis and characterisation of nonclassical ruthenium hydride complexes containing bidentate PP and tridentate PCP and PNP pincer-type ligands are described. The mononuclear and dinuclear ruthenium complexes presented have been synthesised in moderate to high yields by the direct hydrogenation route (one-pot synthesis) or in a two-step procedure. In both cases [Ru(cod)(metallyl)(2)] served as a readily available precursor. The influences of the coordination geometry and the ligand framework on the structure, binding, and chemical properties of the M--H(2) fragments were studied by X-ray crystal structure analysis, spectroscopic methods, and reactivity towards N(2), D(2), and deuterated solvents.

  4. Dinuclear Ruthenium(II) Complexes as Two-Photon, Time-Resolved Emission Microscopy Probes for Cellular DNA**

    PubMed Central

    Baggaley, Elizabeth; Gill, Martin R; Green, Nicola H; Turton, David; Sazanovich, Igor V; Botchway, Stanley W; Smythe, Carl; Haycock, John W; Weinstein, Julia A; Thomas, Jim A

    2014-01-01

    The first transition-metal complex-based two-photon absorbing luminescence lifetime probes for cellular DNA are presented. This allows cell imaging of DNA free from endogenous fluorophores and potentially facilitates deep tissue imaging. In this initial study, ruthenium(II) luminophores are used as phosphorescent lifetime imaging microscopy (PLIM) probes for nuclear DNA in both live and fixed cells. The DNA-bound probes display characteristic emission lifetimes of more than 160 ns, while shorter-lived cytoplasmic emission is also observed. These timescales are orders of magnitude longer than conventional FLIM, leading to previously unattainable levels of sensitivity, and autofluorescence-free imaging. PMID:24458590

  5. Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment.

    PubMed

    Kreitner, Christoph; Heinze, Katja

    2016-09-21

    Deactivation pathways of the triplet metal-to-ligand charge transfer ((3)MLCT) excited state of cyclometalated polypyridine ruthenium complexes with [RuN5C](+) coordination are discussed on the basis of the available experimental data and a series of density functional theory calculations. Three different complex classes are considered, namely with [Ru(N^N)2(N^C)](+), [Ru(N^N^N)(N^C^N)](+) and [Ru(N^N^N)(N^N^C)](+) coordination modes. Excited state deactivation in these complex types proceeds via five distinct decay channels. Vibronic coupling of the (3)MLCT state to high-energy oscillators of the singlet ground state ((1)GS) allows tunneling to the ground state followed by vibrational relaxation (path A). A ligand field excited state ((3)MC) is thermally accessible via a (3)MLCT →(3)MC transition state with the (3)MC state being strongly coupled to the (1)GS surface via a low-energy minimum energy crossing point (path B). Furthermore, a (3)MLCT →(1)GS surface crossing point directly couples the triplet and singlet potential energy surfaces (path C). Charge transfer states either with higher singlet character or with different orbital parentage and intrinsic symmetry restrictions are thermally populated which promote non-radiative decay via tunneling to the (1)GS state (path D). Finally, the excited state can decay via phosphorescence (path E). The dominant deactivation pathways differ for the three individual complex classes. The implications of these findings for isoelectronic iridium(iii) or iron(ii) complexes are discussed. Ultimately, strategies for optimizing the emission efficiencies of cyclometalated polypyridine complexes of d(6)-metal ions, especially Ru(II), are suggested. PMID:27334798

  6. Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment.

    PubMed

    Kreitner, Christoph; Heinze, Katja

    2016-09-21

    Deactivation pathways of the triplet metal-to-ligand charge transfer ((3)MLCT) excited state of cyclometalated polypyridine ruthenium complexes with [RuN5C](+) coordination are discussed on the basis of the available experimental data and a series of density functional theory calculations. Three different complex classes are considered, namely with [Ru(N^N)2(N^C)](+), [Ru(N^N^N)(N^C^N)](+) and [Ru(N^N^N)(N^N^C)](+) coordination modes. Excited state deactivation in these complex types proceeds via five distinct decay channels. Vibronic coupling of the (3)MLCT state to high-energy oscillators of the singlet ground state ((1)GS) allows tunneling to the ground state followed by vibrational relaxation (path A). A ligand field excited state ((3)MC) is thermally accessible via a (3)MLCT →(3)MC transition state with the (3)MC state being strongly coupled to the (1)GS surface via a low-energy minimum energy crossing point (path B). Furthermore, a (3)MLCT →(1)GS surface crossing point directly couples the triplet and singlet potential energy surfaces (path C). Charge transfer states either with higher singlet character or with different orbital parentage and intrinsic symmetry restrictions are thermally populated which promote non-radiative decay via tunneling to the (1)GS state (path D). Finally, the excited state can decay via phosphorescence (path E). The dominant deactivation pathways differ for the three individual complex classes. The implications of these findings for isoelectronic iridium(iii) or iron(ii) complexes are discussed. Ultimately, strategies for optimizing the emission efficiencies of cyclometalated polypyridine complexes of d(6)-metal ions, especially Ru(II), are suggested.

  7. Synthesis, Characterization, and Reactivity of Dicationic Dihydrogen Complexes of Osmium and Ruthenium.

    PubMed

    Luther, Thomas A.; Heinekey, D. Michael

    1998-01-12

    The dicationic complexes [Os(H(2))(PR(3))(2)(bpy)(CO)](2+) [PR(3) = PPh(3), PMePh(2) (2a,b)], [Os(H(2))(PPh(3))(2)(phen)(CO)](2+) (2c), and [Ru(H(2))(PPh(3))(2)(bpy)(CO)](2+) (4) (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline) have been prepared by the protonation of the corresponding monocationic hydrides using an excess of trifluoromethanesulfonic acid. The presence of a bound dihydrogen ligand is indicated by short T(1) minimum values consistent with H-H distances of 0.92-1.04 Å. For the partially deuterated derivatives, J(HD) values of 25.1-31.0 Hz were observed. The dicationic complexes are strong acids, indicating that the bound H(2) is substantially activated toward heterolytic cleavage. The H(2) ligand is tightly bound to the metal center and does not undergo exchange with D(2) over the course of several weeks. The complex [Os(H(2))(PPh(3))(2)(bpy)(CO)](2+) (2a) has been shown to be very stable in solution at room temperature. In contrast, the ruthenium analogue, [Ru(H(2))(PPh(3))(2)(bpy)(CO)](2+) (4), decomposes in solution at room temperature but is relatively stable at temperatures less than 245 K. PMID:11670270

  8. Bis(allyl)-ruthenium(iv) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions.

    PubMed

    Tomás-Mendivil, Eder; Francos, Javier; González-Fernández, Rebeca; González-Liste, Pedro J; Borge, Javier; Cadierno, Victorio

    2016-09-14

    Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P([double bond, length as m-dash]O)H. The compounds [RuCl2(η(3):η(3)-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η(3):η(3)-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η(3):η(3)-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η(3):η(3)-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance. PMID:27510460

  9. Bis(allyl)-ruthenium(iv) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions.

    PubMed

    Tomás-Mendivil, Eder; Francos, Javier; González-Fernández, Rebeca; González-Liste, Pedro J; Borge, Javier; Cadierno, Victorio

    2016-09-14

    Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P([double bond, length as m-dash]O)H. The compounds [RuCl2(η(3):η(3)-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η(3):η(3)-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η(3):η(3)-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η(3):η(3)-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance.

  10. Antimalarial activity of ruthenium(II) and osmium(II) arene complexes with mono- and bidentate chloroquine analogue ligands.

    PubMed

    Ekengard, Erik; Glans, Lotta; Cassells, Irwin; Fogeron, Thibault; Govender, Preshendren; Stringer, Tameryn; Chellan, Prinessa; Lisensky, George C; Hersh, William H; Doverbratt, Isa; Lidin, Sven; de Kock, Carmen; Smith, Peter J; Smith, Gregory S; Nordlander, Ebbe

    2015-11-28

    Eight new ruthenium and five new osmium p-cymene half-sandwich complexes have been synthesized, characterized and evaluated for antimalarial activity. All complexes contain ligands that are based on a 4-chloroquinoline framework related to the antimalarial drug chloroquine. Ligands HL(1-8) are salicylaldimine derivatives, where HL(1) = N-(2-((2-hydroxyphenyl)methylimino)ethyl)-7-chloroquinolin-4-amine, and HL(2-8) contain non-hydrogen substituents in the 3-position of the salicylaldimine ring, viz. F, Cl, Br, I, NO2, OMe and (t)Bu for HL(2-8), respectively. Ligand HL(9) is also a salicylaldimine-containing ligand with substitutions in both 3- and 5-positions of the salicylaldimine moiety, i.e. N-(2-((2-hydroxy-3,5-di-tert-butylphenyl)methyl-imino)ethyl)-7-chloroquinolin-4-amine, while HL(10) is N-(2-((1-methyl-1H-imidazol-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine) The half sandwich metal complexes that have been investigated are [Ru(η(6)-cym)(L(1-8))Cl] (Ru-1-Ru-8, cym = p-cymene), [Os(η(6)-cym)(L(1-3,5,7))Cl] (Os-1-Os-3, Os-5, and Os-7), [M(η(6)-cym)(HL(9))Cl2] (M = Ru, Ru-HL(9); M = Os, Os-HL(9)) and [M(η(6)-cym)(L(10))Cl]Cl (M = Ru, Ru-10; M = Os, Os-10). In complexes Ru-1-Ru-8 and Ru-10, Os-1-Os-3, Os-5 and Os-7 and Os-10, the ligands were found to coordinate as bidentate N,O- and N,N-chelates, while in complexes Ru-HL(9) and Os-HL(9), monodentate coordination of the ligands through the quinoline nitrogen was established. The antimalarial activity of the new ligands and complexes was evaluated against chloroquine sensitive (NF54 and D10) and chloroquine resistant (Dd2) Plasmodium falciparum malaria parasite strains. Coordination of ruthenium and osmium arene moieties to the ligands resulted in lower antiplasmodial activities relative to the free ligands, but the resistance index is better for the ruthenium complexes compared to chloroquine. Overall, osmium complexes appeared to be less active than the corresponding ruthenium complexes. PMID:26491831

  11. Coordination behavior of ligand based on NNS and NNO donors with ruthenium(III) complexes and their catalytic and DNA interaction studies

    NASA Astrophysics Data System (ADS)

    Manikandan, R.; Viswnathamurthi, P.

    2012-11-01

    Reactions of 2-acetylpyridine-thiosemicarbazone HL1, 2-acetylpyridine-4-methyl-thiosemicarbazone HL2, 2-acetylpyridine-4-phenyl-thiosemicarbazone HL3 and 2-acetylpyridine-semicarbazone HL4 with ruthenium(III) precursor complexes were studied and the products were characterized by analytical and spectral (FT-IR, electronic, EPR and EI-MS) methods. The ligands coordinated with the ruthenium(III) ion via pyridine nitrogen, azomethine nitrogen and thiolate sulfur/enolate oxygen. An octahedral geometry has been proposed for all the complexes based on the studies. All the complexes are redox active and display an irreversible and quasireversible metal centered redox processes. Further, the catalytic activity of the new complexes has been investigated for the transfer hydrogenation of ketones in the presence of isopropanol/KOH and the Kumada-Corriu coupling of aryl halides with aryl Grignard reagents. The DNA cleavage efficiency of new complexes has also been tested.

  12. Mechanism elucidation of the cis-trans isomerization of an azole ruthenium-nitrosyl complex and its osmium counterpart.

    PubMed

    Gavriluta, Anatolie; Büchel, Gabriel E; Freitag, Leon; Novitchi, Ghenadie; Tommasino, Jean Bernard; Jeanneau, Erwann; Kuhn, Paul-Steffen; González, Leticia; Arion, Vladimir B; Luneau, Dominique

    2013-06-01

    Synthesis and X-ray diffraction structures of cis and trans isomers of ruthenium and osmium metal complexes of general formulas (nBu4N)[cis-MCl4(NO)(Hind)], where M = Ru (1) and Os (3), and (nBu4N)[trans-MCl4(NO)(Hind)], where M = Ru (2) and Os (4) and Hind = 1H-indazole are reported. Interconversion between cis and trans isomers at high temperatures (80-130 °C) has been observed and studied by NMR spectroscopy. Kinetic data indicate that isomerizations correspond to reversible first order reactions. The rates of isomerization reactions even at 110 °C are very low with rate constants of 10(-5) s(-1) and 10(-6) s(-1) for ruthenium and osmium complexes, respectively, and the estimated rate constants of isomerization at room temperature are of ca. 10(-10) s(-1). The activation parameters, which have been obtained from fitting the reaction rates at different temperatures to the Eyring equation for ruthenium [ΔH(cis-trans)‡ = 122.8 ± 1.3; ΔH(trans-cis)‡ = 138.8 ± 1.0 kJ/mol; ΔS(cis-trans)‡ = -18.7 ± 3.6; ΔS(trans-cis)‡ = 31.8 ± 2.7 J/(mol·K)] and osmium [ΔH(cis-trans)‡ = 200.7 ± 0.7; ΔH(trans-cis)‡ = 168.2 ± 0.6 kJ/mol; ΔS(cis-trans)‡ = 142.7 ± 8.9; ΔS(trans-cis)‡ = 85.9 ± 3.9 J/(mol·K)] reflect the inertness of these systems. The entropy of activation for the osmium complexes is highly positive and suggests the dissociative mechanism of isomerization. In the case of ruthenium, the activation entropy for the cis to trans isomerization is negative [-18.6 J/(mol·K)], while being positive [31.0 J/(mol·K)] for the trans to cis conversion. The thermodynamic parameters for cis to trans isomerization of [RuCl4(NO)(Hind)]-, viz. ΔH° = 13.5 ± 1.5 kJ/mol and ΔS° = -5.2 ± 3.4 J/(mol·K) indicate the low difference between the energies of cis and trans isomers. The theoretical calculation has been carried out on isomerization of ruthenium complexes with DFT methods. The dissociative, associative, and intramolecular twist isomerization

  13. Nature of M-Ga Bonds in cationic metal-gallylene complexes of iron, ruthenium, and osmium, [(η5-C5H5)(L)2M(GaX)]+: a theoretical study.

    PubMed

    Pandey, Krishna K; Aldridge, Simon

    2011-03-01

    Density Functional Theory calculations have been performed for the cationic half-sandwich gallylene complexes of iron, ruthenium, and osmium [(η(5)-C(5)H(5))(L)(2)M(GaX)](+) (M = Fe, L = CO, PMe(3); X = Cl, Br, I, NMe(2), Mes; M = Ru, Os: L = CO, PMe(3); X = I, NMe(2), Mes) at the BP86/TZ2P/ZORA level of theory. Calculated geometric parameters for the model iron iodogallylene system [(η(5)-C(5)H(5))(Me(3)P)(2)Fe(GaI)](+) are in excellent agreement with the recently reported experimental values for [(η(5)-C(5)Me(5))(dppe)Fe(GaI)](+). The M-Ga bonds in these systems are shorter than expected for single bonds, an observation attributed not to significant M-Ga π orbital contributions, but due instead primarily to high gallium s-orbital contributions to the M-Ga bonding orbitals. Such a finding is in line with the tenets of Bent's Rule insofar as correspondingly greater gallium p-orbital character is found in the bonds to the (more electronegative) gallylene substituent X. Consistent with this, ΔE(σ) is found to be overwhelmingly the dominant contribution to the orbital interaction between [(η(5)-C(5)H(5))(L)(2)M](+) and [GaX] fragments (with ΔE(π) equating to only 8.0-18.6% of the total orbital contributions); GaX ligands thus behave as predominantly σ-donor ligands. Electrostatic contributions to the overall interaction energy ΔE(int) are also very important, being comparable in magnitude (or in some cases even larger than) the corresponding orbital interactions. PMID:21204548

  14. Bulky N-Phosphino-Functionalized N-Heterocyclic Carbene Ligands: Synthesis, Ruthenium Coordination Chemistry, and Ruthenium Alkylidene Complexes for Olefin Metathesis.

    PubMed

    Brown, Christopher C; Rominger, Frank; Limbach, Michael; Hofmann, Peter

    2015-11-01

    Ruthenium chemistry and applications in catalytic olefin metathesis based on N-phosphino-functionalized N-heterocyclic carbene ligands (NHCPs) are presented. Alkyl NHCP Ru coordination chemistry is described, and access to several potential synthetic precursors for ruthenium alkylidene complexes is outlined, incorporating both trimethylsilyl and phenyl alkylidenes. The Ru alkylidene complexes are evaluated as potential olefin metathesis catalysts and were shown to behave in a latent fashion. They displayed catalytic activity at elevated temperatures for both ring closing metathesis and ring opening metathesis polymerization.

  15. Bulky N-Phosphino-Functionalized N-Heterocyclic Carbene Ligands: Synthesis, Ruthenium Coordination Chemistry, and Ruthenium Alkylidene Complexes for Olefin Metathesis.

    PubMed

    Brown, Christopher C; Rominger, Frank; Limbach, Michael; Hofmann, Peter

    2015-11-01

    Ruthenium chemistry and applications in catalytic olefin metathesis based on N-phosphino-functionalized N-heterocyclic carbene ligands (NHCPs) are presented. Alkyl NHCP Ru coordination chemistry is described, and access to several potential synthetic precursors for ruthenium alkylidene complexes is outlined, incorporating both trimethylsilyl and phenyl alkylidenes. The Ru alkylidene complexes are evaluated as potential olefin metathesis catalysts and were shown to behave in a latent fashion. They displayed catalytic activity at elevated temperatures for both ring closing metathesis and ring opening metathesis polymerization. PMID:26479425

  16. Protein Nanocages for Delivery and Release of Luminescent Ruthenium(II) Polypyridyl Complexes.

    PubMed

    Li, Xiao; Zhang, Yajie; Chen, Hong; Sun, Jian; Feng, Fude

    2016-09-01

    In this report, noncovalent encapsulation of hydrophobic ruthenium(II) polyridyl complexes, Ru(bpy)2dppz(2+) and Ru(phen)2dppz(2+), into apoferritin cavity was achieved with high loading contents by effective prevention of Ru complex-induced protein aggregation, without disruption of protein native architecture. The Ru-loaded luminescent nanocomposites have demonstrated improved water solubility, easy manipulation, reduced cytotoxicity, and enhanced cellular uptake as compared to the nontreated Ru complexes. PMID:27547981

  17. DNA Interactions with Ruthenium(ll) Polypyridine Complexes Containing Asymmetric Ligands

    PubMed Central

    Chao, Hui

    2005-01-01

    In an attempt to probe nucleic acid structures, numerous Ru(II) complexes with different ligands have been synthesized and investigated. In this contribution we focus on the DNA-binding properties of ruthenium(II) complexes containing asymmetric ligands that have attracted little attention in the past decades. The influences of the shape and size of the ligand on the binding modes, affinity, enantioselectivities and photocleavage of the complexes to DNA are described. PMID:18365086

  18. Mono and binuclear ruthenium(II) complexes containing 5-chlorothiophene-2-carboxylic acid ligands: Spectroscopic analysis and computational studies

    NASA Astrophysics Data System (ADS)

    Swarnalatha, Kalaiyar; Kamalesu, Subramaniam; Subramanian, Ramasamy

    2016-11-01

    New Ruthenium complexes I, II and III were synthesized using 5-chlorothiophene-2-carboxylic acid (5TPC), as ligand and the complexes were characterized by elemental analysis, FT-IR, 1H, 13C NMR, and mass spectroscopic techniques. Photophysical and electrochemical studies were carried out and the structures of the synthesized complex were optimized using density functional theory (DFT). The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and Mulliken atomic charges of the molecules are determined at the B3LYP method and standard 6-311++G (d,p) basis set starting from optimized geometry. They possess excellent stabilities and their thermal decomposition temperatures are 185 °C, 180 °C and 200 °C respectively, indicating that the metal complexes are suitable for the fabrication processes of optoelectronic devices.

  19. Interligand electron transfer in heteroleptic ruthenium(II) complexes occurs on multiple time scales.

    PubMed

    Stark, Charles W; Schreier, Wolfgang J; Lucon, Janice; Edwards, Ethan; Douglas, Trevor; Kohler, Bern

    2015-05-21

    The time-dependent localization of the metal-to-ligand charge transfer (MLCT) excited states of ruthenium(II) complexes containing 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) ligands was studied by femtosecond transient absorption spectroscopy. Time-resolved anisotropy measurements indicate that the excited state hops randomly among the three ligands of each complex by subpicosecond interligand electron transfer (ILET). Although the bpy- and phen-localized (3)MLCT states have similar energies and steady-state emission spectra, pronounced differences in their excited-state absorption spectra make it possible to observe changes in excited state populations using magic angle transient absorption measurements. Analysis of the magic angle signals shows that the excited electron is equally likely to be found on any of the three ligands approximately 1 ps after excitation, but this statistical distribution subsequently evolves to a Boltzmann distribution with a time constant of approximately 10 ps. The apparent contradiction between ultrafast ILET revealed by time-dependent anisotropy measurements and the slower ILET seen in magic angle measurements on the tens of picoseconds time scale is explained by a model in which the underlying rates depend dynamically on excess vibrational energy. The insight that ILET can occur over multiple time scales reconciles contradictory literature observations and may lead to improved photosensitizer performance.

  20. Mechanism of the C-C cleavage of acetone by the ruthenium benzyne complex (PMe sub 3 ) sub 4 Ru(. eta. sup 2 -C sub 6 H sub 4 ): Formation and reactivity of an oxametallacyclobutane complex

    SciTech Connect

    Hartwig, J.F.; Bergman, R.G.; Andersen, R.A. )

    1990-04-11

    The reaction of acetone with the ruthenium benzyne complex (PMe{sub 3}){sub 4}Ru({eta}{sup 2}-C{sub 6}H{sub 4}) (1) results in cleavage of a C-C bond in the ketone, leading to methane and 2, an ortho-metalated enolate complex of acetophenone (Scheme I). The authors now report the generation and spectroscopic characterization of a potential intermediate in this reaction: complex 3, a rare example of an oxametallacyclobutane.

  1. Synthesis of a highly reactive (benzyne)ruthenium complex: C-C, C-H, N-H, and O-H activation reactions

    SciTech Connect

    Hartwig, J.F.; Andersen, R.A.; Bergman, R.G. )

    1989-03-29

    The authors report here the synthesis and chemistry of an exceptionally reactive ruthenium benzyne complex, (PMe{sub 3}){sub 4}Ru({eta}{sup 2}-C{sub 6}H{sub 4}) (1). The ruthenium-carbon bond in this molecule reacts with a wide range of organic substrates that are typically inert toward late transition-metal-carbon bonds, including those in benzyne complexes. For example, complex 1 reacts cleanly with arylamine N-H bonds, water O-H bonds, and benzyl and aryl C-H bonds. It reacts with acetophenone to yield an O-bound enolate complex, inserts benzaldehyde cleanly, and cleaves the C-C bond of acetone.

  2. Ruthenium Dihydroxybipyridine Complexes are Tumor Activated Prodrugs Due to Low pH and Blue Light Induced Ligand Release

    PubMed Central

    Hufziger, Kyle T.; Thowfeik, Fathima Shazna; Charboneau, David J.; Nieto, Ismael; Dougherty, William G.; Kassel, W. Scott; Dudley, Timothy J.; Merino, Edward J.; Papish, Elizabeth T.; Paul, Jared J.

    2013-01-01

    Ruthenium drugs are potent anti-cancer agents, but inducing drug selectivity and enhancing their modest activity remain challenging. Slow Ru ligand loss limits the formation of free sites and subsequent binding to DNA base pairs. Herein, we designed a ligand that rapidly dissociates upon irradiation at low pH. Activation at low pH can lead to cancer selectivity, since many cancer cells have higher metabolism (and thus lower pH) than non-cancerous cells. We have used the pH sensitive ligand, 6,6′-dihydroxy-2,2′-bipyridine (66′bpy(OH)2), to generate [Ru(bpy)2(66′(bpy(OH)2)]2+, which contains two acidic hydroxyl groups with pKa1 = 5.26 and pKa2 = 7.27. Irradiation when protonated leads to photo-dissociation of the 66′bpy(OH)2 ligand. An in-depth study of the structural and electronic properties of the complex was carried out using X-Ray crystallography, electrochemistry, UV/visible spectroscopy, and computational techniques. Notably, Ru-N bond lengths in the 66′bpy(OH)2 complex are longer (by ~0.3 Å) than in polypyridyl complexes that lack 6 and 6′ substitution. Thus, the longer bond length predisposes the complex for photo-dissociation and leads to the anti-cancer activity. When the complex is deprotonated, the 66′bpy(O−)2 ligand molecular orbitals mix heavily with the ruthenium orbitals, making new mixed metal-ligand orbitals that lead to a higher bond order. We investigated the anti-cancer activities of [Ru(bpy)2(66′(bpy(OH)2)]2+, [Ru(bpy)2(44′(bpy(OH)2)]2+, and [Ru(bpy)3]2+ (44′(bpy(OH)2 = 4,4′-dihydroxy-2,2′-bipyridine) in HeLa cells, which have a relatively low pH. It is found that [Ru(bpy)2(66′(bpy(OH)2)]2+ is more cytotoxic than the other ruthenium complexes studied. Thus, we have identified a pH sensitive ruthenium scaffold that can be exploited for photo-induced anti-cancer activity. PMID:24184694

  3. Synthesis and spectral and redox properties of three triply bridged complexes of ruthenium

    USGS Publications Warehouse

    Llobet, A.; Curry, M.E.; Evans, H.T.; Meyer, T.J.

    1989-01-01

    Syntheses are described for the ligand-bridged complexes [(tpm)RuIII(??-O)(??-L)2RuIII(tpm) n+ (L = O2P(O)(OH), n = 0 (1); L = O2CO, n = 0 (2); L = O2CCH3, n = 2 (3); tpm is the tridentate, facial ligand tris(1-pyrazolyl)methane. The X-ray crystal structure of [(tpm)Ru(??-O)(??-O2P(O)(OH))2Ru(tpm)]??8H 2O was determined from three-dimensional X-ray counter data. The complex crystallizes in the trigonal space group P3221 with three molecules in a cell of dimensions a = 18.759 (4) A?? and c = 9.970 (6) A??. The structure was refined to a weighted R factor of 0.042 based on 1480 independent reflections with I ??? 3??(I). The structure reveals that the complex consists of two six-coordinate ruthenium atoms that are joined by a ??-oxo bridge (rRU-O = 1.87 A??; ???RuORu = 124.6??) and two ??-hydrogen phosphato bridges (average rRu-O = 2.07 A??) which are capped by two tpm ligands. The results of cyclic voltammetric and coulometric experiments show that the complexes undergo both oxidative and reductive processes in solution. Upon reduction, the ligand-bridged structure is lost and the monomer [(tpm)Ru(H2O)3]2+ appears quantitatively. All three complexes are diamagnetic in solution. The diamagnetism is a consequence of strong electronic coupling between the low-spin d5 Ru(III) metal ions through the oxo bridge and the relatively small Ru-O-Ru angle. ?? 1989 American Chemical Society.

  4. RNA and DNA binding of inert oligonuclear ruthenium(II) complexes in live eukaryotic cells.

    PubMed

    Li, Xin; Gorle, Anil K; Ainsworth, Tracy D; Heimann, Kirsten; Woodward, Clifford E; Collins, J Grant; Keene, F Richard

    2015-02-28

    Confocal microscopy was used to study the intracellular localisation of a series of inert polypyridylruthenium(II) complexes with three eukaryotic cells lines - baby hamster kidney (BHK), human embryonic kidney (HEK-293) and liver carcinoma (Hep-G2). Co-staining experiments with the DNA-selective dye DAPI demonstrated that the di-, tri- and tetra-nuclear polypyridylruthenium(II) complexes that are linked by the bis[4(4'-methyl-2,2'-bipyridyl)]-1,12-dodecane bridging ligand ("bb12") showed a high degree of selectivity for the nucleus of the eukaryotic cells. Additional co-localisation experiments with the general nucleic acid stain SYTO 9 indicated that the ruthenium complexes showed a considerable preference for the RNA-rich nucleolus, rather than chromosomal DNA. No significant differences were observed in the intracellular localisation between the ΔΔ and ΛΛ enantiomers of the dinuclear complex. Cytotoxicity assays carried out over 72 hours indicated that the ruthenium complexes, particularly the tri- and tetra-nuclear species, were significantly toxic to the eukaryotic cells. However, when the activity of the least cytotoxic compound (the ΔΔ enantiomer of the dinuclear species) was determined over a 24 hour period, the results indicated that the ruthenium complex was approximately a 100-fold less toxic to liver and kidney cells than to Gram positive bacteria. Circular dichroism (CD) spectroscopy was used to examine the effect of the ΔΔ and ΛΛ enantiomers of the dinuclear complex on the solution conformations of RNA and DNA. The CD experiments indicated that the RNA maintained the A-type conformation, and the DNA the B-type structure, upon binding by the ruthenium complexes.

  5. RNA and DNA binding of inert oligonuclear ruthenium(II) complexes in live eukaryotic cells.

    PubMed

    Li, Xin; Gorle, Anil K; Ainsworth, Tracy D; Heimann, Kirsten; Woodward, Clifford E; Collins, J Grant; Keene, F Richard

    2015-02-28

    Confocal microscopy was used to study the intracellular localisation of a series of inert polypyridylruthenium(II) complexes with three eukaryotic cells lines - baby hamster kidney (BHK), human embryonic kidney (HEK-293) and liver carcinoma (Hep-G2). Co-staining experiments with the DNA-selective dye DAPI demonstrated that the di-, tri- and tetra-nuclear polypyridylruthenium(II) complexes that are linked by the bis[4(4'-methyl-2,2'-bipyridyl)]-1,12-dodecane bridging ligand ("bb12") showed a high degree of selectivity for the nucleus of the eukaryotic cells. Additional co-localisation experiments with the general nucleic acid stain SYTO 9 indicated that the ruthenium complexes showed a considerable preference for the RNA-rich nucleolus, rather than chromosomal DNA. No significant differences were observed in the intracellular localisation between the ΔΔ and ΛΛ enantiomers of the dinuclear complex. Cytotoxicity assays carried out over 72 hours indicated that the ruthenium complexes, particularly the tri- and tetra-nuclear species, were significantly toxic to the eukaryotic cells. However, when the activity of the least cytotoxic compound (the ΔΔ enantiomer of the dinuclear species) was determined over a 24 hour period, the results indicated that the ruthenium complex was approximately a 100-fold less toxic to liver and kidney cells than to Gram positive bacteria. Circular dichroism (CD) spectroscopy was used to examine the effect of the ΔΔ and ΛΛ enantiomers of the dinuclear complex on the solution conformations of RNA and DNA. The CD experiments indicated that the RNA maintained the A-type conformation, and the DNA the B-type structure, upon binding by the ruthenium complexes. PMID:25333883

  6. Synthesis, characterization and antibacterial studies of ruthenium(III) complexes derived from chitosan schiff base.

    PubMed

    Vadivel, T; Dhamodaran, M

    2016-09-01

    Chitosan can be modified chemically by condensation reaction of deacetylated chitosan with aldehyde in homogeneous phase. This condensation is carried by primary amine (NH2) with aldehyde (CHO) to form corresponding schiff base. The chitosan biopolymer schiff base derivatives are synthesized with substituted aldehydes namely 4-hydroxy-3-methoxy benzaldehyde, 2-hydroxy benzaldehyde, and 2-hydroxy-3-methoxy benzaldehyde, becomes a complexing agent or ligand. The Ruthenium(III) complexes were obtained by complexation of Ruthenium with schiff base ligands and this product exhibits as an excellent solubility and more biocompatibility. The novel series of schiff base Ruthenium(III) complexes are characterized by Elemental analysis, FT-IR spectroscopy, and Thermo-gravimetric analysis (TGA). The synthesized complexes have been subjected to antibacterial study. The antibacterial results indicated that the antibacterial activity of the complexes were more effective against Gram positive and Gram negative pathogenic bacteria. These findings are giving suitable support for developing new antibacterial agent and expand our scope for applications.

  7. Targeting Large Kinase Active Site with Rigid, Bulky Octahedral Ruthenium Complexes

    SciTech Connect

    Maksimoska, Jasna; Feng, Li; Harms, Klaus; Yi, Chunling; Kissil, Joseph; Marmorstein, Ronen; Meggers, Eric

    2009-09-02

    A strategy for targeting protein kinases with large ATP-binding sites by using bulky and rigid octahedral ruthenium complexes as structural scaffolds is presented. A highly potent and selective GSK3 and Pim1 half-sandwich complex NP309 was successfully converted into a PAK1 inhibitor by making use of the large octahedral compounds {Lambda}-FL172 and {Lambda}-FL411 in which the cyclopentadienyl moiety of NP309 is replaced by a chloride and sterically demanding diimine ligands. A 1.65 {angstrom}cocrystal structure of PAK1 with {Lambda}-FL172 reveals how the large coordination sphere of the ruthenium complex matches the size of the active site and serves as a yardstick to discriminate between otherwise closely related binding sites.

  8. Complexes of ruthenium and rhodium with aliphatic amines in the catalysis of hydrogenation of unsaturated hydrocarbons

    SciTech Connect

    Turisbekova, K.K.; Shuikina, L.P.; Parenago, O.P.; Frolov, V.F.

    1989-02-01

    The authors synthesized new catalysts highly active in the hydrogenations of unsaturated hydrocarbons, based on complexes of ruthenium and rhodium with higher aliphatic amines, which are soluble in aromatic solvents. The complexes acquired catalytic activity in hydrogenation as a result of their treatment with diisobutyl aluminum hydride. Olefins (1-hexene, cyclopentene, cyclohexene) or dienes (isoprene) were used as the unsaturated compounds. For the ruthenium based catalysts, the highest activity was observed during the hydrogenation of 1-hexene. For the rhodium-based catalysts, the activity in the hydrogenation of olefins and dienes was approximately the same. In the case of the rhodium complex catalysts, the hydrogenation of 1-hexene was accompanied by a side-reaction consisting in isomerization into olefins with inner double bonds.

  9. Cytotoxic hydrogen bridged ruthenium quinaldamide complexes showing induced cancer cell death by apoptosis.

    PubMed

    Lord, Rianne M; Allison, Simon J; Rafferty, Karen; Ghandhi, Laura; Pask, Christopher M; McGowan, Patrick C

    2016-08-16

    This report presents the first known p-cymene ruthenium quinaldamide complexes which are stabilised by a hydrogen-bridging atom, [{(p-cym)Ru(II)X(N,N)}{H(+)}{(N,N)XRu(II)(p-cym)}][PF6] (N,N = functionalised quinaldamide and X = Cl or Br). These complexes are formed by a reaction of [p-cymRu(μ-X)2]2 with a functionalised quinaldamide ligand. When filtered over NH4PF6, and under aerobic conditions the equilibrium of NH4PF6 ⇔ NH3 + HPF6 enables incorporation of HPF6 and the stabilisation of two monomeric ruthenium complexes by a bridging H(+), which are counter-balanced by a PF6 counterion. X-ray crystallographic analysis is presented for six new structures with OO distances of 2.420(4)-2.448(15) Å, which is significant for strong hydrogen bonds. Chemosensitivity studies against HCT116, A2780 and cisplatin-resistant A2780cis human cancer cells showed the ruthenium complexes with a bromide ancillary ligand to be more potent than those with a chloride ligand. The 4'-fluoro compounds show a reduction in potency for both chloride and bromide complexes against all cell lines, but an increase in selectivity towards cancer cells compared to non-cancer ARPE-19 cells, with a selectivity index >1. Mechanistic studies showed a clear correlation between IC50 values and induction of cell death by apoptosis. PMID:27417660

  10. Synthesis and characterisation of ruthenium dihydrogen complexes and their reactivity towards B-H bonds.

    PubMed

    Choi, Jong-Hoo; Schloerer, Nils E; Berger, Josefine; Prechtl, Martin H G

    2014-01-01

    In this paper the synthesis and characterisation of ruthenium dihydrogen complexes bearing rigid aliphatic PNP pincer-type ligands are described. As one result hydride complexes were synthesised in good to high yields by a one-pot direct hydrogenation reaction. As another finding the dihydrogen complex, stabilised with a N-Me group in the ligand frame, can be converted with dimethylamine borane into a rare σ-boron complex [RuH2(BH3)(Me-PNP)] with rapid B-N decoupling. Additionally, we present the first mass spectrometric analysis of the synthesised σ-complexes via liquid injection field desorption/ionisation technique (LIFDI-MS).

  11. Osmium Bisterpyridine Complexes with Redox-Active Amine Substituents: A Comparison Study with Ruthenium Analogues.

    PubMed

    Sun, Meng-Jia; Shao, Jiang-Yang; Yao, Chang-Jiang; Zhong, Yu-Wu; Yao, Jiannian

    2015-08-17

    Five osmium complexes with redox-active amine substituents, [Os(ttpy)(Ntpy)](PF6)2 (1(PF6)2), [Os(Ntpy)2](PF6)2 (2(PF6)2), [Os(ttpy)(NPhtpy)](PF6)2 (3(PF6)2), [Os(Ntpy)(NPhtpy)](PF6)2 (4(PF6)2), and [Os(NPhtpy)2](PF6)2 (5(PF6)2), have been prepared, where ttpy is 4'-tolyl-2,2':6',2″-terpyridine, Ntpy is 4'-(di-p-anisylamino)-2,2':6',2″-terpyridine, and NPhtpy is 4'-(di-p-anisylaminophen-4-yl)-2,2':6',2″-terpyridine. X-ray crystallographic data of 2(PF6)2 and 4(PF6)2 are presented. These complexes show rich visible absorptions attributed to the singlet metal-to-ligand charge-transfer ((1)MLCT), triplet MLCT, and intraligand charge-transfer transitions. Complexes 3(PF6)2 and 5(PF6)2 show weak emissions around 720 nm at room temperature. All complexes show stepwise oxidations of the osmium ion and the amine segment. However, the redox potentials and the order of the Os(III/II) and N(•+/0) processes vary significantly, depending on the electronic nature of the amine substituents. In the singly oxidized state, either Os(II) → N(•+) MLCT or N → Os(III) ligand-to-metal charge-transfer transitions in the near-infrared region have been observed. For complexes 2(PF6)2, 4(PF6)2, and 5(PF6)2 with two amine substituents, no evidence has been observed for the presence of osmium-mediated amine-amine electronic coupling. Density functional theory (DFT) and time-dependent DFT calculations have been performed to complement these experimental results. The one-electron-oxidized forms 3(3+) and 5(3+) show distinct electron paramagnetic resonance (EPR) signals in CH3CN at room temperature. However, complexes 1(3+), 2(3+), and 4(3+) are EPR silent under similar conditions. In addition, a comparison study has been made between these osmium complexes and the previously reported ruthenium analogues. PMID:26237331

  12. Antinociceptive properties and nitric oxide synthase inhibitory action of new ruthenium complexes.

    PubMed

    Beirith, A; Creczynski-Pasa, T B; Bonetti, V R; Konzen, M; Seifriz, I; Paula, M S; Franco, C V; Calixto, J B

    1999-03-26

    This study evaluates the actions of the new ruthenium complexes trans-[RuCl2(nic)4] (Complex I) and trans-[RuCl2(i-nic)4] (Complex II) as antinociceptives, and their interaction with nitric oxide isoenzymes and with acetylcholine-induced relaxation of rat and rabbit aorta. Complex II inhibited, in a graded manner, neuronal and inducible nitric oxide (NO) synthase, and was about two fold more effective in inhibiting the neuronal NO synthase than the inducible form of the enzyme. Complex I was inactive. Both complexes failed to interfere with constitutive endothelial nitric oxide synthase because they did not change the mean arterial blood pressure of rats. The vasorelaxant effect of acetylcholine was markedly antagonised by the Complexes I and II in rings of both rat and rabbit aorta. Complexes I and II, given intraperitoneally, like N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(G)-nitro-L-arginine (L-NOARG), inhibited, in a graded manner, both phases of the pain response induced by formalin. The actions of L-NAME, L-NOARG and Complex II, but not that of Complex I, were largely reversed by L-arginine. Both complexes failed to affect the motor response of animals in the rota-rod test and had no effect in the hot-plate assay. Together, these findings provide indications that the new ruthenium complexes, especially Complex II and its derivatives, might be of potential therapeutic benefit in the management of pain disorders.

  13. Proline as chiral auxiliary for the economical asymmetric synthesis of ruthenium(II) polypyridyl complexes.

    PubMed

    Fu, Chen; Wenzel, Marianne; Treutlein, Elisabeth; Harms, Klaus; Meggers, Eric

    2012-09-17

    A straightforward method for the synthesis of virtually enantiomerically pure ruthenium(II) polypyridyl complexes [Ru(pp)(pp')(pp")](PF(6))(2), pp = bidentate polypyridyl has been developed. The synthesis draws from the readily available racemic starting material cis-[Ru(pp)(pp')Cl(2)] and the natural amino acids l- or d-proline and relies on a dynamic asymmetric transformation under thermodynamic control.

  14. New synthetic routes for the preparation of ruthenium-1,10-phenanthroline complexes. Tests of cytotoxic and antibacterial activity of selected ruthenium complexes.

    PubMed

    Turel, Iztok; Golobič, Amalija; Kljun, Jakob; Samastur, Petra; Batista, Urška; Sepčić, Kristina

    2015-01-01

    Three novel complexes have been prepared through reactions of precursor [(dmso)2H][trans-RuCl4(dmso-S)2] (P) and 1,10-phenanthroline (phen) at different conditions. Whereas the analogs of mer-[RuCl3(dmso-S)(phen)] (1) and [Ru(phen)3]Cl2·6CH3OH (3·6CH3OH) have already been prepared by other synthetic routes before, product (H3O)[RuCl4(phen)]·4H2O (2·4H2O) is unprecedented. In the latter, isolated from highly acidic medium, one strongly bound dmso molecule in precursor P was substituted by chloride. Biological activity of 1 and previously isolated ruthenium-purine complexes ([mer-RuCl3(dmso-S)(acv)(CH3OH)] (4) (acv = acyclovir); [trans-RuCl4(dmso-S)(guaH)] (5) (guaH = protonated guanine)) was tested and compared. These data show that compounds 1, 4 and 5 are slightly cytotoxic against B-16 malignant melanoma cells but not against non-transformed V-79-379A cells. It seems that coordinated phen ligand increases the cytotoxicity of 1 in comparison to ruthenium precursor. The inability of tested compounds to induce lysis of bovine erythrocytes suggests that their cytotoxic effect is not due to the membrane damage. PMID:26085415

  15. (Pentamethylcyclopentadienyl)ruthenium complexes. 6. (Pentamethylcyclopentadienyl)(polyarene)ruthenium cations. Synthesis and electrochemical reaction

    SciTech Connect

    Koelle, U.; Wang, Maja Hong )

    1990-01-01

    By treatment of the alkoxo complex (Cp{sup *}Ru(OMe)){sub 2} with acid or trimethylsilyl trifluoromethanesulfonate in the presence of a polycyclic arene, the monocations Cp{sup *}Ru(arene){sup +} (arene = naphthalene ((1){sup +}), phenanthrene ((2){sup +}), pyrene ((3){sup +}), anthracene ((4){sup +})) and dications (Cp{sup *}Ru){sub 2}(arene){sup 2+} (arene = phenanthrene ((5){sup 2+}), pyrene ((6){sup 2+}), and anthracene ((7){sup 2+})) were synthesized. Electrochemistry (cyclic voltammetry) in dichloromethane or propylene carbonate shows all these complexes, in contrast to the case for (Cp or Cp{sup *})Ru(arene) (Cp = {eta}{sup 5}-C{sub 5}H{sub 5}, Cp{sup *} = {eta}{sup 5}-C{sub 5}Me{sub 5}) cations featuring an unfused aromatic ligand, to be reducible. Some of the electron couples are chemically reversible. Potentials and peak current ratios are discussed in terms of interaction of the Cp{sup *}Ru units and of stabilization of the reduction products.

  16. Catalytic water oxidation by ruthenium(II) quaterpyridine (qpy) complexes: evidence for ruthenium(III) qpy-N,N'''-dioxide as the real catalysts.

    PubMed

    Liu, Yingying; Ng, Siu-Mui; Yiu, Shek-Man; Lam, William W Y; Wei, Xi-Guang; Lau, Kai-Chung; Lau, Tai-Chu

    2014-12-22

    Polypyridyl and related ligands have been widely used for the development of water oxidation catalysts. Supposedly these ligands are oxidation-resistant and can stabilize high-oxidation-state intermediates. In this work a series of ruthenium(II) complexes [Ru(qpy)(L)2 ](2+) (qpy=2,2':6',2'':6'',2'''-quaterpyridine; L=substituted pyridine) have been synthesized and found to catalyze Ce(IV) -driven water oxidation, with turnover numbers of up to 2100. However, these ruthenium complexes are found to function only as precatalysts; first, they have to be oxidized to the qpy-N,N'''-dioxide (ONNO) complexes [Ru(ONNO)(L)2 ](3+) which are the real catalysts for water oxidation.

  17. Voltammetric determination of ruthenium in the form of complexes with biologically active ligands

    SciTech Connect

    Medyantseva, E.P.; Budnikov, G.K.; Balakaeva, T.A.

    1992-02-10

    The interest in the analytical chemistry of ruthenium and its compounds has recently been increasing. Ruthenium compounds can be used an antitumor agents and in the treatment of tuberculosis and fungal infections. It has been suggested that there is a specific relationship between the reduction potentials of the compounds and their biological activity. Of greatest interest among the biologically active compounds are the compounds with nitrogen-containing heterocycles. In order to obtain information on the degree of oxidation of the central atom in the complexes and to select the optimum conditions for the determination of the mono- and bi-nuclear complexes of ruthenium compounds with biologically active ligands such as imidazole (Im), histidine (His), benzimidazole (BIm) and its methyl derivative [1,2(CH{sub 3}){sub 2} - BIm], benzohyroxamic acid (Bha), and 1-phenyl-2-methylamino-1-propanol or ephedrine (Eph) in the present work, the authors studied their electrochemical behavior at dropping mercury (dme) and a platinum electrodes. 6 refs., 1 fig., 2 tabs.

  18. Pharmacological Activities of Ruthenium Complexes Related to Their NO Scavenging Properties

    PubMed Central

    Castellarin, Anna; Zorzet, Sonia; Bergamo, Alberta; Sava, Gianni

    2016-01-01

    Angiogenesis is considered responsible for the growth of primary tumours and of their metastases. With the present study, the effects of three ruthenium compounds, potassiumchlorido (ethylendiamminotetraacetate)rutenate(III) (RuEDTA), sodium (bis-indazole)tetrachloro-ruthenate(III), Na[trans-RuCl4Ind2] (KP1339) and trans-imidazoledimethylsulphoxidetetrachloro-ruthenate (NAMI-A), are studied in vitro in models mimicking the angiogenic process. The ruthenium compounds reduced the production and the release of nitrosyls from either healthy macrophages and immortalized EA.hy926 endothelial cells. The effects of NAMI-A are qualitatively similar and sometimes quantitatively superior to those of RuEDTA and KP1339. NAMI-A reduces the production and release of nitric oxide (NO) by the EA.hy926 endothelial cells and correspondingly inhibits their invasive ability; it also strongly inhibits the angiogenesis in matrigel sponges implanted subcutaneously in healthy mice. Taken together, these data support the anti-angiogenic activity of the tested ruthenium compounds and they contribute to explain the selective activity of NAMI-A against solid tumour metastases, the tumour compartment on which angiogenesis is strongly involved. This anti-angiogenic effect may also contribute to the inhibition of the release of metastatic cells from the primary tumour. Investigations on the anti-angiogenic effects of NAMI-A at this level will increase knowledge of its pharmacological properties and it will give a further impulse to the development of this class of innovative metal-based drugs. PMID:27490542

  19. Pharmacological Activities of Ruthenium Complexes Related to Their NO Scavenging Properties.

    PubMed

    Castellarin, Anna; Zorzet, Sonia; Bergamo, Alberta; Sava, Gianni

    2016-01-01

    Angiogenesis is considered responsible for the growth of primary tumours and of their metastases. With the present study, the effects of three ruthenium compounds, potassiumchlorido (ethylendiamminotetraacetate)rutenate(III) (RuEDTA), sodium (bis-indazole)tetrachloro-ruthenate(III), Na[trans-RuCl₄Ind₂] (KP1339) and trans-imidazoledimethylsulphoxidetetrachloro-ruthenate (NAMI-A), are studied in vitro in models mimicking the angiogenic process. The ruthenium compounds reduced the production and the release of nitrosyls from either healthy macrophages and immortalized EA.hy926 endothelial cells. The effects of NAMI-A are qualitatively similar and sometimes quantitatively superior to those of RuEDTA and KP1339. NAMI-A reduces the production and release of nitric oxide (NO) by the EA.hy926 endothelial cells and correspondingly inhibits their invasive ability; it also strongly inhibits the angiogenesis in matrigel sponges implanted subcutaneously in healthy mice. Taken together, these data support the anti-angiogenic activity of the tested ruthenium compounds and they contribute to explain the selective activity of NAMI-A against solid tumour metastases, the tumour compartment on which angiogenesis is strongly involved. This anti-angiogenic effect may also contribute to the inhibition of the release of metastatic cells from the primary tumour. Investigations on the anti-angiogenic effects of NAMI-A at this level will increase knowledge of its pharmacological properties and it will give a further impulse to the development of this class of innovative metal-based drugs. PMID:27490542

  20. New ruthenium carboxylate complexes having a 1-5-. eta. sup 5 -cyclooctadienyl ligand

    SciTech Connect

    Osakada, Kohtaro; Grohmann, A.; Yamamoto, Akio )

    1990-07-01

    Reaction of 3-butenoic acid with Ru(cod)(cot) (cod) = 1-2-{eta}{sup 2}:5-6-{eta}{sup 2}-cyclooctadiene; cot = 1-6-{eta}{sup 6}-cyclooctatriene in the presence of PMe{sub 3} gives a new ruthenium(II) complex formulated as Ru(1-5-{eta}{sup 5}-C{sub 8}H{sub 11}){eta}{sup 1}(O),{eta}{sup 2}(C,C{prime}-OCOCH{sub 2}CH{double bond}CH{sub 2})(PMe{sub 3}) (1). X-ray crystallography revealed its structure as having a piano-stool coordination around the ruthenium center. Crystals of 1 are tetragonal, space group P4{sub 3}2{sub 1}2, with a = 12.559 (3) {angstrom}, c = 20.455 (4) {angstrom}, and Z = 8. {sup 1}H and {sup 13}C({sup 1}H) NMR spectra of 1 agree well for the structure with the allyl entity of the carboxylate {pi}-bonded through the C{double bond}C double bond to ruthenium.

  1. Ruthenium-Vinylidene Complexes: An Efficient Class of Homogeneous Metathesis Catalysts

    NASA Astrophysics Data System (ADS)

    Dragutan, Ileana; Verpoort, Francis; Dragutan, Valerian; Drozdzak, Renata

    Several routes to access ruthenium (Ru)-vinylidene complexes are described, the majority of which employ alkynes and a Ru source as the starting materials. The successful application of Ru-vinylidenes as efficient pre-catalysts for the synthesis of carbocyclic and heterocyclic compounds by ring-closing metathesis (RCM) of αω, -dienes, and in the synthesis of polymers by ring-opening metathesis polymerization (ROMP) of cyclooctene, norbornene, 5-substituted norbornene, and dicyclopentadiene is fully illustrated. Relevant aspects concerning the activity and selectivity of this type of Ru complexes in metathesis reactions are highlighted.

  2. Regioselective Synthesis and Characterization of Multinuclear Convex-Bound Ruthenium-[n]Cycloparaphenylene (n = 5 and 6) Complexes.

    PubMed

    Kayahara, Eiichi; Patel, Vijay Kumar; Mercier, Audrey; Kündig, E Peter; Yamago, Shigeru

    2016-01-01

    Mono- and multinuclear complexes of ruthenium and [n]cycloparaphenylene (CPP, n = 5 and 6) were synthesized in excellent yields through ligand exchange of the cationic complex [(Cp)Ru(CH3CN)3](PF6) with CPP. In the multinuclear complexes, ruthenium selectively coordinated to alternate paraphenylene units to give bis- and tris-coordinated Ru complexes for [5] and [6]CPPs, respectively. Single-crystal X-ray analysis revealed the Ru was coordinated with η(6)-hapticity on the convex surface of CPP. PMID:26494105

  3. Selenoquinones stabilized by ruthenium(II) arene complexes: synthesis, structure, and cytotoxicity.

    PubMed

    Dubarle-Offner, Julien; Clavel, Catherine M; Gontard, Geoffrey; Dyson, Paul J; Amouri, Hani

    2014-05-01

    A new series of monoselenoquinone and diselenoquinone π complexes, [(η(6) -p-cymene)Ru(η(4) -C6 R4 SeE)] (R=H, E=Se (6); R=CH3 , E=Se (7); R=H, E=O (8)), as well as selenolate π complexes [(η(6) -p-cymene)Ru(η(5) -C6 H3 R2 Se)][SbF6 ] (R=H (9); R=CH3 (10)), stabilized by arene ruthenium moieties were prepared in good yields through nucleophilic substitution reactions from dichlorinated-arene and hydroxymonochlorinated-arene ruthenium complexes [(η(6) -p-cymene)Ru(C6 R4 XCl)][SbF6 ]2 (R=H, X=Cl (1); R=CH3 , X=Cl (2); R=H, X=OH (3)) as well as the monochlorinated π complexes [(η(6) -p-cymene)Ru(η(5) -C6 H3 R2 Cl)][SbF6 ]2 (R=H (4); R=CH3 (5)). The X-ray crystallographic structures of two of the compounds, [(η(6) -p-cymene)Ru(η(4) -C6 Me4 Se2 )] (7) and [(η(6) -p-cymene)Ru(η(4) -C6 H4 SeO)] (8), were determined. The structures confirm the identity of the target compounds and ascertain the coordination mode of these unprecedented ruthenium π complexes of selenoquinones. Furthermore, these new compounds display relevant cytotoxic properties towards human ovarian cancer cells.

  4. Photoinduced singlet charge transfer in a ruthenium(II) perylene-3,4:9,10-bis(dicarboximide) complex.

    PubMed

    Gunderson, Victoria L; Krieg, Elisha; Vagnini, Michael T; Iron, Mark A; Rybtchinski, Boris; Wasielewski, Michael R

    2011-06-16

    Elucidation of photoinduced charge transfer behavior in organic dye/metal hybrids is important for developing photocatalytic systems for solar energy conversion. We report the synthesis and photophysical characterization of a perylene-3,4:9,10-bis(dicarboximide) (PDI)-ruthenium(II) complex, bis-PDI-2,2'-bipyridineRu(II)Cl(2)(CN(t)butyl)(2), which has favorable energetics, ΔG(CS) ≈ -1.0 eV, for singlet electron transfer from the Ru complex to PDI. Time-resolved optical spectroscopy reveals that upon selective photoexcitation of PDI, ultrafast charge transfer (<150 fs) from the Ru complex to (1*)PDI generates the Ru(III)-PDI(-•) ion pair. The resulting vibrationally hot Ru(III)-PDI(-•) ion pair exhibits fast relaxation (τ = 3.9 ps) and charge recombination (τ(CR) = 63 ps). Our experimental and computational (DFT and TDDFT) studies show that energy-preserving photodriven singlet electron transfer can dominate in properly designed organic dye/metal complexes, making them of particular interest for use in artificial photosynthetic systems for solar fuels formation. PMID:21598951

  5. The 1:1 co-crystallization of enantiomers of an arene-tethered and ortho-metallated N-heterocyclic carbene ruthenium(II) half-sandwich complex: Synthesis, structural characterization and theoretical study

    NASA Astrophysics Data System (ADS)

    Karabıyık, Hasan; Kılınçarslan, Rafet; Aygün, Muhittin; Çetinkaya, Bekir; García-Granda, Santiago

    2008-01-01

    The reaction of [RuCl 2( p-cymene)] 2 with in situ deprotonated NHC precursor 1,3-bis(biphenyl-2-yl)imidazolinium chloride was carried out in p-xylene at 140 °C to produce ?2, in which the NHC moiety acts as a tridentate C,C',C''-ligand. The complex 2 was characterized by NMR spectroscopy and X-ray crystallographic study. Crystallographic analysis combined with computational study regarding the compound, 1-[η 6-(2'-biphenyl)]-3-[2-phenyl-1,2-phenylene]imidazolidin-2-ylidenechlororuthenium(II), 2, reveals that its metal-centered enantiomers are co-crystallized in 1:1 ratio and NHC frame possessing a tridentate coordination mode consists of σ-donation of the carbene carbon, η 6-arene tethering of terminal biaryl and η 1-coordination of the biphenyl ring at 2-position. Enantiomers of the complex are packed as asymmetric dimers in solid state formed by C-H⋯Cl type weak H-bonds and C-H⋯π type interactions giving rise to asymmetric chains. Both interactions serve to stabilization of the extended structure.

  6. Ruthenium based metals using atomic vapor deposition for gate electrode applications

    NASA Astrophysics Data System (ADS)

    Choi, Changhwan; Ando, Takashi; Narayanan, Vijay

    2011-02-01

    The impacts of ruthenium-based metal gate electrodes (Ru,RuOx,RuSiOx) with atomic vapor deposition (AVD) on flatband voltage (VFB) and equivalent oxide thickness (EOT) are demonstrated using a low temperature (<400 °C) process. Increasing thickness of Ru and RuOx exhibits higher VFB, attributed to filling oxygen vacancies [Vo] in high-k gate dielectric with oxygen supplied from AVD metal gate electrodes upon annealing. Ru is efficient to attain a higher work-function and thinner EOT compared to RuOx and RuSiOx. Subsequent physical-vapor-deposition (PVD) TiN capping on AVD metals blocks oxygen out-diffusion, leading to higher VFB than PVD W or AVD TiN capping.

  7. Ruthenium bistridentate complexes with non-symmetrical hexahydro-pyrimidopyrimidine ligands: a structural and theoretical investigation of their optical and electrochemical properties.

    PubMed

    Laramée-Milette, Baptiste; Hanan, Garry S

    2016-08-01

    Six ruthenium complexes were synthesized based on three non-symmetrical tridentate ligands bearing the strongly electron-donating group 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-α]pyrimidine (hpp), bpyG (bpyG = 2,2'-bipyridyl-6-hpp), phenG (phenG = 2-hpp-1,10-phenanthroline) and QpyG (QpyG = 2-hpp-6-quinolylpyridyl). The fac-/mer-conformation of the homoleptic species has a dramatic effect on the optical properties, where the fac-isomer absorption is red-shifted by 150 nm, thus reaching the near-IR at approximately 850 nm. Owing to the interesting structural effect on the optical properties, density functional theory (DFT) and time-dependent DFT calculations have been implemented to enlighten the experimental data and prove that exciton coupling is at the origin of the observed shift. The electronic properties have been investigated and, as corroborated by electrochemical data, the presence of the hpp ligand strongly affects the oxidation potential of the ruthenium metal ion, which allows facile fine-tuning of the electronic properties. The luminescence properties of all the compounds have also been investigated (λmax emission = 781-817 nm) and the complexes have longer excited-state lifetimes at room temperature than the parent bis(2,2':6',2''-terpyridine)ruthenium(ii) by 10 to 30 times. PMID:27436338

  8. Electrochemical and photophysical properties of new triazole-bridged heterobimetallic ruthenium-rhodium and ruthenium-iridium complexes

    SciTech Connect

    Diemen, J.H. van; Hage, R.; Haasnoot, J.G.; Lempers, H.E.B.; Reedijk, J. ); Vos, J.G. ); Cola, L. de; Barigelletti, F.; Balzani, V. )

    1992-08-19

    The synthesis, characterization, and the electrochemical and photophysical properties of ((bpy){sub 2}Ru{sup II}(bpt)Rh{sup III}(ppy){sub 2}){sup 2+}, ((bpy){sub 2}Ru{sup II}(bpt)Ir{sup III}(ppy){sub 2}){sup 2+}, ((Rh{sup III}(ppy){sub 2}){sub 2}(bpt)){sup +}, and ((Ir{sup III}(ppy){sub 2}){sub 2}(bpt)){sup +} are reported (Hppy = 2-phenylpyridine; bpy = 2,2{prime}-bipyridine, Hbpt = 3,5-bis(pyridin-2-yl)-1,2,4-triazole). The Ru(bpy){sub 2} moiety is bound via N1 of the triazole ring, while the M(ppy){sub 2} center (M = Rh or Ir) is coordinated via the N4 of the triazole ring. The electrochemical measurements show that in the mixed-metal complexes the first oxidized metal is Ru and the first reduced ligand is bpy. The homobimetallic Ir and Rh complexes exhibit a bpt{sup {minus}}-based reduction. The absorption spectra of the mixed-metal complexes exhibit both Ru {yields} bpy and M {yields} ppy{sup {minus}} transitions. The energies of these transitions are different from those of their homobimetallic analogs. The emission observed for ((Rh(ppy){sub 2}){sub 2}-(bpt)){sup +} at 77 K corresponds to a ligand-centered excited state, while for the analogous iridium complex a charge-transfer emission, which involves the bpt{sup {minus}} ligand, is observed. In the mixed-metal complexes efficient energy transfer occurs from higher energy excited states centered on the M(ppy){sub 2} component to the lowest energy excited state, which is a metal-to-ligand charge transfer level localized on the Ru(bpy){sub 2} component.

  9. A ruthenium complex as a single-component redox shuttle for electrochemical photovoltaics.

    PubMed

    Kim, Jeung Yoon; Yun, Won Seok; Son, Ho-Jin; Lee, JaeDong; Jeong, Nak Cheon

    2015-05-01

    A primitive version of a ruthenium complex [Ru(bpy)3(2+)] was employed for the first time as a new conceptual "single-component redox shuttle" for dye-sensitized solar cells. This single shuttle led to a large enhancement of the open-circuit photovoltage (VOC) to ∼940 mV relative to that of conventional iodine-based shuttle and greatly increased the efficiency of the solar-to-electric energy conversion at lower illumination levels by a factor of ca. 5.6.

  10. Scrutinizing the Noninnocence of Quinone Ligands in Ruthenium Complexes: Insights from Structural, Electronic, Energy, and Effective Oxidation State Analyses.

    PubMed

    Skara, Gabriella; Gimferrer, Marti; De Proft, Frank; Salvador, Pedro; Pinter, Balazs

    2016-03-01

    The most relevant manifestations of ligand noninnocence of quinone and bipyridine derivatives are thoroughly scrutinized and discussed through an extensive and systematic set of octahedral ruthenium complexes, [(en)2RuL](z), in four oxidation states (z = +3, +2, +1, and 0). The characteristic structural deformation of ligands upon coordination/noninnocence is put into context with the underlying electronic structure of the complexes and its change upon reduction. In addition, by means of decomposing the corresponding reductions into electron transfer and structural relaxation subprocesses, the energetic contribution of these structural deformations to the redox energetics is revealed. The change of molecular electron density upon metal- and ligand-centered reductions is also visualized and shown to provide novel insights into the corresponding redox processes. Moreover, the charge distribution of the π-subspace is straightforwardly examined and used as indicator of ligand noninnocence in the distinct oxidation states of the complexes. The aromatization/dearomatization processes of ligand backbones are also monitored using magnetic (NICS) and electronic (PDI) indicators of aromaticity, and the consequences to noninnocent behavior are discussed. Finally, the recently developed effective oxidation state (EOS) analysis is utilized, on the one hand, to test its applicability for complexes containing noninnocent ligands, and, on the other hand, to provide new insights into the magnitude of state mixings in the investigated complexes. The effect of ligand substitution, nature of donor atom, ligand frame modification on these manifestations, and measures is discussed in an intuitive and pedagogical manner. PMID:26866981

  11. Unmasking the Action of Phosphinous Acid Ligands in Nitrile Hydration Reactions Catalyzed by Arene-Ruthenium(II) Complexes.

    PubMed

    Tomás-Mendivil, Eder; Cadierno, Victorio; Menéndez, María I; López, Ramón

    2015-11-16

    The catalytic hydration of benzonitrile and acetonitrile has been studied by employing different arene-ruthenium(II) complexes with phosphinous (PR2OH) and phosphorous acid (P(OR)2OH) ligands as catalysts. Marked differences in activity were found, depending on the nature of both the P-donor and η(6)-coordinated arene ligand. Faster transformations were always observed with the phosphinous acids. DFT computations unveiled the intriguing mechanism of acetonitrile hydration catalyzed by these arene-ruthenium(II) complexes. The process starts with attack on the nitrile carbon atom of the hydroxyl group of the P-donor ligand instead of on a solvent water molecule, as previously suggested. The experimental results presented herein for acetonitrile and benzonitrile hydration catalyzed by different arene-ruthenium(II) complexes could be rationalized in terms of such a mechanism.

  12. Electronic Spectra of Bare and Solvated Ruthenium Polypyridine Complexes

    NASA Astrophysics Data System (ADS)

    Xu, Shuang; Smith, James E. T.; Weber, J. Mathias

    2016-06-01

    We present work on a prototypical water oxidation catalyst, namely the aqua-complex [(bpy)(tpy)Ru-OH_2]2+ (2,2'-bpy = bipyridine, tpy = 2,2':6',2"-terpyridine), and its hydrated clusters [(bpy)(tpy)Ru-OH_2]2+ ·(H2O)_n, with n = 1 - 4. This complex is the starting species in a catalytic cycle for water oxidation. We couple electrospray ionization mass spectrometry with laser spectroscopy to circumvent challenges that arise in reactive solutions from speciation. Here, we report the electronic spectrum of [(bpy)(tpy)Ru-OH_2]2+ by photodissociation spectroscopy of mass selected, cryogenically prepared ions, and we examine effects of its microhydration environment on its electronic structure. In particular, we investigate the solvatochromic shift of the spectral envelope upon sequential addition of water molecules up to the tetrahydrate.

  13. Syntheses and properties of phosphine-substituted ruthenium(II) polypyridine complexes with nitrogen oxides.

    PubMed

    Nakamura, Go; Kondo, Mio; Crisalli, Meredith; Lee, Sze Koon; Shibata, Akane; Ford, Peter C; Masaoka, Shigeyuki

    2015-10-21

    Four novel phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides-trans(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (trans-NO2), cis(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (cis-NO2), [Ru(trpy)(dppbz)(NO2)]PF6 (PP-NO2), and cis(P,NO)-[Ru(trpy)(Pqn)(NO)](PF6)3 (cis-NO)-were synthesised (trpy = 2,2':6',2''-terpyridine, Pqn = 8-(diphenylphosphanyl)quinoline, and dppbz = 1,2-bis(diphenylphosphanyl)benzene). The influence of the number and position of the phosphine group(s) on the electronic structure of these complexes was investigated using single-crystal X-ray structural analysis, UV-vis absorption spectroscopy, and electrochemical measurements. The substitution lability of the nitrogen oxide ligand of each complex is discussed in comparison with that of the corresponding acetonitrile complexes.

  14. Reactivity of vinylidene complexes of ruthenium with hydrazines and hydroxylamines.

    PubMed

    Albertin, Gabriele; Antoniutti, Stefano; Bortoluzzi, Marco; Botter, Alessandra; Castro, Jesús

    2015-02-21

    Vinylidene complexes [Ru(η(5)-C5H5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)R}(PPh3)L]BPh4 (, ) [L = P(OMe)3, P(OEt)3; R = Ph, p-tolyl, Bu(t), H] react with hydrazine R1NHNH2 (R1 = H, Me, Ph) to afford nitrile derivatives [Ru(η(5)-C5H5)(N[triple bond, length as m-dash]CCH2R)(PPh3)L]BPh4 (, ) and amine R1NH2. Hydroxylamine NH2OH also reacts with vinylidenes , to yield nitrile derivatives , and H2O. Studies with (15)N-labeled hydrazine and DFT calculations allowed a reaction path to be proposed. The complexes were characterized by spectroscopy (IR, (1)H, (31)P, (13)C and (15)N NMR) and by X-ray crystal structure determination of [Ru(η(5)-C5H5)(N[triple bond, length as m-dash]CCH2Ph)(PPh3){P(OEt)3}]BPh4 ().

  15. Oxidation Reactions of Dithiocarbamate Complexes of Ruthenium(II).

    PubMed

    Leung, Wa-Hung; Chim, Joyce L. C.; Hou, Hongwei; Hun, Tom S. M.; Williams, Ian D.; Wong, Wing-Tak

    1997-09-24

    The reaction of Ru(Et(2)dtc)(2)(DMSO)(2) (Et(2)dtc = N,N-diethyldithiocarbamate; DMSO = dimethyl sulfoxide) with t-BuNC gave trans-Ru(Et(2)dtc)(2)(CN-t-Bu)(2), 1. Complex 1 crystallizes in the monoclinic space group P2(1)/n with a = 9.753(2) Å, b = 11.583(2) Å, c = 12.974(2) Å, and beta = 91.8(2) degrees for Z = 2. The crystal structure of 1 shows the trans disposition of the two isocyanides; the mean Ru-S and Ru-C distances are 2.409 and 1.977(2) Å, respectively. Treatment of [Ru(diene)Cl(2)](n)() with Na(Et(2)dtc) afforded Ru(Et(2)dtc)(2)(diene) (diene = bicyclo[2.2.1]hepta-2,5-diene (NBD), 2, 1,5-cyclooctadiene (COD), 3). Complex 2 crystallizes in the triclinic space group P&onemacr; with a = 7.316(1) Å, b = 10.346(1) Å, c = 15.123(2) Å, alpha = 103.69(2) degrees, beta = 93.54(2) degrees, and gamma = 100.61(2) degrees for Z = 2. The mean Ru-S and Ru-C distances in 2 are 2.416 and 2.137 Å, respectively. The reaction of cis-Ru(Et(2)dtc)(2)(CO)(2) with iodine gave the 2:1 molecular iodine complex cis-Ru(Et(2)dtc)(2)(CO)(2).(1)/(2)I(2) 4, which crystallizes in the monoclinic space group P2(1)/c with a = 7.347(2), b = 22.227(2) Å, c = 12.891(2) Å, and beta =95.98 (2) degrees for Z = 4. The mean Ru-S and Ru-C and the I-I distances in complex 4 are 2.427, 1.903, and 2.745(1) Å, respectively. Treatment of Ru(Et(2)dtc)(2)(DMSO)(2) with I(2) gave the linear Ru(II)-Ru(III)-Ru(III) trimer [Ru(3)(Et(2)dtc)(6)(DMSO)(2)](I(3))(2), 5, which crystallizes in the triclinic space group P&onemacr; with a = 14.125(3) Å, b = 20.829(6) Å, c = 13.658(3) Å, alpha = 97.57(2) degrees, beta = 110.01(2) degrees, and gamma = 71.25(2) degrees for Z = 2. The structure of complex 6 can be viewed as consisting of a {Ru(2)(III)(Et(2)dtc)(4)}(2+) core and a {Ru(II)(Et(2)dtc)(2)(DMSO)(2)} moiety, which are linked together via the two dithiocarbamate sulfurs of the latter. While the two Ru(III) centers are connected by a Ru-Ru single bond (Ru-Ru = 2.826(2) Å), there is no direct

  16. A DFT-D study on the electronic and photophysical properties of ruthenium (II) complex with a chelating sulfoxide group

    NASA Astrophysics Data System (ADS)

    Li, Huifang; Zhang, Lisheng; Lin, Hui; Fan, Xiaolin

    2014-06-01

    Electronic and photophysical properties of [Ru(bpy)2(OSO)]+ (bpy = 2,2‧-bipyridine; OSO = methylsulfinylbenzoate) were examined theoretically to better understand the differences between S- and O-linked ruthenium sulfoxide complexes. It is found that the strength of Ru-O1 linkage is significantly larger than that of Ru-S linkage, which makes the charge transfer amount from surrounding ligands to central Ru decreased. The energy gap is closed due to the highest occupied molecular orbital energy increases to a larger extent than the lowest unoccupied molecular orbital energy. Thereby, red shifted absorption and emission maxima in such photochromic ruthenium sulfoxide complexes can be explained.

  17. Synthesis, electronic structure and catalytic activity of ruthenium-iodo-carbonyl complexes with thioether containing NNS donor ligand

    NASA Astrophysics Data System (ADS)

    Jana, Subrata; Jana, Mahendra Sekhar; Biswas, Sujan; Sinha, Chittaranjan; Mondal, Tapan Kumar

    2014-05-01

    The ruthenium carbonyl complexes 1 and 2 with redox noninnocent NNS donor ligand, 1-methyl-2-{(o-thiomethyl)phenylazo}imidazole (L) have been synthesized and characterized by various analytical and spectroscopic (IR, UV-Vis and 1H NMR) techniques. The complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 1.11 V for 1 and 0.76 V for 2 along with two successive one electron ligand reductions. Catalytic activity of the compounds has been investigated to the oxidation of PhCH2OH to PhCHO, 2-butanol (C4H9OH) to 2-butanone, 1-phenylethanol (PhC2H4OH) to acetophenone, cyclopentanol (C5H9OH) to cyclopentanone, cyclohexanol to cyclohexanone, cycloheptanol to cycloheptanone and cycloctanol to cycloctanone using N-methylmorpholine-N-oxide (NMO) as oxidant. The catalytic efficiency of 2 is greater than complex 1 and well correlate with the metal oxidation potential. DFT, NBO and TDDFT calculations in DFT/B3LYP/6-31G(d)/lanL2TZ(f) method are employed to interpret the structural and electronic features of the complexes.

  18. Selenophene transition metal complexes

    SciTech Connect

    White, C.J.

    1994-07-27

    This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the {eta}{sup 5}- and the {eta}{sup 1}(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenophene complexes more stable than the corresponding thiophene complexes. The {sup 77}Se NMR chemical shift values for selenophene complexes fall within distinct regions primarily depending on the coordination mode of the selenophene ligand. In the final paper, the C-H bond activation of {eta}{sup 1}(S)-bound thiophenes, {eta}{sup 1}(S)-benzothiophene and {eta}{sup 1}(Se)-bound selenophenes has been demonstrated. The deprotonation and rearrangement of the {eta}{sup 1}(E)-bound ligand to the carbon bound L-yl complex readily occurs in the presence of base. Reprotonation with a strong acid gives a carbene complex that is unreactive towards nucleophilic attack at the carbene carbon and is stable towards exposure to air. The molecular structure of [Cp(NO)(PPh{sub 3})Re(2-benzothioenylcarbene)]O{sub 3}SCF{sub 3} was determined and contains a Re-C bond with substantial double bond character. Methyl substitution for the thienylcarbene or selenylcarbene gives a carbene that rearranges thermally to give back the {eta}{sup 1}(E)-bound complex. Based on these model reactions, a new mechanism for the H/D exchange of thiophene over the hydrodesulfurization catalyst has been proposed.

  19. Förster resonance energy transfer studies of luminescent gold nanoparticles functionalized with ruthenium(II) and rhenium(I) complexes: modulation via esterase hydrolysis.

    PubMed

    Leung, Frankie Chi-Ming; Tam, Anthony Yiu-Yan; Au, Vonika Ka-Man; Li, Mei-Jin; Yam, Vivian Wing-Wah

    2014-05-14

    A number of ruthenium(II) and rhenium(I) bipyridine complexes functionalized with lipoic acid moieties have been synthesized and characterized. Functionalization of gold nanoparticles with these chromophoric ruthenium(II) and rhenium(I) complexes has resulted in interesting supramolecular assemblies with Förster resonance energy transfer (FRET) properties that could be modulated via esterase hydrolysis. The luminescence of the metal complex chromophores was turned on upon cleavage of the ester bond linkage by esterase to reduce the efficiency of FRET quenching. The prepared nanoassembly conjugates have been characterized by transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), UV-visible spectroscopy, and emission spectroscopy. The quenching mechanism has also been studied by transient absorption and time-resolved emission decay measurements. The FRET efficiencies were found to vary with the nature of the chromophores and the length of the spacer between the donor (transition metal complexes) and the acceptor (gold nanoparticles).

  20. Conformations of N-Heterocyclic Carbene Ligands in Ruthenium Complexes Relevant to Olefin Metathesis

    PubMed Central

    Stewart, Ian C.; Benitez, Diego; O'Leary, Daniel J.; Tkatchouk, Ekaterina; Day, Michael W.; Goddard, William A.; Grubbs, Robert H.

    2009-01-01

    The structure of ruthenium-based olefin metathesis catalyst 3 and model π-complex 5 in solution and in the solid state are reported. The N-tolyl ligands, due to their lower symmetry than the traditional N-mesityl substituents, complicate this analysis, but ultimately provide explanation for the enhanced reactivity of 3 relative to standard catalyst 2. The tilt of the N-tolyl ring provides additional space near the ruthenium center, which is consistent with the enhanced reactivity of 3 towards sterically demanding substrates. Due to this tilt, the more sterically accessible face bears the two methyl substituents of the N-aryl rings. These experimental studies are supported by computational studies of these complexes by DFT. The experimental data provides a means to validate the accuracy of the B3LYP and M06 functionals. B3LYP provides geometries that match X-ray crystal structural data more closely, though it leads to slightly less (∼0.5 kcal mol−1) accuracy than M06 most likely because it underestimates attractive non-covalent interactions. PMID:19146414

  1. First pentahaptofullerene metal complexes

    SciTech Connect

    Masaya, Sawamura; Iikura, Hitoshi; Nakamura, Eiichi

    1996-12-18

    Cyclopentadienyl metal complexes have played important roles in chemistry owing to their unique structures and functional activities. Here we report the synthesis and characterization of an entirely new class of cyclopentadienyl (Cp) metal complexes ({eta}{sup 5}-C{sub 60}Ph{sub 5})MLn (MLn = Li, K, Tl, and Cu.PEt{sub 3}). In these molecules, the five Cp carbons represent one pentagon of C{sub 60}, isolated from the remaining 50 sp{sup 2} carbon atoms by five surrounding sp{sup 3} carbon atoms each bearing a phenyl group. The X-ray crystal structure analysis of the thallium complex Tl({eta}{sup 5}-C{sub 60}Ph{sub 5}).2.5THF revealed its unique and esthetically pleasing C{sub 5} symmetrical molecular structure with the phenyl groups forming a chiral propeller array. The thallium atom is deeply buried in the cavity created by the phenyl groups, bonding to the five Cp carbons ({eta}{sup 5}-coordination) with an averaged Tl-C distance of 2.87 A. The key finding that we made in this research was a remarkable 5-fold addition of an organocopper reagent to C{sub 60}, which stands in contrast to the monoaddition reaction of Grignard or organolithium reagents. 10 refs., 1 fig.

  2. Preparation of Different Substitued Polypyridine Ligands, Ruthenium(II)-Bridged Complexes and Spectoscopıc Studies.

    PubMed

    Obali, Aslihan Yilmaz; Ucan, Halil Ismet

    2016-09-01

    Novel different substitued polypyridine ligands 4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzaldehyde (BA-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-5amine (FN-PPY), 2-(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline (BR-PPY), 2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (N3-PPY) and triazole containing polypyridine ligand 3,4-bis[(4-(metoxy)-1,2,3-triazole)1-methylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)] benzaldehyde (BA-DIPPY) and Ruthenium(II) complexes were synthesized and characterized. Their photopysical properties were investigated. The complexes RuP(PR-PPY), RuB(PR-PPY, RuP(FN-PPY) and RuB(FN-PPY) exhibited a broad absorption bands at 485, 475, 476, and 453 nm, respectively, assignable to the spin-allowed MLCT (dπ-π*) transition. The emission maxima of the pyrene-appended polypyridine ligand PR-PPY was observed at λems = 616 nm and the phenanthroline-appended polypyridine ligand FN-PPY was observed at λems = 668 nm. And the emission maxima of the complexes RuP(PR-PPY), RuB(PR-PPY), RuP(FN-PPY) and RuB(FN-PPY) were observed at λems = 646, 646, 685 and 685 nm, respectively. As seen in fluorescence spectra, the fluorescence intensities of the ligands are higher than their metal complexes. This is because of quenching effect of Ruthenium(II) metal on chromophore groups. PMID:27351670

  3. Ruthenium(II) hydrazone Schiff base complexes: Synthesis, spectral study and catalytic applications

    NASA Astrophysics Data System (ADS)

    Manikandan, R.; Viswanathamurthi, P.; Muthukumar, M.

    2011-12-01

    Ruthenium(II) hydrazone Schiff base complexes of the type [RuCl(CO)(B)(L)] (were B = PPh 3, AsPh 3 or Py; L = hydrazone Schiff base ligands) were synthesized from the reactions of hydrazone Schiff base ligand (obtained from isonicotinoylhydrazide and different hydroxy aldehydes) with [RuHCl(CO)(EPh 3) 2(B)] (where E = P or As; B = PPh 3, AsPh 3 or Py) in 1:1 molar ratio. All the new complexes have been characterized by analytical and spectral (FT-IR, electronic, 1H, 13C and 31P NMR) data. They have been tentatively assigned an octahedral structure. The synthesized complexes have exhibited catalytic activity for oxidation of benzyl alcohol to benzaldehyde and cyclohexanol to cyclohexanone in the presence of N-methyl morpholine N-oxide (NMO) as co-oxidant. They were also found to catalyze the transfer hydrogenation of aliphatic and aromatic ketones to alcohols in KOH/Isopropanol.

  4. Efficient water oxidation catalyzed by mononuclear ruthenium(II) complexes incorporating Schiff base ligands.

    PubMed

    Li, Ting-Ting; Chen, Yong; Li, Fu-Min; Zhao, Wei-Liang; Wang, Chuan-Jun; Lv, Xiao-Jun; Xu, Quan-Qing; Fu, Wen-Fu

    2014-06-23

    Four new charge-neutral ruthenium(II) complexes containing dianionic Schiff base and isoquinoline or 4-picoline ligands were synthesized and characterized by NMR and ESI-MS spectroscopies, elemental analysis, and X-ray diffraction. The complexes exhibited excellent chemical water oxidation activity and high stability under acidic conditions (pH 1.0) using (NH4)2Ce(NO3)6 as a sacrificial electron acceptor. The high catalytic activities of these complexes for water oxidation were sustained for more than 10 h at low concentrations. High turnover numbers of up to 3200 were achieved. A water nucleophilic attack mechanism was proposed. A Ru(V)=O intermediate was detected during the catalytic cycle by high-resolution mass spectrometry.

  5. Synthesis, characterization, electronic structure and catalytic activity of new ruthenium carbonyl complexes of N-[(2-pyridyl)methylidene]-2-aminothiazole

    NASA Astrophysics Data System (ADS)

    Kundu, Subhankar; Sarkar, Deblina; Jana, Mahendra Sekhar; Pramanik, Ajoy Kumar; Jana, Subrata; Mondal, Tapan Kumar

    2013-03-01

    Reaction of ruthenium carbonyls, [Ru(CO)2Cl2]n/[Ru(CO)4I2] with bidentate Schiffs base ligands derived by the condensation of pyridine-2-carboxaldehyde with 2-aminothiazole in a 1:1 mole ratio in acetonitrile led to the formation of complexes having general formula [Ru(CO)2(L)X2] (X = Cl (1) and I (2)) (L = N-[(2-pyridyl)methylidene]-2-aminothiazole). The compounds have been characterized by various analytical and spectroscopic (IR, electronic and 1H NMR) studies. In acetonitrile solution the complexes exhibit a weak broad metal-ligand to ligand charge transfer (MLLCT) band along with ILCT transitions. The compounds are emissive in room temperature upon excitation in the ILCT band. The complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 1.44 V for 1 and 0.94 V for 2. Catalytic activity of these compounds is investigated to the oxidation of PhCH2OH to PhCHO, 2-butanol (C4H9OH) to 2-butanone, 1-phenylethanol (PhC2H4OH) to acetophenone, cyclopentanol (C5H9OH) to cyclopentanone, cyclohexanol to cyclohexanone, cycloheptanol to cycloheptanone and cycloctanol to cycloctanone using N-methylmorpholine-N-oxide (NMO) as oxidant. The catalytic efficiency of 2 is greater than complex 1 and well correlate with the metal oxidation potential of the complexes. DFT, NBO and TDDFT calculations are employed to explain the structural and electronic features and to support the spectroscopic assignments.

  6. Synthesis and Catalytic Activity of Ruthenium-Indenylidene Complexes for Olefin Metathesis: Microscale Experiments for the Undergraduate Inorganic or Organometallic Laboratories

    ERIC Educational Resources Information Center

    Pappenfus, Ted M.; Hermanson, David L.; Ekerholm, Daniel P.; Lilliquist, Stacie L.; Mekoli, Megan L.

    2007-01-01

    A series of experiments for undergraduate laboratory courses (e.g., inorganic, organometallic or advanced organic) have been developed. These experiments focus on understanding the design and catalytic activity of ruthenium-indenylidene complexes for olefin metathesis. Included in the experiments are the syntheses of two ruthenium-indenylidene…

  7. Iron(II) and ruthenium(II) complexes containing P, N, and H ligands: structure, spectroscopy, electrochemistry, and reactivity.

    PubMed

    Chen, Jinzhu; Szalda, David J; Fujita, Etsuko; Creutz, Carol

    2010-10-18

    The purpose of this work was to explore the possibility of using iron(II) hydrides in CO(2) reduction and to compare their reactivity to that of their ruthenium analogues. Fe(bpy)(P(OEt)(3))(3)H(+) and Ru(bpy)(P(OEt)(3))(3)H(+) do not react with CO(2) in acetonitrile, but the one-electron-reduction products of Ru(bpy)(P(OEt)(3))(3)H(+) and Ru(bpy)(2)(P(OEt)(3))H(+) and the two-electron-reduction product of Fe(bpy)(P(OEt)(3))(3)H(+) do. Ru(bpy)(2)(P(OEt)(3))H(+) also reacts slowly with CO(2) to give a formate complex [as reported previously by Albertin et al. (Inorg. Chem. 2004, 43, 1336)] with a second-order rate constant of ∼4 × 10(-3) M(-1) s(-1) in methanol. The structures for the hydride complexes [Fe(bpy)(P(OEt)(3))(3)H](+) and [Ru(bpy)(2)(P(OEt)(3))H](+) and for the (η(5)-Cp)bis- and -tris-PTA complexes (PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13.7]decane) of iron(II) are reported. These and the CpFe(CO)(bpy)(+) and Fe(II)PNNP compounds have been subjected to electrochemical and UV-vis spectroscopic characterization. Fe(bpy)(P(OEt)(3))(3)H(+) exhibits a quasi-reversible oxidation at +0.42 V vs AgCl/Ag in acetonitrile; Ru(bpy)(P(OEt)(3))(3)H(+) and Ru(bpy)(2)(P(OEt)(3))H(+) are oxidized irreversibly at +0.90 and +0.55 V, respectively, vs AgCl/Ag. The reduction site for Fe(bpy)(P(OEt)(3))(3)H(+) and Fe(bpy)(P(OEt)(3))(3)(CH(3)CN)(2+) appears to be the metal and gives rise to a two-electron process. The bpy-centered reductions are negatively shifted in the ruthenium(II) hydride complexes, compared to the acetonitrile complexes. The results of attempts to prepare other iron(II) hydrides are summarized. PMID:20857940

  8. DNA interaction, antioxidant activity, and bioactivity studies of two ruthenium(II) complexes

    NASA Astrophysics Data System (ADS)

    Han, Bing-Jie; Jiang, Guang-Bin; Yao, Jun-Hua; Li, Wei; Wang, Ji; Huang, Hong-Liang; Liu, Yun-Jun

    2015-01-01

    Two new ruthenium(II) polypyridyl complexes [Ru(dmb)2(dcdppz)](ClO4)2 (1) and [Ru(bpy)2(dcdppz)](ClO4)2 (2) were prepared and characterized. The crystal structure of the complex 2 was solved by single crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group P21/n with a = 12.9622(14) Å, b = 17.1619(19) Å, c = 22.7210(3) Å, β = 100.930(2)°, R = 0.0536, Rω = 0.1111. The DNA-binding constants for complexes 1 and 2 were determined to be 1.92 × 105 (s = 1.72) and 2.24 × 105 (s = 1.86) M-1, respectively. The DNA-binding behaviors showed that complexes 1 and 2 interact with DNA by intercalative mode. The antioxidant activities of the ligand and the complexes were performed. Ligand, dcdppz, has no cytotoxicity against the selected cell lines. Complex 1 shows higher cytotoxicity than complex 2, but lower than cisplatin toward selected cell lines. The apoptosis and cell cycle arrest were investigated, and the apoptotic mechanism of BEL-7402 cells was studied by reactive oxygen species (ROS), mitochondrial membrane potential and western blot analysis. Complex 1 induces apoptosis in BEL-7402 cells through ROS-mediated mitochondrial dysfunction pathway and by regulating the expression of Bcl-2 family proteins.

  9. An efficient synthesis and in vitro antibacterial evaluation of ruthenium-quinolinol complexes.

    PubMed

    Malipeddi, Mahima; Lakhani, Chirag; Chhabra, Mohit; Paira, Priyankar; Vidya, R

    2015-08-01

    A series of ruthenium-quinolinol complexes were synthesized using a simple and effective pathway and their in vitro antibacterial activity against various resistant gram-positive and gram-negative bacteria were evaluated. It was established that compound [(η6-pcymene)RuCl(κ2-O,N-5,7-dibromo-HyQ)]·Cl (3b) & [(η6-pcymene)RuCl(κ2-O,N-5,7-dibromo-HyQ)]·Cl (3e) were significantly active against Staphylococcus aureus, Escherichia coli, Bacillus subtilis &Salmonella sp. The structures of the new compounds were elucidated by the analysis of spectroscopic data. The stability of complex [(η6-pcymene)RuCl(κ2-O,N-5,7-dibromo-HyQ)]·Cl (3b) was measured by UV spectroscopy & time dependent NMR spectroscopy. Compound 3b also shows remarkable fluorescence. PMID:26048801

  10. A trinuclear ruthenium complex as a highly efficient molecular catalyst for water oxidation.

    PubMed

    Zhang, L L; Gao, Y; Liu, Z; Ding, X; Yu, Z; Sun, L C

    2016-03-01

    A trinuclear ruthenium complex, 3, was designed and synthesized with the ligand 2,2'-bipyridine-6,6'-dicarboxylic acid (bda) and we found that this complex could function as a highly efficient molecular catalyst for water oxidation in homogeneous systems. This trinuclear molecular water oxidation catalyst, 3, displayed much higher efficiencies in terms of turnover numbers and initial oxygen evolution rate than its counterparts, a binuclear catalyst, 2, and a mononuclear catalyst, 1, in both chemically driven and photochemically driven water oxidation based on either the whole catalytic molecules or just the active Ru centers. The reasons for the superior performance of catalyst 3 were discussed and we believe that multiple Ru centers in a single molecule are indeed beneficial for increasing the probability of the formation of O-O bonds through an intramolecular radical coupling pathway.

  11. A Ruthenium(II) Complex Supported by Trithiacyclononane and Aromatic Diimine Ligand as Luminescent Switch-On Probe for Biomolecule Detection and Protein Staining

    NASA Astrophysics Data System (ADS)

    Wong, Chun-Yuen; Chung, Lai-Hon; Lin, Sheng; Chan, Daniel Shiu-Hin; Leung, Chung-Hang; Ma, Dik-Lung

    2014-11-01

    A new ruthenium(II) complex has been developed for detection of biomolecules. This complex is highly selective for histidine over other amino acids and has been applied to protein staining in an SDS-PAGE gel.

  12. A Ruthenium(II) Complex Supported by Trithiacyclononane and Aromatic Diimine Ligand as Luminescent Switch-On Probe for Biomolecule Detection and Protein Staining

    PubMed Central

    Wong, Chun-Yuen; Chung, Lai-Hon; Lin, Sheng; Chan, Daniel Shiu-Hin; Ma, Dik-Lung

    2014-01-01

    A new ruthenium(II) complex has been developed for detection of biomolecules. This complex is highly selective for histidine over other amino acids and has been applied to protein staining in an SDS-PAGE gel. PMID:25409703

  13. Atmospheric Hydrogenation of Esters Catalyzed by PNP-Ruthenium Complexes with an N-Heterocyclic Carbene Ligand.

    PubMed

    Ogata, Osamu; Nakayama, Yuji; Nara, Hideki; Fujiwhara, Mitsuhiko; Kayaki, Yoshihito

    2016-08-01

    New pincer ruthenium complexes bearing a monodentate N-heterocyclic carbene ligand were synthesized and demonstrated as powerful hydrogenation catalysts. With an atmospheric pressure of hydrogen gas, aromatic, heteroaromatic, and aliphatic esters as well as lactones were converted into the corresponding alcohols at 50 °C. This reaction protocol offers reliable access to alcohols using an easy operational setup.

  14. A Hexakis Terpyridine-Fullerene Ligand in Six-Fold Ruthenium, Iridium, and Iron Complexes: Synthesis and Electrochemical Properties.

    PubMed

    Yan, Weibo; Réthoré, Céline; Menning, Sebastian; Brenner-Weiß, Gerald; Muller, Thierry; Pierrat, Philippe; Bräse, Stefan

    2016-08-01

    An unprecedented straightforward route to six-fold terpyridine ligands around C60 , the latter being regioselectively functionalized in pseudo-octahedral positions using a six-fold Bingel reaction, is reported. Ruthenium, iridium, and iron complexes have been synthesized, and unambiguously characterized by NMR, MS, and cyclic voltammetry. PMID:27189254

  15. Atmospheric Hydrogenation of Esters Catalyzed by PNP-Ruthenium Complexes with an N-Heterocyclic Carbene Ligand.

    PubMed

    Ogata, Osamu; Nakayama, Yuji; Nara, Hideki; Fujiwhara, Mitsuhiko; Kayaki, Yoshihito

    2016-08-01

    New pincer ruthenium complexes bearing a monodentate N-heterocyclic carbene ligand were synthesized and demonstrated as powerful hydrogenation catalysts. With an atmospheric pressure of hydrogen gas, aromatic, heteroaromatic, and aliphatic esters as well as lactones were converted into the corresponding alcohols at 50 °C. This reaction protocol offers reliable access to alcohols using an easy operational setup. PMID:27439106

  16. Tandem olefin metathesis/hydrogenation at ambient temperature: activation of ruthenium carbene complexes by addition of hydrides.

    PubMed

    Schmidt, Bernd; Pohler, Michael

    2003-07-21

    Sodium hydride activates ruthenium carbene complexes to catalyze hydrogenation reactions subsequent to ring closing olefin metathesis. Under these conditions, hydrogenation of cyclopentenols proceeds smoothly at ambient temperature and under 1 atm of hydrogen in toluene. An alternative protocol was developed that involves the formation of hydrogen in situ by reaction of excess sodium hydride with protic functional groups and water. PMID:12956069

  17. Ruthenium(II) polypyridyl complexes as mitochondria-targeted two-photon photodynamic anticancer agents.

    PubMed

    Liu, Jiangping; Chen, Yu; Li, Guanying; Zhang, Pingyu; Jin, Chengzhi; Zeng, Leli; Ji, Liangnian; Chao, Hui

    2015-07-01

    Clinical acceptance of photodynamic therapy is currently hindered by poor depth efficacy and inefficient activation of the cell death machinery in cancer cells during treatment. To address these issues, photoactivation using two-photon absorption (TPA) is currently being examined. Mitochondria-targeted therapy represents a promising approach to target tumors selectively and may overcome the resistance in current anticancer therapies. Herein, four ruthenium(II) polypyridyl complexes (RuL1-RuL4) have been designed and developed to act as mitochondria-targeted two-photon photodynamic anticancer agents. These complexes exhibit very high singlet oxygen quantum yields in methanol (0.74-0.81), significant TPA cross sections (124-198 GM), remarkable mitochondrial accumulation, and deep penetration depth. Thus, RuL1-RuL4 were utilized as one-photon and two-photon absorbing photosensitizers in both monolayer cells and 3D multicellular spheroids (MCSs). These Ru(II) complexes were almost nontoxic towards cells and 3D MCSs in the dark and generate sufficient singlet oxygen under one- and two-photon irradiation to trigger cell death. Remarkably, RuL4 exhibited an IC50 value as low as 9.6 μM in one-photon PDT (λirr = 450 nm, 12 J cm(-2)) and 1.9 μM in two-photon PDT (λirr = 830 nm, 800 J cm(-2)) of 3D MCSs; moreover, RuL4 is an order of magnitude more toxic than cisplatin in the latter test system. The combination of mitochondria-targeting and two-photon activation provides a valuable paradigm to develop ruthenium(II) complexes for PDT applications.

  18. Visible-Light-Driven Photoisomerization and Increased Rotation Speed of a Molecular Motor Acting as a Ligand in a Ruthenium(II) Complex.

    PubMed

    Wezenberg, Sander J; Chen, Kuang-Yen; Feringa, Ben L

    2015-09-21

    Toward the development of visible-light-driven molecular rotary motors, an overcrowded alkene-based ligand and the corresponding ruthenium(II) complex is presented. In our design, a 4,5-diazafluorenyl coordination motif is directly integrated into the motor function. The photochemical and thermal isomerization behavior has been studied by UV/Vis and NMR spectroscopy. Upon coordination to a Ru(II) bipyridine complex, the photoisomerization process can be driven by visible (λmax = 450 nm) instead of UV light and furthermore, a large increase of the speed of rotation is noted. DFT calculations point to a contraction of the diazafluorenyl lower half upon metal-coordination resulting in reduced steric hindrance in the "fjord region" of the molecule. Consequently, it is shown that metal-ligand interactions can play an important role in the adjustment of both photophysical and thermodynamic properties of molecular motors.

  19. Rational Design of Ruthenium Complexes Containing 2,6-Bis(benzimidazolyl)pyridine Derivatives with Radiosensitization Activity by Enhancing p53 Activation.

    PubMed

    Deng, Zhiqin; Yu, Lianling; Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng

    2015-06-01

    The rational design of metal-based complexes is an effective strategy for the discovery of potent sensitizers for use in cancer radiotherapy. In this study, we synthesized three ruthenium complexes containing bis-benzimidazole derivatives: Ru(bbp)Cl3 (1), [Ru(bbp)2 ]Cl2 (2 a) (in which bbp=2,6-bis(benzimidazol-1-yl)pyridine), and [Ru(bbp)2]Cl2 (2 b) (where bbp=2,6-bis-(6-nitrobenzimidazol-2-yl)pyridine). We evaluated their radiosensitization capacities in vitro and mechanisms of action. Complex 2 b was found to be particularly effective in sensitizing human melanoma A375 cells toward radiation, with a sensitivity enhancement ratio of 2.4. Along with this potency, complex 2 b exhibited a high degree of selectivity between human cancer and normal cells. Mechanistic studies revealed that 2 b promotes radiation-induced accumulation of intracellular reactive oxygen species (ROS) by reacting with cellular glutathione (GSH) and then causing DNA stand breaks. The subsequent DNA damage induces phosphorylation of p53 (p-p53) and upregulates the expression levels of p21, which inhibits the expression of cyclin-B, leading to G2M arrest. Moreover, p-p53 activates caspases-3 and -8, triggers cleavage of poly(ADP-ribose) polymerase (PARP), finally resulting in apoptosis. Taken together, the results of this study provide a strategy for the design of ruthenium-based radiosensitizers for use in cancer therapy. PMID:25914192

  20. Rational Design of Ruthenium Complexes Containing 2,6-Bis(benzimidazolyl)pyridine Derivatives with Radiosensitization Activity by Enhancing p53 Activation.

    PubMed

    Deng, Zhiqin; Yu, Lianling; Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng

    2015-06-01

    The rational design of metal-based complexes is an effective strategy for the discovery of potent sensitizers for use in cancer radiotherapy. In this study, we synthesized three ruthenium complexes containing bis-benzimidazole derivatives: Ru(bbp)Cl3 (1), [Ru(bbp)2 ]Cl2 (2 a) (in which bbp=2,6-bis(benzimidazol-1-yl)pyridine), and [Ru(bbp)2]Cl2 (2 b) (where bbp=2,6-bis-(6-nitrobenzimidazol-2-yl)pyridine). We evaluated their radiosensitization capacities in vitro and mechanisms of action. Complex 2 b was found to be particularly effective in sensitizing human melanoma A375 cells toward radiation, with a sensitivity enhancement ratio of 2.4. Along with this potency, complex 2 b exhibited a high degree of selectivity between human cancer and normal cells. Mechanistic studies revealed that 2 b promotes radiation-induced accumulation of intracellular reactive oxygen species (ROS) by reacting with cellular glutathione (GSH) and then causing DNA stand breaks. The subsequent DNA damage induces phosphorylation of p53 (p-p53) and upregulates the expression levels of p21, which inhibits the expression of cyclin-B, leading to G2M arrest. Moreover, p-p53 activates caspases-3 and -8, triggers cleavage of poly(ADP-ribose) polymerase (PARP), finally resulting in apoptosis. Taken together, the results of this study provide a strategy for the design of ruthenium-based radiosensitizers for use in cancer therapy.

  1. Novel pyrazolylphosphite- and pyrazolylphosphinite-ruthenium(ii) complexes as catalysts for hydrogenation of acetophenone.

    PubMed

    Amenuvor, Gershon; Obuah, Collins; Nordlander, Ebbe; Darkwa, James

    2016-09-14

    The new compounds and potential ligands 2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)ethyldiphenlyphosphinite (L1), 2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)ethyldiethylphosphite (L2), 2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)ethyl-diethylphosphite (L3) and 2-(3,5-diphenyl-1H-pyrazol-1-yl)ethyldiethylphosphite (L4) were prepared from the reaction of (3,5-(disubstituted)pyrazol-1H-yl)ethanol and the appropriate phosphine chloride. The phosphinite (L1) and phosphites (L2-L4) and 2-(3,5-diphenyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L5) were reacted with [Ru(p-cymene)Cl2]2 to afford the ruthenium(ii) complexes [Ru(p-cymene)Cl2(L1)] (1), [Ru(p-cymene)Cl2(L2)] (2), [Ru(p-cymene)Cl2(L3)] (3), [Ru(p-cymene)Cl2(L4)] (4), and [Ru(p-cymene)Cl2(L5)] (5). All ruthenium complexes were characterized by a combination of NMR spectroscopy, elemental analysis and, in selected cases, by single crystal X-ray crystallography. Complexes 1-5 and [Ru(p-cymene)Cl2(L6)] (6) (prepared from 2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L6)) were investigated as catalysts for both transfer and molecular hydrogenation of acetophenone to 1-phenylethanol. At 80 °C the percent conversion of acetophenone in transfer hydrogenation was moderate to high over 10 h (42-87%); for molecular hydrogenation acetophenone, conversions were as high as 98% in 6 h. PMID:27504937

  2. Zero-order and first-derivative spectrophotometric determination of trace amounts of ruthenium after extraction of its ion association complex with 2,4,6-tris(2 prime -pyridyl)-1,3,5-triazine and picrate

    SciTech Connect

    Morales, A.; Toral, M.I.; Richter, P.; Silva, M. )

    1992-01-01

    A solvent extraction-spectrophotometric determination of trace amounts of ruthenium has been developed, based on the formation of an ion association complex of ruthenium (III) with 2,4,6-tris(2{prime}-pyridyl)-1,3,5-triazine as primary ligand and picrate as counter-ion; this complex is then extracted into 1,2-dichloroethane. The complex is formed at pH 2.0-7.0, upon heating at 90 C for 60 min, and the ruthenium concentration can be determined by measuring the absorbance directly in the organic phase. Beer's law is obeyed over the concentration range 1.0-10.0 {mu}g ml{sup {minus}1} corresponding to 0.050-0.500 {mu}g ml{sup {minus}1} of ruthenium in the aqueous solution. The apparent molar absorptivity and the Sandell's sensitivity were found to be 3.4 {center dot} 10{sup 5} 1 mol{sup {minus}1} cm{sup {minus}1} and 0.30 ng cm{sup {minus}2}, respectively. The interference of various ions was examined and the serious interferences from iron and other metals of the VIII group were minimized by employing the derivative spectrophotometric technique in conjunction with appropriate masking agents.

  3. Synthesis and catalytic water oxidation activities of ruthenium complexes containing neutral ligands.

    PubMed

    Xu, Yunhua; Duan, Lele; Åkermark, Torbjörn; Tong, Lianpeng; Lee, Bao-Lin; Zhang, Rong; Åkermark, Björn; Sun, Licheng

    2011-08-16

    Two dinuclear and one mononuclear ruthenium complexes containing neutral polypyridyl ligands have been synthesised as pre-water oxidation catalysts and characterised by (1)H and (13)C NMR spectroscopy and ESI-MS. Their catalytic water oxidation properties in the presence of [Ce(NH(4))(2)(NO(3))(6)] (Ce(IV)) as oxidant at pH 1.0 have been investigated. At low concentrations of Ce(IV) (5 mM), high turnover numbers of up to 4500 have been achieved. An (18)O-labelling experiment established that both O atoms in the evolved O(2) originate from water. Combined electrochemical study and electrospray ionisation mass spectrometric analysis suggest that ligand exchange between coordinated 4-picoline and free water produces Ru aquo species as the real water oxidation catalysts.

  4. Synergism and chemiluminescence of cerium ions and ruthenium complexes in the belousov-zhabotinskii reaction

    SciTech Connect

    Karavaev, A.D.; Kazakov, V.P.; Tolstikov, G.A.

    1986-04-01

    This paper studies chemiluminescence (CL) in the system BrO/sup -//sub 3/-CH/sub 2/ (COOH)/sub 2/ -Ce/sup 3 +/,4+-RuPbipy)/sub 3/ /SUP 2+,/ /sub 3/. The tests were carried out in a CL/sup 3/ unit that included a light-tight chamber, a photoelectron multiplier (FEU-97), a VS-22 high voltage power pack, and an EPPV-60M recording potentiometer. The synergism in chemiluminescence at low concentrations of ruthenium complex does not appear in the oscillation parameters. The periodic CL of this two-catalyst system may be a convenient chemical model for the study of combined chemical reactions in more complicated biochemiluminescent processes, such as that by which the firefly flashes in the dark.

  5. Redox-Active-Ligand-Mediated Formation of an Acyclic Trinuclear Ruthenium Complex with Bridging Nitrido Ligands.

    PubMed

    Bagh, Bidraha; Broere, Daniël L J; Siegler, Maxime A; van der Vlugt, Jarl Ivar

    2016-07-11

    Coordination of a redox-active pyridine aminophenol ligand to Ru(II) followed by aerobic oxidation generates two diamagnetic Ru(III) species [1 a (cis) and 1 b (trans)] with ligand-centered radicals. The reaction of 1 a/1 b with excess NaN3 under inert atmosphere resulted in the formation of a rare bis(nitrido)-bridged trinuclear ruthenium complex with two nonlinear asymmetrical Ru-N-Ru fragments. The spontaneous reduction of the ligand centered radical in the parent 1 a/1 b supports the oxidation of a nitride (N(3-) ) to half an equivalent of N2 . The trinuclear omplex is reactive toward TEMPO-H, tin hydrides, thiols, and dihydrogen. PMID:27321547

  6. Fast atom bombardment mass spectrometry of multiply charged polynuclear rhenium(I)-ruthenium(II) complexes

    SciTech Connect

    Argazzi, R., Bignozzi, C.A.; Bortolini, O. ); Traldi, P. )

    1993-03-31

    The fast atom bombardment (FAB) mass spectrometric behavior of some involatile polynuclear rhenium(I)-ruthenium(II) complexes of general formula [Re(CO)[sub 3](phen)(CN)-[Ru(bpy)[sub 2](CN)]n-Ru(bpy)[sub 2](CN)][sup (n+1)+] (n = 0-2, bpy = 2,2[prime]-bipyridine, phen = 1,10-phenanthroline) is presented. Singly, double, and, for n = 2, also triply charged ions were detected, and the fragmentation patterns of these ionic species were determined by studying unimolecular dissociation reactions. The decomposition pathways involve losses of CO and bpy neutral ligands, oxidative addition of coordinated bpy with expulsion of HX (X = CN[sup [minus

  7. Visible-Light-Responsive Photocatalytic Flow Reactor Composed of Titania Film Photosensitized by Metal Complex-Clay Hybrid.

    PubMed

    Goto, Takehito; Ogawa, Makoto

    2015-06-17

    Synthetic saponite containing a photosensitizing metal complex, tris(2,2'-bipyridine)ruthenium(II)), in the interlayer space was complexed with anatase nanoparticles to obtain transparent hybrid film photocatalyst. The catalyst film was mounted in a flow reactor device to catalyze such photocatalytic reactions as the decomposition of aqueous acetic acid and N-alkylation of benzylamine with ethanol. PMID:26029789

  8. Ruthenium Metal-Organic Frameworks with Different Defect Types: Influence on Porosity, Sorption, and Catalytic Properties.

    PubMed

    Zhang, Wenhua; Kauer, Max; Halbherr, Olesia; Epp, Konstantin; Guo, Penghu; Gonzalez, Miguel I; Xiao, Dianne J; Wiktor, Christian; LIabrés I Xamena, Francesc X; Wöll, Christof; Wang, Yuemin; Muhler, Martin; Fischer, Roland A

    2016-09-26

    By employing the mixed-component, solid-solution approach, various functionalized ditopic isophthalate (ip) defect-generating linkers denoted 5-X-ipH2 , where X=OH (1), H (2), NH2 (3), Br (4), were introduced into the mixed-valent ruthenium analogue of [Cu3 (btc)2 ]n (HKUST-1, btc=benzene-1,3,5-tricarboxylate) to yield Ru-DEMOFs (defect-engineered metal-organic frameworks) of the general empirical formula [Ru3 (btc)2-x (5-X-ip)x Yy ]n . Framework incorporation of 5-X-ip was confirmed by powder XRD, FTIR spectroscopy, ultrahigh-vacuum IR spectroscopy, thermogravimetric analysis, (1) H NMR spectroscopy, N2 sorption, and X-ray absorption near edge structure. Interestingly, Ru-DEMOF 1 c with 32 % framework incorporation of 5-OH-ip shows the highest BET surface area (≈1300 m(2)  g(-1) , N2 adsorption, 77 K) among all materials (including the parent framework [Ru3 (btc)2 Yy ]n ). The characterization data are consistent with two kinds of structural defects induced by framework incorporation of 5-X-ip: modified paddlewheel nodes featuring reduced ruthenium sites (Ru(δ+) , 0<δ<2, type A) and missing nodes leading to enhanced porosity (type B). Their relative abundances depend on the choice of the functional group X in the defect linkers. Defects A and B also appeared to play a key role in sorption of small molecules (i.e., CO2 , CO, H2 ) and the catalytic properties of the materials (i.e., ethylene dimerization and the Paal-Knorr reaction). PMID:27529415

  9. First ruthenium complex of glyoxalbis(N-phenyl)osazone (L(NHPh)H(2)): synthesis, x-ray structure, spectra, and density functional theory calculations of (L(NHPh)H(2))Ru(PPh(3))(2)Cl(2).

    PubMed

    Roy, Amit Saha; Tuononen, Heikki M; Rath, Sankar P; Ghosh, Prasanta

    2007-07-23

    The first ruthenium complex containing the parent osazone ligand, glyoxalbis(N-phenyl)osazone (L(NHPh)H(2)), is reported. The complex (L(NHPh)H(2))Ru(PPh(3))(2)Cl(2) (1) was characterized with mass, IR, (1)H NMR, and UV-vis spectroscopy as well as with theoretical calculations. Density functional theory calculations on the model compound (L(NHPh)H(2))Ru(PMe(3))(2)Cl(2) (2) reproduce the geometrical features observed for 1 and verify that it formally contains a ruthenium(II) metal center coordinated by a neutral osazone. Subsequent bonding analyses identify pi-interactions between the occupied orbitals of the metal fragment and the LUMO of the osazone, which results in transfer of approximately 0.3 electrons from the metal to the ligand. The complex 1 absorbs strongly at 405 nm, which is assigned to a ruthenium-to-ligand charge-transfer band on the basis of results of theoretical calculations. Complex 1 is also electroactive and displays a single one-electron oxidation wave at 0.39 V; coulometric oxidation gives the oxidized species [1]+ as a [PF(6)](-) salt. Simulation of the EPR spectra of [1][PF(6)], a one-electron paramagnetic species, affords g-tensor parameters g(x) = 2.2649, g(y) = 2.0560, and g(z) = 1.9064 consistent with a ruthenium(III) description for [1](+), thereby confirming a metal-centered redox reaction. PMID:17595075

  10. Preparation, spectroscopy, EXAFS, electrochemistry and pharmacology of new ruthenium(II) carbonyl complexes containing ferrocenylthiosemicarbazone and triphenylphosphine/arsine

    NASA Astrophysics Data System (ADS)

    Prabhakaran, R.; Anantharaman, S.; Thilagavathi, M.; Kaveri, M. V.; Kalaivani, P.; Karvembu, R.; Dharmaraj, N.; Bertagnolli, H.; Dallemer, F.; Natarajan, K.

    2011-02-01

    A new series of new hetero-bimetallic complexes containing iron and ruthenium of the general formula [RuCl(CO)(B)(EPh 3)(L)] (where E = P or As; B = PPh 3, AsPh 3, py or pip; L = ferrocene derived monobasic bidentate thiosemicarbazone ligand) have been synthesized by the reaction between ferrocene-derived thiosemicarbazones and ruthenium(II) complexes of the type [RuHCl(CO)(B)(EPh 3) 2] (where E = P or As; B = PPh 3, AsPh 3, py or pip). The new complexes have been characterized by elemental analyses, IR, electronic, NMR ( 1H, 13C and 31P), EXAFS (extended X-ray absorption fine structure spectroscopy) and cyclic voltammetric techniques. Antibacterial activity of the new complexes has been screened against Escherichia coli, Vibrio cholerae, and Pseudomonas aeruginosa species.

  11. A 2,2"-bipyridine ligand for incorporation into oligodeoxynucleotides: synthesis, stability and fluorescence properties of ruthenium-DNA complexes.

    PubMed

    Wiederholt, K; McLaughlin, L W

    1999-06-15

    A non-nucleoside linker based upon the ligand 2,2'-bipyridine and ethylene glycol is prepared and placed into the backbone of a number of oligonucleo-tides. The bipyridine ligand is reacted with cis -dichloro bis(2,2'-bipyridyl) Ru(II) to generate the relatively substitutionally inert complex based upon the well-characterized tris -2,2'-bipyridyl Ru(II). The ruthenium-containing DNA complexes exhibited UV and fluorescence characteristics that are consistent with those previously observed for simple tris -2,2'-bipyridyl Ru(II) complexes. Oligonucleotides containing the ruthenium complex will form both DNA duplexes and triplexes with stabilities that are slightly better than those formed from simple tethered oligonucleotide probes in which the two hybridizing sequences are tethered by simple tri(ethylene glycol) or hexa(ethylene glycol) linkers.

  12. Cyclometalated ruthenium(II) complexes as efficient redox mediators in peroxidase catalysis.

    PubMed

    Alpeeva, Inna S; Soukharev, Valentin S; Alexandrova, Larissa; Shilova, Nadezhda V; Bovin, Nicolai V; Csöregi, Elisabeth; Ryabov, Alexander D; Sakharov, Ivan Yu

    2003-07-01

    Cyclometalated ruthenium(II) complexes, [Ru(II)(C~N)(N~N)(2)]PF(6) [HC~N=2-phenylpyridine (Hphpy) or 2-(4'-tolyl)pyridine; N~N=2,2'-bipyridine, 1,10-phenanthroline, or 4,4'-dimethyl-2,2'-bipyridine], are rapidly oxidized by H(2)O(2) catalyzed by plant peroxidases to the corresponding Ru(III) species. The commercial isoenzyme C of horseradish peroxidase (HRP-C) and two recently purified peroxidases from sweet potato (SPP) and royal palm tree (RPTP) have been used. The most favorable conditions for the oxidation have been evaluated by varying the pH, buffer, and H(2)O(2) concentrations and the apparent second-order rate constants ( k(app)) have been measured. All the complexes studied are oxidized by HRP-C at similar rates and the rate constants k(app) are identical to those known for the best substrates of HRP-C (10(6)-10(7) M(-1) s(-1)). Both cationic (HRP-C) and anionic (SPP and RPTP) peroxidases show similar catalytic efficiency in the oxidation of the Ru(II) complexes. The mediating capacity of the complexes has been evaluated using the SPP-catalyzed co-oxidation of [Ru(II)(phpy)(bpy)(2)]PF(6) and catechol as a poor peroxidase substrate as an example. The rate of enzyme-catalyzed oxidation of catechol increases more than 10000-fold in the presence of the ruthenium complex. A simple routine for calculating the rate constant k(c) for the oxidation of catechol by the Ru(III) complex generated enzymatically from [Ru(II)(phpy)(bpy)(2)](+) is proposed. It is based on the accepted mechanism of peroxidase catalysis and involves spectrophotometric measurements of the limiting Ru(II) concentration at different concentrations of catechol. The calculated k(c) value of 0.75 M(-1) s(-1) shows that the cyclometalated Ru(II) complexes are efficient mediators in peroxidase catalysis. PMID:12774217

  13. A functional ruthenium(ii) complex for imaging biothiols in living bodies.

    PubMed

    Ye, Zhiqiang; Gao, Quankun; An, Xin; Song, Bo; Yuan, Jingli

    2015-05-01

    A unique ruthenium(ii) complex, [Ru(bpy)2(DNS-bpy)](PF6)2 [bpy: 2,2'-bipyridine, DNS-bpy: 4-(2,4-dinitrophenylthio)-2,2'-bipyridine], that can act as a probe for the recognition and luminescence sensing of biothiols has been designed and synthesized. Due to the presence of effective photo-induced electron transfer (PET) from the potent electron donor (Ru-bpy centre) to the strong electron acceptor (2,4-dinitrophenyl moiety), the Ru(ii) complex itself is weakly luminescent. Reaction of [Ru(bpy)2(DNS-bpy)](PF6)2 with biothiols leads to the replacement of the 2,4-dinitrophenyl moiety by biothiols, which results in the loss of PET within the complex, to allow recovery of the MLCT-based emission of the Ru(ii) complex with an 80-fold increase in luminescence intensity. Taking advantage of the high specificity and sensitivity, and the excellent photophysical properties of Ru(ii) complexes, [Ru(bpy)2(DNS-bpy)](PF6)2 was successfully applied to the luminescence imaging of biothiols in living Daphnia magna. The results demonstrated the practical applicability of [Ru(bpy)2(DNS-bpy)](PF6)2 as a luminescent probe for the monitoring of biothiols in living bodies.

  14. Rodlike bimetallic ruthenium and osmium complexes bridged by phenylene spacers. Synthesis, electrochemistry, and photophysics.

    PubMed

    Welter, Steve; Salluce, Nunzio; Benetti, Arianna; Rot, Nicolette; Belser, Peter; Sonar, Prashant; Grimsdale, Andrew C; Müllen, Klaus; Lutz, Martin; Spek, Anthony L; De Cola, Luisa

    2005-06-27

    In the search for light-addressable nanosized compounds we have synthesized 10 dinuclear homometallic trisbipyridyl complexes of linear structure with the general formula [M(bpy)3-BL-M(bpy)3]4+ [M = Ru(II) or Os(II); BL = polyphenylenes (2, 3, 4, or 5 units) or indenofluorene; bpy = 2,2'-bipyridine]. By using a "chemistry on the complex" approach, different sizes of rodlike systems have been obtained with a length of 19.8 and 32.5 A for the shortest and longest complex, respectively. For one of the ruthenium precursors, [Rubpy-ph2-Si(CH3)3][PF6]2, single crystals were obtained by recrystallization from methanol. Their photophysical and electrochemical properties are reported. All the compounds are luminescent both at room and low temperature with long excited-state lifetimes due to an extended delocalization. Nanosecond transient absorption showed that the lowest excited state involves the chelating unit attached to the bridging ligand. Electrochemical data indicated that the first reduction is at a slightly more positive potential than for the reference complexes [M(bpy)3]2+ (M = Ru, Os). This result confirms that the best acceptor is the bipyridine moiety connected to the conjugated spacers. The role of the tilt angle between the phenylene units, in the two series of complexes, for the ground and excited states is discussed.

  15. Density functional theory studies of interactions of ruthenium-arene complexes with base pair steps.

    PubMed

    Mutter, Shaun T; Platts, James A

    2011-10-20

    Density functional theory (DFT) calculations have been performed to determine the strength and geometry of intermolecular interactions of "piano-stool" ruthenium arene complexes, which show potential as anticancer treatments. Model complexes with methane and benzene indicate that the coordinated arene has C-H···π acceptor ability similar to that of free benzene, whereas this arene acts as a much stronger C-H donor or partner in π-stacking than free benzene. The source of these enhanced interactions is identified as a combination of electrostatic and dispersion effects. Complexes of Ru-arene complexes with base-pair step fragments of DNA, in which the arene has the potential to act as an intercalator, have also been investigated. Binding energies are found to be sensitive to the size and nature of the arene, with larger and more flexible arenes having stronger binding. π-stacking and C-H···π interactions between arene and DNA bases and hydrogen bonds from coordinated N-H to DNA oxygen atoms, as well as covalent Ru-N bonding, contribute to the overall binding. The effect of complexation on DNA structure is also examined, with larger rise and more negative slide values than canonical B-DNA observed in all cases.

  16. Electrocatalytic and photocatalytic conversion of CO(2) to methanol using ruthenium complexes with internal pyridyl cocatalysts.

    PubMed

    Boston, David J; Pachón, Yeimi M Franco; Lezna, Reynaldo O; de Tacconi, N R; MacDonnell, Frederick M

    2014-07-01

    The ruthenium complexes [Ru(phen)2(ptpbα)](2+) (Ruα) and [Ru(phen)2(ptpbβ)](2+) (Ruβ), where phen =1,10-phenanthroline ; ptpbα = pyrido[2',3':5,6]pyrazino[2,3-f][1,10]phenanthroline; ptpbβ = pyrido[3',4':5,6]pyrazino[2,3-f][1,10]phenanthroline, are shown as electrocatalysts and photocatalysts for CO2 reduction to formate, formaldehyde, and methanol. Photochemical activity of both complexes is lost in water but is retained in 1 M H2O in DMF. Controlled current electrolysis of a solution of Ruβ in CO2 saturated DMF:H2O (1 M) yields predominantly methanol over a 6 h period at ∼ -0.60 V versus Ag/AgCl, with traces of formaldehyde. After this time, the potential jumped to -1.15 V producing both methanol and CO as products. Irradiation of Ruβ in a solution of DMF:H2O (1 M) containing 0.2 M TEA (as the sacrificial reductant) yields methanol, formaldehyde, and formate. Identifications of all of the relevant redox and protonated states of the respective complexes were obtained by a combination of voltammetry and differential reflectance measurements. Spectroelectrochemistry was particularly useful to probe the photochemical and electrochemical reduction mechanisms of both complexes as well as the complexes speciation in the absence and presence of CO2. PMID:24909055

  17. Electronic Spectra of TRIS(2,2'-BIPYRIDINE)-METAL Complex Ions in Gas Phase

    NASA Astrophysics Data System (ADS)

    Xu, Shuang; Smith, James E. T.; Weber, J. Mathias

    2016-06-01

    Tris(bpy)-metal complexes (bpy = 2,2'-bipyridine) and their derivatives are important systems in metal-organic chemistry. While tris(bpy)-ruthenium, Ru(bpy)32+, has been extensively studied, less attention has been paid to analogous complexes involving first row transition metals. Here we report the electronic spectra of a series of dicationic tris(bpy) chelates with different transition metals, measured by photodisscociation spectroscopy of cryogenically prepared ions. We focus our attention on the π-π* transitions in the UV region of the spectrum.

  18. Ruthenium(II)-Schiff base complexes derived from substituted salicylaldimines and triphenylphosphine

    SciTech Connect

    Armando, M.B.; Lena, R.R.; Rafael, M.E.; Federico, D.R.P.J.

    1993-12-31

    Synthesis and characterization of a series of octahedral ruthenium(II) Schiff base complexes obtained from the interaction of RuCl{sub 2}(PPh{sub 3}){sub 3} with N,N{prime}-ethylene-bis-(5-R-salicylideneimine) are presented. Redox properties and the stability towards oxidation of [Ru(II)(5R-sal{sub 2}en)(PPh{sub 3}){sub 2}] complexes, (R = H-(1), Cl-(2), Br-(3), CH{sub 3}O-(4), NO{sub 2}-(5)) were related to the electron-withdrawing or releasing ability of the substituent in the phenyl ring of the Schiff base. Results show that electron-withdrawing substituents stabilize Ru(II) complexes, while electron-donating groups favour oxidation to Ru(III). Changes in E{sub 1/2} for the complexes, due to remote substituent effects, could be related to changes in basicity of the phenolic oxygen. This variation has more influence on E{sub 1/2} than changes in basicity of the phosphorus in the phosphine ligand. 32 refs., 7 figs., 3 tabs.

  19. From 0 to II in One-Electron Steps: A Series of Ruthenium Complexes Supported by TropPPh2.

    PubMed

    Yang, Xiuxiu; Gianetti, Thomas L; Harbort, Joshua; Wörle, Michael D; Tan, Lilin; Su, Cheng-Yong; Jurt, Pascal; Harmer, Jeffrey R; Grützmacher, Hansjörg

    2016-09-19

    We report the synthesis of a series of ruthenium complexes supported by the phosphine olefin ligand tropPPh2 (trop=5-H-dibenzo-[a,d]cyclohepten-5-yl) in the oxidation states 0, +I, and +II, formed via successive one-electron oxidization steps from Ru(0) (tropPPh2 )2 . The bidentate character of the tropPPh2 ligand and its steric hindrance force the complexes to adopt uncommon geometries, which were investigated by X-ray diffraction analysis. EPR data of the mononuclear Ru(I) complex reveal couplings of the unpaired spin with the ruthenium and two phosphorus nuclei, as well as the olefinic protons which show that the spin is mainly localized on the Ru(I) center. PMID:27557780

  20. Novel 4'-functionalized 4,4''-dicarboxyterpyridine ligands for ruthenium complexes: near-IR sensitization in dye sensitized solar cells.

    PubMed

    Koyyada, Ganesh; Botla, Vinayak; Thogiti, Suresh; Wu, Guohua; Li, Jingzhe; Fang, Xiaqin; Kong, Fantai; Dai, Songyuan; Surukonti, Niveditha; Kotamarthi, Bhanuprakash; Malapaka, Chandrasekharam

    2014-10-28

    Novel ruthenium complexes (MC113-MC117), obtained by modifying the terpyridine ligand of the black dye (N749), have been evaluated as sensitizers for dye sensitized solar cells (DSSCs). The modification is carried out by attaching selected chromophores, with varying electron donating strength, covalently to the central ring of the ligand. The complexes, compared to the parent dye, show red shifted absorption covering visible and near IR regions and higher molar extinction coefficients. We report in this work synthesis of a series of these ruthenium complexes with chromophores such as tert-butyl phenyl, triphenylamine, bithiophene, phenoxazine and phenothiazine. Detailed experimental characterization using optical, electrochemical and photovoltaic techniques has been carried out and complemented by density functional theory studies. The fill factors (ff) obtained for these dyes are larger than those of the parent black dye. In spite of these superior properties, the dyes show only moderate to good power conversion efficiencies. The possible reasons for this have been investigated and discussed.

  1. Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

    NASA Astrophysics Data System (ADS)

    Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Ahmad, Haslina; Heng, Lee Yook; Karim, Nurul Huda Abd; Harun, Siti Norain

    2014-09-01

    A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy)2(PIP)]2+, (bpy = 2,2'bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy)2(PIP)]2+ was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy)2(PIP)]2+ with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.

  2. A dinuclear ruthenium(II) complex as turn-on luminescent probe for hypochlorous acid and its application for in vivo imaging

    PubMed Central

    Liu, Zonglun; Gao, Kuo; Wang, Beng; Yan, Hui; Xing, Panfei; Zhong, Chongmin; Xu, Yongqian; Li, Hongjuan; Chen, Jianxin; Wang, Wei; Sun, Shiguo

    2016-01-01

    A dinuclear ruthenium(II) complex Ruazo was designed and synthesized, in which oxidative cyclization of the azo and o-amino group was employed for the detection of hypochlorous acid (HClO) in aqueous solution. The non-emissive Ruazo formed highly luminescent triazole-ruthenium(II) complex in presence of HClO and successfully imaged HClO in living cell and living mouse. PMID:27356618

  3. A dinuclear ruthenium(II) complex as turn-on luminescent probe for hypochlorous acid and its application for in vivo imaging

    NASA Astrophysics Data System (ADS)

    Liu, Zonglun; Gao, Kuo; Wang, Beng; Yan, Hui; Xing, Panfei; Zhong, Chongmin; Xu, Yongqian; Li, Hongjuan; Chen, Jianxin; Wang, Wei; Sun, Shiguo

    2016-06-01

    A dinuclear ruthenium(II) complex Ruazo was designed and synthesized, in which oxidative cyclization of the azo and o-amino group was employed for the detection of hypochlorous acid (HClO) in aqueous solution. The non-emissive Ruazo formed highly luminescent triazole-ruthenium(II) complex in presence of HClO and successfully imaged HClO in living cell and living mouse.

  4. Ruthenium Polypyridyl Complex Inhibits Growth and Metastasis of Breast Cancer Cells by Suppressing FAK signaling with Enhancement of TRAIL-induced Apoptosis

    NASA Astrophysics Data System (ADS)

    Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng

    2015-03-01

    Ruthenium-based complexes have emerged as promising antitumor and antimetastatic agents during the past decades. However, the limited understanding of the antimetastatic mechanisms of these agents is a roadblock to their clinical application. Herein, we reported that, RuPOP, a ruthenium polypyridyl complex with potent antitumor activity, was able to effectively inhibit growth and metastasis of MDA-MB-231 cells and synergistically enhance TRAIL-induced apoptosis. The selective intracellular uptake and cytotoxic effect of RuPOP was found associated with transferring receptor (TfR)-mediated endocytosis. Further investigation on intracellular mechanisms reveled that RuPOP notably suppressed FAK-mediated ERK and Akt activation. Pretreatment of cells with ERK inhibitor (U0126) and PI3K inhibitor (LY294002) significantly potentiated the inhibitory effect of RuPOP on cell growth, migration and invasion. Moreover, the alternation in the expression levels of metastatic regulatory proteins, including uPA, MMP-2/-9, and inhibition of VEGF secretion were also observed after RuPOP treatment. These results demonstrate the inhibitory effect of RuPOP on the growth and metastasis of cancer cells and the enhancement of TRAIL-induced apoptosis though suppression of FAK-mediated signaling. Furthermore, RuPOP exhibits the potential to be developed as a metal-based antimetastatic agent and chemosensitizer of TRAIL for the treatment of human metastatic cancers.

  5. Biophysical studies of a ruthenium(II) polypyridyl complex binding to DNA and RNA prove that nucleic acid structure has significant effects on binding behaviors.

    PubMed

    Xu, Hong; Liang, Yi; Zhang, Peng; Du, Fen; Zhou, Bing-Rui; Wu, Jun; Liu, Jian-Hong; Liu, Zhi-Gang; Ji, Liang-Nian

    2005-08-01

    The interactions of a metal complex [Ru(phen)(2)PMIP](2+) {Ru=ruthenium, phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)imidazo[4,5-f]1,10-phenanthroline} with yeast tRNA and calf thymus DNA (CT DNA) have been investigated comparatively by UV-vis spectroscopy, fluorescence spectroscopy, viscosity measurements, isothermal titration calorimetry (ITC), as well as equilibrium dialysis and circular dichroism (CD). Spectroscopic studies together with ITC and viscosity measurements indicate that both binding modes of the Ru(II) polypyridyl complex to yeast tRNA and CT DNA are intercalation and yeast tRNA binding of the complex is stronger than CT DNA binding. ITC experiments show that the interaction of the complex with yeast tRNA is driven by a moderately favorable enthalpy decrease in combination with a moderately favorable entropy increase, while the binding of the complex to CT DNA is driven by a large favorable enthalpy decrease with a less favorable entropy increase. The results from equilibrium dialysis and CD suggest that both interactions are enantioselective and the Delta enantiomer of the complex may bind more favorably to both yeast tRNA and CT DNA than the Lambda enantiomer does, and that the complex is a better candidate for an enantioselective binder to yeast tRNA than to CT DNA. Taken together, these results indicate that the structures of nucleic acids have significant effects on the binding behaviors of metal complexes.

  6. Poly(fluoroalkyl acrylate)-bound ruthenium carbene complex: a fluorous and recyclable catalyst for ring-closing olefin metathesis.

    PubMed

    Yao, Qingwei; Zhang, Yiliang

    2004-01-14

    The synthesis of a fluorous olefin metathesis catalyst derived from the Grubbs second-generation ruthenium carbene complex is described. The air stable fluorous polymer-bound ruthenium carbene complex 1 shows high reactivity in effecting the ring-closing metathesis of a broad spectrum of diene and enyne substrates leading to the formation of di-, tri-, and tetrasubstituted cyclic olefins in minimally fluorous solvent systems (PhCF3/CH2Cl2, 1:9-1:49 v/v). The catalyst can be readily separated from the reaction mixture by fluorous extraction with FC-72 and repeatedly reused. The practical advantage offered by the fluorous catalyst is demonstrated by its sequential use in up to five different metathesis reactions. PMID:14709066

  7. Poly(fluoroalkyl acrylate)-bound ruthenium carbene complex: a fluorous and recyclable catalyst for ring-closing olefin metathesis.

    PubMed

    Yao, Qingwei; Zhang, Yiliang

    2004-01-14

    The synthesis of a fluorous olefin metathesis catalyst derived from the Grubbs second-generation ruthenium carbene complex is described. The air stable fluorous polymer-bound ruthenium carbene complex 1 shows high reactivity in effecting the ring-closing metathesis of a broad spectrum of diene and enyne substrates leading to the formation of di-, tri-, and tetrasubstituted cyclic olefins in minimally fluorous solvent systems (PhCF3/CH2Cl2, 1:9-1:49 v/v). The catalyst can be readily separated from the reaction mixture by fluorous extraction with FC-72 and repeatedly reused. The practical advantage offered by the fluorous catalyst is demonstrated by its sequential use in up to five different metathesis reactions.

  8. Highly efficient electrochemical responses on single crystalline ruthenium-vanadium mixed metal oxide nanowires.

    PubMed

    Chun, Sung Hee; Choi, Hyun-A; Kang, Minkyung; Koh, Moonjee; Lee, Nam-Suk; Lee, Sang Cheol; Lee, Minyung; Lee, Youngmi; Lee, Chongmok; Kim, Myung Hwa

    2013-09-11

    Highly efficient single crystalline ruthenium-vanadium mixed metal oxide (Ru1-xVxO2, 0≤x≤1) nanowires were prepared on a SiO2 substrate and a commercial Au microelectrode for the first time through a vapor-phase transport process by adjusting the mixing ratios of RuO2 and VO2 precursors. Single crystalline Ru1-xVxO2 nanowires show homogeneous solid-solution characteristics as well as the distinct feature of having remarkably narrow dimensional distributions. The electrochemical observations of a Ru1-xVxO2 (x=0.28 and 0.66)-decorated Au microelectrode using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrate favorable charge-transfer kinetics of [Fe(CN)6]3-/4- and Ru(NH3)6(3+/2+) couples compared to that of a bare Au microelectrode. The catalytic activity of Ru1-xVxO2 for oxygen and H2O2 reduction at neutral pH increases as the fraction of vanadium increases within our experimental conditions, which might be useful in the area of biofuel cells and biosensors.

  9. Multifunctional, defect-engineered metal-organic frameworks with ruthenium centers: sorption and catalytic properties.

    PubMed

    Kozachuk, Olesia; Luz, Ignacio; Llabrés i Xamena, Francesc X; Noei, Heshmat; Kauer, Max; Albada, H Bauke; Bloch, Eric D; Marler, Bernd; Wang, Yuemin; Muhler, Martin; Fischer, Roland A

    2014-07-01

    A mixed-linker solid-solution approach was employed to modify the metal sites and introduce structural defects into the mixed-valence Ru(II/III) structural analogue of the well-known MOF family [M3(II,II)(btc)2] (M=Cu, Mo, Cr, Ni, Zn; btc=benzene-1,3,5-tricarboxylate), with partly missing carboxylate ligators at the Ru2 paddle-wheels. Incorporation of pyridine-3,5-dicarboxylate (pydc), which is the same size as btc but carries lower charge, as a second, defective linker has led to the mixed-linker isoreticular derivatives of Ru-MOF, which display characteristics unlike those of the defect-free framework. Along with the creation of additional coordinatively unsaturated sites, the incorporation of pydc induces the partial reduction of ruthenium. Accordingly, the modified Ru sites are responsible for the activity of the "defective" variants in the dissociative chemisorption of CO2, the enhanced performance in CO sorption, the formation of hydride species, and the catalytic hydrogenation of olefins. PMID:24838592

  10. Studies of the Antiproliferative Activity of Ruthenium (II) Cyclopentadienyl-Derived Complexes with Nitrogen Coordinated Ligands

    PubMed Central

    Moreno, Virtudes; Lorenzo, Julia; Aviles, Francesc X.; Garcia, M. Helena; Ribeiro, João P.; Morais, Tânia S.; Florindo, Pedro; Robalo, M. Paula

    2010-01-01

    Four cationic ruthenium(II) complexes with the formula [Ru(η5-C5H5)(PPh3)2]+, with L = 5-phenyl-1H-tetrazole (TzH) 1, imidazole (ImH) 2, benzo[1,2-b;4,3-b′] dithio-phen-2-carbonitrile (Bzt) 3, and [5-(2-thiophen-2-yl)-vinyl]-thiophene-2-carbonitrile] (Tvt) 4 were prepared and characterized in view to evaluate their potentialities as antitumor agents. Studies by Circular Dichroism indicated changes in the secondary structure of ct-DNA. Changes in the tertiary structure of pBR322 plasmid DNA were also observed in gel electrophoresis experiment and the images obtained by atomic force microscopy (AFM) suggest strong interaction with pBR322 plasmid DNA; the observed decreasing of the viscosity with time indicates that the complexes do not intercalate between DNA base pairs. Compounds 1, 2, and 3 showed much higher cytotoxicity than the cisplatin against human leukaemia cancer cells (HL-60 cells). PMID:20689715

  11. Studies of the Antiproliferative Activity of Ruthenium (II) Cyclopentadienyl-Derived Complexes with Nitrogen Coordinated Ligands.

    PubMed

    Moreno, Virtudes; Lorenzo, Julia; Aviles, Francesc X; Garcia, M Helena; Ribeiro, João P; Morais, Tânia S; Florindo, Pedro; Robalo, M Paula

    2010-01-01

    Four cationic ruthenium(II) complexes with the formula [Ru(eta(5)-C(5)H(5))(PPh(3))(2)](+), with L = 5-phenyl-1H-tetrazole (TzH) 1, imidazole (ImH) 2, benzo[1,2-b;4,3-b'] dithio-phen-2-carbonitrile (Bzt) 3, and [5-(2-thiophen-2-yl)-vinyl]-thiophene-2-carbonitrile] (Tvt) 4 were prepared and characterized in view to evaluate their potentialities as antitumor agents. Studies by Circular Dichroism indicated changes in the secondary structure of ct-DNA. Changes in the tertiary structure of pBR322 plasmid DNA were also observed in gel electrophoresis experiment and the images obtained by atomic force microscopy (AFM) suggest strong interaction with pBR322 plasmid DNA; the observed decreasing of the viscosity with time indicates that the complexes do not intercalate between DNA base pairs. Compounds 1, 2, and 3 showed much higher cytotoxicity than the cisplatin against human leukaemia cancer cells (HL-60 cells).

  12. New π-arene ruthenium(II) piano-stool complexes with nitrogen ligands.

    PubMed

    Grau, Jordi; Noe, Verónica; Ciudad, Carles; Prieto, Maria J; Font-Bardia, Mercè; Calvet, Teresa; Moreno, Virtudes

    2012-04-01

    The synthesis, characterization, DNA interaction and antiproliferative behavior of new π-arene ruthenium(II) piano-stool complexes with nitrogen ligands are described. Three series of organometallic compounds of formulae [RuCl(2)(η(6)-p-cym)L] were synthesized (with L=2-, 3- or 4-methylpyridine; L=2,3-, 2,4-, 2,5-, 3,4-, 3,5-dimethylpyridine and L=1,2-, 1,3- 1,4-methylaminobenzene). The crystal structures of [RuCl(2)(p-cym)(4-methylpyridine)], [RuCl(2)(p-cym)(3,4-dimethylpyridine)] and [RuCl(2)(p-cym)(1,4-methylaminobenzene)] were resolved and the characterization was completed by spectroscopic UV-vis, FT-IR and (1)H NMR studies. Electrochemical experiments were performed by cyclic voltammetry to estimate the redox potential of the Ru(II)/Ru(III) couple. The interaction with plasmid pBR322 DNA was studied through the examination of the electrophoretical mobility and atomic force microscopy, and interaction with ct-DNA by circular dichroism, viscosity measurements and fluorescence studies based on the DNA-ethidium bromide complex. The antiproliferative behavior of the series with L=methylpyridine was assayed against two tumor cell lines, i.e. LoVo and MiaPaca. The results revealed a moderate cytotoxicity with a higher activity for the LoVo cell line compared to the MiaPaca one. PMID:22387934

  13. Mutual effect of ligands in nitrido and nitroso complexes of osmium and ruthenium from NQR data

    SciTech Connect

    Kravchenko. E.A.; Burtsev, M.Yu.; Sinitsyn, M.N.; Svetlov, A.A.; Kokunov, Ya.V.; Buslaev, A.

    1987-11-01

    The purpose of this investigation was to study by NQR the spectral results of the mutual ligand effect in complex compounds having various types of short bonds. The authors obtained the /sup 35/Cl, /sup 81/Br, and /sup 127/I NQR spectra of a large number of halogen complexes of osmium and ruthenium having short Os=N and M in equilibrium NO bonds of the following types: R(OsNHal/sub 4/) (R = (Ph/sub 4/P)/sup +/, (Bu/sub 4/N)/sup +/; Hal = Cl/sup -/, Br/sup -/, I/sup -/), K/sub 2/(OsNCl/sub 5/), Rb/sub 2/(OsNBr/sub 5/), (NH/sub 4/)/sub 2/(OsNBr/sub 5/), K(OsNHal/sub 4/L) (Hal = Cl/sup -/, Br/sup -/; L = H/sub 2/O, CH/sub 3/CN), K/sub 2/(MNOHal/sub 5/) (M = Os, Ru; Hal = Cl/sup -/, Br/sup -/, I/sup -/). The experimental NQR values measured are connected by the Townes and Dailey theory with the chemical bond characteristics i, sigma, ..pi.., the degree of the ionic, the sigma-covalent, and the ..pi..-covalent natures respectively ( i + sigma + ..pi.. = 1).

  14. A theoretical study of ruthenium complexes with 2,2'-biimidazole-like ligands: structural, optical and emissive properties.

    PubMed

    Xia, Shu-Hua; Fang, Wei-Hai; Cui, Ganglong; Daniel, Chantal

    The structural and optical properties of five ruthenium complexes, recently synthesized for their photooxidative and photophysical properties, have been studied by means of density functional theory (DFT) and time-dependent DFT (TD-DFT). The structures of [Ru(bpy)2(BiimH2)](2+) (bpy = 2,2'-bipyridine; BiimH2 = 2,2'-biimidazole) 1, [Ru(bpy)2(TMBiimH2)](2+) (TM BiimH2 = 4,5,4',5'-tetramethyl-2,2'-biimidazole) 5, [Ru(bpy)2(L1H2)](2+) (L1H2 = 4,5-dimethyl-2(N,N-diacetyl)(carboximidamide-1H-imidazole)) 6, [Ru(bpy)2(L2H2)](2+) (L2H2 = N(1),N(1),N(2),N(2)-tetrakis(acetyl)ethanediimidamide) 7 and [Ru(phen)2(TMBiimH2)](2+) (phen = 1,10'-phenanthroline) 8 have been fully optimized in the electronic ground state as well as in the lowest triplet T1 excited state. The theoretical absorption spectra of the five complexes that compare rather well with the experimental spectra have been analyzed on the basis of TD-DFT calculations without and with spin-orbit coupling (SOC). The deprotonated form [Ru(bpy)2(L2H)](+)7d contributes mostly to the experimental absorption spectrum of complex 7. The spectra of all molecules are characterized by the presence of low-lying metal-to-ligand charge transfer (MLCT) excited states between 500 and 400 nm, ligand-centered (LC) excited states on the biimidazole-like ligands between 350 and 300 nm and on the bpy ligands between 300 and 250 nm. The theoretical emission wavelengths deduced from the lowest triplet T1 properties calculated at 661 nm (1), 690 nm (5) and 660 nm (8) reproduce the experimental emission spectra of these molecules characterized by a maximum at 638 nm (1), 646 nm (5) and 652 nm (8). In contrast the low theoretical emission wavelengths (>1000 nm) obtained for complexes 6, 7 and 7d favorable to non-radiative decays explain the low intensity of the experimental emission spectra of these two complexes. The SOC is of little effect in this class of molecules where metal-centered (MC) excited states do not perturb the lowest part of

  15. A novel ruthenium(II)-cobaloxime supramolecular complex for photocatalytic H2 evolution: Synthesis, characterisation, and mechanistic studies

    PubMed Central

    Cropek, Donald M.; Metz, Anja; Müller, Astrid M.; Gray, Harry B.; Horne, Toyketa; Horton, Dorothy C.; Poluektov, Oleg; Tiede, David M.; Weber, Ralph T.; Jarrett, William L.; Phillips, Joshua D.

    2012-01-01

    We report the synthesis and characterization of novel mixed-metal binuclear ruthenium(II)-cobalt(II) photocatalysts for hydrogen evolution in acidic acetonitrile. First, 2-(2′-pyridyl)benzothiazole (pbt), 1, was reacted with RuCl3·xH2O to produce [Ru(pbt)2Cl2] ·0.25CH3COCH3, 2, which was then reacted with 1,10-phenanthroline-5,6-dione (phendione), 3 in order to produce [Ru(pbt)2(phendione)](PF6)2·4H2O, 4. Compound 4 was then reacted with 4-pyridinecarboxaldehyde in order to produce [Ru(pbt)2(L-pyr)](PF6)2·9.5H2O, 5 (where L-pyr = (4-pyridine)oxazolo[4,5-f]phenanthroline). Compound 5 was then reacted with [Co(dmgBF2)2(H2O)2] (where dmgBF2 = difluorboryldimethylglyoximate) in order to produce the mixed-metal binuclear complex, [Ru(pbt)2(L-pyr)Co(dmgBF2)2(H2O)](PF6)2·11H2O·1.5CH3COCH3, 6. [Ru(Me2bpy)2(L-pyr)Co(dmgBF2)2(OH2)](PF6)2, 7 (where Me2bpy = 1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine) and [Ru(phen)2(L-pyr)Co(dmgBF2)2(OH2)](PF6)2, 8 were also synthesised. All complexes were characterized by elemental analysis, UV-visible absorption, 11B, 19F, and 59Co NMR, ESR spectroscopy, and cyclic voltammetry, where appropriate. Photocatalytic studies carried out in acidified acetonitrile demonstrated constant hydrogen generation longer than a 42 hour period as detected by gas chromatography. Time resolved spectroscopic measurements were performed on compound 6, which proved an intramolecular electron transfer from an excited Ru(II) metal centre to the Co(II) metal centre via the bridging L-pyr ligand. This resulted in the formation of a cobalt(I)-containing species that is essential for the production of H2 gas in the presence of H+ ions. A proposed mechanism for the generation of hydrogen is presented. PMID:23001132

  16. Photochemical reactions of metal nitrosyl complexes. Mechanisms of NO reactions with biologically relevant metal centers

    DOE PAGES

    Ford, Peter C.

    2001-01-01

    Tmore » he discoveries that nitric oxide (a.k.a. nitrogen monoxide) serves important roles in mammalian bioregulation and immunology have stimulated intense interest in the chemistry and biochemistry of NO and derivatives such as metal nitrosyl complexes. Also of interest are strategies to deliver NO to biological targets on demand. One such strategy would be to employ a precursor which displays relatively low thermal reactivity but is photochemically active to release NO.his proposition led us to investigate laser flash and continuous photolysis kinetics of nitrosyl complexes such as the Roussin's iron-sulfur-nitrosyl cluster anions Fe 2 S 2 ( NO ) 4 2 − and Fe 4 S 3 ( NO ) 7 − and several ruthenium salen and porphyrin nitrosyls.hese include studies using metal-nitrosyl photochemistry as a vehicle for delivering NO to hypoxic cell cultures in order to sensitize γ -radiation damage. Also studied were the rates and mechanisms of NO “on” reactions with model water soluble heme compounds, the ferriheme protein met-myoglobin and various ruthenium complexes using ns laser flash photolysis techniques. An overview of these studies is presented.« less

  17. Monometallic osmium(II) complexes with bis(N-methylbenzimidazolyl)benzene or -pyridine: a comparison study with ruthenium(II) analogues.

    PubMed

    Shao, Jiang-Yang; Zhong, Yu-Wu

    2013-06-01

    Seven bis-tridentate osmium complexes with Mebib or Mebip (Mebib is the 2-deprotonated form of 1,3-bis(N-methylbenzimidazolyl)benzene and Mebip is bis(N-methylbenzimidazolyl)pyridine) have been prepared, and their electrochemical and spectroscopic properties are compared with ruthenium structural analogues. Among them, four complexes have the [Os(NCN)(NNN)]-type coordination, including [Os(Mebib)(Mebip)](PF6)2 (1(PF6)2), [Os(dpb)(Mebip)](PF6) (2(PF6), dpb is the 2-deprotonated form of 1,3-di(pyrid-2-yl)benzene), [Os(Mebib)(ttpy)](PF6) (3(PF6), ttpy = 4'-tolyl-2,2':6',2"-terpyridine), and [Os(dpb)(ttpy)](PF6) (4(PF6)). The other three complexes are [Os(Mebip)2](PF6)2 (5(PF6)2), [Os(Mebip)(tpy)](PF6)2 (6(PF6)2, tpy = 2,2':6',2"-terpyridine), and [Os(ttpy)2](PF6)2 (7(PF6)2) with the [Os(NNN)(NNN)]-type coordination. Single crystals of 2(PF6) and 6(PF6)2 have been obtained, and their structures are studied by X-ray crystallographic analysis. The Os(II/III) redox potentials of 1(PF6)2 to 7(PF6)2 progressively increase from +0.04, +0.23, +0.24, +0.36, +0.56, +0.79 to +0.94 V vs Ag/AgCl, which are 200-300 mV less positive relative to the Ru(II/III) potentials of their ruthenium counterparts. The highest occupied molecular orbital energy levels of 1(+)-7(2+) are calculated to vary in a descending order. The ruthenium and osmium complexes have singlet metal-to-ligand charge-transfer (MLCT) transitions of similar energies and band shapes, while the osmium complexes display additional (3)MLCT transitions in the lower-energy region. Complexes 6(PF6)2 and 7(PF6)2 emit weakly at 780 and 740 nm, respectively. Complex 1(PF6)2 was synthesized as the oxidized Os(III) salt because of the low Os(II/III) potential. The transformation of 1(2+) to 1(+) by chemical reduction or electrolysis led to the emergence of the (1)MLCT transitions in the visible region.

  18. Superior Light-Harvesting Heteroleptic Ruthenium(II) Complexes with Electron-Donating Antennas for High Performance Dye-Sensitized Solar Cells.

    PubMed

    Chen, Wang-Chao; Kong, Fan-Tai; Li, Zhao-Qian; Pan, Jia-Hong; Liu, Xue-Peng; Guo, Fu-Ling; Zhou, Li; Huang, Yang; Yu, Ting; Dai, Song-Yuan

    2016-08-01

    Three heteroleptic polypyridyl ruthenium complexes, RC-41, RC-42, and RC-43, with efficient electron-donating antennas in the ancillary ligands were designed, synthesized, and characterized as sensitizers for dye-sensitized solar cell. All the RC dye sensitizers showed remarkable light-harvesting capacity and broadened absorption range. Significantly, RC-43 obtained the lower energy metal-ligand charge transfer (MLCT) band peaked at 557 nm with a high molar extinction coefficient of 27 400 M(-1) cm(-1). In conjunction with TiO2 photoanode of submicrospheres and iodide-based electrolytes, the DSSCs sensitizing with the RC sensitizers, achieved impressively high short-circuit current density (19.04 mA cm(-2) for RC-41, 19.83 mA cm(-2) for RC-42, and 20.21 mA cm(-2) for RC-43) and power conversion efficiency (10.07% for RC-41, 10.52% for RC-42, and 10.78% for RC-43). The superior performances of RC dye sensitizers were attributed to the enhanced light-harvesting capacity and incident-photon-to-current efficiency (IPCE) caused by the introduction of electron-donating antennas in the ancillary ligands. The interfacial charge recombination/regeneration kinetics and electron lifetime were further evaluated by the electrochemical impedance spectroscopy (EIS) and transient absorption spectroscopy (TAS). These data decisively revealed the dependences on the photovoltaic performance of ruthenium sensitizers incorporating electron-donating antennas. PMID:27409513

  19. Superior Light-Harvesting Heteroleptic Ruthenium(II) Complexes with Electron-Donating Antennas for High Performance Dye-Sensitized Solar Cells.

    PubMed

    Chen, Wang-Chao; Kong, Fan-Tai; Li, Zhao-Qian; Pan, Jia-Hong; Liu, Xue-Peng; Guo, Fu-Ling; Zhou, Li; Huang, Yang; Yu, Ting; Dai, Song-Yuan

    2016-08-01

    Three heteroleptic polypyridyl ruthenium complexes, RC-41, RC-42, and RC-43, with efficient electron-donating antennas in the ancillary ligands were designed, synthesized, and characterized as sensitizers for dye-sensitized solar cell. All the RC dye sensitizers showed remarkable light-harvesting capacity and broadened absorption range. Significantly, RC-43 obtained the lower energy metal-ligand charge transfer (MLCT) band peaked at 557 nm with a high molar extinction coefficient of 27 400 M(-1) cm(-1). In conjunction with TiO2 photoanode of submicrospheres and iodide-based electrolytes, the DSSCs sensitizing with the RC sensitizers, achieved impressively high short-circuit current density (19.04 mA cm(-2) for RC-41, 19.83 mA cm(-2) for RC-42, and 20.21 mA cm(-2) for RC-43) and power conversion efficiency (10.07% for RC-41, 10.52% for RC-42, and 10.78% for RC-43). The superior performances of RC dye sensitizers were attributed to the enhanced light-harvesting capacity and incident-photon-to-current efficiency (IPCE) caused by the introduction of electron-donating antennas in the ancillary ligands. The interfacial charge recombination/regeneration kinetics and electron lifetime were further evaluated by the electrochemical impedance spectroscopy (EIS) and transient absorption spectroscopy (TAS). These data decisively revealed the dependences on the photovoltaic performance of ruthenium sensitizers incorporating electron-donating antennas.

  20. Dinuclear Ruthenium Complex Based on a π-Extended Bridging Ligand with Redox-Active Tetrathiafulvalene and 1,10-Phenanthroline Units.

    PubMed

    Chen, Bin; Lv, Zhong-Peng; Hua, Carol; Leong, Chanel F; Tuna, Floriana; D'Alessandro, Deanna M; Collison, David; Zuo, Jing-Lin

    2016-05-01

    The synthesis of a π-extended bridging ligand with both redox-active tetrathiafulvalene (TTF) and 1,10-phenanthroline (phen) units, namely, bis(1,10-phenanthro[5,6-b])tetrathiafulvalene (BPTTF), was realized via a self-coupling reaction. Using this ligand and Ru(tbbpy)2Cl2 (tbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine), the dinuclear ruthenium(II) compound [{Ru(tbbpy)2}2(BPTTF)](PF6)4 (1) has been obtained by microwave-assisted synthesis. Structural characterization of 1 revealed a crossed arrangement of the TTF moieties on adjacent dimers within the crystal structure. The optical and redox properties of 1 were investigated using electrochemical, spectroelectrochemical, electron paramagnetic resonance (EPR), and absorption spectroscopic studies combined with theoretical calculations. One exhibits a rich electrochemical behavior owing to the multiple redox-active centers. Interestingly, both the ligand BPTTF and the ruthenium compound 1 are EPR-active in the solid state owing to intramolecular charge-transfer processes. The results demonstrate that the TTF-annulated bis(phen) ligand is a promising bridging ligand to construct oligomeric or polymeric metal complexes with multiple redox-active centers. PMID:27070295

  1. Conformational analysis and vibrational circular dichroism of tris(ethylenediamine)ruthenium(II) complex: a theoretical study.

    PubMed

    Pandith, Altaf Hussain; Pati, Swapan K

    2010-01-14

    The conformational preferences and vibrational circular dichroism of tris(ethylenediamine)ruthenium complex in two main configurations (Lambda) and (Delta), have been performed using density functional theory. We find that for the free [Ru(en)(3)](2+) ion in the Delta-configuration, the conformational stability order is Delta(deltadeltadelta) > Delta(lambdadeltadelta) > Delta(lambdalambdadelta) > Delta(lambdalambdalambda) and that for the Lambda-configuration it is Lambda(deltadeltadelta) < Lambda(lambdadeltadelta) < Lambda(lambdalambdadelta) < Lambda(lambdalambdalambda). The energy differences between the four conformers for both the configurations Delta and Lambda are relatively small, but the activation barriers for ring inversion from one conformation to another are significant, as compared to other such systems. We trace the origin of these results to the lower oxidation state of Ru and relatively larger Ru-N bond length. We have also studied the effect of counterions on the conformational stability for Ru(en)(3)Cl(2.) Our results indicate a reverse stability order for the associated complex, Ru(en)(3) Cl(2) and higher activation barriers for ring inversion as compared to the free complex ion Ru(en)(3)(2+). It is because of larger hydrogen bonding interactions between the three N-H bonds and the chloride ion in these two conformers as compared to other conformations, which is also evident from the VCD spectra of N-H stretching modes. We also investigate IR spectra for all conformations in Delta- and Lambda-configurations and together with energetics and VCD spectra elucidate the spectroscopic characteristics of Ru(en)(3)(2+) complexes with and without the associated counterions.

  2. Carboxylate-Assisted C(sp3)–H Activation in Olefin Metathesis-Relevant Ruthenium Complexes

    PubMed Central

    2015-01-01

    The mechanism of C–H activation at metathesis-relevant ruthenium(II) benzylidene complexes was studied both experimentally and computationally. Synthesis of a ruthenium dicarboxylate at a low temperature allowed for direct observation of the C–H activation step, independent of the initial anionic ligand-exchange reactions. A first-order reaction supports an intramolecular concerted metalation–deprotonation mechanism with ΔG⧧298K = 22.2 ± 0.1 kcal·mol–1 for the parent N-adamantyl-N′-mesityl complex. An experimentally determined ΔS⧧ = −5.2 ± 2.6 eu supports a highly ordered transition state for carboxylate-assisted C(sp3)–H activation. Experimental results, including measurement of a large primary kinetic isotope effect (kH/kD = 8.1 ± 1.7), agree closely with a computed six-membered carboxylate-assisted C–H activation mechanism where the deprotonating carboxylate adopts a pseudo-apical geometry, displacing the aryl ether chelate. The rate of cyclometalation was found to be influenced by both the electronics of the assisting carboxylate and the ruthenium ligand environment. PMID:24731019

  3. Positional and compositional disorder in a ruthenium(II) piano-stool complex.

    PubMed

    Guzei, Ilia A; Dolinar, Brian S; Khumalo, Nozipho; Darkwa, James

    2013-08-01

    In (η⁶-p-cymene)(difluorophosphinato-κO){2-[(1H-pyrazol-1-yl)methyl-κN²]pyridine-κN}ruthenium(II) 0.85-hexafluorophosphate 0.15-tetrafluoroborate, [Ru(PO₂F₂)(C₁₀H₁₄)(C₉H₉N₃)](PF₆)0.85(BF₄)0.15, (I), the [PO₂F₂]⁻ ligand exhibits positional disorder due to one F atom and one O atom sharing the same two positions related by a mirror reflection across the O-P-F plane. The correct composition of this coordinated anion was successfully determined to be [PO₂F₂]⁻ by refining the complex with various tetrahedral anions in which terminal atoms have similar atomic form factors. The noncoordinated counter-ion is compositionally disordered between [PF₆]⁻ and [BF₄]⁻. The difficulty in determining the correct composition of this anion illustrates the importance of a crystallographer remaining impartial and open to encountering unexpected moieties in the process of elucidating a structure. PMID:23907873

  4. Functionalized Multiwalled Carbon Nanotubes as Carriers of Ruthenium Complexes to Antagonize Cancer Multidrug Resistance and Radioresistance.

    PubMed

    Wang, Ni; Feng, Yanxian; Zeng, Lilan; Zhao, Zhennan; Chen, Tianfeng

    2015-07-15

    Multidrug resistance and radioresistance are major obstacles for successful cancer therapy. Due to the unique characteristics of high surface area, improved cellular uptake, and the possibility to be easily bound with therapeutics, carbon nanotubes (CNTs) have attracted increasing attention as potential nanodrug delivery systems. In this study, a CNT-based radiosensitive nanodrug delivery system was rationally designed to antagonize the multidrug resistance in hepatocellular carcinoma. The nanosystem was loaded with a potent anticancer ruthenium polypyridyl complex (RuPOP) via π-π interaction and formation of a hydrogen bond. The functionalized nanosystem (RuPOP@MWCNTs) enhanced the cellular uptake of RuPOP in liver cancer cells, especially drug-resistant R-HepG2 cells, through endocytosis. Consistently, the selective cellular uptake endowed the nanosystem amplified anticancer efficacy against R-HepG2 cells but not in normal cells. Interestingly, RuPOP@MWCNTs significantly enhanced the anticancer efficacy of clinically used X-ray against R-HepG2 cells through induction of apoptosis and G0/G1 cell cycle arrest, with the involvement of ROS overproduction, which activated several downstream signaling pathways, including DNA damage-mediated p53 phosphorylation, activation of p38, and inactivation of AKT and ERK. Moreover, the nanosystem also effectively reduces the toxic side effects of loaded drugs and prolongs the blood circulation in vivo. Taken together, the results demonstrate the rational design of functionalized carbon nanotubes and their application as effective nanomedicine to overcome cancer multidrug resistance.

  5. IR-doped ruthenium oxide catalyst for oxygen evolution

    NASA Technical Reports Server (NTRS)

    Valdez, Thomas I. (Inventor); Narayanan, Sekharipuram R. (Inventor)

    2012-01-01

    A method for preparing a metal-doped ruthenium oxide material by heating a mixture of a doping metal and a source of ruthenium under an inert atmosphere. In some embodiments, the doping metal is in the form of iridium black or lead powder, and the source of ruthenium is a powdered ruthenium oxide. An iridium-doped or lead-doped ruthenium oxide material can perform as an oxygen evolution catalyst and can be fabricated into electrodes for electrolysis cells.

  6. Binding of mismatch repair protein MutS to mispaired DNA adducts of intercalating ruthenium(II) arene complexes.

    PubMed

    Castellano-Castillo, Maria; Kostrhunova, Hana; Marini, Victoria; Kasparkova, Jana; Sadler, Peter J; Malinge, Jean-Marc; Brabec, Viktor

    2008-08-01

    The present study was performed to examine the affinity of Escherichia coli mismatch repair (MMR) protein MutS for DNA damaged by an intercalating compound. We examined the binding properties of this protein with various DNA substrates containing a single centrally located adduct of ruthenium(II) arene complexes [(eta(6)-arene)Ru(II)(en)Cl][PF(6)] [arene is tetrahydroanthracene (THA) or p-cymene (CYM); en is ethylenediamine]. These two complexes were chosen as representatives of two different classes of monofunctional ruthenium(II) arene compounds which differ in DNA-binding modes: one that involves combined coordination to G N7 along with noncovalent, hydrophobic interactions, such as partial arene intercalation (tricyclic-ring Ru-THA), and the other that binds to DNA only via coordination to G N7 and does not interact with double-helical DNA by intercalation (monoring Ru-CYM). Using electrophoretic mobility shift assays, we examined the binding properties of MutS protein with various DNA duplexes (homoduplexes or mismatched duplexes) containing a single centrally located adduct of ruthenium(II) arene compounds. We have shown that presence of the ruthenium(II) arene adducts decreases the affinity of MutS for ruthenated DNA duplexes that either have a regular sequence or contain a mismatch and that intercalation of the arene contributes considerably to this inhibitory effect. Since MutS initiates MMR by recognizing DNA lesions, the results of the present work support the view that DNA damage due to intercalation is removed from DNA by a mechanism(s) other than MMR.

  7. Energy Dependence of the Ruthenium(II)-Bipyridine Metal-to-Ligand-Charge-Transfer Excited State Radiative Lifetimes: Effects of ππ*(bipyridine) Mixing.

    PubMed

    Thomas, Ryan A; Tsai, Chia Nung; Mazumder, Shivnath; Lu, I Chen; Lord, Richard L; Schlegel, H Bernhard; Chen, Yuan Jang; Endicott, John F

    2015-06-18

    The variations in band shape with excited state energy found for the triplet metal to ligand charge transfer ((3)MLCT) emission spectra of ruthenium-bipyridine (Ru-bpy) chromophores at 77 K have been postulated to arise from excited state/excited state configurational mixing. This issue is more critically examined through the determination of the excited state energy dependence of the radiative rate constants (kRAD) for these emissions. Experimental values for kRAD were determined relative to known literature references for Ru-bpy complexes. When the lowest energy excited states are metal centered, kRAD can be anomalously small and such complexes have been identified using density functional theory (DFT) modeling. When such complexes are removed from the energy correlation, there is a strong (3)MLCT energy-dependent contribution to kRAD in addition to the expected classical energy cubed factor for complexes with excited state energies greater than 10 000 cm(-1). This correlates with the DFT calculations which show significant excited state electronic delocalization between a π(bpy-orbital) and a half-filled dπ*-(Ru(III)-orbital) for Ru-bpy complexes with (3)MLCT excited state energies greater than about 16 000 cm(-1). Overall, this work implicates the "stealing" of emission bandshapes as well as intensity from the higher energy, strongly allowed bpy-centered singlet ππ* excited state.

  8. Using inclusion complexes with cyclodextrins to explore the aggregation behavior of a ruthenium metallosurfactant.

    PubMed

    Iza, Nerea; Guerrero-Martínez, Andrés; Tardajos, Gloria; Ortiz, María José; Palao, Eduardo; Montoro, Teresa; Radulescu, Aurel; Dreiss, Cécile A; González-Gaitano, Gustavo

    2015-03-10

    The aggregation behavior of a chiral metallosurfactant, bis(2,2'-bipyridine)(4,4'-ditridecyl-2,2'-bipyridine)ruthenium(II) dichloride (Ru2(4)C13), synthesized as a racemic mixture was characterized by small-angle neutron scattering, light scattering, NMR, and electronic spectroscopies. The analysis of the SANS data indicates that micelles are prolate ellipsoids over the range of concentrations studied, with a relatively low aggregation number, and the micellization takes place gradually with increasing concentration. The presence of cyclodextrins (β-CD and γ-CD) induces the breakup of the micelles and helps to establish that micellization occurs at a very slow exchange rate compared to the NMR time scale. The open structure of this metallosurfactant enables the formation of very stable complexes of 3:1 stoichiometry, in which one CD threads one of the hydrocarbon tails and two CDs the other, in close contact with the polar head. The complex formed with β-CD, more stable than the one formed with the wider γ-CD, is capable of resolving the Δ and Λ enantiomers at high CD/surfactant molar ratios. The chiral recognition is possible due to the very specific interactions taking place when the β-CD covers-via its secondary rim-part of the diimine moiety connected to the hydrophobic tails. A SANS model comprising a binary mixture of hard spheres (complex + micelles) was successfully used to study quantitatively the effect of the CDs on the aggregation of the surfactant.

  9. Anticancer Activity of Metal Complexes: Involvement of Redox Processes

    PubMed Central

    Jungwirth, Ute; Kowol, Christian R.; Keppler, Bernhard K.; Hartinger, Christian G.; Berger, Walter; Heffeter, Petra

    2012-01-01

    Cells require tight regulation of the intracellular redox balance and consequently of reactive oxygen species for proper redox signaling and maintenance of metal (e.g., of iron and copper) homeostasis. In several diseases, including cancer, this balance is disturbed. Therefore, anticancer drugs targeting the redox systems, for example, glutathione and thioredoxin, have entered focus of interest. Anticancer metal complexes (platinum, gold, arsenic, ruthenium, rhodium, copper, vanadium, cobalt, manganese, gadolinium, and molybdenum) have been shown to strongly interact with or even disturb cellular redox homeostasis. In this context, especially the hypothesis of “activation by reduction” as well as the “hard and soft acids and bases” theory with respect to coordination of metal ions to cellular ligands represent important concepts to understand the molecular modes of action of anticancer metal drugs. The aim of this review is to highlight specific interactions of metal-based anticancer drugs with the cellular redox homeostasis and to explain this behavior by considering chemical properties of the respective anticancer metal complexes currently either in (pre)clinical development or in daily clinical routine in oncology. PMID:21275772

  10. SOLVENT EXTRACTION OF RUTHENIUM

    DOEpatents

    Hyman, H.H.; Leader, G.R.

    1959-07-14

    The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

  11. Preparation, structures and some reactions of novel diynyl complexes of iron and ruthenium.

    PubMed

    Bruce, Michael I; Ellis, Benjamin G; Gaudio, Maryka; Lapinte, Claude; Melino, Giovanni; Paul, Frédéric; Skelton, Brian W; Smith, Mark E; Toupet, Loic; White, Allan H

    2004-05-21

    Reactions between HC triple bond CC triple bond CSiMe3 and several ruthenium halide precursors have given the complexes Ru(C triple bond CC triple bond CSiMe3)(L2)Cp'[Cp'= Cp, L = CO (1), PPh3 (2); Cp' = Cp*, L2= dppe (3)]. Proto-desilylation of 2 and 3 have given unsubstituted buta-1,3-diyn-1-yl complexes Ru(C triple bond CC triple bond CH)(L2)Cp'[Cp'= Cp, L = PPh3 (5); Cp'= Cp*, L2 = dppe (6)]. Replacement of H in 5 or 6 with Au(PR3) groups was achieved in reactions with AuCl(PR3) in the presence of KN(SiMe3)2 to give Ru(C triple bond CC triple bond CAu(PR3)](L2)Cp'[Cp' = Cp, L = PPh3, R = Ph (7); Cp' = Cp*, L2= dppe, R = Ph (8), tol (9)]. The asymmetrically end-capped [Cp(Ph3P)2Ru]C triple bond CC triple bond C[Ru(dppe)Cp*] (10) was obtained from Ru(C triple bond CC triple bond CH)(dppe)Cp* and RuCl(PPh3)2Cp. Single-crystal X-ray structural determinations of and are reported, with a comparative determination of the structure of Fe(C triple bond CC triple bond CSiMe3)(dppe)Cp* (4), and those of a fifth polymorph of [Ru(PPh3)2Cp]2(mu-C triple bond CC triple bond C) (12), and [Ru(dppe)Cp]2(mu-C triple bond CC triple bond C) (13). PMID:15252610

  12. Water oxidation chemistry of a synthetic dinuclear ruthenium complex containing redox-active quinone ligands.

    PubMed

    Isobe, Hiroshi; Tanaka, Koji; Shen, Jian-Ren; Yamaguchi, Kizashi

    2014-04-21

    We investigated theoretically the catalytic mechanism of electrochemical water oxidation in aqueous solution by a dinuclear ruthenium complex containing redox-active quinone ligands, [Ru2(X)(Y)(3,6-tBu2Q)2(btpyan)](m+) [X, Y = H2O, OH, O, O2; 3,6-tBu2Q = 3,6-di-tert-butyl-1,2-benzoquinone; btpyan =1,8-bis(2,2':6',2″-terpyrid-4'-yl)anthracene] (m = 2, 3, 4) (1). The reaction involves a series of electron and proton transfers to achieve redox leveling, with intervening chemical transformations in a mesh scheme, and the entire molecular structure and motion of the catalyst 1 work together to drive the catalytic cycle for water oxidation. Two substrate water molecules can bind to 1 with simultaneous loss of one or two proton(s), which allows pH-dependent variability in the proportion of substrate-bound structures and following pathways for oxidative activation of the aqua/hydroxo ligands at low thermodynamic and kinetic costs. The resulting bis-oxo intermediates then undergo endothermic O-O radical coupling between two Ru(III)-O(•) units in an anti-coplanar conformation leading to bridged μ-peroxo or μ-superoxo intermediates. The μ-superoxo species can liberate oxygen with the necessity for the preceding binding of a water molecule, which is possible only after four-electron oxidation is completed. The magnitude of catalytic current would be limited by the inherent sluggishness of the hinge-like bending motion of the bridged μ-superoxo complex that opens up the compact, hydrophobic active site of the catalyst and thereby allows water entry under dynamic conditions. On the basis of a newly proposed mechanism, we rationalize the experimentally observed behavior of electrode kinetics with respect to potential and discuss what causes a high overpotential for water oxidation by 1.

  13. Proton-Assisted Mechanism of NO Reduction on a Dinuclear Ruthenium Complex.

    PubMed

    Suzuki, Tatsuya; Tanaka, Hiromasa; Shiota, Yoshihito; Sajith, P K; Arikawa, Yasuhiro; Yoshizawa, Kazunari

    2015-08-01

    Density-functional-theory (DFT) calculations are performed for the proposal of a plausible mechanism on the reduction of NO to N2O by a dinuclear ruthenium complex, reported by Arikawa and co-workers [J. Am. Chem. Soc. 2007, 129, 14160]. On the basis of the experimental fact that the reduction proceeds under strongly acidic conditions, the role of protons in the mechanistic pathways is investigated with model complexes, where one or two NO ligands are protonated. The reaction mechanism of the NO reduction is partitioned into three steps: reorientation of N2O2 (cis-NO dimer), O-N bond cleavage, and N2O elimination. A key finding is that the protonation of the NO ligand(s) significantly reduces the activation barrier in the rate-determining reorientation step. The activation energy of 43.1 kcal/mol calculated for the proton-free model is reduced to 30.2 and 17.6 kcal/mol for the mono- and diprotonated models, respectively. The protonation induces the electron transfer from the Ru(II)Ru(II) core to the O═N-N═O moiety to give a Ru(III)Ru(III) core and a hyponitrite (O-N═N-O)(2-) species. The formation of the hyponitrite species provides an alternative pathway for the N2O2 reorientation, resulting in the lower activation energies in the presence of proton(s). The protonation also has a marginal effect on the O-N bond cleavage and the N2O elimination steps. Our calculations reveal a remarkable role of protons in the NO reduction via N2O formation and provide new insights into the mechanism of NO reduction catalyzed by metalloenzymes such as nitric oxide reductase (NOR) that contains a diiron active site. PMID:26186365

  14. Cationic bis-N-heterocyclic carbene (NHC) ruthenium complex: structure and application as latent catalyst in olefin metathesis.

    PubMed

    Rouen, Mathieu; Queval, Pierre; Falivene, Laura; Allard, Jessica; Toupet, Loïc; Crévisy, Christophe; Caijo, Frédéric; Baslé, Olivier; Cavallo, Luigi; Mauduit, Marc

    2014-10-13

    An unexpected cationic bis-N-heterocyclic carbene (NHC) benzylidene ether based ruthenium complex (2 a) was prepared through the double incorporation of an unsymmetrical unsaturated N-heterocyclic carbene (U2 -NHC) ligand that bore an N-substituted cyclododecyl side chain. The isolation and full characterization (including X-ray diffraction studies) of key synthetic intermediates along with theoretical calculations allowed us to understand the mechanism of the overall cationization process. Finally, the newly developed complex 2 a displayed interesting latent behavior during ring-closing metathesis, which could be "switched on" under acidic conditions. PMID:25212827

  15. Cationic bis-N-heterocyclic carbene (NHC) ruthenium complex: structure and application as latent catalyst in olefin metathesis.

    PubMed

    Rouen, Mathieu; Queval, Pierre; Falivene, Laura; Allard, Jessica; Toupet, Loïc; Crévisy, Christophe; Caijo, Frédéric; Baslé, Olivier; Cavallo, Luigi; Mauduit, Marc

    2014-10-13

    An unexpected cationic bis-N-heterocyclic carbene (NHC) benzylidene ether based ruthenium complex (2 a) was prepared through the double incorporation of an unsymmetrical unsaturated N-heterocyclic carbene (U2 -NHC) ligand that bore an N-substituted cyclododecyl side chain. The isolation and full characterization (including X-ray diffraction studies) of key synthetic intermediates along with theoretical calculations allowed us to understand the mechanism of the overall cationization process. Finally, the newly developed complex 2 a displayed interesting latent behavior during ring-closing metathesis, which could be "switched on" under acidic conditions.

  16. Complexity in `simple' metals

    NASA Astrophysics Data System (ADS)

    Rousseau, Bruno; Ashcroft, Neil W.

    2008-03-01

    In electronic and structural terms, the light alkalis have long been regarded as `simple systems', at least under ordinary conditions. However, when compressed they exhibit unforeseen complexity; the melting curve of sodium, for example, has a striking maximum, falling to near room temperature melting where a complex structure (CI16) is found, this being in the cubic class but with 16 atoms per unit cell [1,2]. The light alkalis have been extensively studied using ab initio methods with standard assumptions of transferability made for the key pseudopotential input information, largely atomic based. Lacking still, however, is a somewhat more intuitive and physical understanding of the developments in electronic structure with progressive increase in density. In the present work, the problem is treated with non-linear response theory and non-overlapping pseudopotentials, and the structural complexity traced to effective ion-ion interactions with features that both at short range and long display competing state dependence. [1] Gregoryanz et al., Phys. Rev. Lett. 94, 185502 (2005) [2] McMahon et al., Chem. Soc. Rev. 35, 943 (2006)

  17. Solvent assisted formation of ruthenium(III) and ruthenium(II) hydrazone complexes in one-pot with potential in vitro cytotoxicity and enhanced LDH, NO and ROS release.

    PubMed

    Jayanthi, Eswaran; Kalaiselvi, Sivalingam; Padma, Viswanatha Vijaya; Bhuvanesh, Nattamai S P; Dharmaraj, Nallasamy

    2016-01-28

    A set each of new bivalent and trivalent ruthenium complexes, [Ru(III)(HL)Cl2(EPh3)2] and [Ru(II)(L)(CO)(EPh3)2] (E = P (complexes and ) or As (complexes and )) were synthesised from the reactions of [Ru(III)Cl3(EPh3)3] with 2-hydroxynaphthaldehyde benzoic acid hydrazone (H2L) in methanol-chloroform and characterized by elemental analysis, spectral data and XRD study. A suitable mechanism to account for the formation of bivalent ruthenium carbonyl complexes from the corresponding trivalent precursors is provided by considering the role of added base in the reaction. Interaction of complexes with CT-DNA/bovine serum albumin was analysed with absorption and emission spectral titration studies. In vitro cytotoxic potential of the above ruthenium hydrazone complexes assayed against the A549 cell line revealed a significant growth inhibition. The test complexes added in IC50 concentration into the cell culture medium enhanced the release of lactate dehydrogenase, NO and reactive oxygen species in comparison with the control. Cell death induced by the complexes was studied using a propidium iodide staining assay and showed noticeable changes in the cell morphology which resembled apoptosis.

  18. Solvent assisted formation of ruthenium(III) and ruthenium(II) hydrazone complexes in one-pot with potential in vitro cytotoxicity and enhanced LDH, NO and ROS release.

    PubMed

    Jayanthi, Eswaran; Kalaiselvi, Sivalingam; Padma, Viswanatha Vijaya; Bhuvanesh, Nattamai S P; Dharmaraj, Nallasamy

    2016-01-28

    A set each of new bivalent and trivalent ruthenium complexes, [Ru(III)(HL)Cl2(EPh3)2] and [Ru(II)(L)(CO)(EPh3)2] (E = P (complexes and ) or As (complexes and )) were synthesised from the reactions of [Ru(III)Cl3(EPh3)3] with 2-hydroxynaphthaldehyde benzoic acid hydrazone (H2L) in methanol-chloroform and characterized by elemental analysis, spectral data and XRD study. A suitable mechanism to account for the formation of bivalent ruthenium carbonyl complexes from the corresponding trivalent precursors is provided by considering the role of added base in the reaction. Interaction of complexes with CT-DNA/bovine serum albumin was analysed with absorption and emission spectral titration studies. In vitro cytotoxic potential of the above ruthenium hydrazone complexes assayed against the A549 cell line revealed a significant growth inhibition. The test complexes added in IC50 concentration into the cell culture medium enhanced the release of lactate dehydrogenase, NO and reactive oxygen species in comparison with the control. Cell death induced by the complexes was studied using a propidium iodide staining assay and showed noticeable changes in the cell morphology which resembled apoptosis. PMID:26699435

  19. New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations

    NASA Astrophysics Data System (ADS)

    Prakash, Govindan; Viswanathamurthi, Periasamy

    2014-08-01

    Schiff base disulfide ligands (H2L1-6) were synthesized from the condensation of cystamine with salicylaldehyde(H2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H2L4), 3-methyl-2-hydroxyacetophenone(H2L5), and 2-hydroxy-1-naphthaldehyde(H2L6). H2L1-6 reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L1-6]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR (1H and 13C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

  20. New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations.

    PubMed

    Prakash, Govindan; Viswanathamurthi, Periasamy

    2014-08-14

    Schiff base disulfide ligands (H2L(1-6)) were synthesized from the condensation of cystamine with salicylaldehyde(H2L(1)), 5-chlorosalicylaldehyde(H2L(2)), o-vanillin(H2L(3)), 2-hydroxyacetophenone(H2L(4)), 3-methyl-2-hydroxyacetophenone(H2L(5)), and 2-hydroxy-1-naphthaldehyde(H2L(6)). H2L(1-6) reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L(1-6)]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR ((1)H and (13)C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

  1. Highly Efficient Process for Production of Biofuel from Ethanol Catalyzed by Ruthenium Pincer Complexes.

    PubMed

    Xie, Yinjun; Ben-David, Yehoshoa; Shimon, Linda J W; Milstein, David

    2016-07-27

    A highly efficient ruthenium pincer-catalyzed Guerbet-type process for the production of biofuel from ethanol has been developed. It produces the highest conversion of ethanol (73.4%, 0.02 mol% catalyst) for a Guerbet-type reaction, including significant amounts of C4 (35.8% yield), C6 (28.2% yield), and C8 (9.4% yield) alcohols. Catalyst loadings as low as 0.001 mol% can be used, leading to a record turnover number of 18 209. Mechanistic studies reveal the likely active ruthenium species and the main deactivation process. PMID:27399841

  2. Synthesis, structure, photophysics, electrochemistry, and ion-binding studies of ruthenium(II) 1,10-phenanthroline complexes containing thia-, selena-, and aza-crown pendants.

    PubMed

    Li, Mei-Jin; Chu, Ben Wai-Kin; Zhu, Nianyong; Yam, Vivian Wing-Wah

    2007-02-01

    A series of ruthenium(II) diimine complexes containing thia-, selena- and aza-crowns derived from 1,10-phenanthroline have been synthesized and characterized, and their photophysics and electrochemistry were studied. Their interaction with metal ions was investigated by UV-vis, luminescence, and 1H NMR spectroscopy. The crystal structures of [Ru(bpy)2(L1)](PF6)2, [Ru(bpy)2(L2)](ClO4)2, [Ru(bpy)2(L3)](ClO4)2, and [Ru(bpy)2(L4)](ClO4)2 have been determined. The luminescence properties of [Ru(bpy)2(L1)](ClO4)2 were found to be sensitive and selective toward the presence of Hg2+ ions in an acetonitrile solution. The addition of alkaline-earth metal ions, Zn2+, Cd2+, and Hg2+ ions, to the solution of [Ru(bpy)2(L6)](ClO4)2 in acetonitrile gave rise to large changes in the UV-vis and emission spectra. The binding of metal ions to [Ru(bpy)2(L6)](ClO4)2 was found to cause a strong enhancement in the emission intensities of the complex, with high specificity toward Hg2+ ions.

  3. Functionalized arene-ruthenium(II) complexes: dangling vs. tethering side chain.

    PubMed

    Lastra-Barreira, Beatriz; Díez, Josefina; Crochet, Pascale; Fernández, Israel

    2013-04-21

    The reactivity of compounds [RuCl2(η(6)-C6H5OCH2CH2OH)(L)] (L = phosphine or phosphite) towards the chloride abstractor AgSbF6 has been investigated. Thus, the treatment of the triphenylphosphite complex [RuCl2(η(6)-C6H5OCH2CH2OH){P(OPh)3}] with one equivalent of AgSbF6 gave rise to the formation of the dinuclear dichloro-bridged species [{Ru(μ-Cl)(η(6)-C6H5OCH2CH2OH){P(OPh)3}}2](2+) as the hexafluoroantimonate salt. On the other hand, the triphenylphosphine analog [RuCl2(η(6)-C6H5OCH2CH2OH)(PPh3)] led, under the same experimental conditions, to the di-ruthenium derivative [{RuCl(η(6)-C6H5OCH2CH2OH)(PPh3)}2(μ-Cl)][SbF6] containing only one Cl-bridge. In sharp contrast, treatment of precursors [RuCl2(η(6)-C6H5CH2CH2CH2OH)(L)] (L = P(OPh)3, PPh3, P(OEt)3) with AgSbF6 resulted in the clean formation of the tethered compounds [RuCl{η(6):κ(1)(O)-C6H5CH2CH2CH2OH}(L)][SbF6]. The differences in reactivity observed have been rationalized by theoretical calculations.

  4. Probing the Quenching of Quantum Dot Photoluminescence by Peptide-Labeled Ruthenium(II) Complexes.

    PubMed

    Scott, Amy M; Algar, W Russ; Stewart, Michael H; Trammell, Scott A; Blanco-Canosa, Juan B; Dawson, Philip E; Deschamps, Jeffrey R; Goswami, Ramasis; Oh, Eunkeu; Huston, Alan L; Medintz, Igor L

    2014-05-01

    Charge transfer processes with semiconductor quantum dots (QDs) have generated much interest for potential utility in energy conversion. Such configurations are generally nonbiological; however, recent studies have shown that a redox-active ruthenium(II)-phenanthroline complex (Ru(2+)-phen) is particularly efficient at quenching the photoluminescence (PL) of QDs, and this mechanism demonstrates good potential for application as a generalized biosensing detection modality since it is aqueous compatible. Multiple possibilities for charge transfer and/or energy transfer mechanisms exist within this type of assembly, and there is currently a limited understanding of the underlying photophysical processes in such biocomposite systems where nanomaterials are directly interfaced with biomolecules such as proteins. Here, we utilize redox reactions, steady-state absorption, PL spectroscopy, time-resolved PL spectroscopy, and femtosecond transient absorption spectroscopy (FSTA) to investigate PL quenching in biological assemblies of CdSe/ZnS QDs formed with peptide-linked Ru(2+)-phen. The results reveal that QD quenching requires the Ru(2+) oxidation state and is not consistent with Förster resonance energy transfer, strongly supporting a charge transfer mechanism. Further, two colors of CdSe/ZnS core/shell QDs with similar macroscopic optical properties were found to have very different rates of charge transfer quenching, by Ru(2+)-phen with the key difference between them appearing to be the thickness of their ZnS outer shell. The effect of shell thickness was found to be larger than the effect of increasing distance between the QD and Ru(2+)-phen when using peptides of increasing persistence length. FSTA and time-resolved upconversion PL results further show that exciton quenching is a rather slow process consistent with other QD conjugate materials that undergo hole transfer. An improved understanding of the QD-Ru(2+)-phen system can allow for the design of more

  5. Probing the Quenching of Quantum Dot Photoluminescence by Peptide-Labeled Ruthenium(II) Complexes

    PubMed Central

    2015-01-01

    Charge transfer processes with semiconductor quantum dots (QDs) have generated much interest for potential utility in energy conversion. Such configurations are generally nonbiological; however, recent studies have shown that a redox-active ruthenium(II)–phenanthroline complex (Ru2+-phen) is particularly efficient at quenching the photoluminescence (PL) of QDs, and this mechanism demonstrates good potential for application as a generalized biosensing detection modality since it is aqueous compatible. Multiple possibilities for charge transfer and/or energy transfer mechanisms exist within this type of assembly, and there is currently a limited understanding of the underlying photophysical processes in such biocomposite systems where nanomaterials are directly interfaced with biomolecules such as proteins. Here, we utilize redox reactions, steady-state absorption, PL spectroscopy, time-resolved PL spectroscopy, and femtosecond transient absorption spectroscopy (FSTA) to investigate PL quenching in biological assemblies of CdSe/ZnS QDs formed with peptide-linked Ru2+-phen. The results reveal that QD quenching requires the Ru2+ oxidation state and is not consistent with Förster resonance energy transfer, strongly supporting a charge transfer mechanism. Further, two colors of CdSe/ZnS core/shell QDs with similar macroscopic optical properties were found to have very different rates of charge transfer quenching, by Ru2+-phen with the key difference between them appearing to be the thickness of their ZnS outer shell. The effect of shell thickness was found to be larger than the effect of increasing distance between the QD and Ru2+-phen when using peptides of increasing persistence length. FSTA and time-resolved upconversion PL results further show that exciton quenching is a rather slow process consistent with other QD conjugate materials that undergo hole transfer. An improved understanding of the QD–Ru2+-phen system can allow for the design of more sophisticated

  6. The contrasting chemistry and cancer cell cytotoxicity of bipyridine and bipyridinediol ruthenium(II) arene complexes.

    PubMed

    Bugarcic, Tijana; Habtemariam, Abraha; Stepankova, Jana; Heringova, Pavla; Kasparkova, Jana; Deeth, Robert J; Johnstone, Russell D L; Prescimone, Alessandro; Parkin, Andrew; Parsons, Simon; Brabec, Viktor; Sadler, Peter J

    2008-12-15

    The synthesis and characterization of ruthenium(II) arene complexes [(eta(6)-arene)Ru(N,N)Cl](0/+), where N,N = 2,2'-bipyridine (bipy), 2,2'-bipyridine-3,3'-diol (bipy(OH)(2)) or deprotonated 2,2'-bipyridine-3,3'-diol (bipy(OH)O) as N,N-chelating ligand, arene = benzene (bz), indan (ind), biphenyl (bip), p-terphenyl (p-terp), tetrahydronaphthalene (thn), tetrahydroanthracene (tha) or dihydroanthracene (dha), are reported, including the X-ray crystal structures of [(eta(6)-tha)Ru(bipy)Cl][PF(6)] (1), [(eta(6)-tha)Ru(bipy(OH)O)Cl] (2) and [(eta(6)-ind)Ru(bipy(OH)(2))Cl][PF(6)] (8). Complexes 1 and 2 exibit CH (arene)/pi (bipy or bipy(OH)O) interactions. In the X-ray structure of protonated complex 8, the pyridine rings are twisted (by 17.31 degrees). In aqueous solution (pH = 2-10), only deprotonated (bipy(OH)O) forms are present. Hydrolysis of the complexes was relatively fast in aqueous solution (t(1/2) = 4-15 min, 310 K). When the arene is biphenyl, initial aquation of the complexes is followed by partial arene loss. Complexes with arene = tha, thn, dha, ind and p-terp, and deprotonated bipyridinediol (bipy(OH)O) as chelating ligands, exhibited significant cytotoxicity toward A2780 human ovarian and A549 human lung cancer cells. Complexes [(eta(6)-bip)Ru(bipy(OH)O)Cl] (7) and [(eta(6)-bz)Ru(bipy(OH)O)Cl] (5) exhibited moderate cytotoxicity toward A2780 cells, but were inactive toward A549 cells. These activity data can be contrasted with those of the parent bipyridine complex [(eta(6)-tha)Ru(bipy)Cl][PF(6)] (1) which is inactive toward both A2780 ovarian and A549 lung cell lines. DFT calculations suggested that hydroxylation and methylation of the bipy ligand have little effect on the charge on Ru. The active complex [(eta(6)-tha)Ru(bipy(OH)O)Cl] (2) binds strongly to 9-ethyl-guanine (9-EtG). The X-ray crystal structure of the adduct [(eta(6)-tha)Ru(bipy(OH)O)(9-EtG-N7)][PF(6)] shows intramolecular CH (arene)/pi (bipy(OH)O) interactions and DFT calculations

  7. Titania modification with a ruthenium(II) complex and gold nanoparticles for photocatalytic degradation of organic compounds.

    PubMed

    Zheng, Shuaizhi; Wei, Zhishun; Yoshiiri, Kenta; Braumüller, Markus; Ohtani, Bunsho; Rau, Sven; Kowalska, Ewa

    2016-01-01

    Titania of fine anatase nanoparticles (ST01) was modified successively with two components, i.e., a ruthenium(II) complex with phosphonic anchoring groups [Ru(bpy)2(4,4'-(CH2PO3H2)2bpy)](2+) bpy = 2,2'-bipyridine (Ru(II)CP) and gold nanoparticles (Au). Various compositions of two titania modifiers were investigated, i.e., Au, Au + Ru(II)CP, Au + 0.5Ru(II)CP, Ru(II)CP, 0.5Ru(II)CP and 0.25Ru(II)CP, where Au and Ru(II)CP correspond to 0.81 mol% and 0.34 mol% (with respect to titania), respectively. In the case of hybrid photocatalysts, the sequence of modification (ruthenium(II) complex adsorption or gold deposition) was investigated to check its influence on the resultant properties and thus photocatalytic performance. Diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) were applied to characterize the structural properties of the prepared photocatalysts, which confirmed the successful introduction of modifiers of the ruthenium(II) complex and/or gold NPs. Different distributions of gold particle sizes and chemical compositions were obtained for the hybrid photocatalysts prepared with an opposite sequence. It was found that photocatalytic activities depended on the range of used irradiation (UV/vis or vis) and the kind of modifier in different ways. Gold NPs improved the photocatalytic activities, while Ru(II)CP inhibited the reactions under UV/vis irradiation, i.e., methanol dehydrogenation and acetic acid degradation. Oppositely, Ru(II)CP greatly enhanced the photocatalytic activities for 2-propanol oxidation under visible light irradiation. PMID:26661372

  8. Selective conversion of alcohols in water to carboxylic acids by in situ generated ruthenium trans dihydrido carbonyl PNP complexes.

    PubMed

    Choi, Jong-Hoo; Heim, Leo E; Ahrens, Mike; Prechtl, Martin H G

    2014-12-14

    In this work, we present a mild method for direct conversion of primary alcohols into carboxylic acids with the use of water as an oxygen source. Applying a ruthenium dihydrogen based dehydrogenation catalyst for this cause, we investigated the effect of water on the catalytic dehydrogenation process of alcohols. Using 1 mol% of the catalyst we report up to high yields. Moreover, we isolated key intermediates which most likely play a role in the catalytic cycle. One of the intermediates was identified as a trans dihydrido carbonyl complex which is generated in situ in the catalytic process.

  9. How Does Peripheral Functionalization of Ruthenium(II)-Terpyridine Complexes Affect Spatial Charge Redistribution after Photoexcitation at the Franck-Condon Point?

    PubMed

    Preiß, Julia; Jäger, Michael; Rau, Sven; Dietzek, Benjamin; Popp, Jürgen; Martínez, Todd; Presselt, Martin

    2015-05-18

    Ruthenium polypyridine-type complexes are extensively used sensitizers to convert solar energy into chemical and/or electrical energy, and they can be tailored through their metal-to-ligand charge-transfer (MLCT) properties. Much work has been directed at harnessing the triplet MLCT state in photoinduced processes, from sophisticated molecular architectures to dye-sensitized solar cells. In dye-sensitized solar cells, strong coupling to the semiconductor exploits the high reactivity of the (hot) singlet/triplet MLCT state. In this work, we explore the nature of the (1) MLCT states of remotely substituted Ru(II) model complexes by both experimental and theoretical techniques. Two model complexes with electron-withdrawing (i.e. NO2 ) and electron-donating (i.e. NH2 ) groups were synthesized; these complexes contained a phenylene spacer to serve as a spectroscopic handle and to confirm the contribution of the remote substituent to the (1) MLCT transition. [Ru(tpy)2 ](2+) -based complexes (tpy=2,2':6',2''-terpyridine) were further desymmetrized by tert-butyl groups to yield unidirectional (1) MLCTs with large transition dipole moments, which are beneficial for related directional charge-transfer processes. Detailed comparison of experimental spectra (deconvoluted UV/Vis and resonance Raman spectroscopy data) with theoretical calculations based on density functional theory (including vibronic broadening) revealed different properties of the optically active bright (1) MLCT states already at the Franck-Condon point. PMID:25898828

  10. DFT 2H quadrupolar coupling constants of ruthenium complexes: a good probe of the coordination of hydrides in conjuction with experiments.

    PubMed

    del Rosal, Iker; Gutmann, Torsten; Maron, Laurent; Jolibois, Franck; Chaudret, Bruno; Walaszek, Bernadeta; Limbach, Hans-Heinrich; Poteau, Romuald; Buntkowsky, Gerd

    2009-07-21

    Transition metal (TM) hydrides are of great interest in chemistry because of their reactivity and their potential as catalysts for hydrogenation reactions. 2H solid-state NMR can be used in order to get information about the local environment of hydrogen atoms, and more particularly the coordination mode of hydrides in such complexes. In this work we will show that it is possible to establish at the level of density functional theory (DFT) a viable methodological strategy that allows the determination of 2H NMR parameters, namely the quadrupolar coupling constant (C(Q)) respectively the quadrupolar splitting (deltanuQ) and the asymmetry parameter (etaQ). The reliability of the method (B3PW91-DFT) and basis set effects have been first evaluated for simple organic compounds (benzene and fluorene). A good correlation between experimental and theoretical values is systematically obtained if the large basis set cc-pVTZ is used for the computations. 2H NMR properties of five mononuclear ruthenium complexes (namely Cp*RuD3(PPh3), Tp*RuD(THT)2, Tp*RuD(D2)(THT) and Tp*RuD(D2)2 and RuD2(D2)2(PCy3)2) which exhibit different ligands and hydrides involved in different coordination modes (terminal-H or eta2-H2), have been calculated and compared to previous experimental data. The results obtained are in excellent agreement with experiments. Although 2H NMR spectra are not always easy to analyze, assistance by quantum chemistry calculations allows unambiguous assignment of the signals of such spectra. As far as experiments can be achieved at very low temperatures in order to avoid dynamic effects, this hybrid theoretical/experimental tool may give useful insights in the context of the characterization of ruthenium surfaces or nanoparticles with solid-state NMR. PMID:19842483

  11. Solid-Phase Synthesis as a Platform for the Discovery of New Ruthenium Complexes for Efficient Release of Photocaged Ligands with Visible Light

    PubMed Central

    Sharma, Rajgopal; Knoll, Jessica D.; Ancona, Nicholas; Martin, Phillip D.; Turro, Claudia; Kodanko, Jeremy J.

    2015-01-01

    Ruthenium-based photocaging groups have important applications as biological tools and show great potential as therapeutics. A method was developed to rapidly synthesize, screen and identify ruthenium-based caging groups that release nitriles upon irradiation with visible light. A diverse library of tetra- and pentadentate ligands was synthesized on polystyrene resin. Ruthenium complexes of the general formula [Ru(L)(MeCN)n]m+ (n = 1–3, m = 1–2) were generated from these ligands on solid phase, then cleaved from resin for photochemical analysis. Data indicate a wide range of spectral tuning and reactivity with visible light. Three complexes that showed strong absorbance in the visible range were synthesized by solution phase for comparison. Photochemical behavior of solution- and solid-phase complexes was in good agreement, confirming that the library approach is useful in identifying candidates with desired photoreactivity in short order, avoiding time consuming chromatography and compound purification. PMID:25611351

  12. Ruthenium Vinylidene and Acetylide Complexes. An Advanced Undergraduate Multi-technique Inorganic/Organometallic Chemistry Experiment

    NASA Astrophysics Data System (ADS)

    McDonagh, Andrew M.; Deeble, Geoffrey J.; Hurst, Steph; Cifuentes, Marie P.; Humphrey, Mark G.

    2001-02-01

    This experiment describes the isolation and characterization of complexes containing examples of two important monohapto ligands, namely vinylidene (C=CHR) and alkynyl (C ? CR) ligands. The former is a tautomer of acetylene that has minimal (10-10 s) existence as an uncomplexed molecule, providing an interesting example of the stabilization of reactive organic species at transition metals--an important motif in organometallic chemistry. The latter ligand affords complexes that have attracted a great deal of interest recently for their potentially useful electronic or optical properties, illustrating a major focus of contemporary organometallic chemistry, the search for useful materials. The particular strength of this experiment is in demonstrating the utility of a range of spectroscopic and analytical techniques in inorganic complex identification. The students observe unusual chemical shifts in the 13C NMR (vinylidene metal-bound carbon), meet heteronuclear NMR (31P), assign intense metal-to-ligand charge transfer (MLCT) bands in the UV-visible spectra, observe the utility of mass spectra in characterizing complexes of poly-isotopic transition metals, and are introduced to redox potentials (cyclic voltammetry).

  13. Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

    SciTech Connect

    Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Heng, Lee Yook; Karim, Nurul Huda Abd; Ahmad, Haslina; Harun, Siti Norain

    2014-09-03

    A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy){sub 2}(PIP)]{sup 2+}, (bpy = 2,2′bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy){sub 2}(PIP)]{sup 2+} was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy){sub 2}(PIP)]{sup 2+} with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.

  14. Synthesis, DNA binding and photocleavage, and cellular uptake of an alkyl chain-linked dinuclear ruthenium(II) complex.

    PubMed

    Liu, Ping; Liu, Jin; Zhang, Yu-Qi; Wu, Bao-Yan; Wang, Ke-Zhi

    2015-02-01

    A dinuclear ruthenium(II) complex [(bpy)2Ru(L(1))Ru(bpy)2]Cl4 {bpy=2,2'-bipyridine, L(1)=1,6-bis(3-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-9H-carbazol-9-yl)hexane} was synthesised and characterized. The calf thymus DNA (ct-DNA) binding properties of the complex were investigated by means of UV-Visible absorption and emission spectrophotometric titrations, ethidium bromide competitive binding, steady-state emission quenching with ferrocyanide, DNA viscosity measurements, and DNA thermal denaturation. The results indicated that the complex avidly binds to ct-DNA most probably through a threading bis-intercalative mode. The complex was also evidenced to act as an efficient DNA photocleaver, and an effective luminescent stain for cytoplasmic of HeLa cells with low cytotoxicity.

  15. Synthesis, characterization, DNA binding studies, photocleavage, cytotoxicity and docking studies of ruthenium(II) light switch complexes.

    PubMed

    Gabra, Nazar Mohammed; Mustafa, Bakheit; Kumar, Yata Praveen; Devi, C Shobha; Srishailam, A; Reddy, P Venkat; Reddy, Kotha Laxma; Satyanarayana, S

    2014-01-01

    A new ligand 3-(1H-imidazo[4,5-f][1,10]phenanthrolin-2yl)phenylboronic acid and its (IPPBA) three ruthenium(II) complexes [Ru(phen)2(IPPBA)](ClO4)2 (1), [Ru(bpy)2(IPPBA)](ClO4)2 (2) and [Ru(dmb)2(IPPBA)](ClO4)2 (3) have been synthesized and characterized by elemental analysis, UV/VIS, IR, (1)H-NMR,(13)C-NMR and mass spectra. The binding behaviors of the three complexes to calf thymus DNA were investigated by absorption spectra, emission spectroscopy, viscosity measurements, thermal denaturation and photoactivated cleavage. The DNA-binding constants for complexes 1, 2 and 3 have been determined to be 7.9 × 10(5) M(-1), 6.7 × 10(5) M(-1) and 2.9 × 10(5) M(-1). The results suggest that these complexes bound to double-stranded DNA in an intercalation mode. Upon irradiation at 365 nm, three ruthenium complexes were found to promote the cleavage of plasmid pBR322 DNA from super coiled form І to nicked form ІІ. Further in the presence of Co(2+), the emission of DNA-Ru(ΙΙ) complexes can be quenched. And when EDTA was added, the emission was recovered. The experimental results show that all three complexes exhibited the "on-off-on" properties of molecular "light switch". The highest Cytotoxicity potential of the complex1 was observed on the Human alveolar adenocarcinoma (A549) cell line. Good agreement was generally found between the spectroscopic techniques and molecular docked model which provides further evidence of groove binding. PMID:23982735

  16. Electronic structures of ruthenium and osmium complexes of 9,10-phenanthrenequinone.

    PubMed

    Biswas, Manas Kumar; Patra, Sarat Chandra; Maity, Amarendra Nath; Ke, Shyue-Chu; Adhikary, Nirmal Das; Ghosh, Prasanta

    2012-06-18

    The reaction of 9,10-phenanthrenequinone (PQ) with [M(II)(H)(CO)(X)(PPh(3))(3)] in boiling toluene leads to the homolytic cleavage of the M(II)-H bond, affording the paramagnetic trans-[M(PQ)(PPh(3))(2)(CO)X] (M = Ru, X = Cl, 1; M = Os, X = Br, 3) and cis-[M(PQ)(PPh(3))(2)(CO)X] (M = Ru, X = Cl, 2; M = Os, X = Br, 4) complexes. Single-crystal X-ray structure determinations of 1, 2·toluene, and 4·CH(2)Cl(2), EPR spectra, and density functional theory (DFT) calculations have substantiated that 1-4 are 9,10-phenanthrenesemiquinone radical (PQ(•-)) complexes of ruthenium(II) and osmium(II) and are defined as trans-[Ru(II)(PQ(•-))(PPh(3))(2)(CO)Cl] (1), cis-[Ru(II)(PQ(•-))(PPh(3))(2)(CO)Cl] (2), trans-[Os(II)(PQ(•-))(PPh(3))(2)(CO) Br] (3), and cis-[Os(II)(PQ(•-))(PPh(3))(2)(CO)Br] (4). Two comparatively longer C-O [average lengths: 1, 1.291(3) Å; 2·toluene, 1.281(5) Å; 4·CH(2)Cl(2), 1.300(8) Å] and shorter C-C lengths [1, 1.418(5) Å; 2·toluene, 1.439(6) Å; 4·CH(2)Cl(2), 1.434(9) Å] of the OO chelates are consistent with the presence of a reduced PQ(•-) ligand in 1-4. A minor contribution of the alternate resonance form, trans- or cis-[M(I)(PQ)(PPh(3))(2)(CO)X], of 1-4 has been predicted by the anisotropic X- and Q-band electron paramagnetic resonance spectra of the frozen glasses of the complexes at 25 K and unrestricted DFT calculations on 1, trans-[Ru(PQ)(PMe(3))(2)(CO)Cl] (5), cis-[Ru(PQ)(PMe(3))(2)(CO)Cl] (6), and cis-[Os(PQ)(PMe(3))(2)(CO)Br] (7). However, no thermodynamic equilibria between [M(II)(PQ(•-))(PPh(3))(2)(CO)X] and [M(I)(PQ)(PPh(3))(2)(CO)X] tautomers have been detected. 1-4 undergo one-electron oxidation at -0.06, -0.05, 0.03, and -0.03 V versus a ferrocenium/ferrocene, Fc(+)/Fc, couple because of the formation of PQ complexes as trans-[Ru(II)(PQ)(PPh(3))(2)(CO)Cl](+) (1(+)), cis-[Ru(II)(PQ)(PPh(3))(2)(CO)Cl](+) (2(+)), trans-[Os(II)(PQ)(PPh(3))(2)(CO)Br](+) (3(+)), and cis-[Os(II)(PQ)(PPh(3))(2)(CO)Br](+) (4(+)). The trans

  17. Electronic structures of ruthenium and osmium complexes of 9,10-phenanthrenequinone.

    PubMed

    Biswas, Manas Kumar; Patra, Sarat Chandra; Maity, Amarendra Nath; Ke, Shyue-Chu; Adhikary, Nirmal Das; Ghosh, Prasanta

    2012-06-18

    The reaction of 9,10-phenanthrenequinone (PQ) with [M(II)(H)(CO)(X)(PPh(3))(3)] in boiling toluene leads to the homolytic cleavage of the M(II)-H bond, affording the paramagnetic trans-[M(PQ)(PPh(3))(2)(CO)X] (M = Ru, X = Cl, 1; M = Os, X = Br, 3) and cis-[M(PQ)(PPh(3))(2)(CO)X] (M = Ru, X = Cl, 2; M = Os, X = Br, 4) complexes. Single-crystal X-ray structure determinations of 1, 2·toluene, and 4·CH(2)Cl(2), EPR spectra, and density functional theory (DFT) calculations have substantiated that 1-4 are 9,10-phenanthrenesemiquinone radical (PQ(•-)) complexes of ruthenium(II) and osmium(II) and are defined as trans-[Ru(II)(PQ(•-))(PPh(3))(2)(CO)Cl] (1), cis-[Ru(II)(PQ(•-))(PPh(3))(2)(CO)Cl] (2), trans-[Os(II)(PQ(•-))(PPh(3))(2)(CO) Br] (3), and cis-[Os(II)(PQ(•-))(PPh(3))(2)(CO)Br] (4). Two comparatively longer C-O [average lengths: 1, 1.291(3) Å; 2·toluene, 1.281(5) Å; 4·CH(2)Cl(2), 1.300(8) Å] and shorter C-C lengths [1, 1.418(5) Å; 2·toluene, 1.439(6) Å; 4·CH(2)Cl(2), 1.434(9) Å] of the OO chelates are consistent with the presence of a reduced PQ(•-) ligand in 1-4. A minor contribution of the alternate resonance form, trans- or cis-[M(I)(PQ)(PPh(3))(2)(CO)X], of 1-4 has been predicted by the anisotropic X- and Q-band electron paramagnetic resonance spectra of the frozen glasses of the complexes at 25 K and unrestricted DFT calculations on 1, trans-[Ru(PQ)(PMe(3))(2)(CO)Cl] (5), cis-[Ru(PQ)(PMe(3))(2)(CO)Cl] (6), and cis-[Os(PQ)(PMe(3))(2)(CO)Br] (7). However, no thermodynamic equilibria between [M(II)(PQ(•-))(PPh(3))(2)(CO)X] and [M(I)(PQ)(PPh(3))(2)(CO)X] tautomers have been detected. 1-4 undergo one-electron oxidation at -0.06, -0.05, 0.03, and -0.03 V versus a ferrocenium/ferrocene, Fc(+)/Fc, couple because of the formation of PQ complexes as trans-[Ru(II)(PQ)(PPh(3))(2)(CO)Cl](+) (1(+)), cis-[Ru(II)(PQ)(PPh(3))(2)(CO)Cl](+) (2(+)), trans-[Os(II)(PQ)(PPh(3))(2)(CO)Br](+) (3(+)), and cis-[Os(II)(PQ)(PPh(3))(2)(CO)Br](+) (4(+)). The trans

  18. Photochemical, electrochemical, and photoelectrochemical water oxidation catalyzed by water-soluble mononuclear ruthenium complexes.

    PubMed

    Li, Ting-Ting; Zhao, Wei-Liang; Chen, Yong; Li, Fu-Min; Wang, Chuan-Jun; Tian, Yong-Hua; Fu, Wen-Fu

    2014-10-20

    Two mononuclear ruthenium complexes [Ru(H2tcbp)(isoq)2] (1) and [Ru(H2tcbp)(pic)2] (2) (H4tcbp=4,4',6,6'-tetracarboxy-2,2'-bipyridine, isoq=isoquinoline, pic=4-picoline) are synthesized and fully characterized. Two spare carboxyl groups on the 4,4'-positions are introduced to enhance the solubility of 1 and 2 in water and to simultaneously allow them to tether to the electrode surface by an ester linkage. The photochemical, electrochemical, and photoelectrochemical water oxidation performance of 1 in neutral aqueous solution is investigated. Under electrochemical conditions, water oxidation is conducted on the deposited indium-tin-oxide anode, and a turnover number higher than 15,000 per water oxidation catalyst (WOC) 1 is obtained during 10 h of electrolysis under 1.42 V vs. NHE, corresponding to a turnover frequency of 0.41 s(-1). The low overpotential (0.17 V) of electrochemical water oxidation for 1 in the homogeneous solution enables water oxidation under visible light by using [Ru(bpy)3](2+) (P1) (bpy=2,2'-bipyridine) or [Ru(bpy)2(4,4'-(COOEt)2-bpy)](2+) (P2) as a photosensitizer. In a three-component system containing 1 or 2 as a light-driven WOC, P1 or P2 as a photosensitizer, and Na2S2O8 or [CoCl(NH3)5]Cl2 as a sacrificial electron acceptor, a high turnover frequency of 0.81 s(-1) and a turnover number of up to 600 for 1 under different catalytic conditions are achieved. In a photoelectrochemical system, the WOC 1 and photosensitizer are immobilized together on the photoanode. The electrons efficiently transfer from the WOC to the photogenerated oxidizing photosensitizer, and a high photocurrent density of 85 μA cm(-2) is obtained by applying 0.3 V bias vs. NHE. PMID:25205065

  19. Electrochemical Sensing of Casein Based on the Interaction between Its Phosphate Groups and a Ruthenium(III) Complex.

    PubMed

    Inaba, Iku; Kuramitz, Hideki; Sugawara, Kazuharu

    2016-01-01

    A reaction to casein, along with β-lactoglobulin, is a main cause of milk allergies, and also is a useful indicator of protein in allergic analyses. In the present study, a simple casein sensor was developed based on the interaction between a phosphate group of casein and electroactive [Ru(NH3)6](3+). We evaluated the voltammetric behavior of a casein-[Ru(NH3)6](3+) complex using a glassy carbon electrode. When the ruthenium(III) complex was combined with the phosphate groups of casein, the structure of the casein was changed. Since the hydrophobicity of casein was increased due to the binding, the casein was adsorbed onto the electrode. Furthermore, we modified an electrode with a ruthenium(III) ions/collagen film. When the sensor was applied to the detection of the casein contained in milk, the values coincided with those indicated by the manufacturer. Accordingly, this electrode could be a powerful sensor for the determination of casein in several foods. PMID:27506711

  20. Anticancer activity of ruthenium(II) arene complexes bearing 1,2,3,4-tetrahydroisoquinoline amino alcohol ligands.

    PubMed

    Chelopo, Madichaba P; Pawar, Sachin A; Sokhela, Mxolisi K; Govender, Thavendran; Kruger, Hendrik G; Maguire, Glenn E M

    2013-08-01

    Ruthenium complexes offer potential reduced toxicity compared to current platinum anticancer drugs. 1,2,3,4-tetrahydrisoquinoline amino alcohol ligands were synthesised, characterised and coordinated to an organometallic Ru(II) centre. These complexes were evaluated for activity against the cancer cell lines MCF-7, A549 and MDA-MB-231 as well as for toxicity in the normal cell line MDBK. They were observed to be moderately active against only the MCF-7 cells with the best IC₅₀ value of 34 μM for the cis-diastereomeric complex C4. They also displayed excellent selectivity by being relatively inactive against the normal MDBK cell line with SI values ranging from 2.3 to 7.4. PMID:23827181

  1. Anticancer activity of ruthenium(II) arene complexes bearing 1,2,3,4-tetrahydroisoquinoline amino alcohol ligands.

    PubMed

    Chelopo, Madichaba P; Pawar, Sachin A; Sokhela, Mxolisi K; Govender, Thavendran; Kruger, Hendrik G; Maguire, Glenn E M

    2013-08-01

    Ruthenium complexes offer potential reduced toxicity compared to current platinum anticancer drugs. 1,2,3,4-tetrahydrisoquinoline amino alcohol ligands were synthesised, characterised and coordinated to an organometallic Ru(II) centre. These complexes were evaluated for activity against the cancer cell lines MCF-7, A549 and MDA-MB-231 as well as for toxicity in the normal cell line MDBK. They were observed to be moderately active against only the MCF-7 cells with the best IC₅₀ value of 34 μM for the cis-diastereomeric complex C4. They also displayed excellent selectivity by being relatively inactive against the normal MDBK cell line with SI values ranging from 2.3 to 7.4.

  2. Metal-Ligand Cooperativity in a Methandiide-Derived Iridium Carbene Complex.

    PubMed

    Weismann, Julia; Waterman, Rory; Gessner, Viktoria H

    2016-03-01

    The synthesis, electronic structure, and reactivity of the first Group 9 carbene complex, [Cp*IrL] [L=C(Ph2 PS)(SO2 Ph)] (2), based on a dilithio methandiide are reported. Spectroscopic as well as computational studies have shown that, despite using a late transition-metal precursor, sufficient charge transfer occurred from the methandiide to the metal, resulting in a stable, nucleophilic carbene species with pronounced metal-carbon double-bond character. The potential of this iridium complex in the activation of a series of E-H bonds by means of metal-ligand cooperation has been tested. These studies have revealed distinct differences in the reactivity of 2 compared to a previously reported ruthenium analogue. Whereas attempts to activate the O-H bond in different phenol derivatives resulted in ligand cleavage, H-H and Si-H activation as well as dehydrogenation of isopropanol have been accomplished. These reactions are driven by the transformation of the carbene to an alkyl ligand. Contrary to a previously reported ruthenium carbene system, the dihydrogen activation has been found to proceed by a stepwise mechanism, with the activation first taking place solely at the metal. The activated products further reacted to afford a cyclometalated complex through liberation of the activated substrates. In the case of triphenylsilane, cyclometalation could thus be induced by a substoichiometric (i.e., catalytic) amount of silane. PMID:26748420

  3. Redox properties of ruthenium nitrosyl porphyrin complexes with different axial ligation: structural, spectroelectrochemical (IR, UV-visible, and EPR), and theoretical studies.

    PubMed

    Singh, Priti; Das, Atanu Kumar; Sarkar, Biprajit; Niemeyer, Mark; Roncaroli, Federico; Olabe, José A; Fiedler, Jan; Zális, Stanislav; Kaim, Wolfgang

    2008-08-18

    Experimental and computational results for different ruthenium nitrosyl porphyrin complexes [(Por)Ru(NO)(X)] ( n+ ) (where Por (2-) = tetraphenylporphyrin dianion (TPP (2 (-) )) or octaethylporphyrin dianion (OEP (2-)) and X = H 2O ( n = 1, 2, 3) or pyridine, 4-cyanopyridine, or 4- N,N-dimethylaminopyridine ( n = 1, 0)) are reported with respect to their electron-transfer behavior. The structure of [(TPP)Ru(NO)(H 2O)]BF 4 is established as an {MNO} species with an almost-linear RuNO arrangement at 178.1(3) degrees . The compound [(Por)Ru(NO)(H 2O)]BF 4 undergoes two reversible one-electron oxidation processes. Spectroelectrochemical measurements (IR, UV-vis-NIR, and EPR) indicate that the first oxidation occurs on the porphyrin ring, as evident from the appearance of diagnostic porphyrin radical-anion vibrational bands (1530 cm (-1) for OEP (*-) and 1290 cm (-1) for TPP (*-)), from the small shift of approximately 20 cm (-1) for nu NO and from the EPR signal at g iso approximately 2.00. The second oxidation, which was found to be electrochemically reversible for the OEP compound, shows a 55 cm (-1) shift in nu NO, suggesting a partially metal-centered process. The compounds [(Por)Ru(NO)(X)]BF 4, where X = pyridines, undergo a reversible one-electron reduction. The site of the reduction was determined by spectroelectrochemical studies to be NO-centered with a ca. -300 cm (-1) shift in nu NO. The EPR response of the NO (*) complexes was essentially unaffected by the variation in the substituted pyridines X. DFT calculations support the interpretation of the experimental results because the HOMO of [(TPP)Ru(NO)(X)] (+), where X = H 2O or pyridines, was calculated to be centered at the porphyrin pi system, whereas the LUMO of [(TPP)Ru(NO)(X)] (+) has about 50% pi*(NO) character. This confirms that the (first) oxidation of [(Por)Ru(NO)(H 2O)] (+) occurs on the porphyrin ring wheras the reduction of [(Por)Ru(NO)(X)] (+) is largely NO-centered with the metal remaining in

  4. Pyrithione-based ruthenium complexes as inhibitors of aldo-keto reductase 1C enzymes and anticancer agents.

    PubMed

    Kljun, Jakob; Anko, Maja; Traven, Katja; Sinreih, Maša; Pavlič, Renata; Peršič, Špela; Ude, Žiga; Codina, Elisa Esteve; Stojan, Jure; Lanišnik Rižner, Tea; Turel, Iztok

    2016-08-01

    Four ruthenium complexes of clinically used zinc ionophore pyrithione and its oxygen analog 2-hydroxypyridine N-oxide were prepared and evaluated as inhibitors of enzymes of the aldo-keto reductase subfamily 1C (AKR1C). A kinetic study assisted with docking simulations showed a mixed type of inhibition consisting of a fast reversible and a slow irreversible step in the case of both organometallic compounds 1A and 1B. Both compounds also showed a remarkable selectivity towards AKR1C1 and AKR1C3 which are targets for breast cancer drug design. The organoruthenium complex of ligand pyrithione as well as pyrithione itself also displayed toxicity on the hormone-dependent MCF-7 breast cancer cell line with EC50 values in the low micromolar range. PMID:27357845

  5. Sodium lauryl sulfate-ruthenium(II) interactions: Photogalvanic and photophysical behavior of Ru(II)-diimine complexes

    SciTech Connect

    Akasheh, T.S.; Al-Rawashdeh, N.A.F. )

    1990-11-15

    The photogalvanic and photophysical behavior of a number of mixed-ligand ruthenium(II) complexes of 2,2{prime}-bipyridine (bpy), 3,3{prime}-bipyradzine (bpd), 2-(2{prime}-pyridyl)quinoline (pyrq), 4,4{prime}-dimethyl-2,2{prime}-bipyridine (dmbpy), and 2,3-bis(2{prime}-pyridyl)pyrazine (dpp) is reported both in water and in sodium lauryl sulfate (SDS) solutions. The effect of SDS on the photogalvanic experiment is predominantly an enhancement and/or modification of the photochemical and electrochemical processes. Luminescence, lifetime measurements, and photochemical behavior are affected by SDS and are used to predict possible modes of micelle-complex interactions.

  6. Selective Hydrogen Generation from Formic Acid with Well-Defined Complexes of Ruthenium and Phosphorus-Nitrogen PN(3) -Pincer Ligand.

    PubMed

    Pan, Yupeng; Pan, Cheng-Ling; Zhang, Yufan; Li, Huaifeng; Min, Shixiong; Guo, Xunmun; Zheng, Bin; Chen, Hailong; Anders, Addison; Lai, Zhiping; Zheng, Junrong; Huang, Kuo-Wei

    2016-05-01

    An unsymmetrically protonated PN(3) -pincer complex in which ruthenium is coordinated by one nitrogen and two phosphorus atoms was employed for the selective generation of hydrogen from formic acid. Mechanistic studies suggest that the imine arm participates in the formic acid activation/deprotonation step. A long life time of 150 h with a turnover number over 1 million was achieved.

  7. Ruthenium(ii) complexes of hemilabile pincer ligands: synthesis and catalysing the transfer hydrogenation of ketones.

    PubMed

    Nair, Ashwin G; McBurney, Roy T; Walker, D Barney; Page, Michael J; Gatus, Mark R D; Bhadbhade, Mohan; Messerle, Barbara A

    2016-09-28

    A series of Ru(ii) complexes were synthesised based on a hemilabile pyrazole-N-heterocyclic carbene (NHC)-pyrazole (C3N2H3)CH2(C3N2H2)CH2(C3N2H3) NCN pincer ligand 1. All complexes were fully characterised using single crystal X-ray crystallography and multinuclear NMR spectroscopy. Hemilabile ligands provide flexible coordination modes for the coordinating metal ion which can play a significant effect on the efficiency and mechanism of catalysis by the resulting complex. Here we observed and isolated mono-, bi- and tri-dentate complexes of both Ag(i) and Ru(ii) with 1 in which the resultant coordination mode was controlled by careful reagent selection. The catalytic activity of the Ru(ii) complexes for the transfer hydrogenation reaction of acetophenone with isopropanol was investigated. The unexpected formation of the pentaborate anion, [B5O6(OH)4](-), during the synthesis of complex 6a was found to have an unexpected positive effect by enhancing the catalysis rate. This work provides insights into the roles that different coordination modes, counterions and ligand hemilability play on the catalytic activity in transfer hydrogenations. PMID:27539740

  8. A chelate-stabilized ruthenium(sigma-pyrrolato) complex: resolving ambiguities in nuclearity and coordination geometry through 1H PGSE and 31P solid-state NMR studies.

    PubMed

    Foucault, Heather M; Bryce, David L; Fogg, Deryn E

    2006-12-11

    Reaction of RuCl2(PPh3)3 with LiNN' (NN' = 2-[(2,6-diisopropylphenyl)imino]pyrrolide) affords a single product, with the empirical formula RuCl[(2,6-iPr2C6H3)N=CHC4H3N](PPh3)2. We identify this species as a sigma-pyrrolato complex, [Ru(NN')(PPh3)2]2(mu-Cl)2 (3b), rather than mononuclear RuCl(NN')(PPh3)2 (3a), on the basis of detailed 1D and 2D NMR characterization in solution and in the solid state. Retention of the chelating, sigma-bound iminopyrrolato unit within 3b, despite the presence of labile (dative) chloride and PPh3 donors, indicates that the chelate effect is sufficient to inhibit sigma --> pi isomerization of 3b to a piano-stool, pi-pyrrolato structure. 2D COSY, SECSY, and J-resolved solid-state 31P NMR experiments confirm that the PPh3 ligands on each metal center are magnetically and crystallographically inequivalent, and 31P CP/MAS NMR experiments reveal the largest 99Ru-31P spin-spin coupling constant (1J(99Ru,31P) = 244 +/- 20 Hz) yet measured. Finally, 31P dipolar-chemical shift spectroscopy is applied to determine benchmark phosphorus chemical shift tensors for phosphine ligands in hexacoordinate ruthenium complexes.

  9. Application of capillary electrophoresis-inductively coupled plasma mass spectrometry to comparative studying of the reactivity of antitumor ruthenium(III) complexes differing in the nature of counter-ion toward human serum proteins.

    PubMed

    Połeć-Pawlak, Kasia; Abramski, Jan K; Ferenc, Julia; Foteeva, Lidia S; Timerbaev, Andrei R; Keppler, Bernhard K; Jarosz, Maciej

    2008-05-30

    Varying the counter-ion is a highly supportive practice in tackling the problem of poor water-solubility of metal complexes of pharmaceutical importance. As a matter of fact, the relevant structural modification may alter the metabolic pathways and possibly the mode of action of a drug. To prove that this does not take place for one of the lead anticancer metal-based developmental compounds, indazolium trans-[RuCl(4)(1H-indazole)(2)] (KP1019), its reactivity toward human serum proteins was assessed under simulated physiological conditions and compared to that of a much more soluble analogue, sodium trans-[RuCl(4)(1H-indazole)(2)] (KP1339). For such kinetic assaying, capillary electrophoresis (CE) interfaced online with inductively coupled plasma mass spectrometry (ICP-MS) to specifically monitor changes in the metal speciation following the formation of ruthenium-protein adducts was applied. The rate constants of interaction with albumin and transferrin were determined at pharmacologically fitting drug-to-protein ratios as on average 0.0319+/-0.0021 min(-1) and 0.0931+/-0.0019 min(-1) (KP1019) and 0.0316+/-0.0018 min(-1) and 0.0935+/-0.0053 min(-1) (KP1339), respectively. The results of this brief study showed that changing from organic to inorganic counter-ion at the stage of formulation could commonly be recommended for improving ruthenium-based drug solubility and bioavailability.

  10. Highly efficient redox isomerization of allylic alcohols at ambient temperature catalyzed by novel ruthenium-cyclopentadienyl complexes--new insight into the mechanism.

    PubMed

    Martín-Matute, Belén; Bogár, Krisztián; Edin, Michaela; Kaynak, F Betül; Bäckvall, Jan-E

    2005-10-01

    A range of ruthenium cyclopentadienyl (Cp) complexes have been prepared and used for isomerization of allylic alcohols to the corresponding saturated carbonyl compounds. Complexes bearing CO ligands show higher activity than those with PPh3 ligands. The isomerization rate is highly affected by the substituents on the Cp ring. Tetra(phenyl)methyl-substituted catalysts rapidly isomerize allylic alcohols under very mild reaction conditions (ambient temperature) with short reaction times. Substituted allylic alcohols have been isomerized by employing Ru-Cp complexes. A study of the isomerization catalyzed by [Ru(Ph5Cp)(CO)2H] (14) indicates that the isomerization catalyzed by ruthenium hydrides partly follows a different mechanism than that of ruthenium halides activated by KOtBu. Furthermore, the lack of ketone exchange when the isomerization was performed in the presence of an unsaturated ketone (1 equiv), different from that obtained by dehydrogenation of the starting allylic alcohol, supports a mechanism in which the isomerization takes place within the coordination sphere of the ruthenium catalyst. PMID:16028298

  11. Ruthenium(II) and osmium(II) vinyl complexes as highly sensitive and selective chromogenic and fluorogenic probes for the sensing of carbon monoxide in air.

    PubMed

    Toscani, Anita; Marín-Hernández, Cristina; Moragues, María E; Sancenón, Félix; Dingwall, Paul; Brown, Neil J; Martínez-Máñez, Ramón; White, Andrew J P; Wilton-Ely, James D E T

    2015-10-01

    The detection of carbon monoxide in solution and air has been achieved using simple, inexpensive systems based on the vinyl complexes [M(CHCHR)Cl(CO)(BTD)(PPh3 )2 ] (R=aryl, BTD=2,1,3-benzothiadiazole). Depending on the nature of the vinyl group, chromogenic and fluorogenic responses signalled the presence of this odourless, tasteless, invisible, and toxic gas. Solutions of the complexes in CHCl3 underwent rapid change between easily differentiated colours when exposed to air samples containing CO. More significantly, the adsorption of the complexes on silica produced colorimetric probes for the naked-eye detection of CO in the gas phase. Structural data for key species before and after the addition of CO were obtained by means of single X-ray diffraction studies. In all cases, the ruthenium and osmium vinyl complexes studied showed a highly selective response to CO with exceptionally low detection limits. Naked-eye detection of CO at concentrations as low as 5 ppb in air was achieved with the onset of toxic levels (i.e., 100 ppm), thus resulting in a remarkably clear colour change. Moreover, complexes bearing pyrenyl, naphthyl, and phenanthrenyl moieties were fluorescent, and greater sensitivities were achieved (through turn-on emission fluorescence) in the presence of CO both in solution and air. This behaviour was explored computationally using time-dependent density functional theory (TDDFT) experiments. In addition, the systems were shown to be selective for CO over all other gases tested, including water vapour and common organic solvents. Supporting the metal complexes on cellulose strips for use in an existing optoelectronic device allows numerical readings for the CO concentration to be obtained and provision of an alarm system.

  12. Ruthenium(II) and osmium(II) vinyl complexes as highly sensitive and selective chromogenic and fluorogenic probes for the sensing of carbon monoxide in air.

    PubMed

    Toscani, Anita; Marín-Hernández, Cristina; Moragues, María E; Sancenón, Félix; Dingwall, Paul; Brown, Neil J; Martínez-Máñez, Ramón; White, Andrew J P; Wilton-Ely, James D E T

    2015-10-01

    The detection of carbon monoxide in solution and air has been achieved using simple, inexpensive systems based on the vinyl complexes [M(CHCHR)Cl(CO)(BTD)(PPh3 )2 ] (R=aryl, BTD=2,1,3-benzothiadiazole). Depending on the nature of the vinyl group, chromogenic and fluorogenic responses signalled the presence of this odourless, tasteless, invisible, and toxic gas. Solutions of the complexes in CHCl3 underwent rapid change between easily differentiated colours when exposed to air samples containing CO. More significantly, the adsorption of the complexes on silica produced colorimetric probes for the naked-eye detection of CO in the gas phase. Structural data for key species before and after the addition of CO were obtained by means of single X-ray diffraction studies. In all cases, the ruthenium and osmium vinyl complexes studied showed a highly selective response to CO with exceptionally low detection limits. Naked-eye detection of CO at concentrations as low as 5 ppb in air was achieved with the onset of toxic levels (i.e., 100 ppm), thus resulting in a remarkably clear colour change. Moreover, complexes bearing pyrenyl, naphthyl, and phenanthrenyl moieties were fluorescent, and greater sensitivities were achieved (through turn-on emission fluorescence) in the presence of CO both in solution and air. This behaviour was explored computationally using time-dependent density functional theory (TDDFT) experiments. In addition, the systems were shown to be selective for CO over all other gases tested, including water vapour and common organic solvents. Supporting the metal complexes on cellulose strips for use in an existing optoelectronic device allows numerical readings for the CO concentration to be obtained and provision of an alarm system. PMID:26270512

  13. Mechanism of ruthenium-catalyzed hydrogen transfer reactions. Concerted transfer of OH and CH hydrogens from an alcohol to a (Cyclopentadienone)ruthenium complex.

    PubMed

    Johnson, Jeffrey B; Bäckvall, Jan-E

    2003-10-01

    Kinetic studies of the ruthenium-catalyzed dehydrogenation of 1-(4-fluorophenyl)ethanol (4) by tetrafluorobenzoquinone (7) using the Shvo catalyst 1 at 70 degrees C show that the dehydrogenation by catalytic intermediate 2 is rate-determining with the rate = k[4][1](1/2) and with deltaH++ = 17.7 kcal mol(-1) and deltaS++ = -13.0 eu. The use of specifically deuterated derivative 4-CHOD and 4-CDOH gave individual isotope effects of k(CHOH)/k(CHOD) = 1.87 +/- 0.17 and k(CHOH)/k(CDOH) = 2.57 +/- 0.26, respectively. Dideuterated derivative 4-CDOD gave a combined isotope effect of k(CHOH)/k(CDOD) = 4.61 +/- 0.37. These isotope effects are consistent with a concerted transfer of both hydrogens of the alcohol to ruthenium species 2. PMID:14510542

  14. Transient Absorption and Time-Resolved Fluorescence Studies of Solvated Ruthenium Di-Bipyridine Pseudo-Halide Complexes

    NASA Astrophysics Data System (ADS)

    Compton, R.; Weidinger, D.; Owrutsky, J. C.

    2012-06-01

    Time-resolved IR and fluorescence measurements were performed to probe the vibrational and electronic properties, respectively, of ruthenium di-bipyridine pseudo-halide (Ru(Bpy){_2}(X){_2} (where X = CN, N{_3} or NCS)) complexes. Vibrational energy relaxation (VER) times were determined for the complexes dissolved in dimethyl sulfoxide (DMSO) with a trend in VER time of NCS > CN > N{_3}. A similar trend and comparable absolute rates for NCS- and N3- were previously observed by our group and others for simple inorganic anions in solution, suggesting a minimal contribution due to complexation. Measurements of the VER time of the CN complex in various solvents provide VER times in ethanol (42.3 ps) and DMSO (53.3 ps), which shows that protic solvents promote the relaxation. Time-resolved fluorescence measurements indicate a strong ligand dependence, with a factor of five decrease in the excited electronic state decay time from the CN (215 ns) to the NCS (39 ns) complex. A solvent dependence of the CN complex reveals a nearly 3-fold increase in the fluorescence decay time from acetonitrile (70 ns) to DMSO (215 ns).

  15. Cyclometalated complexes of ruthenium. 3. Spectral, electrochemical, and two-dimensional proton NMR of (Ru(bpy)/sub 2/(cyclometalating ligand))/sup +/

    SciTech Connect

    Reveco, P.; Cherry, W.R.; Medley, J.; Garber, A.; Gale, R.J.; Selbin, J.

    1986-05-21

    Cyclometalated complexes of ruthenium(II), (Ru(bpy)/sub 2/(L))/sup +/, where L = 2-(3-nitrophenyl)pyridine, phenylpyridine, benzo(h)quinoline, azobenzene, and p-(dimethylamino)azobenzene, have been prepared and characterized by two-dimensional proton NMR (HDCOSY) spectra and by cyclic voltammetry. Excited-state behavior of the complexes of the first three listed ligands has been investigated by absorption and emission spectroscopy and the photochemical stability of these species monitored. A substantial decrease is found in oxidation potential (the oxidations are metal-centered, with the electron coming from a t/sub 2/ orbital) in going from a dication (e.g. (Ru(bpy)/sub 3/)/sup 2 +/) containing bidentate nitrogen donors only to our monocation containing a cyclometalated anion. This decrease undoubtedly results from both the ion charge decrease and the replacement of a sigma-donor/..pi..-acceptor nitrogen by a much stronger sigma-donor carbanion. The one-electron reduction of (Ru(bpy)/sub 3/)/sup 2 +/ results in (Ru(bpy)/sub 2/(bpy/sup -/))/sup +/. Absorption bands of our new species found in the visible region (450-550 nm) are assigned as metal-to-ligand transitions (MLCT), the lower energy one associated with the bpy ligand and the higher energy one associated with the carbon-bonded anion. All three complexes emit in a glass at 77 K. Temperature dependence of the emission intensities and lifetimes is discussed as is evidence for photoanation or very rapid nonradiative decay for different species.

  16. Thiol-Activated HNO Release from a Ruthenium Antiangiogenesis Complex and HIF-1α Inhibition for Cancer Therapy

    PubMed Central

    2016-01-01

    Metallonitrosyl complexes are promising as nitric oxide (NO) donors for the treatment of cardiovascular, endothelial, and pathogenic diseases, as well as cancer. Recently, the reduced form of NO– (protonated as HNO, nitroxyl, azanone, isoelectronic with O2) has also emerged as a candidate for therapeutic applications including treatment of acute heart failure and alcoholism. Here, we show that HNO is a product of the reaction of the RuII complex [Ru(bpy)2(SO3)(NO)]+ (1) with glutathione or N-acetyl-L-cysteine, using met-myoglobin and carboxy-PTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) as trapping agents. Characteristic absorption spectroscopic profiles for HNO reactions with met-myoglobin were obtained, as well as EPR evidence from carboxy-PTIO experiments. Importantly, the product HNO counteracted NO-induced as well as hypoxia-induced stabilization of the tumor-suppressor HIF-1α in cancer cells. The functional disruption of neovascularization by HNO produced by this metallonitrosyl complex was demonstrated in an in vitro angiogenesis model. This behavior is consistent with HNO biochemistry and contrasts with NO-mediated stabilization of HIF-1α. Together, these results demonstrate for the first time thiol-dependent production of HNO by a ruthenium complex and subsequent destabilization of HIF-1α. This work suggests that the complex warrants further investigation as a promising antiangiogenesis agent for the treatment of cancer. PMID:27191177

  17. Metal oxide films on metal

    DOEpatents

    Wu, Xin D.; Tiwari, Prabhat

    1995-01-01

    A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

  18. Luminescent Ruthenium(II) Complex Bearing Bipyridine and N-Heterocyclic Carbene-based C∧N∧C Pincer Ligand for Live-Cell Imaging of Endocytosis

    NASA Astrophysics Data System (ADS)

    Tsui, Wai-Kuen; Chung, Lai-Hon; Wong, Matthew Man-Kin; Tsang, Wai-Him; Lo, Hoi-Shing; Liu, Yaxiang; Leung, Chung-Hang; Ma, Dik-Lung; Chiu, Sung-Kay; Wong, Chun-Yuen

    2015-03-01

    Luminescent ruthenium(II)-cyanide complex with N-heterocyclic carbene pincer ligand C∧N∧C = 2,6-bis(1-butylimidazol-2-ylidene)pyridine and 2,2'-bipyridine (bpy) shows minimal cytotoxicity to both human breast carcinoma cell (MCF-7) and human retinal pigmented epithelium cell (RPE) in a wide range of concentration (0.1-500 μM), and can be used for the luminescent imaging of endocytosis of the complex in these cells.

  19. Proton coupled electron transfer from the excited state of a ruthenium(II) pyridylimidazole complex.

    PubMed

    Pannwitz, Andrea; Wenger, Oliver S

    2016-04-28

    Proton coupled electron transfer (PCET) from the excited state of [Ru(bpy)2pyimH](2+) (bpy = 2,2'-bipyridine; pyimH = 2-(2'-pyridyl)imidazole) to N-methyl-4,4'-bipyridinium (monoquat, MQ(+)) was studied. While this complex has been investigated previously, our study is the first to show that the formal bond dissociation free energy (BDFE) of the imidazole-N-H bond decreases from (91 ± 1) kcal mol(-1) in the electronic ground state to (43 ± 5) kcal mol(-1) in the lowest-energetic (3)MLCT excited state. This makes the [Ru(bpy)2pyimH](2+) complex a very strong (formal) hydrogen atom donor even when compared to metal hydride complexes, and this is interesting for light-driven (formal) hydrogen atom transfer (HAT) reactions with a variety of different substrates. Mechanistically, formal HAT between (3)MLCT excited [Ru(bpy)2pyimH](2+) and monoquat in buffered 1 : 1 (v : v) CH3CN/H2O was found to occur via a sequence of reaction steps involving electron transfer from Ru(ii) to MQ(+) coupled to release of the N-H proton to buffer base, followed by protonation of reduced MQ(+) by buffer acid. Our study is relevant in the larger contexts of photoredox catalysis and light-to-chemical energy conversion. PMID:27094541

  20. A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo

    PubMed Central

    Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

    2015-01-01

    Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42 nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully. PMID:25640000

  1. A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo

    NASA Astrophysics Data System (ADS)

    Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

    2015-02-01

    Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42 nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully.

  2. Efficient and selective hydrogen generation from bioethanol using ruthenium pincer-type complexes.

    PubMed

    Sponholz, Peter; Mellmann, Dörthe; Cordes, Christoph; Alsabeh, Pamela G; Li, Bin; Li, Yang; Nielsen, Martin; Junge, Henrik; Dixneuf, Pierre; Beller, Matthias

    2014-09-01

    Catalytic generation of hydrogen from aqueous ethanol solution proceeds in the presence of pincer-type transition metal catalysts. Optimal results are obtained applying a [Ru(H)(Cl)(CO)(iPr2PEtN(H)EtPiPr2)] complex (catalyst TON 80,000) in the presence of water and base. This dehydrogenation reaction provides up to 70% acetic acid in a selective manner. For the first time, it is shown that bioethanol obtained from fermentation processes can be used directly in this protocol without the need for water removal. The produced hydrogen can be directly utilized in proton exchange membrane (PEM) fuel cells, since very low amounts of CO are formed.

  3. Efficient and selective hydrogen generation from bioethanol using ruthenium pincer-type complexes.

    PubMed

    Sponholz, Peter; Mellmann, Dörthe; Cordes, Christoph; Alsabeh, Pamela G; Li, Bin; Li, Yang; Nielsen, Martin; Junge, Henrik; Dixneuf, Pierre; Beller, Matthias

    2014-09-01

    Catalytic generation of hydrogen from aqueous ethanol solution proceeds in the presence of pincer-type transition metal catalysts. Optimal results are obtained applying a [Ru(H)(Cl)(CO)(iPr2PEtN(H)EtPiPr2)] complex (catalyst TON 80,000) in the presence of water and base. This dehydrogenation reaction provides up to 70% acetic acid in a selective manner. For the first time, it is shown that bioethanol obtained from fermentation processes can be used directly in this protocol without the need for water removal. The produced hydrogen can be directly utilized in proton exchange membrane (PEM) fuel cells, since very low amounts of CO are formed. PMID:25088665

  4. Optimization of conditions for the determination of boron by a ruthenium(II) complex having diol moiety: A mechanistic study.

    PubMed

    Nakano, Eiko; Iwatsuki, Satoshi; Inamo, Masahiko; Takagi, Hideo D; Ishihara, Koji

    2008-01-15

    Two ruthenium(II) complexes, [Ru(bpy)(2)(dhbpy-H(-1))](+) and [Ru(bpy)(2)(dhphen)](2+) (bpy=2,2'-bipyridine, dhbpy=3,3'-dihydroxy-2,2'-bipyridine, dhphen=5,6-dihydroxy-1,10-phenanthroline) were examined for use as a colorimetric reagent for the determination of boron. The reactions of boric acid with these two complexes were thermodynamically and kinetically studied in detail in order to specify the reactive species and to set up optimum condition for the determination of boron. The detailed analysis of the kinetic data for the reaction of the latter water-soluble complex showed that both boric acid and borate ion were reactive in an alkaline solution. The thermodynamically and kinetically optimum pH for the determination of boron was ca. 9 at 25 degrees C. A spectrofluorimetric determination of boron with the latter complex was attempted at 600nm with excitation at 360nm, and at pH 8.9 using CHES (N-cyclohexyl-2-aminoethanesulfonic acid) buffer. It was found that a trace amount of boron as low as ca. 2x10(-5)M ( approximately 1ppm) could be detectable.

  5. Ruthenium, osmium and rhodium complexes of 1,4-diaryl 1,4-diazabutadiene: radical versus non-radical states.

    PubMed

    Chandra Patra, Sarat; Saha Roy, Amit; Manivannan, Vadivelu; Weyhermüller, Thomas; Ghosh, Prasanta

    2014-09-28

    Ruthenium, osmium and rhodium complexes of 1,4-di(3-nitrophenyl)-1,4-diazabutadiene (LDAB) of types trans-[RuII(LDAB)(PPh3)2Cl2] (1), trans-[OsII(LDAB)(PPh3)2Br2] (2) and trans-[Rh(LDAB)(PPh3)2Cl2] (3) are isolated and characterized by elemental analyses, IR, mass and 1H NMR spectra including the single crystal X-ray structure determination of 1·2toluene. The α-diimine fragment of the LDAB ligand in 1·2toluene is deformed, showing a relatively longer -C=N- bond, 1.320 Å, and a shorter =CH–CH= bond, 1.395 Å. Density functional theory (DFT) calculations on trans-[Ru(LDAB)(PMe3)2Cl2] (1Me) and trans-[Os(LDAB)(PMe3)2Br2] (2Me) with singlet spin states authenticated that the closed shell singlet state (CSS) solutions of 1 and 2 are stable and no perturbation occurs because of the diradical open shell singlet (OSS) state. The EPR spectra of 3 and the Mulliken spin density distribution obtained from the DFT calculation on trans-[Rh(LDAB)(PMe3)2Cl2] (3Me) imply that the ground electronic state of 3 can be defined by the [RhIII(LDAB˙−)(PPh3)2Cl2] (3RhL˙) ↔ [RhII(LDAB)(PPh3)2Cl2] (3Rh˙L) resonating states. In solid, the contribution of 3RhL˙ is higher and the gav is 2.018 with Δg = 0.10, whereas in frozen glasses the contribution of 3Rh˙L is higher and the gav is 2.026 with Δg (frozen glasses) = 0.13. The g parameters of the electrogenerated [1]+ (g1 = 2.456, g2 = 2.128 and g3 = 1.624, Δg = 0.824), [2]+ (g1 = 2.599, g2 = 2.041 and g3 = 1.965, Δg = 0.634), [1]− (g1 = 2.138, g2 = 2.109, g3 = 1.978 and Δg = 0.160) and [2]− (g1 = 2.168, g2 = 2.097, g3 = 1.987 and Δg = 0.181) ions and the spin density distributions obtained from the DFT calculations on [1Me]+, [2Me]+, [1Me]− and [2Me]− reveal that the reversible anodic peaks of 1 and 2 at 0.11 and 0.34 V, referenced versus Fc+/Fc couple, are due to the M(III)/M(II) redox couple, while the reversible cathodic waves at −1.27 V and −0.82 V of 1 and 2 are caused by the LDAB/LDAB˙− redox couple

  6. Steric and Electronic Effects of Bidentate Phosphine Ligands on Ruthenium(II)-Catalyzed Hydrogenation of Carbon Dioxide.

    PubMed

    Zhang, Pan; Ni, Shao-Fei; Dang, Li

    2016-09-20

    The reactivity difference between the hydrogenation of CO2 catalyzed by various ruthenium bidentate phosphine complexes was explored by DFT. In addition to the ligand dmpe (Me2 PCH2 CH2 PMe2 ), which was studied experimentally previously, a more bulky diphosphine ligand, dmpp (Me2 PCH2 CH2 CH2 PMe2 ), together with a more electron-withdrawing diphosphine ligand, PN(Me) P (Me2 PCH2 N(Me) CH2 PMe2 ), have been studied theoretically to analyze the steric and electronic effects on these catalyzed reactions. Results show that all of the most favorable pathways for the hydrogenation of CO2 catalyzed by bidentate phosphine ruthenium dihydride complexes undergo three major steps: cis-trans isomerization of ruthenium dihydride complex, CO2 insertion into the Ru-H bond, and H2 insertion into the ruthenium formate ion. Of these steps, CO2 insertion into the Ru-H bond has the lowest barrier compared with the other two steps in each preferred pathway. For the hydrogenation of CO2 catalyzed by ruthenium complexes of dmpe and dmpp, cis-trans isomerization of ruthenium dihydride complex has a similar barrier to that of H2 insertion into the ruthenium formate ion. However, in the reaction catalyzed by the PN(Me) PRu complex, cis-trans isomerization of the ruthenium dihydride complex has a lower barrier than H2 insertion into the ruthenium formate ion. These results suggest that the steric effect caused by the change of the outer sphere of the diphosphine ligand on the reaction is not clear, although the electronic effect is significant to cis-trans isomerization and H2 insertion. This finding refreshes understanding of the mechanism and provides necessary insights for ligand design in transition-metal-catalyzed CO2 transformation. PMID:27500596

  7. MOLYBDENUM, RUTHENIUM, AND THE HEAVY r-PROCESS ELEMENTS IN MODERATELY METAL-POOR MAIN-SEQUENCE TURNOFF STARS

    SciTech Connect

    Peterson, Ruth C.

    2013-05-01

    The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and s-processes, dominant production mechanisms of light trans-ironic elements were obscure until recently. This work investigates further our 2011 conclusion that the low-entropy regime of a high-entropy wind (HEW) produced molybdenum and ruthenium in two moderately metal-poor turnoff stars that showed extreme overabundances of those elements with respect to iron. Only a few, rare nucleosynthesis events may have been involved. Here we determine abundances for Mo, Ru, and other trans-Fe elements for 28 similar stars by matching spectral calculations to well-exposed near-UV Keck HIRES spectra obtained for beryllium abundances. In each of the 26 turnoff stars with Mo or Ru line detections and no evidence for s-process production (therefore old), we find Mo and Ru to be three to six times overabundant. In contrast, the maximum overabundance is reduced to factors of three and two for the neighboring elements zirconium and palladium. Since the overproduction peaks sharply at Mo and Ru, a low-entropy HEW is confirmed as its origin. The overabundance level of the heavy r-process elements varies significantly, from none to a factor of four, but is uncorrelated with Mo and Ru overabundances. Despite their moderate metallicity, stars in this group trace the products of different nucleosynthetic events: possibly very few events, possibly events whose output depended on environment, metallicity, or time.

  8. Molybdenum, Ruthenium, and the Heavy r-process Elements in Moderately Metal-poor Main-sequence Turnoff Stars

    NASA Astrophysics Data System (ADS)

    Peterson, Ruth C.

    2013-05-01

    The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and s-processes, dominant production mechanisms of light trans-ironic elements were obscure until recently. This work investigates further our 2011 conclusion that the low-entropy regime of a high-entropy wind (HEW) produced molybdenum and ruthenium in two moderately metal-poor turnoff stars that showed extreme overabundances of those elements with respect to iron. Only a few, rare nucleosynthesis events may have been involved. Here we determine abundances for Mo, Ru, and other trans-Fe elements for 28 similar stars by matching spectral calculations to well-exposed near-UV Keck HIRES spectra obtained for beryllium abundances. In each of the 26 turnoff stars with Mo or Ru line detections and no evidence for s-process production (therefore old), we find Mo and Ru to be three to six times overabundant. In contrast, the maximum overabundance is reduced to factors of three and two for the neighboring elements zirconium and palladium. Since the overproduction peaks sharply at Mo and Ru, a low-entropy HEW is confirmed as its origin. The overabundance level of the heavy r-process elements varies significantly, from none to a factor of four, but is uncorrelated with Mo and Ru overabundances. Despite their moderate metallicity, stars in this group trace the products of different nucleosynthetic events: possibly very few events, possibly events whose output depended on environment, metallicity, or time.

  9. Novel N-coordinate half-sandwich ruthenium(II) arene complexes bearing sulfonamide fragments: Catalytic activities in the TH of acetophenone derivatives

    NASA Astrophysics Data System (ADS)

    Kayaci, Nilgün; Dayan, Serkan; Kalaycioglu Ozpozan, Nilgun

    2015-11-01

    The novel cationic N-coordinate ruthenium(II)/arene complexes (6-10) were prepared from the starting complex [RuCl2(p-cymene)]2 dimer. The structures of the [(p-cymene)RuLCl]Cl (L = N-arenesulfonyl-4,5-dimethyl-o-phenylenediamines) complexes were elucidated by FT-IR, 1H-NMR, 13C-NMR, ionic conductivity techniques, and elemental analysis methods. The 6-10 complexes were applied as catalyst in the transfer hydrogenation (TH) of ketones. The catalytic tests showed that all the complexes are moderate catalysis precursors. Especially, {[N-benzenesulfonyl-4,5-dimethyl-o-phenylenediamine]-(p-cymene)-di-chloro-ruthenium(II)} (8) and {[N-4-chlorobenzenesulfonyl-4,5-dimethyl-o-phenylenediamine]-(p-cymene)-di-chloro-ruthenium(II)} (9) compounds were found to be a good catalysts in comparison to the others giving the corresponding alcohols in a good turnover frequency value of 1534 and 1731 h-1, respectively.

  10. Cellular uptake, cytotoxicity, apoptosis, DNA-binding, photocleavage and molecular docking studies of ruthenium(II) polypyridyl complexes.

    PubMed

    Srishailam, A; Kumar, Yata Praveen; Venkat Reddy, P; Nambigari, Navaneetha; Vuruputuri, Uma; Singh, Surya S; Satyanarayana, S

    2014-03-01

    Three new mononuclear [Ru (phen)2 ptip](2+) (1), [Ru (bpy)2 ptip](2+) (2) and [Ru (dmb)2 ptip](2+) (3) [ptip=(2-(5-phenylthiophen-2-yl)-1H-imidazo[4, 5-f][1,10 phenanthroline, phen=1, 10 phenanthroline, bpy=2, 2' bipyridine, dmb=4, 4'-dimethyl 2, 2' bipyridine] complexes were synthesized and characterised by elemental analysis, IR, NMR and Mass spectra. The DNA-binding behaviours were investigated by electronic absorption titration, luminescence spectra, viscosity measurements and photo-activated cleavage. The DNA-binding constants Kb of complexes 1, 2 and 3 were determined to be 7.0 (± 0.06)× 10(5), 3.87 (± 0.04) × 10(5), 2.79 (±0.07) × 10(5) respectively. The results showed that these complexes interact with CT-DNA by intercalative mode. Cell viability experiments indicated that the Ru(II) complex showed significant dose-dependent cytotoxicity to HeLa tumour cell lines. Further flow cytometry experiments showed that the cytotoxic Ru(II) complex induced apoptosis of HeLa tumour cell lines. Our data demonstrated that the Ru(II) polypyridyl complex binds to DNA and thereby induces apoptosis in tumor cells, suggesting that anti-tumor activity of the Ru(II) complex could be related to its interaction with DNA. The molecular dynamic simulations and docking methods were used to predict the DNA binding affinity of ruthenium complexes and with good visualisation images supporting with experimental results.

  11. Derivation of structure-activity relationships from the anticancer properties of ruthenium(II) arene complexes with 2-aryldiazole ligands.

    PubMed

    Martínez-Alonso, Marta; Busto, Natalia; Jalón, Félix A; Manzano, Blanca R; Leal, José M; Rodríguez, Ana M; García, Begoña; Espino, Gustavo

    2014-10-20

    The ligands 2-pyridin-2-yl-1H-benzimidazole (HL(1)), 1-methyl-2-pyridin-2-ylbenzimidazole (HL(2)), and 2-(1H-imidazol-2-yl)pyridine (HL(3)) and the proligand 2-phenyl-1H-benzimidazole (HL(4)) have been used to prepare five different types of new ruthenium(II) arene compounds: (i) monocationic complexes with the general formula [(η(6)-arene)RuCl(κ(2)-N,N-HL)]Y [HL = HL(1), HL(2), or HL(3); Y = Cl or BF4; arene = 2-phenoxyethanol (phoxet), benzene (bz), or p-cymene (p-cym)]; (ii) dicationic aqua complexes of the formula [(η(6)-arene)Ru(OH2)(κ(2)-N,N-HL(1))](Y)2 (Y = Cl or TfO; arene = phoxet, bz, or p-cym); (iii) the nucleobase derivative [(η(6)-arene)Ru(9-MeG)(κ(2)-N,N-HL(1))](PF6)2 (9-MeG = 9-methylguanine); (iv) neutral complexes consistent with the formulation [(η(6)-arene)RuCl(κ(2)-N,N-L(1))] (arene = bz or p-cym); (v) the neutral cyclometalated complex [(η(6)-p-cym)RuCl(κ(2)-N,C-L(4))]. The cytototoxic activity of the new ruthenium(II) arene compounds has been evaluated in several cell lines (MCR-5, MCF-7, A2780, and A2780cis) in order to establish structure-activity relationships. Three of the compounds with the general formula [(η(6)-arene)RuCl(κ(2)-N,N-HL(1))]Cl differing in the arene moiety have been studied in depth in terms of thermodynamic dissociation constants, aquation kinetic constants, and DNA binding measurements. The biologically most active compound is the p-cym derivative, which strongly destabilizes the DNA double helix, whereas those with bz and phoxet have only a small effect on the stability of the DNA double helix. Moreover, the inhibitory activity of several compounds toward CDK1 has also been evaluated. The DNA binding ability of some of the studied compounds and their CDK1 inhibitory effect suggest a multitarget mechanism for their biological activity.

  12. Ruthenium-Aryloxide Catalysts for Olefin Metathesis

    NASA Astrophysics Data System (ADS)

    Monfette, Sebastien; Blacquiere, Johanna M.; Conrad, Jay C.; Beach, Nicholas J.; Fogg, Deryn E.

    : Advances in design of ruthenium aryloxide catalysts for olefin metathesis are described. The target complexes are accessible on reaction of RuCl2(NHC)(py)2 (CHPh) (NHC - N-heterocyclic carbene) with electron-deficient, monodentate aryl- oxides, or aryloxides that yield small, rigid chelate rings. The best of these catalysts offer activity comparable to or greater than that of the parent chloride (Grubbs) systems in ring-closing metathesis (RCM). Preliminary studies of the electronic nature of the Ru-X bond suggest that the metal center is more electropositive in the aryloxide complexes than in the Grubbs systems.

  13. Competitive Binding Sites of a Ruthenium Arene Anticancer Complex on Oligonucleotides Studied by Mass Spectrometry: Ladder-Sequencing versus Top-Down

    NASA Astrophysics Data System (ADS)

    Wu, Kui; Hu, Wenbing; Luo, Qun; Li, Xianchan; Xiong, Shaoxiang; Sadler, Peter J.; Wang, Fuyi

    2013-03-01

    We report identification of the binding sites for an organometallic ruthenium anticancer complex [( η 6-biphenyl)Ru(en)Cl][PF6] ( 1; en = ethylenediamine) on the 15-mer single-stranded oligodeoxynucleotides (ODNs), 5'-CTCTCTX7G8Y9CTTCTC-3' [X = Y = T ( I); X = C and Y = A ( II); X = A and Y = T ( III); X = T and Y = A ( IV)] by electrospray ionization mass spectrometry (ESI-MS) in conjunction with enzymatic digestion or tandem mass spectrometry (top-down MS). ESI-MS combined with enzymatic digestion (termed MS-based ladder-sequencing), is effective for identification of the thermodynamically-favored G-binding sites, but not applicable to determine the thermodynamically unstable T-binding sites because the T-bound adducts dissociate during enzymatic digestion. In contrast, top-down MS is efficient for localization of the T binding sites, but not suitable for mapping ruthenated G bases, due to the facile fragmentation of G bases from ODN backbones prior to the dissociation of the phosphodiester bonds. The combination of the two MS approaches reveals that G8 in each ODN is the preferred binding site for 1, and that the T binding sites of 1 are either T7 or T11 on I and IV, and either T6 or T11 on II and III, respectively. These findings not only demonstrate for the first time that T-bases in single-stranded oligonucleotides are kinetically competitive with guanine for such organoruthenium complexes, but also illustrate the relative merits of the combination of ladder-sequencing and top-down MS approaches to elucidate the interactions of metal anticancer complexes with DNA.

  14. Conversion of cellulose and cellobiose into sorbitol catalyzed by ruthenium supported on a polyoxometalate/metal-organic framework hybrid.

    PubMed

    Chen, Jinzhu; Wang, Shengpei; Huang, Jing; Chen, Limin; Ma, Longlong; Huang, Xing

    2013-08-01

    Cellulose and cellobiose were selectively converted into sorbitol over water-tolerant phosphotungstic acid (PTA)/metal- organic-framework-hybrid-supported ruthenium catalysts, Ru-PTA/MIL-100(Cr), under aqueous hydrogenation conditions. The goal was to investigate the relationship between the acid/metal balance of bifunctional catalysts Ru-PTA/MIL-100(Cr) and their performance in the catalytic conversion of cellulose and cellobiose into sugar alcohols. The control of the amount and strength of acid sites in the supported PTA/MIL-100(Cr) was achieved through the effective control of encapsulated-PTA loading in MIL-100(Cr). This design and preparation method led to an appropriately balanced Ru-PTA/MIL-100(Cr) in terms of Ru dispersion and hydrogenation capacity on the one hand, and acid site density of PTA/MIL-100(Cr) (responsible for acid-catalyzed hydrolysis) on the other hand. The ratio of acid site density to the number of Ru surface atoms (nA /nRu ) of Ru-PTA/MIL-100(Cr) was used to monitor the balance between hydrogenation and hydrolysis functions; the optimum balance between the two catalytic functions, that is, 8.84metal bifunctional catalysts for biomass conversion. PMID:23619979

  15. Conversion of cellulose and cellobiose into sorbitol catalyzed by ruthenium supported on a polyoxometalate/metal-organic framework hybrid.

    PubMed

    Chen, Jinzhu; Wang, Shengpei; Huang, Jing; Chen, Limin; Ma, Longlong; Huang, Xing

    2013-08-01

    Cellulose and cellobiose were selectively converted into sorbitol over water-tolerant phosphotungstic acid (PTA)/metal- organic-framework-hybrid-supported ruthenium catalysts, Ru-PTA/MIL-100(Cr), under aqueous hydrogenation conditions. The goal was to investigate the relationship between the acid/metal balance of bifunctional catalysts Ru-PTA/MIL-100(Cr) and their performance in the catalytic conversion of cellulose and cellobiose into sugar alcohols. The control of the amount and strength of acid sites in the supported PTA/MIL-100(Cr) was achieved through the effective control of encapsulated-PTA loading in MIL-100(Cr). This design and preparation method led to an appropriately balanced Ru-PTA/MIL-100(Cr) in terms of Ru dispersion and hydrogenation capacity on the one hand, and acid site density of PTA/MIL-100(Cr) (responsible for acid-catalyzed hydrolysis) on the other hand. The ratio of acid site density to the number of Ru surface atoms (nA /nRu ) of Ru-PTA/MIL-100(Cr) was used to monitor the balance between hydrogenation and hydrolysis functions; the optimum balance between the two catalytic functions, that is, 8.84metal bifunctional catalysts for biomass conversion.

  16. Controlling ground and excited state properties through ligand changes in ruthenium polypyridyl complexes.

    PubMed

    Ashford, Dennis L; Glasson, Christopher R K; Norris, Michael R; Concepcion, Javier J; Keinan, Shahar; Brennaman, M Kyle; Templeton, Joseph L; Meyer, Thomas J

    2014-06-01

    The capture and storage of solar energy requires chromophores that absorb light throughout the solar spectrum. We report here the synthesis, characterization, electrochemical, and photophysical properties of a series of Ru(II) polypyridyl complexes of the type [Ru(bpy)2(N-N)](2+) (bpy = 2,2'-bipyridine; N-N is a bidentate polypyridyl ligand). In this series, the nature of the N-N ligand was altered, either through increased conjugation or incorporation of noncoordinating heteroatoms, as a way to use ligand electronic properties to tune redox potentials, absorption spectra, emission spectra, and excited state energies and lifetimes. Electrochemical measurements show that lowering the π* orbitals on the N-N ligand results in more positive Ru(3+/2+) redox potentials and more positive first ligand-based reduction potentials. The metal-to-ligand charge transfer absorptions of all of the new complexes are mostly red-shifted compared to Ru(bpy)3(2+) (λmax = 449 nm) with the lowest energy MLCT absorption appearing at λmax = 564 nm. Emission energies decrease from λmax = 650 nm to 885 nm across the series. One-mode Franck-Condon analysis of room-temperature emission spectra are used to calculate key excited state properties, including excited state redox potentials. The impacts of ligand changes on visible light absorption, excited state reduction potentials, and Ru(3+/2+) potentials are assessed in the context of preparing low energy light absorbers for application in dye-sensitized photoelectrosynthesis cells.

  17. Evaluation of optical excitation conditions for ruthenium complex for biosensor optodes

    NASA Astrophysics Data System (ADS)

    Pieper, Sean; Zhong, Zhong; Lear, Kevin L.; Reardon, Ken

    2007-03-01

    Development of a fiber optic biosensor incorporating genetically engineered enzymes which catalyze chlorinated ethenes in an oxygen-consuming reaction for in situ monitoring of groundwater contaminants motivates optimization of optode excitation conditions. These conditions affect the sensitivity, signal-to-noise, and optode service life impacting the quality of the overall biosensor. Optodes are generally comprised of a fluorophore conjugated with a polymer as a substrate cross linked at the distal end of a fiber optic. We investigate the excitation conditions of tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) chloride (Ru(dpp)3) conjugated with poly(vinyl alcohol) (PVOH) as an optode. A reported advantage of Ru(dpp)3 is that it has no emission spectral shift occurring under varying chemical and environmental conditions. Photostability degradation due to photobleaching of Ru(dpp)3 with PVOH as a substrate is explored by varying the optical irradiance of the fluorophore containing optode. Other issues relating to practical implementation of Ru(dpp)3 as oxygen sensitive biosensors will be discussed.

  18. Enantiomorphs of a carbene-ruthenium(II)-porphyrin complex with four 'chiral pillars'.

    PubMed

    Hirasawa, Kai; Yuge, Hidetaka; Miyamoto, Takeshi Ken

    2008-02-01

    The chiral metalloporphyrin (dibenzoylmethylene-kappaC)(ethanol-kappaO){5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracen-9-yl]porphyrinato-kappa(4)N}ruthenium(II)-ethanol-dichloromethane (1/2/2), [Ru(C(84)H(76)N(4))(C(15)H(10)O(2))(C(2)H(6)O)].2C(2)H(6)O.2CH(2)Cl(2), and its enantiomorph were prepared from enantiomerically pure porphyrins. The enantiomers are potential versatile catalysts for asymmetric cyclopropanation, aziridination or epoxidation. In each compound, the rather large dibenzoylcarbene group is squeezed between four columnar 1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracen-9-yl groups at the meso positions resulting in a doming deformation of the porphyrin core. The dibenzoylcarbene group has an anti conformation. The benzoyl O atoms make short van der Waals contacts (< 2.6 A) with the methine groups of the chiral columnar substituents at the 10 and 20 positions of the porphyrin rings. A hydrogen-bonded supramolecular chain is formed parallel to the b axis by interactions between the benzoyl O atom and the hydroxy groups of the coordinated and uncoordinated ethanol molecules. PMID:18252997

  19. Direct Observation of Photoinduced Charge Separation in Ruthenium Complex/Ni(OH)2 Nanoparticle Hybrid

    DOE PAGES

    Tang, Yu; Pattengale, Brian A.; Ludwig, John M.; Atifi, Abderrahman; Zinovev, Alexander V.; Dong, Bin; Kong, Qingyu; Zuo, Xiaobing; Zhang, Xiaoyi; Huang, Jier

    2015-12-17

    We report that Ni(OH)2 have emerged as important functional materials for solar fuel conversion because of their potential as cost-effective bifunctional catalysts for both hydrogen and oxygen evolution reactions. However, their roles as photocatalysts in the photoinduced charge separation (CS) reactions remain unexplored. In this paper, we investigate the CS dynamics of a newly designed hybrid catalyst by integrating a Ru complex with Ni(OH)2 nanoparticles (NPs). Using time resolved X-ray absorption spectroscopy (XTA), we directly observed the formation of the reduced Ni metal site (~60 ps), unambiguously demonstrating CS process in the hybrid through ultrafast electron transfer from Ru complexmore » to Ni(OH)2 NPs. Compared to the ultrafast CS process, the charge recombination in the hybrid is ultraslow (>>50 ns). These results not only suggest the possibility of developing Ni(OH)2 as solar fuel catalysts, but also represent the first time direct observation of efficient CS in a hybrid catalyst using XTA.« less

  20. Synthesis and structure of electron rich ruthenium polyhydride complexes and clusters containing AlCp* and GaCp*.

    PubMed

    Cadenbach, Thomas; Bollermann, Timo; Gemel, Christian; Fischer, Roland A

    2009-01-14

    The reactions of the ruthenium hydride complexes [{Ru(COD)(H)(NH2NMe2)3}{BArF}] (BArF=B{C6H3(CF3)2}4), [{Cp*Ru}2(micro-H)4] and [{Cp*Ru}3(micro-H)3(micro3-H)2] with GaCp* and AlCp* are investigated. The reaction of [{Ru(COD)(H)(NH2NMe2)3}{BArF}] with GaCp* leads to substitution of the hydrazine ligands by GaCp* and the formation of [{Ru(COD)(H)(GaCp*)3}{BArF}] (), while the reactions of [{Cp*Ru}2(micro-H)4] and [{Cp*Ru}3(micro-H)3(micro3-H)2] with ECp* (E=Al, Ga) results in the formation of the polyhydride clusters [{Cp*Ru(micro-H)(H)(micro-ECp*)}2] (, E=Ga; , E=Al) and [{Cp*Ru}3(micro-H)5(micro3-ECp*)] (, E=Al; , E=Ga). All Ru complexes react upon coordination of the group 13 ligand without loss of H2 or reductive elimination of Cp*H and without insertion into the Ru-H bonds; some of the products, however, showing Ru-H-E bridging motifs. All compounds were characterized by NMR spectroscopy, elemental analysis and single crystal X-ray diffraction studies. PMID:19089014

  1. Ruthenium(III)/phosphine/pyridine complexes applied in the hydrogenation reactions of polar and apolar double bonds

    NASA Astrophysics Data System (ADS)

    Rodrigues, Claudia; Delolo, Fábio G.; Ferreira, Lucas M.; da S. Maia, Pedro I.; Deflon, Victor M.; Rabeah, Jabor; Brückner, Angelika; Norinder, Jakob; Börner, Armin; Bogado, André L.; Batista, Alzir A.

    2016-05-01

    In this work, five ruthenium(III) complexes containing phosphine and pyridine based ligands with general formula mer-[RuCl3(dppb)(N)] [where dppb = 1,4-bis(diphenylphosphino)butane and N = pyridine (py), 4-methylpyridine (4-Mepy), 4-vinylpyridine (4-Vpy), 4-tert-butylpyridine (4-tBupy) and 4-phenylpyridine (4-Phpy)] were synthesized and characterized using spectroscopic and electrochemical techniques, as well as magnetic susceptibility to check the paramagnetism of these compounds. These complexes were tested as catalytic precursors in hydrogenation reactions with cyclohexene, undecanal and cyclohexanecarboxaldehyde, as compounds bearing Cdbnd C and Cdbnd O groups. Broad screening was carried out in order to find the optimal reaction conditions with the highest conversion. It was found that by using a ratio of Ru-catalyst/substrate = 1:530 at 80 °C and 15 bar of H2 for 24 h, cyclohexene can be reduced. Hydrogenation of undecanal was possible using a Ru-catalyst/substrate ratio of 1:100 at 160 °C and 100 bar for 24 h, and for the reduction of cyclohexanecarboxaldehyde the reaction conditions were Ru-catalyst/substrate ratio of 1:100 at 160 °C and 50 bar for 24 h.

  2. Structural studies on dinuclear ruthenium(II) complexes that bind diastereoselectively to an antiparallel folded human telomere sequence.

    PubMed

    Wilson, Tom; Costa, Paulo J; Félix, Vítor; Williamson, Mike P; Thomas, Jim A

    2013-11-14

    We report DNA binding studies of the dinuclear ruthenium ligand [{Ru(phen)2}2tpphz](4+) in enantiomerically pure forms. As expected from previous studies of related complexes, both isomers bind with similar affinity to B-DNA and have enhanced luminescence. However, when tested against the G-quadruplex from human telomeres (which we show to form an antiparallel basket structure with a diagonal loop across one end), the ΛΛ isomer binds approximately 40 times more tightly than the ΔΔ, with a stronger luminescence. NMR studies show that the complex binds at both ends of the quadruplex. Modeling studies, based on experimentally derived restraints obtained for the closely related [{Ru(bipy)2}2tpphz](4+), show that the ΛΛ isomer fits neatly under the diagonal loop, whereas the ΔΔ isomer is unable to bind here and binds at the lateral loop end. Molecular dynamics simulations show that the ΔΔ isomer is prevented from binding under the diagonal loop by the rigidity of the loop. We thus present a novel enantioselective binding substrate for antiparallel basket G-quadruplexes, with features that make it a useful tool for quadruplex studies.

  3. Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: Synthesis, structure, electrochemistry and DFT calculations

    NASA Astrophysics Data System (ADS)

    Al-Noaimi, Mousa; Awwadi, Firas F.; Mansi, Ahmad; Abdel-Rahman, Obadah S.; Hammoudeh, Ayman; Warad, Ismail

    2015-01-01

    The novel azoimine ligand, Phsbnd NHsbnd Ndbnd C(COCH3)sbnd NHPh(Ctbnd CH) (H2L), was synthesized and its molecular structure was determined by X-ray crystallography. Catalytic hydration of the terminal acetylene of H2L in the presence of RuCl3·3H2O in ethanol at reflux temperature yielded a ketone (L1 = Phsbnd Ndbnd Nsbnd C(COCH3)dbnd Nsbnd Ph(COCH3) and an enol (L2 = Phsbnd Ndbnd Nsbnd C(COCH3)dbnd Nsbnd PhC(OH)dbnd CH2) by Markovnikov addition of water. Two mixed-ligand ruthenium complexes having general formula, trans-[Ru(bpy)(Y)Cl2] (1-2) (where Y = L1 (1) and Y = L2 (2), bpy is 2.2‧-bipyrdine) were achieved by the stepwise addition of equimolar amounts of (H2L) and bpy ligands to RuCl3·3H2O in absolute ethanol. Theses complexes were characterized by elemental analyses and spectroscopic (IR, UV-Vis, and NMR (1D 1H NMR, 13C NMR, (DEPT-135), (DEPT-90), 2D 1H-1H and 13C-1H correlation (HMQC) spectroscopy)). The two complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 604 mV vs. ferrocene/ferrocenium (Cp2Fe0/+) couple along with one electron ligand reduction at -1010 mV. The crystal structure of complex 1 showed that the bidentate ligand L1 coordinates to Ru(II) by the azo- and imine-nitrogen donor atoms. The complex adopts a distorted trans octahedral coordination geometry of chloride ligands. The electronic spectra of 1 and 1+ in dichloromethane have been modeled by time-dependent density functional theory (TD-DFT).

  4. Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: synthesis, structure, electrochemistry and DFT calculations.

    PubMed

    Al-Noaimi, Mousa; Awwadi, Firas F; Mansi, Ahmad; Abdel-Rahman, Obadah S; Hammoudeh, Ayman; Warad, Ismail

    2015-01-25

    The novel azoimine ligand, Ph-NH-N=C(COCH3)-NHPh(C≡CH) (H2L), was synthesized and its molecular structure was determined by X-ray crystallography. Catalytic hydration of the terminal acetylene of H2L in the presence of RuCl3·3H2O in ethanol at reflux temperature yielded a ketone (L1=Ph-N=N-C(COCH3)=N-Ph(COCH3) and an enol (L2=Ph-N=N-C(COCH3)=N-PhC(OH)=CH2) by Markovnikov addition of water. Two mixed-ligand ruthenium complexes having general formula, trans-[Ru(bpy)(Y)Cl2] (1-2) (where Y=L1 (1) and Y=L2 (2), bpy is 2.2'-bipyrdine) were achieved by the stepwise addition of equimolar amounts of (H2L) and bpy ligands to RuCl3·3H2O in absolute ethanol. Theses complexes were characterized by elemental analyses and spectroscopic (IR, UV-Vis, and NMR (1D (1)H NMR, (13)C NMR, (DEPT-135), (DEPT-90), 2D (1)H-(1)H and (13)C-(1)H correlation (HMQC) spectroscopy)). The two complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 604 mV vs. ferrocene/ferrocenium (Cp2Fe(0/+)) couple along with one electron ligand reduction at -1010 mV. The crystal structure of complex 1 showed that the bidentate ligand L1 coordinates to Ru(II) by the azo- and imine-nitrogen donor atoms. The complex adopts a distorted trans octahedral coordination geometry of chloride ligands. The electronic spectra of 1 and 1+ in dichloromethane have been modeled by time-dependent density functional theory (TD-DFT).

  5. Synthesis of Ruthenium Boryl Analogues of the Shvo Metal–Ligand Bifunctional Catalyst

    PubMed Central

    Koren-Selfridge, Liza; Query, Ian P.; Hanson, Joel A.; Isley, Nicholas A.; Guzei, Ilia A.; Clark, Timothy B.

    2010-01-01

    Metal boryl complexes have received significant attention in the literature in recent years due to their role as key intermediates in a number of metal-catalyzed borylation reactions. The ligand scaffold is known to have a significant impact on the observed reactivity of these metal boryl complexes. A synthetic strategy to access ruthenium boryl analogues of the Shvo metal–ligand catalysts is described. Heating a precursor to Shvo’s catalyst (1) with bis(catecholato)diboron at 50 °C provided ruthenium boryl complex 3 [2,5-Ph2-3,4-Tol2(η5-C4COBcat)Ru(CO)2Bcat] (Bcat = catecholatoboryl). Addition of bis(catecholato)diboron to complex 1 in the presence of a phenol results in ruthenium boryl complex5 [2,5-Ph2-3,4-Tol2(η5-C4COH)Ru(CO)2Bcat] at 22 °C in 30% isolated yield. A single crystal X-ray analysis of complex 5 confirmed the assigned structure. An improved synthesis of ruthenium boryl complex 5 was developed by the in situ formation of complex 3 [2,5-Ph2-3,4-Tol2(η5-C4COBcat)Ru(CO)2Bcat] followed by addition of the phenol, resulting in a 51% yield. PMID:20835402

  6. Ruthenium Bis-diimine Complexes with a Chelating Thioether Ligand: Delineating 1,10-Phenanthrolinyl and 2,2'-Bipyridyl Ligand Substituent Effects

    SciTech Connect

    Al-Rawashdeh, Nathir A. F.; Chatterjee, Sayandev; Krause, Jeanette A.; Connick, William B.

    2014-01-06

    A new series of ruthenium(II) bis-diimine complexes with a chelating thioether donor ligand has been prepared: Ru(diimine)2(dpte)2+ (diimine=1,10-phenanthroline (phen) (1); 5-CH3-phen (2), 5-Cl-phen (3); 5-Br-phen (4); 5-NO2-phen (5); 3,4,7,8-tetramethyl-phen (6); 4,7-diphenyl-phen (7); 5,5'-dimethyl-2,2'-bipyridine (8); 4,4'-di-tert-butyl-2,2'-bipyridine (9)). Crystal structures of 2, 5, 7 and 9 show that the complexes form 2 of the 12 possible conformational/configurational isomers, adopting compact C2-symmetric structures with short intramolecular transannular interactions between the diimine ligands and dpte phenyl groups; crystals of 2 and 5 contain non-statistical distributions of geometric isomers. In keeping with the π-acidity of the dpte, the Ru(III/II) couple, E°'(Ru3+/2+), occurs at relatively high potentials (1.4-1.7 V vs Ag/AgCl), and the lowest spin-allowed MLCT absorption band occurs near 400 nm. Surprisingly, the complexes also exhibit fluid-solution luminescence originating from a lowest MLCT excited state with lifetimes in the 140-750 ns time range; in acetonitrile, compound 8 undergoes photo-induced solvolysis. Variations in the MLCT energies and redox potentials are quantitatively described using a summative Hammett parameter (σT), as well as using Lever's electrochemical parameters (EL). Recommended parameterizations for 2,2'-bipyridyl and 1,10-phenanthrolinyl ligands were derived from analysis of correlations based on 199 measurements of E°'(Ru3+/2+) for 99 homo- and heteroleptic ruthenium(II) tris-diimine complexes. Variations in E°'(Ru3+/2+) due to substituents at the 4- and 4'-positions of bipyridyl ligands and 4- and 7-positions of phenanthrolinyl ligands are significantly more strongly correlated with σp+ than either σm or σp. Substituents at the 5- and 6-positions of phenanthrolinyl ligands are best described by σm and have effects comparable to those of substituents at the 3- and 8-positions. Correlations of EL with σT for 20

  7. Activation of amide N-H bonds by organotransition metal complexes

    SciTech Connect

    Schaad, D.R.

    1992-01-01

    This research was aimed at developing new homogeneous transition metal hydroamination catalysts, specifically for hydroamination reactions involving the addition of amides to olefins. New iron-, ruthenium-, palladium- and platinum-amido complexes were formed via amide N-H bond activation reactions to zerovalent and divalent organotransition metal complexes. Complexes of the general formula trans-MW(amido) (diphosphine)[sub 2] were synthesized by reaction of amides with FeH(C[sub 6]H[sub 4]PPhCH[sub 2]CH[sub 2]PPh[sub 2]) (dppe) and cis-RuHNp(dmpe)[sub 2]. Photolysis of cis-FeH[sub 2](dmpe)[sub 2] or Pt(C[sub 2]O[sub 4] (PEt[sub 3])[sub 2] in the presence of amides yielded trans-FeH(amido)(dmple)[sub 2] and trans-PtH (amido) IPEt[sub 3]) products. Reactions of amides with cis-M(PEtt[sub 3])[sub 2]Me[sub 2] yielded compounds with the general formula M(amido)Me(PEt[sub 3])[sub 2] (M = Pd, Pt). The reaction of M(diphosphine)Me[sub 2] complexes with amides produced compounds with the general formula M(amido)Me(diphosphine) (M = Pd, Pt). Reaction of amides with PtMe[sub 2](COD) yielded complexes with the general formula PtMe(amido)(COD). The compounds were characterized by multinuclear NMR spectroscopy. The reactions were proposed to occur by two routes: oxidative addition of the amid eN-H bond to the metal complex or direct protonation of the metal complex by the N-H bond of the amide. The rate of formation and the stability of the metal-amido products depended on the nature of the metal complex and the amide employed. Only acidic amides reacted with the iron complexes. For the thermal reactions of amides with the metal complexes, the reactions proceeded to completion faster as the acidity of the amide was increased. The new iron-, ruthenium-, palladium- and platinum-amido complexes were inert to further reaction.

  8. pH luminescence switching, dihydrogen phosphate sensing, and cellular uptake of a heterobimetallic ruthenium(II)-rhenium(I) complex.

    PubMed

    Zheng, Ze-Bao; Wu, Yong-Quan; Wang, Ke-Zhi; Li, Fuyou

    2014-02-28

    A new heterobimetallic ruthenium(II)-rhenium(I) complex of [Ru(bpy)2(HL)Re(CO)3Cl](ClO4)2·6H2O (RuHLRe) {bpy = 2,2'-bipyridine and HL = 2-(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} was synthesised and characterised by elemental analysis, proton nuclear magnetic resonance spectroscopy, and mass spectrometry. The ground- and excited-state acid-base properties of RuHLRe were studied using UV-Vis absorption spectrophotometric and spectrofluorimetric titrations in a 100 : 1 (v/v) Britton-Robinson buffer-CH3CN solution combined with luminescence lifetime measurements. The complex exhibited two-step separate protonation-deprotonation processes in both the ground and excited states. The complex acted as pH-induced "off-on-off" luminescence switches (I(on)/I(off) = 31.0 and 14.6), with one of the switching actions being driven by pH variations over the physiological pH range (5.3-8.0). Importantly, cellular imaging and cytotoxicity experiments demonstrated that RuHLRe rapidly and selectively illuminated the membrane of HeLa cells over fixed cells and exhibited reduced cytotoxicity at the imaging concentration compared to the Re(I)-free parent Ru(II) complex. In addition, RuHLRe acted as an efficient "turn on" emission sensor for H2PO4(-) and "turn off" emission sensor for F(-) and OAc(-).

  9. Synthesis, reactivity studies, structural aspects, and solution behavior of half sandwich ruthenium(II) N,N',N''-triarylguanidinate complexes.

    PubMed

    Singh, Taruna; Kishan, Ram; Nethaji, Munirathinam; Thirupathi, Natesan

    2012-01-01

    [(η(6)-C(10)H(14))RuCl(μ-Cl)](2) (η(6)-C(10)H(14) = η(6)-p-cymene) was subjected to a bridge-splitting reaction with N,N',N''-triarylguanidines, (ArNH)(2)C═NAr, in toluene at ambient temperature to afford [(η(6)-C(10)H(14))RuCl{κ(2)(N,N')((ArN)(2)C-N(H)Ar)}] (Ar = C(6)H(4)Me-4 (1), C(6)H(4)(OMe)-2 (2), C(6)H(4)Me-2 (3), and C(6)H(3)Me(2)-2,4 (4)) in high yield with a view aimed at understanding the influence of substituent(s) on the aryl rings of the guanidine upon the solid-state structure, solution behavior, and reactivity pattern of the products. Complexes 1-3 upon reaction with NaN(3) in ethanol at ambient temperature afforded [(η(6)-C(10)H(14))RuN(3){κ(2)(N,N')((ArN)(2)C-N(H)Ar)}] (Ar = C(6)H(4)Me-4 (5), C(6)H(4)(OMe)-2 (6), and C(6)H(4)Me-2 (7)) in high yield. [3 + 2] cycloaddition reaction of 5-7 with RO(O)C-C≡C-C(O)OR (R = Et (DEAD) and Me (DMAD)) (diethylacetylenedicarboxylate, DEAD; dimethylacetylenedicarboxylate, DMAD) in CH(2)Cl(2) at ambient temperature afforded [(η(6)-C(10)H(14))Ru{N(3)C(2)(C(O)OR)(2)}{κ(2)(N,N')((ArN)(2)C-N(H)Ar)}]·xH(2)O (x = 1, R = Et, Ar = C(6)H(4)Me-4 (8·H(2)O); x = 0, R = Me, Ar = C(6)H(4)(OMe)-2 (9), and C(6)H(4)Me-2 (10)) in moderate yield. The molecular structures of 1-6, 8·H(2)O, and 10 were determined by single crystal X-ray diffraction data. The ruthenium atom in the aforementioned complexes revealed pseudo octahedral "three legged piano stool" geometry. The guanidinate ligand in 2, 3, and 6 revealed syn-syn conformation and that in 4, and 10 revealed syn-anti conformation, and the conformational difference was rationalized on the basis of subtle differences in the stereochemistry of the coordinated nitrogen atoms caused by the aryl moiety in 3 and 4 or steric overload caused by the substituents around the ruthenium atom in 10. The bonding pattern of the CN(3) unit of the guanidinate ligand in the new complexes was explained by invoking n-π conjugation involving the interaction of the NHAr/N(coord)Ar lone

  10. Role of intercalation and redox potential in DNA photosensitization by ruthenium(II) polypyridyl complexes: assessment using DNA repair protein tests.

    PubMed

    Gicquel, Etienne; Souchard, Jean-Pierre; Magnusson, Fay; Chemaly, Jad; Calsou, Patrick; Vicendo, Patricia

    2013-08-01

    Here we report that the photoreactivity of ruthenium(II) complexes with nucleobases may not only be modulated by their photoredox properties but also by their DNA binding mode. The damage resulting from photolysis of synthetic oligonucleotides and plasmid DNA by [Ru(bpz)3](2+), [Ru(bipy)3](2+) and the two DNA intercalating agents [Ru(bpz)2dppz](2+) and [Ru(bipy)2dppz](2+) has been monitored by polyacrylamide gel electrophoresis and by tests using proteins involved in DNA repair processes (DNA-PKCs, Ku80, Ku70, and PARP-1). The data show that intercalation controls the nature of the DNA damage photo-induced by ruthenium(II) complexes reacting with DNA via an electron transfer process. The intercalating agent [Ru(bpz)2dppz](2+) is a powerful DNA breaker inducing the formation of both single and double (DSBs) strand breaks which are recognized by the PARP-1 and DNA-PKCs proteins respectively. [Ru(bpz)2dppz](2+) is the first ruthenium(II) complex described in the literature that is able to induce DSBs by an electron transfer process. In contrast, its non-intercalating parent compound, [Ru(bpz)3](2+), is mostly an efficient DNA alkylating agent. Photoadducts are recognized by the proteins Ku70 and Ku80 as with cisplatin adducts. This result suggests that photoaddition of [Ru(bpz)2dppz](2+) is strongly affected by its DNA intercalation whereas its photonuclease activity is exalted. The data clearly show that DNA intercalation decreases drastically the photonuclease activity of ruthenium(II) complexes oxidizing guanine via the production of singlet oxygen. Interestingly, the DNA sequencing data revealed that the ligand dipyridophenazine exhibits on single-stranded oligonucleotides a preference for the 5'-TGCGT-3' sequence. Moreover the use of proteins involved in DNA repair processes to detect DNA damage was a powerful tool to examine the photoreactivity of ruthenium(II) complexes with nucleic acids. PMID:23835850

  11. Influence of ligand and environment substitution on photo-triggered linkage isomerization of photochromic ruthenium sulfoxide complexes

    NASA Astrophysics Data System (ADS)

    Springfeld, Kristin; Dieckmann, Volker; Eicke, Sebastian; Imlau, Mirco

    2012-02-01

    The group of ruthenium polypyridine sulfoxides features a pronounced photochromism in the UV/VIS spectral range based on an ultrafast photo-triggered linkage isomerization located at the SO-ligand. This isomerization exhibits a tremendous photosensitivity and a high thermal stability of the two metastable structural isomers. Here, we discuss the characteristic photochromic properties of the compounds in the frame of ligand substitution and the replacement of the dielectric environment. The complex [Ru(bpy)2(ROSO)].PF6 [1] (with OSO: 2-methylsulfinylbenzoate) has been modified with the groups R = H, Bn, BnCl and BnMe [2] and studied in different solvents as well as in polydimethylsiloxane. The analysis is performed by cw-pump-probe technique as a function of temperature and exposure. Our results reveal a selective adjustability of the thermal stability in the compounds, while the photosensitivity and the characteristic absorption spectra remain unchanged. We discuss the impact of sulfoxide compounds with the desired features in view of application in molecular photonic devices.[4pt] [1] V. Dieckmann et al., Opt. Express 17, 15052 (2009)[2] V. Dieckmann et al., Opt. Express 18, 23495 (2010)

  12. Optical limiting and dynamical two-photon absorption of porphyrin with ruthenium outlying complexes for a picosecond pulse train

    NASA Astrophysics Data System (ADS)

    Zhang, Yu-Jin; Sun, Yu-Ping; Wang, Chuan-Kui

    2016-01-01

    Propagation and nonlinear optical absorption of a picosecond pulse train in strong reverse saturable absorption (RSA) materials (free-based tetrapyridyl porphyrin H2TPyP with ruthenium (Ru) outlying complexes) are investigated by solving coupled rate equations and field intensity equation. Influence of outlying Ru groups on optical limiting (OL) properties is studied. Propagation of the front subpulses is mainly affected by linear transition between the ground state and the first excited singlet state, while intensity of the latter subpulses is attenuated by the excited state absorption (ESA). These two different absorption mechanisms result in asymmetric distribution of the transmitted pulse. It is shown that effective population transfer time from the ground state to the lowest triplet state and RSA play important roles in the OL performance and pulse shaping. Moreover, our results indicate that the porphyrins studied are ideal optical limiters because of their large ESA cross section and long lifetime of the lowest triplet state. Compounds with the presence of Ru group possess preferable power limiting ability. Ligand group attached to Ru also influences the nonlinear optical absorption of compounds. Special attention has been paid on dynamical two-photon absorption (TPA) cross section which depends crucially on the duration of the subpulse as well as time interval between subpulses. The present study provides a way to modulate nonlinear optical absorption properties of the medium by changing parameters of the pulse train.

  13. Substituents Dependent Capability of bis(ruthenium-dioxolene-terpyridine)Complexes Toward Water Oxidation

    SciTech Connect

    Wada, T.; Muckerman, J.; Fujita, E.; Tanaka, K.

    2010-12-23

    The bridging ligand, 1,8-bis(2,2':6',2{double_prime}-terpyrid-4'-yl)anthracene (btpyan) was synthesized by the Miyaura-Suzuki cross coupling reaction of anthracenyl-1,8-diboronic acid and 4'-triflyl-2,2':6'-2{double_prime}-terpyridine in the presence of Pd(PPh{sub 3}){sub 4} (5 mol%) with 68% in yield. Three ruthenium-dioxolene dimers, [Ru{sub 2}(OH){sub 2}(dioxolene){sub 2}(btpyan)]{sup 0} (dioxolene = 3,6-di-tert-butyl-1,2-benzosemiquinone ([1]{sup 0}), 3,5-dichloro-1,2-benzosemiquinone ([2]{sup 0}) and 4-nitro-1,2-benzosemiquinone ([3]{sup 0})) were prepared by the reaction of [Ru{sub 2}Cl{sub 6}(btpyan)]{sup 0} with the corresponding catechol. The electronic structure of [1]{sup 0} is approximated by [Ru{sub 2}{sup II}(OH){sub 2}(sq){sub 2}(btpyan)]{sup 0} (sq = semiquinonato). On the other hand, the electronic states of [2]{sup 0} and [3]{sup 0} are close to [Ru{sub 2}{sup III}(OH){sub 2} (cat){sub 2}(btpyan)]{sup 0} (cat = catecholato), indicating that a dioxolene having electron-withdrawing groups stabilizes [Ru{sub 2}{sup III}(OH){sub 2}(cat){sub 2}(btpyan)]{sup 0} rather than [Ru{sub 2}{sup II}(OH){sub 2}(sq){sub 2}(btpyan)]{sup 0} as resonance isomers. No sign was found of deprotonation of the hydroxo groups of [1]{sup 0}, whereas [2]{sup 0} and [3]{sup 0} showed an acid-base equilibrium in treatments with t-BuOLi followed by HClO{sub 4}. Furthermore, controlled potential electrolysis of [1]{sup 0} deposited on an ITO (indium-tin oxide) electrode catalyzed the four-electron oxidation of H{sub 2}O to evolve O{sub 2} at potentials more positive than +1.6 V (vs. SCE) at pH 4.0. On the other hand, the electrolysis of [2]{sup 0} and [3]{sup 0} deposited on ITO electrodes did not show catalytic activity for water oxidation under similar conditions. Such a difference in the reactivity among [1]{sup 0}, [2]{sup 0} and [3]{sup 0} is ascribed to the shift of the resonance equilibrium between [Ru{sub 2}{sup II}(OH){sub 2}(sq){sub 2}(btpyan)]{sup 0} and [Ru{sub 2

  14. Troponate/Aminotroponate Ruthenium-Arene Complexes: Synthesis, Structure, and Ligand-Tuned Mechanistic Pathway for Direct C-H Bond Arylation with Aryl Chlorides in Water.

    PubMed

    Dwivedi, Ambikesh D; Binnani, Chinky; Tyagi, Deepika; Rawat, Kuber S; Li, Pei-Zhou; Zhao, Yanli; Mobin, Shaikh M; Pathak, Biswarup; Singh, Sanjay K

    2016-07-01

    A series of water-soluble troponate/aminotroponate ruthenium(II)-arene complexes were synthesized, where O,O and N,O chelating troponate/aminotroponate ligands stabilized the piano-stool mononuclear ruthenium-arene complexes. Structural identities for two of the representating complexes were also established by single-crystal X-ray diffraction studies. These newly synthesized troponate/aminotroponate ruthenium-arene complexes enable efficient C-H bond arylation of arylpyridine in water. The unique structure-activity relationship in these complexes is the key to achieve efficient direct C-H bond arylation of arylpyridine. Moreover, the steric bulkiness of the carboxylate additives systematically directs the selectivity toward mono- versus diarylation of arylpyridines. Detailed mechanistic studies were performed using mass-spectral studies including identification of several key cyclometalated intermediates. These studies provided strong support for an initial cycloruthenation driven by carbonate-assisted deprotonation of 2-phenylpyridine, where the relative strength of η(6)-arene and the troponate/aminotroponate ligand drives the formation of cyclometalated 2-phenylpyridine Ru-arene species, [(η(6)-arene)Ru(κ(2)-C,N-phenylpyridine) (OH2)](+) by elimination of troponate/aminotroponate ligands and retaining η(6)-arene, while cyclometalated 2-phenylpyridine Ru-troponate/aminotroponate species [(κ (2)-troponate/aminotroponate)Ru(κ(2)-C,N-phenylpyridine)(OH2)2] was generated by decoordination of η(6)-arene ring during initial C-H bond activation of 2-phenylpyridine. Along with the experimental mass-spectral evidence, density functional theory calculation also supports the formation of such species for these complexes. Subsequently, these cycloruthenated products activate aryl chloride by facile oxidative addition to generate C-H arylated products. PMID:27305143

  15. SO2-Binding Properties of Cationic η6,η1-NCN-Pincer Arene Ruthenium Platinum Complexes: Spectroscopic and Theoretical Studies

    SciTech Connect

    Bonnet, Sylvestre A.; Van Lenthe, Joop H.; van Dam, Hubertus JJ; van Koten, Gerard; Klein Gebbink, Robertus J M

    2011-03-01

    The SO2-binding properties of a series of η6,η1-NCN-pincer ruthenium platinum complexes have been studied by both UV-visible spectroscopy, and theoretical calculations. When an electronwithdrawing [Ru(C5R5)]+ fragment (R = H or Me) is η6-coordinated to the phenyl ring of the NCNpincer platinum fragment (cf. [2]+ and [3]+, see scheme 1), the characteristic orange coloration (pointing to η1- SO2 binding to Pt) of a solution of the parent NCN-pincer platinum complex 1 in dichloromethane upon SO2-bubbling is not observed. However, when the ruthenium center is η6- coordinated to a phenyl substituent linked in para-position to the carbon-to-platinum bond, i.e. complex [4]+, the SO2-binding property of the NCN-platinum center seems to be retained, as bubbling SO2 into a solution of the latter complex produces the characteristic orange color. We performed theoretical calculations at the MP2 level of approximation and TD-DFT studies, which enabled us to interpret the absence of color change in the case of [2]+ as an absence of coordination of SO2 to platinum. We analyze this absence or weaker SO2-coordination in dichloromethane to be a consequence of the relative electron-poorness of the platinum center in the respective η6- ruthenium coordinated NCN-pincer platinum complexes, that leads to a lower binding energy and an elongated calculated Pt-S bond distance. We also discuss the effects of electrostatic interactions in these cationic systems, which also seems to play a destabilizing role for complex [2(SO2)]+.

  16. Troponate/Aminotroponate Ruthenium-Arene Complexes: Synthesis, Structure, and Ligand-Tuned Mechanistic Pathway for Direct C-H Bond Arylation with Aryl Chlorides in Water.

    PubMed

    Dwivedi, Ambikesh D; Binnani, Chinky; Tyagi, Deepika; Rawat, Kuber S; Li, Pei-Zhou; Zhao, Yanli; Mobin, Shaikh M; Pathak, Biswarup; Singh, Sanjay K

    2016-07-01

    A series of water-soluble troponate/aminotroponate ruthenium(II)-arene complexes were synthesized, where O,O and N,O chelating troponate/aminotroponate ligands stabilized the piano-stool mononuclear ruthenium-arene complexes. Structural identities for two of the representating complexes were also established by single-crystal X-ray diffraction studies. These newly synthesized troponate/aminotroponate ruthenium-arene complexes enable efficient C-H bond arylation of arylpyridine in water. The unique structure-activity relationship in these complexes is the key to achieve efficient direct C-H bond arylation of arylpyridine. Moreover, the steric bulkiness of the carboxylate additives systematically directs the selectivity toward mono- versus diarylation of arylpyridines. Detailed mechanistic studies were performed using mass-spectral studies including identification of several key cyclometalated intermediates. These studies provided strong support for an initial cycloruthenation driven by carbonate-assisted deprotonation of 2-phenylpyridine, where the relative strength of η(6)-arene and the troponate/aminotroponate ligand drives the formation of cyclometalated 2-phenylpyridine Ru-arene species, [(η(6)-arene)Ru(κ(2)-C,N-phenylpyridine) (OH2)](+) by elimination of troponate/aminotroponate ligands and retaining η(6)-arene, while cyclometalated 2-phenylpyridine Ru-troponate/aminotroponate species [(κ (2)-troponate/aminotroponate)Ru(κ(2)-C,N-phenylpyridine)(OH2)2] was generated by decoordination of η(6)-arene ring during initial C-H bond activation of 2-phenylpyridine. Along with the experimental mass-spectral evidence, density functional theory calculation also supports the formation of such species for these complexes. Subsequently, these cycloruthenated products activate aryl chloride by facile oxidative addition to generate C-H arylated products.

  17. Metal-metal multiply bonded complexes of technetium. Final report

    SciTech Connect

    Cotton, F.A.; Haefner, S.C.

    1995-03-30

    The primary objective of this project was to explore and develop the area of technetium metal-metal multiple bond chemistry. At the outset of the project, examples of metal-metal multiply bonded complexes of technetium were primarily limited to those supported by halide and carboxylate ligands. As a result, we intended to significantly expand the number of complexes containing Tc-Tc multiple bonds using ligands other than carboxylates or halides. In order to achieve this goal, the results obtained from years of dirhenium research was used as a guide for the development of new technetium compounds. Our emphasis, however, was on pursuing unanticipated results and exploiting the inherent differences between technetium and rhenium in order to develop chemistry beyond that which exists for rhenium. We have focused our attention on the preparation of dinuclear complexes with ligand sets that are known to support dinuclear metal-metal bonded cores in a variety of different metal oxidation states. Investigation of the consequences of electron addition and removal from metal-metal bonding manifold on the structural and physical properties of such dinuclear species will provide vital information regarding the electronic structure of Tc-Tc multiply bonded compounds.

  18. RECOVERY OF RUTHENIUM VALUES

    DOEpatents

    Grummitt, W.E.; Hardwick, W.H.

    1961-01-01

    A process is given for the recovery of ruthenium from its aqueous solutions by oxidizing the ruthenium to the octavalent state and subsequently extracting the ruthenium into a halogen-substituted liquid paraffin.

  19. Luminescent Ruthenium(II) Complex Bearing Bipyridine and N-Heterocyclic Carbene-based C∧N∧C Pincer Ligand for Live-Cell Imaging of Endocytosis

    PubMed Central

    Tsui, Wai-Kuen; Chung, Lai-Hon; Wong, Matthew Man-Kin; Tsang, Wai-Him; Lo, Hoi-Shing; Liu, Yaxiang; Leung, Chung-Hang; Ma, Dik-Lung; Chiu, Sung-Kay; Wong, Chun-Yuen

    2015-01-01

    Luminescent ruthenium(II)-cyanide complex with N-heterocyclic carbene pincer ligand C∧N∧C = 2,6-bis(1-butylimidazol-2-ylidene)pyridine and 2,2′-bipyridine (bpy) shows minimal cytotoxicity to both human breast carcinoma cell (MCF-7) and human retinal pigmented epithelium cell (RPE) in a wide range of concentration (0.1–500 μM), and can be used for the luminescent imaging of endocytosis of the complex in these cells. PMID:25765974

  20. Ruthenium(II) polypyridyl complexes with hydrophobic ancillary ligand as Aβ aggregation inhibitors.

    PubMed

    Vyas, Nilima A; Ramteke, Shefali N; Kumbhar, Avinash S; Kulkarni, Prasad P; Jani, Vinod; Sonawane, Uddhavesh B; Joshi, Rajendra R; Joshi, Bimba; Erxleben, Andrea

    2016-10-01

    The synthesis, spectral and electrochemical characterization of the complexes of the type [Ru(NN)2(txbg)](2+) where NN is 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), dipyrido [3,2-d:2',3f] quinoxaline (dpq) (3), and dipyrido[3,2-a:2',3'-c]phenazine (dppz) (4) which incorporate the tetra-xylene bipyridine glycoluril (txbg) as the ancillary ligand are described in detail. Crystal structures of ligand txbg and complex 2 were solved by single crystal X-ray diffraction. Thioflavin T (ThT) fluorescence and Transmission Electron Microscopy (TEM) results indicated that at micromolar concentration all complexes exhibit significant potential of Aβ aggregation inhibition, while the ligand txbg displayed weak activity towards Aβ aggregation. Complex 1 showed relatively low inhibition (70%) while complexes 2-4 inhibited nearly 100% Aβ aggregation after 240 h of incubation. The similar potential of complexes 2-4 and absence of any trend in their activity with the planarity of polypyridyl ligands suggests there is no marked effect of planarity of coligands on their inhibitory potential. Further studies on acetylcholinesterase (AChE) inhibition indicated very weak activity of these complexes against AChE. Detailed interactions of Aβ with both ligand and complex 2 have been studied by molecular modeling. Complex 2 showed interactions involving all three polypyridyl ligands with hydrophobic region of Aβ. Furthermore, the toxicity of these complexes towards human neuroblastoma cells was evaluated by MTT assay and except complex 4, the complexes displayed very low toxicity. PMID:27406812

  1. Asymmetric dimerization of aniline-ruthenium-dioxolene complex driven by stepwise PCET.

    PubMed

    Kikuchi, T; Kobayashi, K; Tsuge, K; Kitagawa, S; Tanaka, K

    2016-09-28

    The base-assisted oxidation of an aniline-Ru-quinone complex produced an anilinyl radical-Ru-semiquinone. Furthermore, base-assisted oxidation of the radical complex resulted in selective C-N bond formation through an intermolecular coupling between nitrogen and carbon atoms at the para-position of the anilinyl ligand. PMID:27535700

  2. Ruthenium(II) and iridium(III) complexes featuring NHC-sulfonate chelate.

    PubMed

    Rajaraman, A; Sahoo, A R; Hild, F; Fischmeister, C; Achard, M; Bruneau, C

    2015-10-28

    Three new complexes bearing a chelating (κ(2)C,O) NHC-SO3 ligand have been prepared. An original method for the synthesis of the imidazolium-sulfonate NHC precursor is described. The 5-membered ruthena- and irida-cycle containing complexes were fully characterized and evaluated in a series of catalytic transformations involving hydrogen auto-transfer processes.

  3. Antiproliferative activity of ruthenium(ii) arene complexes with mono- and bidentate pyridine-based ligands.

    PubMed

    Richter, Stefan; Singh, Sushma; Draca, Dijana; Kate, Anup; Kumbhar, Anupa; Kumbhar, Avinash S; Maksimovic-Ivanic, Danijela; Mijatovic, Sanja; Lönnecke, Peter; Hey-Hawkins, Evamarie

    2016-08-16

    A series of Ru(II) arene complexes of mono- and bidentate N-donor ligands with carboxyl or ester groups and chlorido ancillary ligands were synthesised and structurally characterised. The complexes have a distorted tetrahedral piano-stool geometry. The binding interaction was studied with calf thymus DNA (CT-DNA) by absorption titration, viscosity measurement, thermal melting, circular dichroism, ethidium bromide displacement assay and DNA cleavage of plasmid DNA (pBR322), investigated by gel electrophoresis. The dichlorido complexes bind covalently to DNA in the dark, similar to cisplatin, while the monochlorido complexes bind covalently on irradiation, similar to cisplatin analogues. The compounds are selectively cytotoxic against several tumour cell lines and show specific nonlinear correlation between dose and activity. This phenomenon is closely related to their potential to act preferentially as inhibitors of cell division. PMID:27264161

  4. Oxidation state characterization of ruthenium 2-iminoquinone complexes through experimental and theoretical studies.

    PubMed

    Rochford, Jonathan; Tsai, Ming-Kang; Szalda, David J; Boyer, Julie L; Muckerman, James T; Fujita, Etsuko

    2010-02-01

    The synthesis of complexes [Ru(II)(trpy)(2-imino-4-tert-butylquinone)(Cl)](+) and [Ru(II)(trpy)(NIL)(OAc)](+) (where trpy = 2:2',6':2''-terpyridyl, NIL = 2-imino-4-tert-butylquinone, 2-imino-4-methylquinone, 2-iminoquinone, 2-imino-4-chloroquinone, 2-imino-5-chloroquinone, 2-imino-4,6-di-tert-butyl-N-phenyl-quinone, 2-imino-4,6-di-tert-butyl-N-(2'-trifluoromethylphenyl)-quinone) is reported. The oxidation states of these complexes, as well as the previously reported [Ru(III)(trpy)(2-iminosemiquinone)(Cl)](+) complex, are investigated by spectroscopic, electrochemical and theoretical methods resulting in the latter complex being reassigned as [Ru(II)(trpy)(2-iminoquinone)(Cl)](+). Evidence for the presence of two structural isomers was found for all complexes, and crystal structures for both isomers of the [Ru(II)(trpy)(2-imino-4-tert-butylquinone)(Cl)]ClO(4) complex are reported, as well as for the cis isomer of [Ru(II)(trpy)(2-imino-4,6-di-tert-butyl-N-phenyl-quinone)(OAc)]PF(6). Redox control is also demonstrated based on the Hammett parameters of the substituents on the 2-iminoquinone ligand.

  5. Kinetic effects of sulfur oxidation on catalytic nitrile hydration: nitrile hydratase insights from bioinspired ruthenium(II) complexes.

    PubMed

    Kumar, Davinder; Nguyen, Tho N; Grapperhaus, Craig A

    2014-12-01

    Kinetic investigations inspired by the metalloenzyme nitrile hydratase were performed on a series of ruthenium(II) complexes to determine the effect of sulfur oxidation on catalytic nitrile hydration. The rate of benzonitrile hydration was quantified as a function of catalyst, nitrile, and water concentrations. Precatalysts L(n)RuPPh3 (n = 1-3; L(1) = 4,7-bis(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(2) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(3) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-sulfenato-propyl)-1-thia-4,7-diazacyclononane) were activated by substitution of triphenylphosphine with substrate in hot dimethylformamide solution. Rate measurements are consistent with a dynamic equilibrium between inactive aqua (L(n)Ru-OH2) and active nitrile (L(n)Ru-NCR) derivatives with K = 21 ± 1, 9 ± 0.9, and 23 ± 3 for L(1) to L(3), respectively. Subsequent hydration of the L(n)Ru-NCR intermediate yields the amide product with measured hydration rate constants (k's) of 0.37 ± 0.01, 0.82 ± 0.07, and 1.59 ± 0.12 M(-1) h(-1) for L(1) to L(3), respectively. Temperature dependent studies reveal that sulfur oxidation lowers the enthalpic barrier by 27 kJ/mol, but increases the entropic barrier by 65 J/(mol K). Density functional theory (DFT) calculations (B3LYP/LanL2DZ (Ru); 6-31G(d) (all other atoms)) support a nitrile bound catalytic cycle with lowering of the reaction barrier as a consequence of sulfur oxidation through enhanced nitrile binding and attack of the water nucleophile through a highly organized transition state. PMID:25397591

  6. Are Very Small Emission Quantum Yields Characteristic of Pure Metal-to-Ligand Charge-Transfer Excited States of Ruthenium(II)-(Acceptor Ligand) Chromophores?

    PubMed

    Tsai, Chia Nung; Mazumder, Shivnath; Zhang, Xiu Zhu; Schlegel, H Bernhard; Chen, Yuan Jang; Endicott, John F

    2016-08-01

    Metal to ligand charge-transfer (MLCT) excited state emission quantum yields, ϕem, are reported in 77 K glasses for a series of pentaammine and tetraammine ruthenium(II) complexes with monodentate aromatic acceptor ligands (Ru-MDA) such as pyridine and pyrazine. These quantum yields are only about 0.2-1% of those found for their Ru-bpy (bpy = 2,2'-bipyridine) analogs in similar excited state energy ranges (hνem). The excited state energy dependencies of the emission intensity are characterized by mean radiative decay rate constants, kRAD, resolved from ϕem/τobs = kRAD (τobs = the observed emission decay lifetime; τobs(-1) = kRAD + kNRD; kNRD = nonradiative decay rate constant). Except for the Ru-pz chromophores in alcohol glasses, the values of kNRD for the Ru-MDA chromophores are slightly smaller, and their dependences on excited state energies are very similar to those of related Ru-bpy chromophores. In principle, one expects kRAD to be proportional to the product of (hνem)(3) and the square of the transition dipole moment (Me,g).(2) However, from experimental studies of Ru-bpy chromophores, an additional hνem dependence has been found that originates in an intensity stealing from a higher energy excited state with a much larger value of Me,g. This additional hνem dependence is not present in the kRAD energy dependence for Ru-MDA chromophores in the same energy regime. Intensity stealing in the phosphorescence of these complexes is necessary since the triplet-to-singlet transition is only allowed through spin-orbit coupling and since the density functional theory modeling implicates configurational mixing between states in the triplet spin manifold; this is treated by setting Me,g equal to the product of a mixing coefficient and the difference between the molecular dipole moments of the states involved, which implicates an experimental first order dependence of kRAD on hνem. The failure to observe intensity stealing for the Ru-MDA complexes suggests

  7. Are Very Small Emission Quantum Yields Characteristic of Pure Metal-to-Ligand Charge-Transfer Excited States of Ruthenium(II)-(Acceptor Ligand) Chromophores?

    PubMed

    Tsai, Chia Nung; Mazumder, Shivnath; Zhang, Xiu Zhu; Schlegel, H Bernhard; Chen, Yuan Jang; Endicott, John F

    2016-08-01

    Metal to ligand charge-transfer (MLCT) excited state emission quantum yields, ϕem, are reported in 77 K glasses for a series of pentaammine and tetraammine ruthenium(II) complexes with monodentate aromatic acceptor ligands (Ru-MDA) such as pyridine and pyrazine. These quantum yields are only about 0.2-1% of those found for their Ru-bpy (bpy = 2,2'-bipyridine) analogs in similar excited state energy ranges (hνem). The excited state energy dependencies of the emission intensity are characterized by mean radiative decay rate constants, kRAD, resolved from ϕem/τobs = kRAD (τobs = the observed emission decay lifetime; τobs(-1) = kRAD + kNRD; kNRD = nonradiative decay rate constant). Except for the Ru-pz chromophores in alcohol glasses, the values of kNRD for the Ru-MDA chromophores are slightly smaller, and their dependences on excited state energies are very similar to those of related Ru-bpy chromophores. In principle, one expects kRAD to be proportional to the product of (hνem)(3) and the square of the transition dipole moment (Me,g).(2) However, from experimental studies of Ru-bpy chromophores, an additional hνem dependence has been found that originates in an intensity stealing from a higher energy excited state with a much larger value of Me,g. This additional hνem dependence is not present in the kRAD energy dependence for Ru-MDA chromophores in the same energy regime. Intensity stealing in the phosphorescence of these complexes is necessary since the triplet-to-singlet transition is only allowed through spin-orbit coupling and since the density functional theory modeling implicates configurational mixing between states in the triplet spin manifold; this is treated by setting Me,g equal to the product of a mixing coefficient and the difference between the molecular dipole moments of the states involved, which implicates an experimental first order dependence of kRAD on hνem. The failure to observe intensity stealing for the Ru-MDA complexes suggests

  8. Photoactivity of mono- and dicarbonyl complexes of ruthenium(II) bearing an N,N,S-donor ligand: role of ancillary ligands on the capacity of CO photorelease.

    PubMed

    Gonzalez, Margarita A; Carrington, Samantha J; Chakraborty, Indranil; Olmstead, Marilyn M; Mascharak, Pradip K

    2013-10-01

    One monocarbonyl and one dicarbonyl complex of ruthenium(II), namely, [Ru(Cl)(CO)(qmtpm)(PPh3)]BF4 (2) and [Ru(Cl)(CO)2(qmtpm)]ClO4 (3), derived from the tridentate ligand 2-quinoline-N-(2'-methylthiophenyl)methyleneimine (qmtpm) have been synthesized and structurally characterized. The qmtpm ligand binds in a meridional fashion in these carbonyl complexes, and in 3, the two carbon monoxide (CO) ligands are cis to each other. Solutions of 2 in ethanol, chloroform, or acetonitrile rapidly release CO upon illumination with low-power (3-15 mW) light in the 300-450 nm range. Loss of CO from 2 brings about a dramatic color change from yellow to magenta because of the formation of [Ru(Cl)(MeCN)(qmtpm)(PPh3)]BF4 (4). In acetonitrile, photorelease of CO from 3 under 360 nm light occurs in two steps, and the violet photoproduct [Ru(Cl)(MeCN)2(qmtpm)](+) upon reaction with Ag(+) and PPh3 affords red [Ru(MeCN)2(qmtpm)(PPh3)](ClO4)2 (5). The structure of 5 has also been determined by X-ray crystallography. Reduced myoglobin assay confirms that 2 and 3 act as photoactive CO-releasing molecules (photoCORMs) that deliver 1 and 2 equiv of CO, respectively. The results of density functional theory (DFT) and time-dependent DFT studies confirm that electronic transitions from molecular orbitals with predominantly Ru-CO character to ligand-based π* orbitals facilitate CO release from these two photoCORMs. Complexes 2-5 have provided an additional opportunity to analyze the roles of the ancillary ligands, namely, PPh3, Cl(-), and MeCN, in shifting the positions of the metal-to-ligand charge-transfer bands and the associated sensitivity of the two photoCORMs to different wavelengths of light. Collectively, the results provide helpful hints toward the future design of photoCORMs that release CO upon exposure to visible light.

  9. Imidazolium ionic liquids as promoters and stabilising agents for the preparation of metal(0) nanoparticles by reduction and decomposition of organometallic complexes.

    PubMed

    Prechtl, Martin H G; Campbell, Paul S; Scholten, Jackson D; Fraser, Georgina B; Machado, Giovanna; Santini, Catherine C; Dupont, Jairton; Chauvin, Yves

    2010-12-01

    The organometallic complexes ([Ru(COD)(2-methylallyl)2] and [Ni(COD)2] (COD=1,5-cyclooctadiene) dissolved in imidazolium ionic liquids (ILs) undergo reduction and decomposition, respectively, to afford stable ruthenium and nickel metal(0) nanoparticles (Ru(0)-NPs and Ni(0)-NPs) in the absence of classical reducing agents. Depending on the case, the reduction/auto-decomposition is promoted by either the cation and/or anion of the neat imidazolium ILs.

  10. Protein-binding, cytotoxicity in vitro and cell cycle arrest of ruthenium(II) polypyridyl complexes

    NASA Astrophysics Data System (ADS)

    Liu, Si-Hong; Zhu, Jian-Wei; Xu, Hui-Hua; Wang, Yan; Liu, Ya-Min; Liang, Jun-Bo; Zhang, Gui-Qiang; Cao, Di-Hua; Lin, Yang-Yang; Wu, Yong; Guo, Qi-Feng

    2016-05-01

    The cytotoxic activity of two Ru(II) complexes against A549, BEL-7402, HeLa, PC-12, SGC-7901 and SiHa cell lines was investigated by MTT method. Complexes 1 and 2 show moderate cytotoxicity toward BEL-7402 cells with an IC50 value of 53.9 ± 3.4 and 39.3 ± 2.1 μM. The effects of the complexes inducing apoptosis, cellular uptake, reactive oxygen species and mitochondrial membrane potential in BEL-7402 cells have been studied by fluorescence microscopy. The percentages of apoptotic and necrotic cells and cell cycle arrest were studied by flow cytometry. The BSA-binding behaviors were investigated by UV/visible and fluorescent spectra.

  11. Cobalt-ruthenium catalysts for Fischer-Tropsch synthesis

    SciTech Connect

    Iglesia, E.; Soled, S.L.; Fiato, R.A.

    1989-04-18

    A hydrocarbon synthesis process is described which comprises reacting hydrogen and carbon monoxide in the presence of a catalyst comprised of cobalt and ruthenium on titania, at reaction conditions suitable for the formation of higher hydrocarbons. The catalyst is prepared by impregnating titania with solutions of cobalt and ruthenium salts, drying the impregnated support, reducing the cobalt and ruthenium, treating the reduced metals with an oxygen containing stream at conditions sufficient to form oxides of cobalt and oxides of ruthenium and reducing the cobalt and ruthenium oxides.

  12. Modular Attachment of Appended Boron Lewis Acids to a Ruthenium Pincer Catalyst: Metal-Ligand Cooperativity Enables Selective Alkyne Hydrogenation.

    PubMed

    Tseng, Kuei-Nin T; Kampf, Jeff W; Szymczak, Nathaniel K

    2016-08-24

    A new series of bifunctional Ru complexes with pendent Lewis acidic boranes were prepared by late-stage modification of an active hydrogen-transfer catalyst. The appended boranes modulate the reactivity of a metal hydride as well as catalytic hydrogenations. After installing acidic auxiliary groups, the complexes become multifunctional and catalyze the cis-selective hydrogenation of alkynes with higher rates, conversions, and selectivities compared with the unmodified catalyst. PMID:27472301

  13. Sensitive fluorescence detection of lysozyme using a tris(bipyridine)ruthenium(II) complex containing multiple cyclodextrins.

    PubMed

    Zhang, Fan; Zhao, Ying-Ying; Chen, Hong; Wang, Xiu-Hua; Chen, Qiong; He, Pin-Gang

    2015-04-18

    A new series of photoactive metallocyclodextrins with increased fluorescence intensity upon binding with ssDNAs/aptamers has been demonstrated to sensitively and selectively detect lysozyme. The detection mechanism relies on the formation of an aptamer-lysozyme complex, which leads to reduction of fluorescence intensity.

  14. Sticking and patching: tuning and anchoring cyclometallated ruthenium(II) complexes.

    PubMed

    Ertl, Cathrin D; Ris, Daniel P; Meier, Stefan C; Constable, Edwin C; Housecroft, Catherine E; Neuburger, Markus; Zampese, Jennifer A

    2015-01-28

    A series of [Ru(bpy)2(C^N)][PF6] (HC^N = 2-phenylpyridine derivative) complexes functionalized in the cyclometallating C^N phenyl ring with F, Me, OMe, CO2Me, S(t)Bu, SO2Me (ligands H1-H6) or in the C^N pyridine ring with 4-CO2Me or 4-C6H4P(O)(OEt)2 substituents (ligands H7 or H9) have been prepared and characterized; representative crystal structures confirm the structural features of the complexes. When the C^N ligand contains a CO2H substituent (ligand H28), deprotonation in addition to cyclometallation occurs to give a neutral, zwitter-ionic complex [Ru(bpy)2(8)]. The synthesis of the cationic complexes requires addition of a silver(i) salt (AgPF6 or AgBF4) to abstract Cl(-) from cis-[Ru(bpy)2Cl2] and (1)H NMR spectroscopic data are consistent with interactions between Ag(+) and the coordinated C^N ligand in [Ru(bpy)2(C^N)](+). The absorption spectra of [Ru(bpy)2(C^N)][PF6] (C^N = 1-6) are similar, but the introduction of the anchoring domains in [Ru(bpy)2(C^N)][PF6] with C^N = 7 or 9 enhances the absorption response; the greatest influence is observed in [Ru(bpy)2(9)](+) with the introduction of the 4-C6H4P(O)(OEt)2 substituent. Trends in emission and electrochemical behaviours of the complexes are interpreted in terms of the influence of the electronic properties of the C^N ligand substituents on the energies of the HOMO which is localized on the C^N ligand and Ru centre. This study provides an optimized synthetic route to the phosphonate ester derivative [Ru(bpy)2(9)][PF6], designed to anchor to a semiconductor surface; this complex also exhibits the most favourable absorption properties among the complexes studied.

  15. Cyclometallation of arylimines and nitrogen-containing heterocycles via room-temperature C-H bond activation with arene ruthenium(II) acetate complexes.

    PubMed

    Li, Bin; Roisnel, Thierry; Darcel, Christophe; Dixneuf, Pierre H

    2012-08-28

    The reaction of [RuCl(2)(p-cymene)](2) with arylimines and 4 equiv. of KOAc in methanol at room temperature produces stable (N^C)-cyclometallated ruthenium(II) complexes via C-H bond activation/deprotonation. This method can be applied also to nitrogen-containing molecules: N-phenylpyrazole, 2-phenyl-2-oxazoline and benzo[h]quinoline. N-Phenyl-pyrazole, [RuCl(2)(p-cymene)](2) and diphenylacetylene directly lead to alkyne insertion into the metallacycle C-Ru bond. PMID:22890507

  16. Structure-function relationships within Keppler-type antitumor ruthenium(III) complexes: the case of 2-aminothiazolium[trans-tetrachlorobis(2-aminothiazole)ruthenate(III)].

    PubMed

    Mura, Pasquale; Piccioli, Francesca; Gabbiani, Chiara; Camalli, Mercedes; Messori, Luigi

    2005-07-11

    Keppler-type ruthenium(III) complexes exhibit promising antitumor properties. We report here a study of 2-aminothiazolium[trans-tetrachlorobis(2-aminothiazole)ruthenate(III)], both in the solid state and in solution. The crystal structure has been solved and found to exhibit classical features. Important solvatochromic effects were revealed. Notably, we observed that introduction of an amino group in position 2 greatly accelerates chloride hydrolysis compared to the thiazole analogue; this latter finding may be of interest for a fine-tuning of the reactivity of these novel metallodrugs.

  17. Ruthenium and osmium complexes of dihydroperimidine-based N-heterocyclic carbene pincer ligands.

    PubMed

    McQueen, Caitlin M A; Hill, Anthony F; Ma, Chenxi; Ward, Jas S

    2015-12-21

    The reactions of N,N'-bis(phosphinomethyl)dihydroperimidine pro-ligands H2C(NCH2PR2)2C10H6 (R = Cy 1a, R = Ph 1b) with [RuCl2(PPh3)3] give markedly different products. Chelate-assisted double C-H activation in the former affords the perimidinylidene-based N-heterocyclic carbene (per-NHC) pincer complex [RuCl2(OC4H8){κ(3)-P,C,P'-C(NCH2PCy2)2C10H6}] (2), while the latter reaction provides the asymmetric PNP-coordinated complex [RuCl2(PPh3){κ(3)-P,N,P'-CH2(NCH2PPh2)2C10H6}] (3), in which no C-H activation has occurred. Subsequent reactions of the per-NHC complex 2 with carbon monoxide and mesityl isocyanide readily displaced the labile THF ligand to afford the complexes [RuCl2(CA){κ(3)-P,C,P'-C(NCH2PCy2)2C10H6}] (A = O 4, A = NC6H2Me35). Double C-H activation of 1a and 1b was significantly more facile on reaction with [OsCl2(PPh3)3], providing the per-NHC complexes [OsHCl(PPh3){κ(3)-P,C,P'-C(NCH2PR2)2C10H6}] (R = Cy 7a, R = Ph 7b, respectively), each as two isomers. The reactions of 1b with [Ru2(μ-Cl)2Cl2(η-C6H3Me3)2] or [AuCl(THT)] (THT = tetrahydrothiophene) provide the bimetallic complexes [Ru2{μ-H2C(NCH2PPh2)2C10H6}Cl4(η-C6H3Me3)2] (8) and [Au2{μ-H2C(NCH2PPh2)2C10H6}Cl2] (9) without C-H activation occurring. PMID:26492361

  18. PALLADIUM, PLATINUM, RHODIUM, RUTHENIUM AND IRIDIUM IN PERIDOTITES AND CHROMITITES FROM OPHIOLITE COMPLEXES IN NEWFOUNDLAND.

    USGS Publications Warehouse

    Page, Norman J; Talkington, Raymond W.

    1984-01-01

    Samples of spinel lherzolite, harzburgite, dunite, and chromitite from the Bay of Islands, Lewis Hills, Table Mountain, Advocate, North Arm Mountain, White Hills Periodite Point Rousse, Great Bend and Betts Cove ophiolite complexes in Newfoundland were analyzed for the platinum-group elements (PGE) Pd, Pt, Rh, Ru and Ir. The ranges of concentration (in ppb) observed for all rocks are: less than 0. 5 to 77 (Pd), less than 1 to 120 (Pt), less than 0. 5 to 20 (Rh), less than 100 to 250 (Ru) and less than 20 to 83 (Ir). Chondrite-normalized PGE ratios suggest differences between rock types and between complexes. Samples of chromitite and dunite show relative enrichment in Ru and Ir and relative depletion in Pt and Pd.

  19. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants.

    PubMed

    Morris, Robert H

    2014-02-01

    A simple equation (pKa(THF) = ∑AL + Ccharge + Cnd + Cd6) can be used to obtain an estimate of the pKa of diamagnetic transition metal hydride and dihydrogen complexes in tetrahydrofuran, and, by use of conversion equations, in other solvents. It involves adding acidity constants AL for each of the ligands in the 5-, 6-, 7-, or 8-coordinate conjugate base complex of the hydride or dihydrogen complex along with a correction for the charge (Ccharge = -15, 0 or 30 for x = +1, 0 or -1 charge, respectively) and the periodic row of the transition metal (Cnd = 0 for 3d or 4d metal, 2 for 5d metal) as well as a correction for d(6) octahedral acids (Cd6 = 6 for d(6) metal ion in the acid, 0 for others) that are not dihydrogen complexes. Constants AL are provided for 13 commonly occurring ligand types; of these, nine neutral ligands are correlated with Lever's electrochemical ligand parameters EL. This method gives good estimates of the over 170 literature pKa values that range from less than zero to 50 with a standard deviation of 3 pKa units for complexes of the metals chromium to nickel, molybdenum, ruthenium to palladium, and tungsten to platinum in the periodic table. This approach allows a quick assessment of the acidity of hydride complexes found in nature (e.g., hydrogenases) and in industry (e.g., catalysis and hydrogen energy applications). The pKa values calculated for acids that have bulky or large bite angle chelating ligands deviate the most from this correlation. The method also provides an estimate of the base strength of the deprotonated form of the complex.

  20. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants.

    PubMed

    Morris, Robert H

    2014-02-01

    A simple equation (pKa(THF) = ∑AL + Ccharge + Cnd + Cd6) can be used to obtain an estimate of the pKa of diamagnetic transition metal hydride and dihydrogen complexes in tetrahydrofuran, and, by use of conversion equations, in other solvents. It involves adding acidity constants AL for each of the ligands in the 5-, 6-, 7-, or 8-coordinate conjugate base complex of the hydride or dihydrogen complex along with a correction for the charge (Ccharge = -15, 0 or 30 for x = +1, 0 or -1 charge, respectively) and the periodic row of the transition metal (Cnd = 0 for 3d or 4d metal, 2 for 5d metal) as well as a correction for d(6) octahedral acids (Cd6 = 6 for d(6) metal ion in the acid, 0 for others) that are not dihydrogen complexes. Constants AL are provided for 13 commonly occurring ligand types; of these, nine neutral ligands are correlated with Lever's electrochemical ligand parameters EL. This method gives good estimates of the over 170 literature pKa values that range from less than zero to 50 with a standard deviation of 3 pKa units for complexes of the metals chromium to nickel, molybdenum, ruthenium to palladium, and tungsten to platinum in the periodic table. This approach allows a quick assessment of the acidity of hydride complexes found in nature (e.g., hydrogenases) and in industry (e.g., catalysis and hydrogen energy applications). The pKa values calculated for acids that have bulky or large bite angle chelating ligands deviate the most from this correlation. The method also provides an estimate of the base strength of the deprotonated form of the complex. PMID:24410025

  1. Charge-transfer luminescence from ruthenium(II) complexes containing tridentate ligands

    NASA Astrophysics Data System (ADS)

    Stone, M. L.; Crosby, G. A.

    Four complexes of the general formula Ru(NNN) 2+2 (N NN = tridentate N-heterocyclic ligand) were synthesized and studied spectroscopically. All exhibit visible absorption spectra that are charge-transfer-to-ligand in origin, are luminescent in glasses at 77 K, and display emission spectra that possess energies, structures, and decay tines that label them as charge transfer.

  2. From ruthenium olefin metathesis catalyst to (η5-3-phenylindenyl)hydrido complex via alcoholysis.

    PubMed

    Manzini, Simone; Nelson, David J; Lebl, Tomas; Poater, Albert; Cavallo, Luigi; Slawin, Alexandra M Z; Nolan, Steven P

    2014-02-28

    The synthesis and characterisation of [Ru(H)(η(5)-3-phenylindenyl)((i)Bu-Phoban)2] 4 is reported ((i)Bu-Phoban = 9-isobutyl-9-phosphabicyclo-[3.3.1]-nonane). 4 is obtained via alcoholysis of metathesis pre-catalyst M11, in a process that was previously thought to be limited to analogous complex [RuCl2(PPh3)2(3-phenylindenylidene)] (M10). PMID:24435451

  3. From ruthenium olefin metathesis catalyst to (η5-3-phenylindenyl)hydrido complex via alcoholysis.

    PubMed

    Manzini, Simone; Nelson, David J; Lebl, Tomas; Poater, Albert; Cavallo, Luigi; Slawin, Alexandra M Z; Nolan, Steven P

    2014-02-28

    The synthesis and characterisation of [Ru(H)(η(5)-3-phenylindenyl)((i)Bu-Phoban)2] 4 is reported ((i)Bu-Phoban = 9-isobutyl-9-phosphabicyclo-[3.3.1]-nonane). 4 is obtained via alcoholysis of metathesis pre-catalyst M11, in a process that was previously thought to be limited to analogous complex [RuCl2(PPh3)2(3-phenylindenylidene)] (M10).

  4. Controllable ROMP Tacticity by Harnessing the Fluxionality of Stereogenic-at-Ruthenium Complexes.

    PubMed

    Mikus, Malte S; Torker, Sebastian; Hoveyda, Amir H

    2016-04-11

    Readily accessible and easy-to-handle Ru complexes capable of generating all-Z polynorbornene and polynorbornadiene by ring-opening metathesis polymerization (ROMP) with controllable selectivity, ranging from ≈50 to ≥95% syndiotactic, are introduced. It is demonstrated that the rate of non-metathesis based polytopal isomerization and levels of syndiotacticity may be fine-tuned by the adjustment of monomer concentration and catalyst's steric and electronic characteristics. PMID:26992043

  5. Structural Determinants of p53-Independence in Anticancer Ruthenium-Arene Schiff-Base Complexes.

    PubMed

    Chow, Mun Juinn; Babak, Maria V; Wong, Daniel Yuan Qiang; Pastorin, Giorgia; Gaiddon, Christian; Ang, Wee Han

    2016-07-01

    p53 is a key tumor suppressor gene involved in key cellular processes and implicated in cancer therapy. However, it is inactivated in more than 50% of all cancers due to mutation or overexpression of its negative regulators. This leads to drug resistance and poor chemotherapeutic outcome as most clinical drugs act via a p53-dependent mechanism of action. An attractive strategy to circumvent this resistance would be to identify new anticancer drugs that act via p53-independent mode of action. In the present study, we identified 9 Ru (II)-Arene Schiff-base (RAS) complexes able to induce p53-independent cytotoxicity and discuss structural features that are required for their p53-independent activity. Increasing hydrophobicity led to an increase in cellular accumulation in cells with a corresponding increase in efficacy. We further showed that all nine complexes demonstrated p53-independent activity. This was despite significant differences in their physicochemical properties, suggesting that the iminoquinoline ligand, a common structural feature for all the complexes, is required for the p53-independent activity.

  6. Is matching ruthenium with dithiocarbamato ligands a potent chemotherapeutic weapon in oncology?

    PubMed

    Nardon, Chiara; Brustolin, Leonardo; Fregona, Dolores

    2016-02-01

    In the last years, several metal-based compounds have been designed and biologically investigated worldwide in order to obtain chemotherapeutics with a better toxicological profile and comparable or higher antiblastic activity than the clinically-established platinum-based drugs. In this context, researchers have addressed their attention to alternative nonplatinum derivatives able to maximize the anticancer activity of the new drugs and to minimize the side effects. Among them, a number of ruthenium complexes have been developed, including the compounds NAMI-A and KP1019, now in clinical trials. Here, we report the results collected so far for a particular class of ruthenium complexes - the ruthenium(II/III)-dithiocarbamates - which proved more potent than cisplatin in vitro, even at nanomolar concentrations, against a wide panel of human tumor cell lines. PMID:26807601

  7. Teaching Inorganic Photophysics and Photochemistry with Three Ruthenium(II) Polypyridyl Complexes: A Computer-Based Exercise

    ERIC Educational Resources Information Center

    Garino, Claudio; Terenzi, Alessio; Barone, Giampaolo; Salassa, Luca

    2016-01-01

    Among computational methods, DFT (density functional theory) and TD-DFT (time-dependent DFT) are widely used in research to describe, "inter alia," the optical properties of transition metal complexes. Inorganic/physical chemistry courses for undergraduate students treat such methods, but quite often only from the theoretical point of…

  8. Photoreduction of methyl viologen mediated by tris(bipyridyl)ruthenium(II) in inert colloidal suspensions

    SciTech Connect

    Kelly, L.A.; Rodgers, M.A.J. )

    1994-06-23

    The photoreduction of methyl viologen, covalently attached to a tris(bipyridyl)ruthenium(II) chromophore, in suspensions of positively charged alumina-coated colloidal silica particles, via N-phenylglycine electron donor, is reported. In the tris(bipyridyl)ruthenium(II) complexes, the central metal atom is coordinated to two 4,4[prime]-dicarboxy-2,2[prime]-bipyridine ligands and thus carries a net 2-charge at pH 5.0. Coadsorption of the N-phenylglycine and ruthenium chromophore to the colloidal particles results in rapid production of reduced viologen following visible laser flash excitation of the tris(bipyridyl)ruthenium(II) complex. The yield of the radical was dependent upon the concentration of the electron donor added to the system, but its multiphasic decay was independent of both the N-phenylglycine concentration and the initial concentration of viologen radical cation. Furthermore, both the yield and decay kinetics of the viologen radical cation were relatively independent of the number of intervening methylene units between the ruthenium complex and viologen electron acceptor. 18 refs., 5 figs., 2 tabs.

  9. In vitro and in vivo activity and cross resistance profiles of novel ruthenium (II) organometallic arene complexes in human ovarian cancer

    PubMed Central

    Aird, R E; Cummings, J; Ritchie, A A; Muir, M; Morris, R E; Chen, H; Sadler, P J; Jodrell, D I

    2002-01-01

    Ruthenium complexes offer the potential of reduced toxicity, a novel mechanism of action, non-cross resistance and a different spectrum of activity compared to platinum containing compounds. Thirteen novel ruthenium(II) organometallic arene complexes have been evaluated for activity (in vitro and in vivo) in models of human ovarian cancer, and cross-resistance profiles established in cisplatin and multi-drug-resistant variants. A broad range of IC50 values was obtained (0.5 to >100 μM) in A2780 parental cells with two compounds (RM175 and HC29) equipotent to carboplatin (6 μM), and the most active compound (HC11) equipotent to cisplatin (0.6 μM). Stable bi-dentate chelating ligands (ethylenediamine), a more hydrophobic arene ligand (tetrahydroanthracene) and a single ligand exchange centre (chloride) were associated with increased activity. None of the six active ruthenium(II) compounds were cross-resistant in the A2780cis cell line, demonstrated to be 10-fold resistant to cisplatin/carboplatin by a mechanism involving, at least in part, silencing of MLH1 protein expression via methylation. Varying degrees of cross-resistance were observed in the P-170 glycoprotein overexpressing multi-drug-resistant cell line 2780AD that could be reversed by co-treatment with verapamil. In vivo activity was established with RM175 in the A2780 xenograft together with non-cross-resistance in the A2780cis xenograft and a lack of activity in the 2780AD xenograft. High activity coupled to non cross-resistance in cisplatin resistant models merit further development of this novel group of anticancer compounds. British Journal of Cancer (2002) 86, 1652–1657. DOI: 10.1038/sj/bjc/6600290 www.bjcancer.com © 2002 Cancer Research UK PMID:12085218

  10. Ruthenium(II) bipyridine complexes bearing quinoline-azoimine (NN‧N″) tridentate ligands: Synthesis, spectral characterization, electrochemical properties and single-crystal X-ray structure analysis

    NASA Astrophysics Data System (ADS)

    Al-Noaimi, Mousa; Abdel-Rahman, Obadah S.; Fasfous, Ismail I.; El-khateeb, Mohammad; Awwadi, Firas F.; Warad, Ismail

    Four octahedral ruthenium(II) azoimine-quinoline complexes having the general molecular formula [RuII(Lsbnd Y)(bpy)Cl](PF6) {Lsbnd Y = YC6H4Ndbnd NC(COCH3)dbnd NC9H6N, Y = H (1), CH3 (2), Br (3), NO2 (4) and bpy = 2,2‧-bipyrdine} were synthesized. The azoimine-quinoline based ligands behave as NN‧N″ tridentate donors and coordinated to ruthenium via azo-N‧, imine-N‧ and quinolone-N″ nitrogen atoms. The composition of the complexes has been established by elemental analysis, spectral methods (FT-IR, electronic, 1H NMR, UV/Vis and electrochemical (cyclic voltammetry) techniques. The crystal structure of complex 1 is reported. The Ru(II) oxidation state is greatly stabilized by the novel tridentate ligands, showing Ru(III/II) couples ranging from 0.93-1.27 V vs. Cp2Fe/Cp2Fe+. The absorption spectrum of 1 in dichloromethane was modeled by time-dependent density functional theory (TD-DFT).

  11. Formic acid dehydrogenation catalysed by ruthenium complexes bearing the tripodal ligands triphos and NP3.

    PubMed

    Mellone, Irene; Peruzzini, Maurizio; Rosi, Luca; Mellmann, Dörthe; Junge, Henrik; Beller, Matthias; Gonsalvi, Luca

    2013-02-21

    The selective formic acid dehydrogenation to a mixture of CO(2) and H(2) was achieved with moderate to good productivities in the presence of homogeneous Ru catalysts bearing the polydentate tripodal ligands 1,1,1-tris-(diphenylphosphinomethyl)ethane (triphos) and tris-[2-(diphenylphosphino)ethyl]amine (NP(3)), either made in situ from suitable Ru(III) precursors or as molecular complexes. Preliminary mechanistic studies highlighting subtle differences due to ligand effects in the corresponding systems under study are also presented. PMID:23212285

  12. Preparation and reactivity of mixed-ligand ruthenium(II) hydride complexes with phosphites and polypyridyls.

    PubMed

    Albertin, Gabriele; Antoniutti, Stefano; Bacchi, Alessia; D'Este, Claudia; Pelizzi, Giancarlo

    2004-02-23

    Chloro complexes [RuCl(N-N)P3]BPh4 (1-3) [N-N = 2,2'-bipyridine, bpy; 1,10-phenanthroline, phen; 5,5'-dimethyl-2,2'-bipyridine, 5,5'-Me2bpy; P = P(OEt)3, PPh(OEt)2 and PPh2OEt] were prepared by allowing the [RuCl4(N-N)].H2O compounds to react with an excess of phosphite in ethanol. The bis(bipyridine) [RuCl(bpy)2[P(OEt)3

  13. New water-soluble ruthenium(II) cytotoxic complex: biological activity and cellular distribution.

    PubMed

    Morais, Tânia S; Santos, Filipa C; Jorge, Tiago F; Côrte-Real, Leonor; Madeira, Paulo J Amorim; Marques, Fernanda; Robalo, M Paula; Matos, António; Santos, Isabel; Garcia, M Helena

    2014-01-01

    A novel water soluble organometallic compound, [RuCp(mTPPMSNa)(2,2'-bipy)][CF3SO3] (TM85, where Cp=η(5)-cyclopentadienyl, mTPPMS=diphenylphosphane-benzene-3-sulfonate and 2,2'-bipy=2,2'-bipyridine) is presented herein. Studies of interactions with relevant proteins were performed to understand the behavior and mode of action of this complex in the biological environment. Electrochemical and fluorescence studies showed that TM85 strongly binds to albumin. Studies carried out to study the formation of TM85 which adducts with ubiquitin and cytochrome c were performed by electrospray ionization mass spectrometry (ESI-MS). Antitumor activity was evaluated against a variety of human cancer cell lines, namely A2780, A2780cisR, MCF7, MDAMB231, HT29, PC3 and V79 non-tumorigenic cells and compared with the reference drug cisplatin. TM85 cytotoxic effect was reduced in the presence of endocytosis modulators at low temperatures, suggesting an energy-dependent mechanism consistent with endocytosis. Ultrastructural analysis by transmission electron microscopy (TEM) revealed that TM85 targets the endomembranar system disrupting the Golgi and also affects the mitochondria. Disruption of plasma membrane observed by flow cytometry could lead to cellular damage and cell death. On the whole, the biological activity evaluated herein combined with the water solubility property suggests that complex TM85 could be a promising anticancer agent. PMID:24145065

  14. Orbital entanglement and CASSCF analysis of the Ru–NO bond in a Ruthenium nitrosyl complex

    PubMed Central

    Freitag, Leon; Knecht, Stefan; Keller, Sebastian F.; Delcey, Mickaël G.; Aquilante, Francesco; Bondo Pedersen, Thomas; Lindh, Roland

    2015-01-01

    Complete active space self-consistent field (CASSCF) wavefunctions and an orbital entanglement analysis obtained from a density-matrix renormalisation group (DMRG) calculation are used to understand the electronic structure, and, in particular, the Ru–NO bond of a Ru nitrosyl complex. Based on the configurations and orbital occupation numbers obtained for the CASSCF wavefunction and on the orbital entropy measurements evaluated for the DMRG wavefunction, we unravel electron correlation effects in the Ru coordination sphere of the complex. It is shown that Ru–NO π bonds show static and dynamic correlation, while other Ru–ligand bonds feature predominantly dynamic correlation. The presence of static correlation requires the use of multiconfigurational methods to describe the Ru–NO bond. Subsequently, the CASSCF wavefunction is analysed in terms of configuration state functions based on localised orbitals. The analysis of the wavefunctions in the electronic singlet ground state and the first triplet state provides a picture of the Ru–NO moiety beyond the standard representation based on formal oxidation states. A distinct description of the Ru and NO fragments is advocated. The electron configuration of Ru is an equally weighted superposition of RuII and RuIII configurations, with the RuIII configuration originating from charge donation mostly from Cl ligands. However, and contrary to what is typically assumed, the electronic configuration of the NO ligand is best described as electroneutral. PMID:25767830

  15. Synthesis, characterization and biological evaluation of labile intercalative ruthenium(ii) complexes for anticancer drug screening.

    PubMed

    Huang, Huaiyi; Zhang, Pingyu; Chen, Yu; Qiu, Kangqiang; Jin, Chengzhi; Ji, Liangnian; Chao, Hui

    2016-08-16

    DNA binding and DNA transcription inhibition is regarded as a promising strategy for cancer chemotherapy. Herein, chloro terpyridyl Ru(ii) complexes, [Ru(tpy)(N^N)Cl](+) (Ru1, N^N = 2,2'-bipyridine; Ru2, N^N = 3-(pyrazin-2-yl)-as-triazino[5,6-f]acenaphthylene; Ru3, N^N = 3-(pyrazin-2-yl)-as-triazino[5,6-f]phenanthrene; Ru4, N^N = 3-(pyrazin-2-yl)-as-triazino[5,6-f]pyrene) were prepared as DNA intercalative and covalent binding anticancer agents. The chloro ligand hydrolysis slowly and the octanol and water partition coefficient of Ru2-Ru4 were between 0.6 and 1.2. MALDI-TOF mass, DNA gel electrophoresis confirmed covalent and intercalative DNA binding modes of Ru2-Ru4, while Ru1 can only bind DNA covalently. As a result, Ru2-Ru4 exhibited stronger DNA transcription inhibition activity, higher cell uptake efficiency and better anticancer activity than Ru1. Ru4 was the most toxic complex toward all cancer cells which inhibited DNA replication and transcription. AO/EB, Annexin V/PI, nuclear staining, JC-1 assays further confirmed that Ru2-Ru4 induced cancer cell death by an apoptosis mechanism. PMID:27294337

  16. Complexes of ruthenium(III) with some 2-aminothiazole derivatives/synthesis, properties and pharmacological studies.

    PubMed

    Nikolova, Antonina; Ivanov, Darvin; Bontchev, Panayot; Buyukliev, Rossen; Mehandjiev, Dimitar; Gochev, Georgi; Konstantinov, Spiro; Karaivanova, Margarita

    2004-01-01

    Four new complexes of Ru(III) with a general formula [Ru(L)2Cl2]Cl, where L = 2-amino-4-phenylthiazole (CAS 2010-06-2), 2-amino-4-methylthiazole (CAS 1603-91-4), ethyl 2-amino-4-methyl-5-thiazolecarboxylate (CAS 7210-76-6) and ethyl 2-amino-4-phenyl-5-thiazolecarboxylate (CAS 64399-23-1), were prepared. The syntheses were carried out in polar medium and inert atmosphere at a molar ratio Ru:L = 1:2 or 1:3. The compounds obtained were characterised by IR-, 1H-NMR- 13C-NMR-, UV-VIS-, EPR spectroscopy, magnetochemical and conductivity measurements. The ligands behaved as bidental, bounding Ru(III) through the nitrogen atoms from the amino group and the heterocycle. The complex of ethyl 2-amino-4-phenyl-5-thiazolecarboxylate showed significant antileukaemic activity on various human cells (IC50 values ranging from 20 to 92 micromol/l). Toxicological studies on mice indicated that such concentrations could be reached without mortality. This compound exhibited a promising antineoplastic potential and needs further pharmacological and toxicological evaluation.

  17. Novel metals and metal complexes as platforms for cancer therapy.

    PubMed

    Frezza, Michael; Hindo, Sarmad; Chen, Di; Davenport, Andrew; Schmitt, Sara; Tomco, Dajena; Dou, Q Ping

    2010-06-01

    Metals are essential cellular components selected by nature to function in several indispensable biochemical processes for living organisms. Metals are endowed with unique characteristics that include redox activity, variable coordination modes, and reactivity towards organic substrates. Due to their reactivity, metals are tightly regulated under normal conditions and aberrant metal ion concentrations are associated with various pathological disorders, including cancer. For these reasons, coordination complexes, either as drugs or prodrugs, become very attractive probes as potential anticancer agents. The use of metals and their salts for medicinal purposes, from iatrochemistry to modern day, has been present throughout human history. The discovery of cisplatin, cis-[Pt(II) (NH(3))(2)Cl(2)], was a defining moment which triggered the interest in platinum(II)- and other metal-containing complexes as potential novel anticancer drugs. Other interests in this field address concerns for uptake, toxicity, and resistance to metallodrugs. This review article highlights selected metals that have gained considerable interest in both the development and the treatment of cancer. For example, copper is enriched in various human cancer tissues and is a co-factor essential for tumor angiogenesis processes. However the use of copper-binding ligands to target tumor copper could provide a novel strategy for cancer selective treatment. The use of nonessential metals as probes to target molecular pathways as anticancer agents is also emphasized. Finally, based on the interface between molecular biology and bioinorganic chemistry the design of coordination complexes for cancer treatment is reviewed and design strategies and mechanisms of action are discussed.

  18. High-valent corrole metal complexes.

    PubMed

    Gross, Z

    2001-09-01

    This commentary concentrates on corrole complexes with the three metal ions that are most relevant to oxidation catalysis: chromium, manganese, and iron. Particular emphasis is devoted to the only recently introduced meso-triarylcorroles and a comparison with the traditionally investigated beta-pyrrole-substituted corroles. Based on a combination of spectroscopic methods, electrochemistry, and X-ray crystallography, it is concluded that in most high-valent metallocorroles the corrole is not oxidized. Both experimental (for (oxo)chromium(V) corrole) and computational (for (oxo)manganese(V) corrole) evidence indicate that the stabilization of high-valent metal ions by corroles originates from a combination of short metal-nitrogen bonds and large metal out-of-plane displacements in the corrole, which lead to quite unexpected interactions of the oxo-metal pi* orbitals with the in-plane orbitals of the corrole.

  19. Optical properties of beta-iron silicide, ruthenium silicide and osmium silicide: Semiconducting transition metal silicides

    NASA Astrophysics Data System (ADS)

    Birdwell, Anthony Glen

    2001-09-01

    Various optical techniques were used to study the semiconducting transition metal silicides of β- FeSi2, Ru2Si3, and OsSi2. The Raman spectra of ion beam synthesized (IBS) β-FeSi 2 were shown to provide evidence of a net tensile stress in these IBS materials. Possible origins of the observed stress were suggested and a simple model was proposed in order to calculate a value of the observed stress. A correlation between the tensile stress, the nature of the band gap, and the resulting light emitting properties of IBS β-FeSi2 was suggested. The photoreflectance (PR) spectra of IBS β- FeSi2 reveals a direct gap at 0.815 eV and were shown to agree with the band gap value obtained by photoluminescence (PL) once the adjustments for the temperature difference and trap related recombination effects were made. This provides very convincing evidence for intrinsic light emission from IBS β- FeSi2. Furthermore, a model was developed that helps to clarify the variety of inconsistent results obtained by optical absorption measurements. When the results of PL and PR were inserted into this model, a good agreement was obtained with our measured optical absorption results. We also obtained PR spectra of β-FeSi 2 thin films grown by molecular beam epitaxy. These spectra reveal the multiple direct transitions near the fundamental absorption edge of β-FeSi 2 that were predicted by theory. We suggest an order of these critical point transitions following the trends reported in the theoretical investigations. Doping these β-FeSi2 thin films with small amounts of chromium was shown to have a measurable effect on the interband optical spectra. We also report on the effects of alloying β- FeSi2 with cobalt. A decrease in the critical point transitions nearest the fundamental absorption edge was observed as the cobalt concentration increased. Finally, Raman spectroscopy was used to study the vibrational properties of β-FeSi2. The measured Raman spectra agreed very well with the

  20. Ring opening and carbonylation of 3,3-dimethylthietane ligands in ruthenium carbonyl cluster complexes

    SciTech Connect

    Adams, R.D.; Belinski, J.A.; Yamamoto, J.H.

    1992-10-01

    When heated to 97{degrees}C, the complex Ru{sub 4}(CO){sub 12}[{mu}-SCH{sub 2}CMe{sub 2}CH{sub 2}]2 (1) was transformed into two new hexaruthenium cluster complexes, Ru{sub 6}(CO){sub 13}({mu}{sub 3}-SCH{sub 2}CMe{sub 2}CH{sub 2}){sub 4} (2) and Ru{sub 6}(CO){sub 12}({mu}-SCH{sub 2}CMe{sub 2}CH{sub 2})({mu}{sub 3}-SCH{sub 2}CMe{sub 2}CH{sub 2}){sub 3}[{mu}{sub 3}-SCH{sub 2}C(Me)(CH{sub 2})CH{sub 2}] ({mu}-H) (3), that contain four and five ring-opened 3,3-dimethylthietane (3,3-DMT) ligands, respectively. In compound 3 one of the ring-opened DMT ligands has also undergone a CH activation on one of the methyl groups. Compound 2 reacts with additional 3,3-DMT at 97{degrees}C to form 3 in 18% yield. When treated with CO at 95{degrees}C (500 psi), compound 2 yielded 4,4-dimethylthiobutyrolactone and Ru{sub 3}(CO){sub 12}. It was also found that the complex Os{sub 3}(CO){sub 11-}(SCH{sub 2}CMe{sub 2}CH{sub 2}C{double_bond}O) (4) yields 4,4-dimethylthiobutyrolactone when treated with CO at 120{degrees}C (1200 psi). Crystal data for 2: space group P2{sub 1}/n, {alpha} = 22.652 (7) A, {beta} = 11.712 (2) A, c = 19.965 (6) A, {Beta} = 115.75 (2){degrees} Z = 4, 3665 reflections, R = 0.021. Crystal data for 3: space group P2{sub 1}/c, {alpha} = 17.332 (8) A, {Beta} = 14.668 (9) A, c = 19.823 (9) A, {Beta} = 91.27 (4){degrees}, Z = 4, 1875 reflections, R = 0.050. 13 refs., 2 figs., 13 refs.

  1. Two Oxygen-Coordinated Metastable Ru-ON States for Ruthenium Mononitrosyl Complex.

    PubMed

    Vorobyev, Vasily; Kostin, Gennadiy A; Kuratieva, Natalia V; Emelyanov, Vyacheslav A

    2016-09-19

    The properties of Ru-ON states were studied in cis-[RuNO(NH3)2(NO2)2OH] under illumination. The structure contains two nonequivalent complexes, and the metastable state was generated for both molecules with 19(1) and 31(1)% populations. The MS1 thermal decay occurs as a one-step process at about 240 K according to differential scanning calorimetry (DSC). For the first-order reaction, the frequency factor and activation energy for the decay process were determined as 2.0(2) × 10(13) s(-1) and 68.3(4) kJ mol(-1), respectively. Also, the simultaneous metastable state decay observed via DSC was in agreement with IR spectroscopy. PMID:27598533

  2. Phenyl substituted indenylphosphine ruthenium complexes as catalysts for dehydrogenation of alcohols.

    PubMed

    Yuan, Jia; Sun, Yue; Yu, Guang-Ao; Zhao, Cui; She, Neng-Fang; Mao, Shu-Lan; Huang, Peng-Shou; Han, Zhi-Jun; Yin, Jun; Liu, Sheng-Hua

    2012-09-14

    Thermal treatment of (1H-inden-3-yl)dicyclohexylphosphinium tetrafluoroborate (1) and (3-mesityl-1H-inden-3-yl)dicyclohexylphosphinium tetrafluoroborate (3) with tBuONa followed by [(η(6)-cymene)RuCl(2))](2) in methanol gave the adduct {(η(6)-cymene)RuCl(2)[(1H-inden-3-yl)PCy(2)]} (6) and {(η(6)-cymene)RuCl(2)[(3-mesityl-1H-inden-3-yl)PCy(2)]} (7), respectively. Thermal treatment of (2-phenyl-1H-inden-3-yl)dicyclohexylphosphinium tetrafluoroborate (4) with tBuONa followed by [(η(6)-cymene)RuCl(2))](2) or RuCl(3)·3H(2)O in methanol gave {Ru[κ(P):(η(6)-2-phenyl-1H-inden-3-yl)PCy(2)]Cl(2)} (8). Whereas (2-mesityl-1H-inden-3-yl)dicyclohexylphosphine (5) reacted with [(η(6)-cymene)RuCl(2))](2) (in toluene) or RuCl(3)·3H(2)O (in ethanol) to afford {Ru[κ(P):(η(6)-2-mesityl-1H-inden-3-yl)PCy(2)]Cl(2)} (9). The molecular structures of complexes 6, 8 and 9 have been determined by single-crystal X-ray diffraction analysis. In addition, complexes 8 and 9 have been found to catalyze the acceptorless dehydrogenation of alcohols in toluene. 9 displayed high activity and different substrates, including cyclic and linear alcohols, were efficiently oxidized to ketones by using 2.0 mol% of catalyst. PMID:22806176

  3. Preparation of novel alkylated ruthenium {alpha}-diimine complexes: Reactivity toward carbon monoxide and phosphines

    SciTech Connect

    Kraakman, M.J.A.; Vrieze, K.; Kooijman, H.; Spek, A.L.

    1992-11-01

    Ru{sub 2}(CO){sub 5}({sup i}Pr-DAB) (1) reacts with MeI at room temperature to give Ru{sub 2}(Me)(I)(CO){sub 4}({sup i}Pr-DAB) (2a), and a single-crystal X-ray structure determination of 2a has been obtained. Treatment of 2a with CO leads to substitution of the iodide bridge and the two coordinated imine bonds with the formation of Ru(Me)(I)(CO{sub 2})({sup i}Pr-DAB) (3a) and Ru(CO){sub 5}. This reaction, which is reversible, provides a new synthetic route for the preparation of monomeric methylated {alpha}-diimine complexes. Several other reaction routes for the formation of the complexes Ru(X)(Y)(CO){sub 2}({alpha}-diimine) (X = Me, Y = I, {alpha}-diimine Y = I, {alpha}-diimine = {sup i}Pr-Pyca (3b); X = Y = I, {alpha}-diimine = {sup i}Pr-DAB (3c); X = Y = I, {alpha}-diimine = {sup i}Pr-pyca (3d); X = Cl, Y = benzyl, {alpha}-diimine = {sup i}Pr-DAB (3e)) are presented. Treatment of 2a with phosphines leads to substitution of only one coordinated imine bond, with the formation of Ru{sub 2}(Me)(I)(CO){sub 4}(PR{sub 3})({sup i}Pr-DAB) (PR{sub 3} = PPh{sub 3} (4a), PMe{sub 2}Ph (4b), P(OMe){sub 3} (4c)). 62 refs., 4 figs., 13 tabs.

  4. Fully Borylated Methane and Ethane by Ruthenium-Mediated Cleavage and Coupling of CO.

    PubMed

    Batsanov, Andrei S; Cabeza, Javier A; Crestani, Marco G; Fructos, Manuel R; García-Álvarez, Pablo; Gille, Marie; Lin, Zhenyang; Marder, Todd B

    2016-04-01

    Many transition-metal complexes and some metal-free compounds are able to bind carbon monoxide, a molecule which has the strongest chemical bond in nature. However, very few of them have been shown to induce the cleavage of its C-O bond and even fewer are those that are able to transform CO into organic reagents with potential in organic synthesis. This work shows that bis(pinacolato)diboron, B2pin2, reacts with ruthenium carbonyl to give metallic complexes containing borylmethylidyne (CBpin) and diborylethyne (pinBC≡CBpin) ligands and also metal-free perborylated C1 and C2 products, such as C(Bpin)4 and C2 (Bpin)6, respectively, which have great potential as building blocks for Suzuki-Miyaura cross-coupling and other reactions. The use of (13)CO-enriched ruthenium carbonyl has demonstrated that the boron-bound carbon atoms of all of these reaction products arise from CO ligands.

  5. Photoresponsive Molecular Memory Films Composed of Sequentially Assembled Heterolayers Containing Ruthenium Complexes.

    PubMed

    Nagashima, Takumi; Ozawa, Hiroaki; Suzuki, Takashi; Nakabayashi, Takuya; Kanaizuka, Katsuhiko; Haga, Masa-Aki

    2016-01-26

    Photoresponsive molecular memory films were fabricated by a layer-by-layer (LbL) assembling of two dinuclear Ru complexes with tetrapodal phosphonate anchors, containing either 2,3,5,6-tetra(2-pyridyl)pyrazine or 1,2,4,5-tetra(2-pyridyl)benzene as a bridging ligand (Ru-NP and Ru-CP, respectively), using zirconium phosphonate to link the layers. Various types of multilayer homo- and heterostructures were constructed. In the multilayer heterofilms such as ITO||(Ru-NP)m |(Ru-CP)n , the difference in redox potentials between Ru-NP and Ru-CP layers was approximately 0.7 V, which induced a potential gradient determined by the sequence of the layers. In the ITO||(Ru-NP)m |(Ru-CP)n multilayer heterofilms, the direct electron transfer (ET) from the outer Ru-CP layers to the ITO were observed to be blocked for m>2, and charge trapping in the outer Ru-CP layers became evident from the appearance of an intervalence charge transfer (IVCT) band at 1140 nm from the formation of the mixed-valent state of Ru-CP units, resulting from the reductive ET mediation of the inner Ru-NP layers. Therefore, the charging/discharging ("1"and "0") states in the outer Ru-CP layers could be addressed and interconverted by applying potential pulses between -0.5 and +0.7 V. The two states could be read out by the direction of the photocurrent (anodic or cathodic). The molecular heterolayer films thus represent a typical example of a photoresponsive memory device; that is, the writing process may be achieved by the applied potential (-0.5 or +0.7 V), while the readout process is achieved by measuring the direction of the photocurrent (anodic or cathodic). Sequence-sensitive multilayer heterofilms, using redox-active complexes as building blocks, thus demonstrate great potential for the design of molecular functional devices.

  6. Bis-mixed-carbene ruthenium-thiolate-alkylidene complexes: synthesis and olefin metathesis activity.

    PubMed

    Dahcheh, Fatme; Stephan, Douglas W

    2015-01-28

    A series of bis-carbene Ru-hydride species, including (IMes)(Im(OMe)2)(PPh3)RuHCl (1) and (SIMes)(Me2Im(OMe)2)(PPh3)RuHCl (2) were prepared and subsequently shown to react with aryl-vinyl-sulfides to give the bis-carbene-alkylidene complexes: Im(OMe)2(SIMes)RuCl(SR)(=CHCH3) (R = p-FC6H4 (3), p-(NO2)C6H4 (4)), Im(OMe)2(IMes)RuCl(=CHCH3)(SPh) (5), Me2Im(OMe)2(SIMes)RuCl(=CHCH3)(SPh) (6), Im(OMe)2(SIMes)(F5C6S)RuCl(=CHR) (R = C4H9 (9), C5H11 (10)). The activity of these species in the standard Grubbs' tests for ring-opening metathesis polymerization, ring-closing and cross-metathesis are reported. Although these thiolate derivatives are shown to exhibit modest metathesis activities, the reactivity is enhanced in the presence of BCl3. PMID:25462569

  7. Bis-mixed-carbene ruthenium-thiolate-alkylidene complexes: synthesis and olefin metathesis activity.

    PubMed

    Dahcheh, Fatme; Stephan, Douglas W

    2015-01-28

    A series of bis-carbene Ru-hydride species, including (IMes)(Im(OMe)2)(PPh3)RuHCl (1) and (SIMes)(Me2Im(OMe)2)(PPh3)RuHCl (2) were prepared and subsequently shown to react with aryl-vinyl-sulfides to give the bis-carbene-alkylidene complexes: Im(OMe)2(SIMes)RuCl(SR)(=CHCH3) (R = p-FC6H4 (3), p-(NO2)C6H4 (4)), Im(OMe)2(IMes)RuCl(=CHCH3)(SPh) (5), Me2Im(OMe)2(SIMes)RuCl(=CHCH3)(SPh) (6), Im(OMe)2(SIMes)(F5C6S)RuCl(=CHR) (R = C4H9 (9), C5H11 (10)). The activity of these species in the standard Grubbs' tests for ring-opening metathesis polymerization, ring-closing and cross-metathesis are reported. Although these thiolate derivatives are shown to exhibit modest metathesis activities, the reactivity is enhanced in the presence of BCl3.

  8. Ruthenium terpyridine complexes containing a pyrrole-tagged 2,2'-dipyridylamine ligand-synthesis, crystal structure, and electrochemistry.

    PubMed

    Cheung, Kwong-Chak; Guo, Peng; So, Ming-Him; Zhou, Zhong-Yuan; Lee, Lawrence Yoon Suk; Wong, Kwok-Yin

    2012-06-18

    Ruthenium(II) terpyridine complexes containing the pyrrole-tagged 2,2'-dipyridylamine ligand PPP (where PPP stands for N-(3-bis(2-pyridyl)aminopropyl)pyrrole with the general formula [Ru(tpy)(PPP)X](n+) (1, X = Cl(-); 2, X = H(2)O; 3, X = CH(3)CN; tpy = 2,2':6',2"-terpyridine) have been synthesized and characterized by (1)H NMR, IR, UV-vis, mass spectrometry, and elemental analysis. 1 and 2 have been structurally characterized by X-ray crystallography. Both 1 and 2 were successfully immobilized onto glassy carbon electrode via anodic oxidation of the pyrrole moiety on the PPP ligand to give stable and highly electroactive polymer films. Cyclic voltammetric studies of 1 in acetonitrile revealed a Ru(III)/Ru(II) couple at 0.4 V vs Cp(2)Fe(+/0) initially, but another redox couple resulting from chloride substitution by acetonitrile developed at E(1/2) = 0.82 V upon repetitive potential scan. This ligand substitution was induced by the acidic local environment caused by the release of protons during pyrrole polymerization. The electropolymerization of 2 in aqueous medium allowed the observation of the formation of Ru(IV)═O species in polypyrrole film. As the film grew thicker, the size of the Ru(III)/(/)Ru(II) couple (E(1/2) = 0.8 V vs SCE at pH 1) of poly[Ru(tpy)(PPP)(OH(2))](n+) increased accordingly, whereas the growth of the Ru(IV)/Ru(III) couple (E(1/2) = 0.89 V vs SCE at pH 1) leveled off after the film had reached a certain thickness. The Pourbaix diagram of the E(1/2) of the Ru(III) /Ru(II) and Ru(IV)/Ru(III) couples vs pH of the electrolyte medium has been obtained. The resulting poly[Ru(tpy)(PPP)(OH(2))](n+) film is electrocatalytically active toward the oxidation of benzyl alcohol.

  9. Synthesis, characterization, and reactivity of ruthenium diene/diamine complexes including catalytic hydrogenation of ketones.

    PubMed

    Morilla, M Esther; Rodríguez, Pilar; Belderrain, Tomas R; Graiff, Claudia; Tiripicchio, Antonio; Nicasio, M Carmen; Pérez, Pedro J

    2007-10-29

    Thermal reactions between [RuCl2(diene)]n (diene = 2,5-norbornadiene, nbd; 1,5-cyclooctadiene, cod) with an excess of N,N,N',N'-tetramethylethylene diamine (tmeda) afforded derivatives [RuCl2(diene)(tmeda)] (diene = nbd, 1; cod, 2) as a mixture of cis and trans isomers. When thermolysis was performed under H2 mixtures of hydride species [RuCl(H)(diene)(tmeda)] (diene = nbd, 3; cod, 4) and the bis-tmeda adduct trans-[RuCl2(tmeda)2] (5) were obtained in different ratios depending upon the reaction conditions and reaction times. Heating polymeric Ru(II) precursors in toluene in the presence of a 5-fold excess of the bulkier N,N,N',N'-tetraethylethylene diamine (teeda) resulted in a rare diamine dealkylation process with formation of trans-[RuCl2(nbd)(Et2NCH2CH2NHEt)] (6) and trans-[RuCl2(cod)(EtHNCH2CH2NHEt)] (7) in high yields. The presence of N-H functionalities in the coordinated diamine ligands of 6 and 7 was unambiguously established by single-crystal X-ray diffraction studies. The dealkylation process of the teeda ligand seems to proceed intramolecularly as shown by solution NMR studies performed with the soluble Ru(II) precursors trans-[RuCl2(amine)2(diene)] (diene = nbd, amine = morpholine, 9; diene = cod, amine = Et2NH, 10). The above complexes [RuCl2(diene)(diamine)] have been tested as precatalysts in the hydrogenation of ketones both for transfer as well as direct hydrogenation, the latter route being the most effective.

  10. Photoinduced processes within compact dyads based on triphenylpyridinium-functionalized bipyridyl complexes of ruthenium(II).

    PubMed

    Lainé, Philippe P; Ciofini, Ilaria; Ochsenbein, Philippe; Amouyal, Edmond; Adamo, Carlo; Bedioui, Fethi

    2005-06-01

    As an alternative to conventional charge-separation functional molecular models based on long-range ET within redox cascades, a "compact approach" has been examined. To this end, spacer elements usually inserted between main redox-active units within polyad systems have been removed, allowing extended rigidity but at the expense of enhanced intercomponent electronic communication. The molecular assemblies investigated here are of the P-(theta (1))-A type, where the theta (1) twist angle is related to the degree of conjugation between the photosensitizer (P, of {Ru(bpy)(3)}(2+) type) and the electron-acceptor (A). 4-N- and 4-N-,4'-N-(2,4,6-triphenylpyridinio)-2,2'-bipyridine ligands (A(1)-bpy and A(2)-bpy, respectively) have been synthesized to give complexes with Ru(II), 1-bpy and 2-bpy, respectively. Combined solid-state analysis (X-ray crystallography), solution studies ((1)H NMR, cyclic voltammetry) and computational structural optimization allowed verifying that theta (1) angle approaches 90 degrees within 1-bpy and 2-bpy in solution. Also, anticipated existence of strong intercomponent electronic coupling has been confirmed by investigating electronic absorption properties and electrochemical behavior of the compounds. The capability of 1-bpy and 2-bpy to undergo PET process was evaluated by carrying out their photophysical study (steady state emission and time-resolved spectroscopy at both 293 and 77 K). The conformational dependence of photoinduced processes within P-(theta (1))-A systems has been established by comparing the photophysical properties of 1-bpy (and 2-bpy) with those of an affiliated species reported in the literature, 1-phen. A complementary theoretical analysis (DFT) of the change of spin density distribution within model [1-bpy(theta (1))](-) mono-reduced species as a function of theta (1) has been undertaken and the possibility of conformationally switching emission properties of P was derived. PMID:15822134

  11. Biomimetic cavity-based metal complexes.

    PubMed

    Rebilly, Jean-Noël; Colasson, Benoit; Bistri, Olivia; Over, Diana; Reinaud, Olivia

    2015-01-21

    The design of biomimetic complexes for the modeling of metallo-enzyme active sites is a fruitful strategy for obtaining fundamental information and a better understanding of the molecular mechanisms at work in Nature's chemistry. The classical strategy for modeling metallo-sites relies on the synthesis of metal complexes with polydentate ligands that mimic the coordination environment encountered in the natural systems. However, it is well recognized that metal ion embedment in the proteic cavity has key roles not only in the recognition events but also in generating transient species and directing their reactivity. Hence, this review focuses on an important aspect common to enzymes, which is the presence of a pocket surrounding the metal ion reactive sites. Through selected examples, the following points are stressed: (i) the design of biomimetic cavity-based complexes, (ii) their corresponding host-guest chemistry, with a special focus on problems related to orientation and exchange mechanisms of the ligand within the host, (iii) cavity effects on the metal ion binding properties, including 1st, 2nd, and 3rd coordination spheres and hydrophobic effects and finally (iv) the impact these factors have on the reactivity of embedded metal ions. Important perspectives lie in the use of this knowledge for the development of selective and sensitive probes, new reactions, and green and efficient catalysts with bio-inspired systems.

  12. A dendritic nano-sized hexanuclear ruthenium(II) complex as a one- and two-photon luminescent tracking non-viral gene vector

    PubMed Central

    Qiu, Kangqiang; Yu, Bole; Huang, Huaiyi; Zhang, Pingyu; Huang, Juanjuan; Zou, Shanshan; Chen, Yu; Ji, Liangnian; Chao, Hui

    2015-01-01

    Fluorescent tracking gene delivery could provide us with a better understanding of the critical steps in the transfection process. However, for in vivo tracking applications, a small diameter (<10 nm) is one of the rigorous requirements for tracking vectors. Herein, we have demonstrated a new paradigm for two-photon tracking gene delivery based on a dendritic nano-sized hexanuclear ruthenium(II) polypyridyl complex. Because this metallodendrimer has a multivalent periphery, the complex, which is 6.1 nm, showed high stability and excellent dispersibility and could stepwise condense DNA in vitro. With the outstanding photochemical properties of Ru(II) polypyridyl, this complex could track gene delivery in vivo using one- and two-photon imaging. PMID:26185052

  13. New bipyridyl/phenanthroline ruthenium(II) and ruthenium(III) complexes possessing acetate appended thioether. Evidence for oxidative linkage isomerization

    NASA Astrophysics Data System (ADS)

    Prasad, Rajendra; Kumar, Ajay; Kumar, Rajeev

    2006-03-01

    The acetate bearing dithioether, sodium di(2-carboxymethylsufanyl)maleonitrile, L 1 upon reaction with [Ru II(bpy) 2Cl 2]·2H 2O, [Ru II(phen) 2Cl 2]·2H 2O, [Ru III(bpy) 2Cl 2] + or [Ru III(phen) 2Cl 2] + in methanol formed complexes of the type [(bpy) 2Ru{S 2(CH 2COO) 2C 2(CN) 2}], ( 1), [(phen) 2Ru{S 2(CH 2COO) 2C 2(CN) 2}], ( 2), [(bpy) 2Ru{(OOCCH 2) 2S 2C 2(CN) 2}] +, ( 5) and [(phen) 2Ru{(OOCCH 2) 2S 2C 2(CN) 2}] +, ( 6) respectively. Four other Ru(III) complexes with di(benzylsulfanyl)maleonitrile, L 2, [(bpy) 2Ru{S 2(PhCH 2)C 2(CN) 2}] 3+, ( 7) and [(phen) 2Ru{S 2(PhCH 2) 2C 2(CN) 2}] 3+, ( 8), and with acetate, [(bpy) 2Ru(OOCCH 3) 2] +, ( 9) and [(phen) 2Ru(OOCCH 3) 2] +, ( 10) were also synthesized. In the cyclic voltammetry, complexes ( 1) and ( 2) exhibited quasireversible oxidation waves at 1.01 and 1.02 V vs. Ag/AgCl over GC electrode in DMF, while the corresponding Ru(III) L 1 complexes ( 5) and ( 6) exhibit reversible oxidation at E1/2 0.59 and 0.58 V, respectively, under identical conditions. This is unlike the voltammetric behavior of the Ru(II) and Ru(III) L 2 complexes, wherein the complex pairs ( 3), ( 7) and ( 4), ( 8) exhibited identical voltammograms with single reversible one electron waves at E1/2 0.98 and 0.92 V, respectively under identical conditions. The voltammograms of Ru(II)-L 2 complexes (3) and (4) also became irreversible in presence of nearly four molar equivalent of sodium acetate. Hence, the irreversible redox behavior of complexes (1) and (2) has been interpreted in terms of rapid linkage isomerization, i.e. shift in κ 2-S,S' to κ 2-O,O' coordination, following the Ru(II)/Ru(III) electrode process. The electronic spectra of Ru(III)-L 1 complexes ( 5) and ( 6) resemble closely with that of ( 9) and ( 10) instead of Ru(III)-L 2 complexes ( 7) and ( 8), further supports proposed linkage isomerization. The cationic complexes were obtained as [PF 6] - salts and all compounds were characterized using analytical and spectral (IR

  14. Alkene epoxidation employing metal nitro complexes

    DOEpatents

    Andrews, M.A.; Cheng, C.W.; Kelley, K.P.

    1982-07-15

    Process for converting alkenes to form epoxides utilizes transition metal nitro complexes of the formula: M(RCN)/sub 2/XNO/sub 2/ wherein M is palladium or platinum, R is an alkyl or aryl group containing up to 12 carbon atoms, and X is a monoanionic, monodentate ligand such as chlorine, optionally in the presence of molecular oxygen.

  15. Ruthenium, rhodium, osmium, and iridium complexes of osazones (osazones = bis-arylhydrazones of glyoxal): radical versus nonradical states.

    PubMed

    Patra, Sarat Chandra; Weyhermüller, Thomas; Ghosh, Prasanta

    2014-03-01

    Phenyl osazone (L(NHPh)H2), phenyl osazone anion radical (L(NHPh)H2(•-)), benzoyl osazone (L(NHCOPh)H2), benzoyl osazone anion radical (L(NHCOPh)H2(•-)), benzoyl osazone monoanion (L(NCOPh)HMe(-)), and anilido osazone (L(NHCONHPh)HMe) complexes of ruthenium, osmium, rhodium, and iridium of the types trans-[Os(L(NHPh)H2)(PPh3)2Br2] (3), trans-[Ir(L(NHPh)H2(•-))(PPh3)2Cl2] (4), trans-[Ru(L(NHCOPh)H2)(PPh3)2Cl2] (5), trans-[Os(L(NHCOPh)H2)(PPh3)2Br2] (6), trans- [Rh(L(NHCOPh)H2(•-))(PPh3)2Cl2] (7), trans-[Rh(L(NHCOPh)HMe(-))(PPh3)2Cl]PF6 ([8]PF6), and trans-[Ru(L(NHCONHPh)HMe)(PPh3)2Cl]Cl ([9]Cl) have been isolated and compared (osazones = bis-arylhydrazones of glyoxal). The complexes have been characterized by elemental analyses and IR, mass, and (1)H NMR spectra; in addition, single-crystal X-ray structure determinations of 5, 6, [8]PF6, and [9]Cl have been carried out. EPR spectra of 4 and 7 reveal that in the solid state they are osazone anion radical complexes (4, gav = 1.989; 7, 2.028 (Δg = 0.103)), while in solution the contribution of the M(II) ions is greater (4, gav = 2.052 (Δg = 0.189); 7, gav = 2.102 (Δg = 0.238)). Mulliken spin densities on L(NHPh)H2 and L(NHCOPh)H2 obtained from unrestricted density functional theory (DFT) calculations on trans-[Ir(L(NHPh)H2)(PMe3)2Cl2] (4(Me)) and trans-[Rh(L(NHCOPh)H2)(PMe3)2Cl2] (7(Me)) in the gas phase with doublet spin states authenticated the existence of L(NHPh)H2(•-) and L(NHCOPh)H2(•-) anion radicals in 4 and 7 coordinated to iridium(III) and rhodium(III) ions. DFT calculations on trans-[Os(L(NHPh)H2)(PMe3)2Br2] (3(Me)), trans-[Os(L(NHCOPh)H2)(PMe3)2Br2] (6(Me)), and trans-[Ru(L(NHCONHPh)HMe(-))(PMe3)2Cl] [9(Me)](+) with singlet spin states established that the closed-shell singlet state (CSS) solutions of 3, 5, 6, and [9]Cl are stable. The lower value of M(III)/M(II) reduction potentials and lower energy absorption bands corroborate the higher extent of mixing of d orbitals with the π* orbital

  16. Comparative chemistry of bipyrazyl and bipyridyl metal complexes: spectroscopy, electrochemistry, and photoanation

    SciTech Connect

    Crutchley, R.J.; Lever, A.B.P.

    1982-06-01

    The photoanation of the bipyrazyl complex Ru(bpz)/sub 3/(PF/sub 6/)/sub 2/, in acetonitrile containing chloride ion, leads to the formation of cis-Ru(bpz)/sub 2/(CH/sub 3/CN)Cl/sup +/ (maximum quantium yield 0.37), cis-Ru(bpz)/sub 2/Cl/sub 2/ (maximum quantum yield 0.001), and an unidentified mono(bipyrazl)ruthenium (II) derivative. The mechanism of this reaction is discussed. Reaction of M(CO)/sub 2/ (M = W, Mo) with bipyrazyl yields M(CO)/sub 4/bpz. The electronic, vibrational, and /sup 1/H NMR spetra and electrochemistry of these products were compared with those of their bipyridyl analogues. It is concluded that bipyrazyl is no better a ..pi.. acceptor than bipyridyl because of weaker sigma bonding leaving the metal ion more positively charged.

  17. Lifetimes, spectra, and quenching of the excited states of polypyridine complexes of iron(II), ruthenium(II), and osmium(II)

    SciTech Connect

    Creutz, C.; Chou, M.; Netzel, T.L.; Okumura, M.; Sutin, N.

    1980-02-13

    The lifetimes of the excited states formed by 530-nm excitation of polypyridine complexes of iron(II) (FeL/sub 3//sup 2 +/) and osmium(II) (OsL/sub 3//sup 2 +/) have been determined by laser flash-photolysis techniques. The FeL/sub 3//sup 2 +/ lifetimes, measured in water at room temperature using picosecond absorption spectrometry, are as follows (L,tau +- sigma(ns)):2,2',2''-terpyridine (2.54 +- 0.13); 2,2'-bipyridine (0.81 +- 0.07); 4,4'-dimethyl(2,2'-bipyridine) (0.76 +- 0.04); 1,10-phenanthroline (0.80 +- 0.07); 4,7-(diphenyl sulfonate)-1,10-phenanthroline (0.43 +- 0.03). Lifetimes for the analogous complexes of osmium(II) lie in the range 10-100 ns under the same conditions. Unlike the excited states of Ru(bpy)/sub 3//sup 2 +/ and Os(bpy)/sub 3//sup 2 +/ (lambda/sub max/430-460 nm, epsilon approx. 5 x 10/sup 3/ M/sup -1/ cm-/sup 1/), the excited state of Fe(bpy)/sub 3//sup 2 +/ does not luminesce or absorb significantly in the visible (epsilon < 10/sup 3/ M/sup -1/ cm/sup -1/ at lambda greater than or equal to 350 nm) but does exhibit intense absorption below approx. 325 nm. Rate constants for the quenching of the excited states of polypyridine complexes of osmium(II) and ruthenium(II) by ground-state polypyridine complexes of iron(II), ruthenium(II), and osmium(II) are reported and are ascribed to either electron-transfer or energy-transfer processes. The excited states of tris(2,2'-bipyridine)iron(II) and of bis(2,2',2''-terpyridine)iron(II) undergo reaction with Fe/sub aq//sup 3 +/ (0.5 M H/sub 2/SO/sub 4/, 25/sup 0/C) with a rate constant less than or equal to 1 x 10/sup 7/ M-/sup 1/ s/sup -1/. Based on a comparison of its properties with those of the luminescent charge-transfer excited states of ruthenium(II) and osmium(II) polypyridine complexes the excited state of FeL/sub 3//sup 2 +/ is identified as a ligand-field state.

  18. In vitro evaluation of the cyto-genotoxic potential of Ruthenium(II) SCAR complexes: a promising class of antituberculosis agents.

    PubMed

    De Grandis, Rone Aparecido; Resende, Flávia Aparecida; da Silva, Monize Martins; Pavan, Fernando Rogério; Batista, Alzir Azevedo; Varanda, Eliana Aparecida

    2016-03-01

    Tuberculosis is a top infectious disease killer worldwide, caused by the bacteria Mycobacterium tuberculosis. Increasing incidences of multiple drug-resistance (MDR) strains are emerging as one of the major public health threats. However, the drugs in use are still incapable of controlling the appalling upsurge of MDR. In recent years a marked number of research groups have devoted their attention toward the development of specific and cost-effective antimicrobial agents against targeted MDR-Tuberculosis. In previous studies, ruthenium(II) complexes (SCAR) have shown a promising activity against MDR-Tuberculosis although few studies have indeed considered ruthenium toxicity. Therefore, within the preclinical requirements, we have sought to determine the cyto-genotoxicity of three SCAR complexes in this present study. The treatment with the SCARs induced a concentration-dependent decrease in cell viability in CHO-K1 and HepG2 cells. Based on the clonogenic survival, SCAR 5 was found to be more cytotoxic while SCAR 6 exhibited selectivity action on tumor cells. Although SCAR 4 and 5 did not indicate any mutagenic activity as evidenced by the Ames and Cytokinesis block micronucleus cytome assays, the complex SCAR 6 was found to engender a frameshift mutation detected by Salmonella typhimurium in the presence of S9. Similarly, we observed a chromosomal damage in HepG2 cells with significant increases of micronuclei and nucleoplasmic bridges. These data indicate that SCAR 4 and 5 complexes did not show genotoxicity in our models while SCAR 6 was considered mutagenic. This study presented a comprehensive genotoxic evaluation of SCAR complexes were shown to be genotoxic in vitro. All in all, further studies are required to fully elucidate how the properties can affect human health.

  19. 4,4'-dithiodipyridine as a bridging ligand in osmium and ruthenium complexes: the electron conductor ability of the -S-S- bridge.

    PubMed

    Silva, Welter C; Lima, Joacy B; Moreira, Icaro S; Neto, Antônio M; Gandra, Flávio C G; Ferreira, Antônio G; McGarvey, Bruce R; Franco, Douglas W

    2003-10-20

    [(NH(3))(5)Os(III)(dtdp)Ru(II)(NH(3))(5)](5+) (lambda(MMCT) = 965 nm, epsilon = 2.2 x 10(2) M(-)(1) cm(-)(1), deltanu(1/2) = 3.0 x 10(3) cm(-)(1), and H(AB) = 2.2 x 10(2) cm(-)(1)) and [(NH(3))(5)Os(III)(dtdp)Fe(II)(CN)(5)] (lambda(MMCT) = 790 nm, epsilon = 7.5 x 10 M(-)(1) cm(-)(1), deltanu(1/2) = 5.4 x 10(3) cm(-)(1), and H(AB) = 2.0 x 10(2) cm(-)(1)) also suggest a considerable electron delocalization through the S-S bridge. As indicated by a comparison of K(c) and energy of the MMCT process in the iron, ruthenium, and osmium complexes, the electron delocalization between the two metal centers increases in the following order: Fe < Ru < Os. PMID:14552641

  20. A fast-initiating ionically tagged ruthenium complex: a robust supported pre-catalyst for batch-process and continuous-flow olefin metathesis.

    PubMed

    Borré, Etienne; Rouen, Mathieu; Laurent, Isabelle; Magrez, Magaly; Caijo, Fréderic; Crévisy, Christophe; Solodenko, Wladimir; Toupet, Loic; Frankfurter, René; Vogt, Carla; Kirschning, Andreas; Mauduit, Marc

    2012-12-14

    In this study, a new pyridinium-tagged Ru complex was designed and anchored onto sulfonated silica, thereby forming a robust and highly active supported olefin-metathesis pre-catalyst for applications under batch and continuous-flow conditions. The involvement of an oxazine-benzylidene ligand allowed the reactivity of the formed Ru pre-catalyst to be efficiently controlled through both steric and electronic activation. The oxazine scaffold facilitated the introduction of the pyridinium tag, thereby affording the corresponding cationic pre-catalyst in good yield. Excellent activities in ring-closing (RCM), cross (CM), and enyne metathesis were observed with only 0.5 mol % loading of the pre-catalyst. When this powerful pre-catalyst was immobilized onto a silica-based cationic-exchange resin, a versatile catalytically active material for batch reactions was generated that also served as fixed-bed material for flow reactors. This system could be reused at 1 mol % loading to afford metathesis products in high purity with very low ruthenium contamination under batch conditions (below 5 ppm). Scavenging procedures for both batch and flow processes were conducted, which led to a lowering of the ruthenium content to as little as one tenth of the original values.

  1. Chemical and structural investigations of the incorporation of metal manganese into ruthenium thin films for use as copper diffusion barrier layers

    SciTech Connect

    McCoy, A. P.; Casey, P.; Bogan, J.; Hughes, G.; Lozano, J. G.; Nellist, P. D.

    2012-12-03

    The incorporation of manganese into a 3 nm ruthenium thin-film is presented as a potential mechanism to improve its performance as a copper diffusion barrier. Manganese ({approx}1 nm) was deposited on an atomic layer deposited Ru film, and the Mn/Ru/SiO{sub 2} structure was subsequently thermally annealed. X-ray photoelectron spectroscopy studies reveal the chemical interaction of Mn with the SiO{sub 2} substrate to form manganese-silicate (MnSiO{sub 3}), implying the migration of the metal through the Ru film. Electron energy loss spectroscopy line profile measurements of the intensity of the Mn signal across the Ru film confirm the presence of Mn at the Ru/SiO{sub 2} interface.

  2. Development of metal-containing polymers for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Chan, Wai Kin; Hou, Sijian; Ng, Po K.; Wong, Chi T.; Yu, Sze C.

    1999-11-01

    Most of the work in organic electroluminescent polymers has been focused on organic conjugated polymers. However, polymers attached with transition metal complex have received relatively less attention. We have synthesized and studied the light emitting properties of some metal containing polymers based on the polypyridine complexes of rhenium and ruthenium. These complexes exhibit long-lived excited states caused by the metal to ligand charge transfer transitions. By varying the structure of the ligand and/or the transition metal, we are able to fine-tune the electronic properties of the resulting metal complexes. We have synthesized a series of poly(phenylenevinylene) (PPV) derivatives which are functionalized with ruthenium polypyridine complexes at the polymer mainchain or side chain. These complexes are able to act as photosensitizers which enhance the photoconductivity of these polymers at longer wavelength. Both the conjugated backbone and the metal complex can emit light upon excitation. As a result, it is possible to tune the color by loading different amount of ruthenium complex to the polymer. Luminescence studies showed that the ruthenium complex could quench the emission of the conjugated backbone in some polymers, which suggests an energy transfer process between the backbone and the metal complexes. It was also found that the presence of metal complexes could enhance the charge carrier mobilities of the polymers, as the metal and/or ligands can act as extra charge carriers in the charge transport process.

  3. Evaluation of DNA binding, DNA cleavage, protein binding, radical scavenging and in vitro cytotoxic activities of ruthenium(II) complexes containing 2,4-dihydroxy benzylidene ligands.

    PubMed

    Mohanraj, Maruthachalam; Ayyannan, Ganesan; Raja, Gunasekaran; Jayabalakrishnan, Chinnasamy

    2016-12-01

    The new ruthenium(II) complexes with hydrazone ligands, 4-Methyl-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL(1)), 4-Methoxy-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL(2)), 4-Bromo-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL(3)), were synthesized and characterized by various spectro analytical techniques. The molecular structures of the ligands were confirmed by single crystal X-ray diffraction technique. The DNA binding studies of the ligands and complexes were examined by absorption, fluorescence, viscosity and cyclic voltammetry methods. The results indicated that the ligands and complexes could interact with calf thymus DNA (CT-DNA) through intercalation. The DNA cleavage activity of the complexes was evaluated by gel electrophoresis assay, which revealed that the complexes are good DNA cleaving agents. The binding interaction of the ligands and complexes with bovine serum albumin (BSA) was investigated using fluorescence spectroscopic method. Antioxidant studies showed that the complexes have a strong radical scavenging properties. Further, the cytotoxic effect of the complexes examined on cancerous cell lines showed that the complexes exhibit significant anticancer activity. PMID:27612830

  4. Development of a stable cobalt-ruthenium Fisher-Tropsch catalyst. Final report

    SciTech Connect

    Frame, R.R.; Gala, H.B.

    1995-02-01

    The reverse micelle catalyst preparation method has been used to prepare catalysts on four supports: magnesium oxide, carbon, alumina- titania and steamed Y zeolite. These catalysts were not as active as a reference catalyst prepared during previous contracts to Union Carbide Corp. This catalyst was supported on steamed Y zerolite support and was impregnated by a pore-filling method using a nonaqueous solvent. Additional catalysts were prepared via pore- filling impregnation of steamed Y zeolites. These catalysts had levels of cobalt two to three and a half times as high as the original Union Carbide catalyst. On a catalyst volume basis they were much more active than the previous catalyst; on an atom by atom basis the cobalt was about of the same activity, i.e., the high cobalt catalysts` cobalt atoms were not extensively covered over and deactivated by other cobalt atoms. The new, high activity, Y zerolite catalysts were not as stable as the earlier Union Carbide catalyst. However, stability enhancement of these catalysts should be possible, for instance, through adjustment of the quantity and/or type of trace metals present. A primary objective of this work was determination whether small amounts of ruthenium could enhance the activity of the cobalt F-T catalyst. The reverse micelle catalysts were not activated by ruthenium, indeed scanning transmission electronic microscopy (STEM) analysis provided some evidence that ruthenium was not present in the cobalt crystallites. Ruthenium did not seem to activate the high cobalt Y zeolite catalyst either, but additional experiments with Y zeolite-supported catalysts are required. Should ruthenium prove not to be an effective promoter under the simple catalyst activation procedure used in this work, more complex activation procedures have been reported which are claimed to enhance the cobalt/ruthenium interaction and result in activity promotion by ruthenium.

  5. Synthesis and reactivity of compounds containing ruthenium-carbon, -nitrogen, and -oxygen bonds

    SciTech Connect

    Hartwig, J.F.

    1990-12-01

    The products and mechanisms of the thermal reactions of several complexes of the general structure (PMe{sub 3}){sub 4}Ru(X)(Y) and (DMPM){sub 2}Ru(X)(Y) where X and Y are hydride, aryl, and benzyl groups, have been investigated. The mechanism of decomposition depends critically on the structure of the complex and the medium in which the thermolysis is carried out. The alkyl hydride complexes are do not react with alkane solvent, but undergo C-H activation processes with aromatic solvents by several different mechanisms. Thermolysis of (PMe{sub 3}){sub 4}Ru(Ph)(Me) or (PMe{sub 3}){sub 4}Ru(Ph){sub 2} leads to the ruthenium benzyne complex (PMe{sub 3}){sub 4}Ru({eta}{sup 2}-C{sub 6}H{sub 4}) (1) by a mechanism which involves reversible dissociation of phosphine. In many ways its chemistry is analogous to that of early rather than late organo transition metal complexes. The synthesis, structure, variable temperature NMR spectroscopy and reactivity of ruthenium complexes containing aryloxide or arylamide ligands are reported. These complexes undergo cleavage of a P-C bond in coordinated trimethylphosphine, insertion of CO and CO{sub 2} and hydrogenolysis. Mechanistic studies on these reactions are described. The generation of a series of reactive ruthenium complexes of the general formula (PMe{sub 3}){sub 4}Ru(R)(enolate) is reported. Most of these enolates have been shown to bind to the ruthenium center through the oxygen atom. Two of the enolate complexes 8 and 9 exist in equilibrium between the O- and C-bound forms. The reactions of these compounds are reported, including reactions to form oxygen-containing metallacycles. The structure and reactivity of these ruthenium metallacycles is reported, including their thermal chemistry and reactivity toward protic acids, electrophiles, carbon monoxide, hydrogen and trimethylsilane. 243 refs., 10 tabs.

  6. Molecular Dynamics Approach for Predicting Helical Twisting Powers of Metal Complex Dopants in Nematic Solvents.

    PubMed

    Watanabe, Go; Yoshida, Jun

    2016-07-14

    Nematic liquid crystals of small molecules are known to transform into chiral nematic liquid crystals with supramolecular helical structures upon doping with enantiomeric compounds. Although this phenomenon is well established, the basic mechanism is still unclear. We have previously examined metal complexes with Δ and Λ chiralities as dopants in nematic liquid crystals and have found that slight differences in the molecular structure determine the handedness of the induced helical structure. In this study, we investigated the microscopic arrangement of liquid crystal molecules around metal complex dopants with the aid of molecular dynamics (MD) simulations. There are several restrictions to performing MD simulations of the chiral nematic system; for example, one pitch of the helix usually exceeds one side of an applicable periodic boundary box (∼10(2) nm). In view of these simulation problems, we therefore examined racemic systems in which a pair of Δ- and Λ-isomers of the chiral dopant is mixed with liquid crystal molecules. We selected two different octahedral ruthenium complexes as the chiral dopant molecules. As a result, we accurately calculated the ordering matrix that is essential parameter to estimate the helical twisting power of the chiral dopant based on the surface chirality model. Since the microscopic ordering is experimentally hard to be determined, our new approach with using MD simulations accurately deduced the ordering matrix and, with the aid of the surface chirality model, gave reasonable values for the helical twisting powers of each complex. PMID:27333445

  7. Metal-Metal Bonding in Uranium-Group 10 Complexes.

    PubMed

    Hlina, Johann A; Pankhurst, James R; Kaltsoyannis, Nikolas; Arnold, Polly L

    2016-03-16

    Heterobimetallic complexes containing short uranium-group 10 metal bonds have been prepared from monometallic IU(IV)(OAr(P)-κ(2)O,P)3 (2) {[Ar(P)O](-) = 2-tert-butyl-4-methyl-6-(diphenylphosphino)phenolate}. The U-M bond in IU(IV)(μ-OAr(P)-1κ(1)O,2κ(1)P)3M(0), M = Ni (3-Ni), Pd (3-Pd), and Pt (3-Pt), has been investigated by experimental and DFT computational methods. Comparisons of 3-Ni with two further U-Ni complexes XU(IV)(μ-OAr(P)-1κ(1)O,2κ(1)P)3Ni(0), X = Me3SiO (4) and F (5), was also possible via iodide substitution. All complexes were characterized by variable-temperature NMR spectroscopy, electrochemistry, and single crystal X-ray diffraction. The U-M bonds are significantly shorter than any other crystallographically characterized d-f-block bimetallic, even though the ligand flexes to allow a variable U-M separation. Excellent agreement is found between the experimental and computed structures for 3-Ni and 3-Pd. Natural population analysis and natural localized molecular orbital (NLMO) compositions indicate that U employs both 5f and 6d orbitals in covalent bonding to a significant extent. Quantum theory of atoms-in-molecules analysis reveals U-M bond critical point properties typical of metallic bonding and a larger delocalization index (bond order) for the less polar U-Ni bond than U-Pd. Electrochemical studies agree with the computational analyses and the X-ray structural data for the U-X adducts 3-Ni, 4, and 5. The data show a trend in uranium-metal bond strength that decreases from 3-Ni down to 3-Pt and suggest that exchanging the iodide for a fluoride strengthens the metal-metal bond. Despite short U-TM (transition metal) distances, four other computational approaches also suggest low U-TM bond orders, reflecting highly transition metal localized valence NLMOs. These are more so for 3-Pd than 3-Ni, consistent with slightly larger U-TM bond orders in the latter. Computational studies of the model systems (PH3)3MU(OH)3I (M = Ni, Pd) reveal

  8. The development of a selective ruthenium catalyst. Technical progress report, October 1, 1987--December 31, 1987

    SciTech Connect

    Abrevaya, H.

    1987-12-31

    A micelle technique was developed for preparing supported catalysts with different size ruthenium particles. Ruthenium was stabilized on the support, light ends make was minimized and activity was maximized by adjusting the ruthenium particle size and the metal-support interaction. The most promising catalysts consisted of 10--15 nm ruthenium particles on an alumina-titania support and 4--6 nm ruthenium particles on an alumina support. Stability improvement was determined to be the major catalyst developmental need. Work during the next quarter will focus on the development of a stable ruthenium catalyst.

  9. Noble metals in oncology

    PubMed Central

    Markowska, Anna; Jaszczyńska-Nowinka, Karolina; Lubin, Jolanta; Markowska, Janina

    2015-01-01

    Worldwide research groups are searching for anticancer compounds, many of them are organometalic complexes having platinum group metals as their active centers. Most commonly used cytostatics from this group are cisplatin, carboplatin and oxaliplatin. Cisplatin was used fot the first time in 1978, from this time many platinum derivatives were created. In this review we present biological properties and probable future clinical use of platinum, gold, silver, iridium and ruthenium derivatives. Gold derivative Auranofin has been studied extensively. Action of silver nanoparticles on different cell lines was analysed. Iridium isotopes are commonly used in brachyterapy. Ruthenium compound new anti-tumour metastasis inhibitor (NAMI-A) is used in managing lung cancer metastases. Electroporation of another ruthenium based compound KP1339 was also studied. Most of described complexes have antiproliferative and proapoptotic properties. Further studies need to be made. Nevertheless noble metal based chemotherapheutics and compounds seem to be an interesting direction of research. PMID:26557773

  10. [2+2+2] cyclotrimerization of alkynes and isocyanates/isothiocyanates catalyzed by ruthenium-alkylidene complexes.

    PubMed

    Alvarez, Silvia; Medina, Sandra; Domínguez, Gema; Pérez-Castells, Javier

    2013-10-01

    Ruthenium carbene catalysts are able to catalyze crossed [2+2+2] cyclotrimerizations of α,ω-diynes with isocyanates, isothiocyanates, and carbon disulfide. Both aliphatic and aromatic isocyanates can be used to produce fused 2-pyridones, although aliphatic isocyanates were more reactive. Aromatic isocyanates give better results when they bear electron-donating substituents. The reaction of unsymmetrical α,ω-diynes gave a product only with the substituent adjacent to the 2-pyridone nitrogen. Isothiocyanates gave thiopyranimines upon reaction with the C═S bond, whereas CS2 reacted efficiently to give a thioxothiopyrane.

  11. Triplet–triplet annihilation upconversion followed by FRET for the red light activation of a photodissociative ruthenium complex in liposomes† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5cp04352b

    PubMed Central

    Askes, Sven H. C.; Kloz, Miroslav; Bruylants, Gilles; Kennis, John T. M.

    2015-01-01

    Upconversion is a promising way to trigger high-energy photochemistry with low-energy photons. However, combining upconversion schemes with non-radiative energy transfer is challenging because bringing several photochemically active components in close proximity results in complex multi-component systems where quenching processes may deactivate the whole assembly. In this work, PEGylated liposomes were prepared that contained three photoactive components: a porphyrin dye absorbing red light, a perylene moiety emitting in the blue, and a light-activatable ruthenium prodrug sensitive to blue light. Time-dependent spectroscopic studies demonstrate that singlet perylene excited states are non-radiatively transferred to the nearby ruthenium complex by Förster resonance energy transfer (FRET). Under red-light irradiation of the three-component membranes, triplet–triplet annihilation upconversion (TTA-UC) occurs followed by FRET, which results in a more efficient activation of the ruthenium prodrug compared to a physical mixture of two-component upconverting liposomes and liposomes containing only the ruthenium complex. This work represents a rare example where TTA-UC and Förster resonance energy transfer are combined to achieve prodrug activation in the phototherapeutic window. PMID:26420663

  12. Cis- &trans-isomerism in [Cl2Ru(dppb)N-N] complexes: Synthesis, structural characterization and X-ray crystal structure of dichloromethane solvated cis-diaminebis(diphenylphosphinobutane)ruthenium(II) complex

    NASA Astrophysics Data System (ADS)

    Warad, Ismail; Azam, Mohammad; Asad, Mohammad; Al-Resayes, Saud I.; Asadi, Ahmad I.; Wanrosli, W. D.; Barakat, Assem; Jodeh, Shehdeh; Abu-Obid, Ahmed; Al-Noaimi, Mousa

    2014-11-01

    Three diamine-bis(diphenylphosphinobutane)ruthenium(II) complexes, isolated from the reaction of [Cl2Ru(dppb)] with diamines viz., 2,2-dimethyl-1,3-diamnopropane, 1,2-diaminocyclohexane and 1,8-diaminonaphthalene are reported. The synthesized complexes have been characterized on the basis of various physico-chemical studies viz., EDX, IR, FAB-MS, UV/Vis, NMR, TG-DTG and EXAFS studies. 31P NMR investigations confirm that the complex 3 is in cis form while the complexes 1-2 appear in trans form. The structure of complex 3 has been additionally determined by single crystal X-ray diffraction showing solvated dichloromethane. Furthermore, complex 3 crystallizes as monoclinic unit cell with P2(1)/n space group.

  13. Oxidative addition of allylic halides to ruthenium(II) compounds. Preparation, reactions, and X-ray crystallographic structure of ruthenium(IV)-allyl complexes

    SciTech Connect

    Nagashima, Hideo; Mukai, Katsunori; Shiota, Yusuke; Yamaguchi, Keitaro; Ara, Kenichi; Fukahori, Takahiko; Itoh, Kenji ); Suzuki, Hiroharu; Akita, Munetaka; Moro-oka, Yoshihiko )

    1990-03-01

    The oxidative addition of allylic halides to (C{sub 5}R{sub 5})RuL{sub 2}X (R = H, Me; L = CO, PPh{sub 3}) gave new Ru(IV)-{eta}{sup 3}-allyl complexes, (C{sub 5}R{sub 5})RuX{sub 2}({eta}{sup 3}-allyl). An X-ray structure determination was carried out on (C{sub 5}Me{sub 5})RuBr{sub 2}({eta}{sup 3}-C{sub 3}H{sub 5}), indicating a pseudo-piano-stool structure having two Br atoms and two terminal carbons of the endo-{eta}{sup 3}-allyl ligand located at the basal positions. There is a crystal mirror plane bisecting the pentamethylcyclopentadienyl and the {pi}-allyl ligands. Crystal data: orthorhombic, space group P2{sub 1}2{sub 1}2{sub 1}, a = 22.738 (1) {angstrom}, b = 13.367 (7) {angstrom}, c = 9.383 (1) {angstrom}, Z = 4., data refined to R = 0.0695. Its {sup 1}H and {sup 13}C NMR spectra showed symmetric allyl signals, supporting that the above-described piano-stool structure is maintained even in solution.

  14. Binuclear ruthenium η6-arene complexes with tetradentate N,S-ligands containing the ortho-aminothiophenol motif.

    PubMed

    Acosta-Ramirez, Alberto; Cross, Edward D; McDonald, Robert; Bierenstiel, Matthias

    2014-02-28

    A series of cationic binuclear (η(6)-cymene-Ru)2 complexes with N2S2-ligands were synthesized in 64% to 85% yield by reaction of [Ru(η(6)-cymene)Cl2]2 with bis-S,S'-(ortho-aminothiophenol)-xylenes as BF4(-) and PF6(-) salts. The compounds were studied using NMR, HRMS, UV-vis and IR spectroscopy, EA and inductively coupled plasma (ICP) MS. It was determined that the hinged binuclear Ru complexes were anti and syn diastereomers obtained in 2 : 1 ratio for ortho- and meta-xylylene bridged ligands and in a 1 : 1 ratio for the para-xylylene bridged ligand. An anion effect was found for the presence of NaBF4 with the meta-xylylene bridged system yielding the targeted binuclear Ru complex and a mononuclear Ru complex. This mononuclear S,S'-coordinated η(6)-cymene Ru chloride structure lacked amine-metal coordination and was obtained in a 1 : 3 ratio of anti : syn diastereomers which were insoluble in CH2Cl2 and soluble in DMSO and DMF. X-ray crystallographic analysis was obtained for the N2S2 ligand, 1,2-bis{(2-aminophenyl)thiomethyl}benzene, showing a CS symmetry with amine groups facing outwards with a tilt of 28.95° from the ortho-aminothiophenol pendant ring. The interatomic sulfur-sulfur distance (S-S') is 4.6405 Å within the crystal structure while accommodating a potential metal bite angle from 1.0 Å to 5.9 Å when allowing rotation of the methylene phenyl bond. PMID:24284434

  15. Efficient Removal of Ruthenium Byproducts from Olefin Metathesis Products by Simple Aqueous Extraction

    PubMed Central

    Hong, Soon Hyeok; Grubbs, Robert H.

    2008-01-01

    Simple aqueous extraction removed ruthenium byproducts efficiently from ring-closing metathesis (RCM) reactions catalyzed by a PEG-supported N-heterocyclic carbene-based ruthenium complex. PMID:17428062

  16. Nickel/ruthenium catalyst and method for aqueous phase reactions

    DOEpatents

    Elliott, Douglas C.; Sealock, John L.

    1998-01-01

    A method of hydrogenation using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions.

  17. Effect of pH in the photoluminescence of a ruthenium complex featuring a derivative of the ligand pyrazine[2,3-f][1,10]-phenanthroline.

    PubMed

    Pizarro, Sebastián; Gallardo, Miguel; Leyton, Constanza; Castro, Eileen; Gajardo, Francisco; Delgadillo, Alvaro

    2015-07-01

    A new ruthenium complex, [Ru(bpy)2(dbe-ppl)](PF6)2 (bpy=2,2'-bipyridine and dbe-ppl=dimethyl 4,4'-(pyrazino[2,3-f][1,10]phenanthroline-2,3-diyl)dibenzoate, has been synthesized and characterized by (1)H NMR spectroscopy, UV-Vis, IR, and cyclic voltammetry. Irradiation on the MLCT band results in photoluminescence in both protic and aprotic solvents. The photoluminescence in water is pH dependent, it shows a behavior which can be described by the Henderson-Hasselbalch assuming the protonation/deprotonation of the excited state with a pKa of 2.40±0.01.

  18. Effect of pH in the photoluminescence of a ruthenium complex featuring a derivative of the ligand pyrazine[2,3-f][1,10]-phenanthroline

    NASA Astrophysics Data System (ADS)

    Pizarro, Sebastián; Gallardo, Miguel; Leyton, Constanza; Castro, Eileen; Gajardo, Francisco; Delgadillo, Alvaro

    2015-07-01

    A new ruthenium complex, [Ru(bpy)2(dbe-ppl)](PF6)2 (bpy = 2,2‧-bipyridine and dbe-ppl = dimethyl 4,4‧-(pyrazino[2,3-f][1,10]phenanthroline-2,3-diyl)dibenzoate, has been synthesized and characterized by 1H NMR spectroscopy, UV-Vis, IR, and cyclic voltammetry. Irradiation on the MLCT band results in photoluminescence in both protic and aprotic solvents. The photoluminescence in water is pH dependent, it shows a behavior which can be described by the Henderson-Hasselbalch assuming the protonation/deprotonation of the excited state with a pKa of 2.40 ± 0.01.

  19. Two-dimensional self-assembly of a porphyrin-polypyridyl ruthenium(II) hybrid on hopg surface through metal-ligand interactions.

    PubMed

    Gao, Aimei; Miao, Xinrui; Liu, Jie; Zhao, Ping; Huang, Jinwang; Deng, Wenli

    2010-06-21

    The synthesis and self-assembly behavior of porphyrin-polypyridyl ruthenium(II) hybrid, which consists of a flexible alkyl chain attached with two conjugated moieties is described. The electronic absorption spectrum and emission spectra show that the [C(8)-TPP-(ip)Ru(phen)(2)](ClO(4))(2), abbreviated as (C(8)ip)TPPC has optical properties. Scanning tunneling microscopy (STM) studies found that the pi-pi interaction and metal-ligand interaction allow (C(8)ip)TPPC to form self-assembled structure and have an edge-on orientation on the highly oriented pyrolytic graphite (HOPG) surface. The multidentate structure in (C(8)ip)TPPC molecules act as linkers between the molecules and form metal-ligand coordination, which forces the assembly process in the direction of stable columnar arrays. In addition, although the sample was stored for two months in ambient conditions, STM experiments showed that the order of (C(8)ip)TPPC self-assembly only slightly decreased which indicates that the self-assembled monolayer is stable. This work demonstrates that introducing a metal-ligand in the porphyrin-polypyridyl compound is a useful strategy to obtain novel surface assemblies.

  20. Mixed ligand ruthenium(III) complexes of benzaldehyde 4-methyl-3-thiosemicarbazones with triphenylphosphine/triphenylarsine co-ligands: Synthesis, DNA binding, DNA cleavage, antioxidative and cytotoxic activity

    NASA Astrophysics Data System (ADS)

    Sampath, K.; Sathiyaraj, S.; Raja, G.; Jayabalakrishnan, C.

    2013-08-01

    The new ruthenium(III) complexes with 4-methyl-3-thiosemicarbazone ligands, (E)-2-(2-chlorobenzylidene)-N-methylhydrazinecarbothioamide (HL1) and (E)-2-(2-nitrobenzylidene)-N-methylhydrazinecarbothioamide (HL2), were prepared and characterized by various physico-chemical and spectroscopic methods. The title compounds act as bidentate, monobasic chelating ligands with S and N as the donor sites and are preferably found in the thiol form in all the complexes studied. The molecular structure of HL1 and HL2 were determined by single crystal X-ray diffraction method. DNA binding of the ligands and complexes were investigated by absorption spectroscopy and IR spectroscopy. It reveals that the compounds bind to nitrogenous bases of DNA via intercalation. The oxidative cleavage of the complexes with CT-DNA inferred that the effects of cleavage are dose dependent. Antioxidant study of the ligands and complexes showed the significant antioxidant activity against DPPH radical. In addition, the in vitro cytotoxicity of the ligands and complexes against MCF-7 cell line was assayed which showed higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing the cancer cells even at low concentrations.

  1. Insights into anticancer activity and mechanism of action of a ruthenium(II) complex in human esophageal squamous carcinoma EC109 cells.

    PubMed

    Guo, Liubin; Lv, Gaochao; Qiu, Ling; Yang, Hui; Zhang, Li; Yu, Huixin; Zou, Meifen; Lin, Jianguo

    2016-09-01

    A ruthenium(II) complex [Ru(p-cymene)(NHC)Cl2] (NHC=1,3-bis(4-(tert-butyl)benzylimidazol-2-ylidene), referred to as L-4, has been designed and synthesized recently in order to look for new anticancer drugs with high efficacy and low side effects. The anticancer activity and mechanism of action of L-4 in human esophageal squamous carcinoma EC109 cells were systematically investigated. The results revealed that L-4 exerted strong inhibitory effect on the proliferation of EC109 cells, and it arrested EC109 cells at G2/M phase, accompanied with the up-regulation of p53 and p21 and the down-regulation of cyclin D1. The results also showed that the reactive oxygen species (ROS)-dependent apoptosis of EC109 can be induced by L-4 via inhibiting the activity of glutathione reductase (GR), decreasing the ratio of glutathione to oxidized glutathione (GSH/GSSG), and leading to the generation of reactive oxygen species. The mitochondria-mediated apoptosis of EC109 induced by L-4 was also observed from the increase of Bax/Bcl-2 ratio, overload of Ca(2+), disruption of mitochondrial membrane potential (MMP), redistribution of cytochrome c, and activation of caspase-3/-9. However, the effects of L-4 on the cell viability, GR activity, GSH/GSSG ratio, reactive oxygen species level, mitochondria dysfunction and apoptosis induction were remarkably attenuated by adding the reactive oxygen species scavenger, NAC. Therefore, it was concluded that L-4 can inhibit the proliferation of EC109 cells via blocking cell cycle progression and inducing reactive oxygen species-dependent and mitochondria-mediated apoptosis. These findings suggested that the ruthenium(II) complex might be a potential effective chemotherapeutic agent for human esophageal squamous carcinoma (ESCC) and worthy of further investigation. PMID:27262377

  2. Scope and Mechanistic Analysis for Chemoselective Hydrogenolysis of Carbonyl Compounds Catalyzed by a Cationic Ruthenium Hydride Complex with a Tunable Phenol Ligand.

    PubMed

    Kalutharage, Nishantha; Yi, Chae S

    2015-09-01

    A cationic ruthenium hydride complex, [(C6H6)(PCy3)(CO)RuH](+)BF4(-) (1), with a phenol ligand was found to exhibit high catalytic activity for the hydrogenolysis of carbonyl compounds to yield the corresponding aliphatic products. The catalytic method showed exceptionally high chemoselectivity toward the carbonyl reduction over alkene hydrogenation. Kinetic and spectroscopic studies revealed a strong electronic influence of the phenol ligand on the catalyst activity. The Hammett plot of the hydrogenolysis of 4-methoxyacetophenone displayed two opposite linear slopes for the catalytic system 1/p-X-C6H4OH (ρ = -3.3 for X = OMe, t-Bu, Et, and Me; ρ = +1.5 for X = F, Cl, and CF3). A normal deuterium isotope effect was observed for the hydrogenolysis reaction catalyzed by 1/p-X-C6H4OH with an electron-releasing group (kH/kD = 1.7-2.5; X = OMe, Et), whereas an inverse isotope effect was measured for 1/p-X-C6H4OH with an electron-withdrawing group (kH/kD = 0.6-0.7; X = Cl, CF3). The empirical rate law was determined from the hydrogenolysis of 4-methoxyacetophenone: rate = kobsd[Ru][ketone][H2](-1) for the reaction catalyzed by 1/p-OMe-C6H4OH, and rate = kobsd[Ru][ketone][H2](0) for the reaction catalyzed by 1/p-CF3-C6H4OH. Catalytically relevant dinuclear ruthenium hydride and hydroxo complexes were synthesized, and their structures were established by X-ray crystallography. Two distinct mechanistic pathways are presented for the hydrogenolysis reaction on the basis of these kinetic and spectroscopic data. PMID:26235841

  3. Lead-ruthenium pyrochlores as oxygen electrocatalysts

    NASA Technical Reports Server (NTRS)

    Anderson, E. B.; Taylor, E. J.; Moniz, G. A.

    1990-01-01

    An investigation of lead-ruthenium pyrochlores of the structure Pb2(Ru/2-x/Pb/x/) O7-y for use as oxygen electrocatalysts in alkaline media is discussed. Lead-ruthenium pyrochlore mixed metal oxides were prepared and characterized by X-ray diffraction, BET surface area, dry powder conductivity, and chemical stability. Gas diffusion electrodes were developed specifically for the lead-ruthenium pyrochlore materials. Also investigated were the effects of varying electrode fabrication parameters on the oxygen reduction performance of the lead-ruthenium pyrochlore electrocatalyst. Long-term stability performance was also evaluated. The oxygen reduction performance of the pyrochlore electrocatalyst is considerably higher than that of the state-of-the-art gold-platinum alloy electrocatalyst currently used by NASA. Furthermore, the pyrochlore electrocatalysts are attractive candidates for high-performance pressurized alkaline fuel cells.

  4. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  5. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... metal complex. 721.4596 Section 721.4596 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4596 Diazo substituted carbomonocyclic metal complex. (a) Chemical... as a diazo substituted carbomonocyclic metal complex (PMN P-94-1039) is subject to reporting...

  6. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  7. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  8. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... metal complex. 721.4596 Section 721.4596 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4596 Diazo substituted carbomonocyclic metal complex. (a) Chemical... as a diazo substituted carbomonocyclic metal complex (PMN P-94-1039) is subject to reporting...

  9. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  10. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metal complex. 721.4596 Section 721.4596 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4596 Diazo substituted carbomonocyclic metal complex. (a) Chemical... as a diazo substituted carbomonocyclic metal complex (PMN P-94-1039) is subject to reporting...

  11. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... metal complex. 721.4596 Section 721.4596 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4596 Diazo substituted carbomonocyclic metal complex. (a) Chemical... as a diazo substituted carbomonocyclic metal complex (PMN P-94-1039) is subject to reporting...

  12. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... metal complex. 721.4596 Section 721.4596 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4596 Diazo substituted carbomonocyclic metal complex. (a) Chemical... as a diazo substituted carbomonocyclic metal complex (PMN P-94-1039) is subject to reporting...

  13. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  14. Reactivity of nitrido complexes of ruthenium(VI), osmium(VI), and manganese(V) bearing Schiff base and simple anionic ligands.

    PubMed

    Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

    2014-02-18

    Nitrido complexes (M≡N) may be key intermediates in chemical and biological nitrogen fixation and serve as useful reagents for nitrogenation of organic compounds. Osmium(VI) nitrido complexes bearing 2,2':6',2″-terpyridine (terpy), 2,2'-bipyridine (bpy), or hydrotris(1-pyrazolyl)borate anion (Tp) ligands are highly electrophilic: they can react with a variety of nucleophiles to generate novel osmium(IV)/(V) complexes. This Account describes our recent results studying the reactivity of nitridocomplexes of ruthenium(VI), osmium(VI), and manganese(V) that bear Schiff bases and other simple anionic ligands. We demonstrate that these nitrido complexes exhibit rich chemical reactivity. They react with various nucleophiles, activate C-H bonds, undergo N···N coupling, catalyze the oxidation of organic compounds, and show anticancer activities. Ruthenium(VI) nitrido complexes bearing Schiff base ligands, such as [Ru(VI)(N)(salchda)(CH3OH)](+) (salchda = N,N'-bis(salicylidene)o-cyclohexyldiamine dianion), are highly electrophilic. This complex reacts readily at ambient conditions with a variety of nucleophiles at rates that are much faster than similar reactions using Os(VI)≡N. This complex also carries out unique reactions, including the direct aziridination of alkenes, C-H bond activation of alkanes and C-N bond cleavage of anilines. The addition of ligands such as pyridine can enhance the reactivity of [Ru(VI)(N)(salchda)(CH3OH)](+). Therefore researchers can tune the reactivity of Ru≡N by adding a ligand L trans to nitride: L-Ru≡N. Moreover, the addition of various nucleophiles (Nu) to Ru(VI)≡N initially generate the ruthenium(IV) imido species Ru(IV)-N(Nu), a new class of hydrogen-atom transfer (HAT) reagents. Nucleophiles also readily add to coordinated Schiff base ligands in Os(VI)≡N and Ru(VI)≡N complexes. These additions are often stereospecific, suggesting that the nitrido ligand has a directing effect on the incoming nucleophile. M≡N is also

  15. Methyl Complexes of the Transition Metals.

    PubMed

    Campos, Jesús; López-Serrano, Joaquín; Peloso, Riccardo; Carmona, Ernesto

    2016-05-01

    Organometallic chemistry can be considered as a wide area of knowledge that combines concepts of classic organic chemistry, that is, based essentially on carbon, with molecular inorganic chemistry, especially with coordination compounds. Transition-metal methyl complexes probably represent the simplest and most fundamental way to view how these two major areas of chemistry combine and merge into novel species with intriguing features in terms of reactivity, structure, and bonding. Citing more than 500 bibliographic references, this review aims to offer a concise view of recent advances in the field of transition-metal complexes containing M-CH3 fragments. Taking into account the impressive amount of data that are continuously provided by organometallic chemists in this area, this review is mainly focused on results of the last five years. After a panoramic overview on M-CH3 compounds of Groups 3 to 11, which includes the most recent landmark findings in this area, two further sections are dedicated to methyl-bridged complexes and reactivity.

  16. Simultaneous realization of Hg(2+) sensing, magnetic resonance imaging and upconversion luminescence in vitro and in vivo bioimaging based on hollow mesoporous silica coated UCNPs and ruthenium complex.

    PubMed

    Ge, Xiaoqian; Sun, Lining; Ma, Binbin; Jin, Di; Dong, Liang; Shi, Liyi; Li, Nan; Chen, Haige; Huang, Wei

    2015-09-01

    We have constructed a multifunctional nanoprobe with sensing and imaging properties by using hollow mesoporous silica coated upconversion nanoparticles (UCNPs) and Hg(2+) responsive ruthenium (Ru) complex. The Ru complex was loaded into the hollow mesoporous silica and the UCNPs acted as an energy donor, transferring luminescence energy to the Ru complex. Furthermore, polyethylenimine (PEI) was assembled on the surface of mesoporous silica to achieve better hydrophilic and bio-compatibility. Upon addition of Hg(2+), a blue shift of the absorption peak of the Ru complex is observed and the energy transfer process between the UCNPs and the Ru complex was blocked, resulting in an increase of the green emission intensity of the UCNPs. The un-changed 801 nm emission of the nanoprobe was used as an internal standard reference and the detection limit of Hg(2+) was determined to be 0.16 μM for this nanoprobe in aqueous solution. In addition, based on the low cytotoxicity as studied by CCK-8 assay, the nanoprobe was successfully applied for cell imaging and small animal imaging. Furthermore, when doped with Gd(3+) ions, the nanoprobe was successfully applied to in vivo magnetic resonance imaging (MRI) of Kunming mice, which demonstrates its potential as a MRI positive-contrast agent. Therefore, the method and results may provide more exciting opportunities to afford nanoprobes with multimodal bioimaging and multifunctional applications. PMID:26219919

  17. Simultaneous realization of Hg(2+) sensing, magnetic resonance imaging and upconversion luminescence in vitro and in vivo bioimaging based on hollow mesoporous silica coated UCNPs and ruthenium complex.

    PubMed

    Ge, Xiaoqian; Sun, Lining; Ma, Binbin; Jin, Di; Dong, Liang; Shi, Liyi; Li, Nan; Chen, Haige; Huang, Wei

    2015-09-01

    We have constructed a multifunctional nanoprobe with sensing and imaging properties by using hollow mesoporous silica coated upconversion nanoparticles (UCNPs) and Hg(2+) responsive ruthenium (Ru) complex. The Ru complex was loaded into the hollow mesoporous silica and the UCNPs acted as an energy donor, transferring luminescence energy to the Ru complex. Furthermore, polyethylenimine (PEI) was assembled on the surface of mesoporous silica to achieve better hydrophilic and bio-compatibility. Upon addition of Hg(2+), a blue shift of the absorption peak of the Ru complex is observed and the energy transfer process between the UCNPs and the Ru complex was blocked, resulting in an increase of the green emission intensity of the UCNPs. The un-changed 801 nm emission of the nanoprobe was used as an internal standard reference and the detection limit of Hg(2+) was determined to be 0.16 μM for this nanoprobe in aqueous solution. In addition, based on the low cytotoxicity as studied by CCK-8 assay, the nanoprobe was successfully applied for cell imaging and small animal imaging. Furthermore, when doped with Gd(3+) ions, the nanoprobe was successfully applied to in vivo magnetic resonance imaging (MRI) of Kunming mice, which demonstrates its potential as a MRI positive-contrast agent. Therefore, the method and results may provide more exciting opportunities to afford nanoprobes with multimodal bioimaging and multifunctional applications.

  18. Evaluation of DNA-binding, DNA cleavage, antioxidant and cytotoxic activity of mononuclear ruthenium(II) carbonyl complexes of benzaldehyde 4-phenyl-3-thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Sampath, Krishnan; Sathiyaraj, Subbaiyan; Jayabalakrishnan, Chinnasamy

    2013-11-01

    Two 4-phenyl-3-thiosemicarbazone ligands, (E)-2-(2-chlorobenzylidene)-N-phenylhydrazinecarbothioamide (HL1) and (E)-2-(2-nitrobenzylidene)-N-phenylhydrazinecarbothioamide (HL2), and its ruthenium(II) complexes were synthesized and characterized by physico-chemical and spectroscopic methods. The Schiff bases act as bidentate, monobasic chelating ligands with S and N as the donor sites and are preferably found in the thiol form in all the complexes studied. The molecular structure of HL1 and HL2 were determined by single crystal X-ray diffraction method. DNA binding of the compounds was investigated by absorption spectroscopy which indicated that the compounds bind to DNA via intercalation. The oxidative cleavage of the complexes with CT-DNA inferred that the effects of cleavage are dose dependent. Antioxidant study of the ligands and complexes showed significant antioxidant activity against DPPH radical. In addition, the in vitro cytotoxicity of the ligands and complexes assayed against HeLa and MCF-7 cell lines showed higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing the cancer cells even at low concentrations.

  19. Analysis of metal-EDTA complexes by electrospray mass spectrometry

    SciTech Connect

    Baron, D.; Hering, J.G.

    1998-07-01

    Solutions of the strong complexing agent ethylenediaminetetraacetic acid (EDTA) and Cu, Pb, Cd, Al, and Fe(III) were examined by electrospray mass spectrometry (ES/MS). Uncomplexed EDTA and metal-EDTA complexes survive the electrospray process intact and can be detected simultaneously by mass spectrometry. Best sensitivity was achieved in the positive ion mode in which EDTA and EDTA-metal complexes (present in solution as anions) were detected as protonated species with a single positive charge. Except for the protonation, the aqueous metal-EDTA complexes are preserved and neither fragmentation of complexes nor formation of clusters with more than one metal or ligand were observed in the mass spectra. Detection limits are between approximately 1 to 2 {micro}M for uncomplexed EDTA and for the Cu-EDTA and Pb-EDTA complexes, with a linear range up to 10{sup {minus}4} M. Calibrations based on solutions with equimolar concentrations of EDTA and Cu or Pb can be used to quantify EDTA-metal complexes in solutions with excess EDTA or metal, and in solutions with more than one metal present. Isotopic signatures of metals in the metal-ligand complexes are preserved, allowing the identification of the metal in a metal-ligand complex. Isotopic signatures of metals can therefore aid in the identification of metal-ligand complexes in unknown samples.

  20. Metal–Arene Complexes with Indolo[3,2-c]-quinolines: Effects of Ruthenium vs Osmium and Modifications of the Lactam Unit on Intermolecular Interactions, Anticancer Activity, Cell Cycle, and Cellular Accumulation

    PubMed Central

    2013-01-01

    Six novel ruthenium(II)– and osmium(II)–arene complexes with three modified indolo[3,2-c]quinolines have been synthesized in situ starting from 2-aminoindoloquinolines and 2-pyridinecarboxaldehyde in the presence of [M(p-cymene)Cl2]2 (M = Ru, Os) in ethanol. All complexes have been characterized by elemental analysis, spectroscopic techniques (1H, 13C NMR, IR, UV–vis), and ESI mass spectrometry, while four complexes were investigated by X-ray diffraction. The complexes have been tested for antiproliferative activity in vitro in A549 (non-small cell lung), SW480 (colon), and CH1 (ovarian) human cancer cell lines and showed IC50 values between 1.3 and >80 μM. The effects of Ru vs Os and modifications of the lactam unit on intermolecular interactions, antiproliferative activity, and cell cycle are reported. One ruthenium complex and its osmium analogue have been studied for anticancer activity in vivo applied both intraperitoneally and orally against the murine colon carcinoma model CT-26. Interestingly, the osmium(II) complex displayed significant growth-inhibitory activity in contrast to its ruthenium counterpart, providing stimuli for further investigation of this class of compounds as potential antitumor drugs. PMID:23431223

  1. Ruthenium(II) carbonyl complexes bearing quinoline-based NNO tridentate ligands as catalyst for one-pot conversion of aldehydes to amides and o-allylation of phenols.

    PubMed

    Manikandan, R; Prakash, G; Kathirvel, R; Viswanathamurthi, P

    2013-12-01

    Six new octahedral ruthenium(II) carbonyl complexes having the general molecular formula [RuCl(CO)(B)L(1-2)] (B = PPh3, AsPh3 or py; L(1-2) = quinoline based NNO ligand) were synthesized. The quinoline based ligands behave as monoanionic tridentate donor and coordinated to ruthenium via ketoenolate oxygen, azomethine nitrogen and quinoline nitrogen. The composition of the complexes has been established by elemental analysis and spectral methods (FT-IR, electronic, (1)H NMR, (13)C NMR, (31)P NMR and ESI-Mass). The complexes were used as efficient catalysts for one-pot conversion of various aldehydes to their corresponding primary amides in presence of NH2OH · HCl and NaHCO3. The effect of catalyst loading and reaction temperature on catalytic activity of the ruthenium(II) carbonyl complexes were also investigated. The synthesized complexes also possess good catalytic activity for the o-allylation of phenols in the presence of K2CO3 under mild conditions. The complexes afforded branched allyl aryl ethers according to a regioselective reaction. PMID:23978737

  2. Ruthenium(II) carbonyl complexes bearing quinoline-based NNO tridentate ligands as catalyst for one-pot conversion of aldehydes to amides and o-allylation of phenols

    NASA Astrophysics Data System (ADS)

    Manikandan, R.; Prakash, G.; Kathirvel, R.; Viswanathamurthi, P.

    2013-12-01

    Six new octahedral ruthenium(II) carbonyl complexes having the general molecular formula [RuCl(CO)(B)L1-2] (B = PPh3, AsPh3 or py; L1-2 = quinoline based NNO ligand) were synthesized. The quinoline based ligands behave as monoanionic tridentate donor and coordinated to ruthenium via ketoenolate oxygen, azomethine nitrogen and quinoline nitrogen. The composition of the complexes has been established by elemental analysis and spectral methods (FT-IR, electronic, 1H NMR, 13C NMR, 31P NMR and ESI-Mass). The complexes were used as efficient catalysts for one-pot conversion of various aldehydes to their corresponding primary amides in presence of NH2OH·HCl and NaHCO3. The effect of catalyst loading and reaction temperature on catalytic activity of the ruthenium(II) carbonyl complexes were also investigated. The synthesized complexes also possess good catalytic activity for the o-allylation of phenols in the presence of K2CO3 under mild conditions. The complexes afforded branched allyl aryl ethers according to a regioselective reaction.

  3. Metal complex polymers for electroluminescent applications

    SciTech Connect

    Tao, X.T.; Suzuki, H.; Zhang, Y.D.; Watanabe, T.; Miyata, S.; Wada, T.; Sasabe, H.

    1998-07-01

    The authors report the synthesis and characterization of a soluble metal complex polymer for electroluminescent (EL) applications. The polymer was prepared by the reaction of a zinc Schiff base with 4,4{prime}-diphenylmethane-diisocyanate. The polymer is amorphous and with glass transition temperature of 156 C and is soluble in common organic solvents such as chloroform, tetrahydrofuran (THF), and N-methylpyrrolidinone (NMP). The zinc Schiff base, and the polyurethane (PU) shows strong photoluminescence under a UV-lamp illumination. Single and double layer EL devices consisting ITO/hole transfer layer (HTL)/PU/AL have been fabricated and characterized. The results indicated that the complex polymer could act as both electron transport and emissive layers for EL devices.

  4. Synthesis, spectroscopic and DFT structural characterization of two novel ruthenium(III) oxicam complexes. In vivo evaluation of anti-inflammatory and gastric damaging activities.

    PubMed

    Tamasi, Gabriella; Bernini, Caterina; Corbini, Gianfranco; Owens, Natalie F; Messori, Luigi; Scaletti, Federica; Massai, Lara; Giudice, Pietro Lo; Cini, Renzo

    2014-05-01

    The reactions of ruthenium(III) chloride trihydrate with piroxicam (H2PIR) and tenoxicam (H2TEN), two widely used non-steroidal anti-inflammatory drugs, afforded [Ru(III)Cl2(H2PIR)(HPIR)],·1, and [Ru(III)Cl2(H2TEN)(HTEN)],·2. Both compounds were obtained as pure green solids through purification via flash column chromatography. Characterizations were accomplished through UV-vis and IR spectroscopy, potentiometry and HPLC. Quantum mechanics and density functional computational methods were applied to investigate their respective molecular structures. The experimental and computational results are in agreement with a pseudo-octahedral coordination where the two chlorido ligands are in trans positions (apical) and the two trans-N,O chelating oxicam ligands occupy the equatorial sites. Both compounds revealed an acceptable solubility and stability profile upon dissolution in a standard buffer at physiological pH. Nonetheless, the addition of biologically occurring reducing agents caused spectral changes. The two complexes manifested a poor reactivity with the model proteins cytochrome c and lysozyme: no evidence for adduct formation was indeed obtained based on a standard ESI MS analysis; in contrast, some significant reactivity with serum albumin was proved spectrophotometrically. Remarkably, both study compounds revealed pronounced anti-edema effects in vivo suggesting that the pharmacological actions of the ligands are mostly retained; in addition, they were less irritating than piroxicam on the gastric mucosa when the coordination compounds and free oxicam were administered at the same overall molar concentration of the ligand. Overall, the present results point out that ruthenium coordination may represent an effective strategy to improve the pharmacological properties of oxicam drugs reducing their undesired side effects.

  5. Theoretical and experimental studies of phenol oxidation by ruthenium complex with N,N,N-tris(benzimidazol-2yl-methyl)amine.

    PubMed

    Hernandez, J Guadalupe; Silva, Antonio Romero; Thangarasu, Pandiyan; Najera, Rafael Herrera; Moreno, Alfonso Duran; Ledesma, M Teresa Orta; Cruz-Borbolla, Julian; Singh, Narinder

    2015-09-01

    The ruthenium complex with (N,N,N-tris(benzimidazol-2yl-methyl)amine, L(1)) was prepared, and characterized. Fukui data were used to localize the reactive sites on the ligand. The structural and electronic properties of the complex were analyzed by DFT in different oxidation states in order to evaluate its oxidant properties for phenol oxidation. The results show that the hard Ru(IV) cation bonds preferentially with a hard base (Namine = amine nitrogen, or axial chloride ion), and soft Ru(II) with a soft base (Nbzim = benzimidazole nitrogen or axial triphenyl phosphine). Furthermore, the Jahn-Teller effect causes an elongation of the axial bond in the octahedral structure. The bonding nature and the orbital contribution to the electronic transitions of the complex were studied. The experimental UV-visible bands were interpreted by using TD-DFT studies. The complex oxidizes phenol to benzoquinone in the presence of H2O2 and the intermediate was detected by HPLC and (13)C NMR. A possible mechanism and rate law are proposed for the oxidation. The adduct formation of phenol with [Ru(O)L(1)](2+) or [Ru(OH)L(1)](+) is theoretically analyzed to show that [Ru(OH)L(1)-OPh](+) could produce the phenol radical.

  6. Bimetallic ruthenium complexes bridged by divinylphenylene bearing oligo(ethylene glycol)methylether: synthesis, (spectro)electrochemistry and the lithium cation effect.

    PubMed

    Tian, Li Yan; Liu, Yuan Mei; Tian, Guang-Xuan; Wu, Xiang Hua; Li, Zhen; Kou, Jun-Feng; Ou, Ya-Ping; Liu, Sheng Hua; Fu, Wen-Fu

    2014-03-14

    A series of 1,4-disubstituted ruthenium-vinyl complexes, (E,E)-[{(PMe3)3(CO)ClRu}2(μ-HC=CH-Ar-CH=CH)], in which the 1,4-diethenylphenylene bridge bears two oligo(ethylene glycol)methyl ether side chains at different positions (2,5- and 2,3-positions), were prepared. The respective products were characterized by elemental analyses and NMR spectroscopy. The structures of complexes 1b and 1e were established by X-ray crystallography. The electronic properties of the complexes were investigated by cyclic voltammetry, and IR and UV-vis/NIR spectroscopies. Electrochemical studies showed that the 2,5-substituents better stabilized the mixed-valence states; the electrochemical behavior was greatly affected by lithium cations, especially complex 1g with 2,3-substituents, which was further supported by IR and UV-vis/NIR spectra changes. Spectroelectrochemical studies showed that the redox chemistry was dominated by the non-innocent character of the bridging fragment. PMID:24457499

  7. Theoretical and experimental studies of phenol oxidation by ruthenium complex with N,N,N-tris(benzimidazol-2yl-methyl)amine.

    PubMed

    Hernandez, J Guadalupe; Silva, Antonio Romero; Thangarasu, Pandiyan; Najera, Rafael Herrera; Moreno, Alfonso Duran; Ledesma, M Teresa Orta; Cruz-Borbolla, Julian; Singh, Narinder

    2015-09-01

    The ruthenium complex with (N,N,N-tris(benzimidazol-2yl-methyl)amine, L(1)) was prepared, and characterized. Fukui data were used to localize the reactive sites on the ligand. The structural and electronic properties of the complex were analyzed by DFT in different oxidation states in order to evaluate its oxidant properties for phenol oxidation. The results show that the hard Ru(IV) cation bonds preferentially with a hard base (Namine = amine nitrogen, or axial chloride ion), and soft Ru(II) with a soft base (Nbzim = benzimidazole nitrogen or axial triphenyl phosphine). Furthermore, the Jahn-Teller effect causes an elongation of the axial bond in the octahedral structure. The bonding nature and the orbital contribution to the electronic transitions of the complex were studied. The experimental UV-visible bands were interpreted by using TD-DFT studies. The complex oxidizes phenol to benzoquinone in the presence of H2O2 and the intermediate was detected by HPLC and (13)C NMR. A possible mechanism and rate law are proposed for the oxidation. The adduct formation of phenol with [Ru(O)L(1)](2+) or [Ru(OH)L(1)](+) is theoretically analyzed to show that [Ru(OH)L(1)-OPh](+) could produce the phenol radical. PMID:26252971

  8. Bimetallic ruthenium complexes bridged by divinylphenylene bearing oligo(ethylene glycol)methylether: synthesis, (spectro)electrochemistry and the lithium cation effect.

    PubMed

    Tian, Li Yan; Liu, Yuan Mei; Tian, Guang-Xuan; Wu, Xiang Hua; Li, Zhen; Kou, Jun-Feng; Ou, Ya-Ping; Liu, Sheng Hua; Fu, Wen-Fu

    2014-03-14

    A series of 1,4-disubstituted ruthenium-vinyl complexes, (E,E)-[{(PMe3)3(CO)ClRu}2(μ-HC=CH-Ar-CH=CH)], in which the 1,4-diethenylphenylene bridge bears two oligo(ethylene glycol)methyl ether side chains at different positions (2,5- and 2,3-positions), were prepared. The respective products were characterized by elemental analyses and NMR spectroscopy. The structures of complexes 1b and 1e were established by X-ray crystallography. The electronic properties of the complexes were investigated by cyclic voltammetry, and IR and UV-vis/NIR spectroscopies. Electrochemical studies showed that the 2,5-substituents better stabilized the mixed-valence states; the electrochemical behavior was greatly affected by lithium cations, especially complex 1g with 2,3-substituents, which was further supported by IR and UV-vis/NIR spectra changes. Spectroelectrochemical studies showed that the redox chemistry was dominated by the non-innocent character of the bridging fragment.

  9. Direct Observation of Photoinduced Charge Separation in Ruthenium Complex/Ni(OH)2 Nanoparticle Hybrid

    SciTech Connect

    Tang, Yu; Pattengale, Brian A.; Ludwig, John M.; Atifi, Abderrahman; Zinovev, Alexander V.; Dong, Bin; Kong, Qingyu; Zuo, Xiaobing; Zhang, Xiaoyi; Huang, Jier

    2015-12-17

    We report that Ni(OH)2 have emerged as important functional materials for solar fuel conversion because of their potential as cost-effective bifunctional catalysts for both hydrogen and oxygen evolution reactions. However, their roles as photocatalysts in the photoinduced charge separation (CS) reactions remain unexplored. In this paper, we investigate the CS dynamics of a newly designed hybrid catalyst by integrating a Ru complex with Ni(OH)2 nanoparticles (NPs). Using time resolved X-ray absorption spectroscopy (XTA), we directly observed the formation of the reduced Ni metal site (~60 ps), unambiguously demonstrating CS process in the hybrid through ultrafast electron transfer from Ru complex to Ni(OH)2 NPs. Compared to the ultrafast CS process, the charge recombination in the hybrid is ultraslow (>>50 ns). These results not only suggest the possibility of developing Ni(OH)2 as solar fuel catalysts, but also represent the first time direct observation of efficient CS in a hybrid catalyst using XTA.

  10. Electrophilic Activation of Oxidized Sulfur Ligands and Implications for the Biological Activity of Ruthenium(II) Arene Anticancer Complexes.

    PubMed

    Sriskandakumar, Thamayanthy; Behyan, Shirin; Habtemariam, Abraha; Sadler, Peter J; Kennepohl, Pierre

    2015-12-01

    Surprisingly, the anticancer activity of half-sandwich Ru arene complexes [(η(6)-arene)Ru(en)Cl](+) appears to be promoted and not inhibited by binding to the intracellular thiol glutathione. Labilization of the Ru-S bond allowing DNA binding appeared to be initiated by oxygenation of the thiolate ligand, although oxidation by itself did not seem to weaken the Ru-S bond. In this study, we have investigated the solvation and acidic perturbations of mono (sulfenato) and bis (sulfinato) oxidized species of [(η(6)-arene)Ru(en) (SR)](+) complex in the presence of Brønsted and Lewis acids. Sulfur K-edge X-ray absorption spectroscopy together with density functional theory calculations show that solvation and acidic perturbation of sulfenato species produce a significant decrease in the S3p character of the Ru-S bond (Ru4dσ* ← S1s charge donation). Also there is a drastic fall in the overall ligand charge donation to the metal center in both sulfenato and sulfinato species. Our investigation clearly shows that mono oxidized sulfenato species are most susceptible to ligand exchange, hence providing a possible pathway for in vivo activation and biological activity.

  11. Electrochemical deposition of conducting ruthenium oxide films from solution

    SciTech Connect

    Anderson, D.P.; Warren, L.F.

    1984-02-01

    In the last decade, ruthenium oxide, RuO /sub x/ (x less than or equal to 2), has been used extensively as the active anode electrocatalyst constituent for Cl/sub 2/ and O/sub 2/ evolution reactions, in chlorate production, and in metal electrowinning from mixed chloride-sulfate solutions. More recently, this material has been incorporated in several light-induced water electrolysis schemes and apparently possesses the ability to inhibit CdS photocorrosion by acting as a hole scavenger. The numerous applications for this catalyst material certainly warrant further studies of its electrochemical properties on a variety of substrates, e.g., semiconductors. The lack of a simple technique for controlled deposition of ruthenium oxide onto conducting substrates prompted us to investigate an electrochemical approach to this problem. We describe here a new way to electrochemically deposit conducting films of hydrated ruthenium oxide from an aqueous solution of the benzeneruthenium (II)aqua complex. The films slowly dissolve in aqueous electrolytes upon potential cycling, yet appear to be catalytic with regards to water oxidation.

  12. Synthesis, Structure and Antitumour Properties of a New 1,2-Propylenediaminetetraacetate-Ruthenium(III) Compound

    PubMed Central

    Vilaplana, R.; Romero, M. A.; Quirós, M.; Salas, J. M.

    1995-01-01

    A novel complex formed by ruthenium (III) and the sequestering ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been synthetized and characterized. The structure of the monomeric compound, studied by X-ray diffraction , shows an almost symmetric octahedral geometry around the metal ion, with two chlorine atoms in a cis conformation. The antitumour activity against a variety of murine and human cancers is reported. PMID:18472768

  13. A triphenylamine-grafted imidazo[4,5-f][1,10]phenanthroline ruthenium(II) complex: acid-base and photoelectric properties.

    PubMed

    Fan, Su-Hua; Zhang, An-Guo; Ju, Chuan-Chuan; Gao, Li-Hua; Wang, Ke-Zhi

    2010-04-19

    A new heteroleptic ruthenium(II) complex of [Ru(Hipdpa)(Hdcbpy)(NCS)(2)](-).0.5H(+).0.5[N(C(4)H(9))(4)](+) Ru(Hipdpa) {where Hdcbpy = monodeprotonated 4,4'-dicarboxy-2,2'-bipyridine and Hipdpa = 4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline} was synthesized and characterized by elementary analysis, standard spectroscopy techniques, and cyclic voltammetry. The ground- and excited-state acid-base properties of Ru(Hipdpa) were studied by means of UV-vis absorption spectrophotometric and spectrofluorimetric titrations in 4:1(v/v) Britton-Robinson/dimethylformamide buffer solution. The four-step separate protonation/deprotonation processes were found in the ground states, and one of which taking place near the physiological pH range. The two observable excited-state protonation/deprotonation processes were found for the Ru(Hipdpa), constituting pH-induced "off-on-off" emission switches. The performance of the complexes as photosensitizers in nanocrystalline TiO(2)-based liquid solar cells containing an electrolyte solution (0.05 M I(2), 0.5 M LiI, and 0.5 M 4-tert-butylpyridine in 50% acetonitrile and 50% propylene carbonate) was investigated and found to achieve a much improved device performance (a short-circuit photocurrent density of 18.7 mA cm(-2), an open-circuit voltage of 630 mV, and an overall conversion efficiency of 6.85%) compared to a triphenylamine-free parent complex [Ru(Hpip)(Hdcbpy)(NCS)(2)](-).[N(C(4)H(9))(4)](+)-based device {Hpip = 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline} and a comparable performance to that of cis-bis(isothiocyanato)bis(2,2'-bipyridine-4,4'-dicarboxylic acid)ruthenium(II) (N3) under identical experimental conditions. A density functional theory calculation of the molecular structures and electronic properties of the complexes was also carried out in an effort to understand their effectiveness in TiO(2)-based solar cells.

  14. Unexpected higher stabilisation of two classical antiaromatic frameworks with a ruthenium fragment compared to the osmium counterpart: origin probed by DFT calculations.

    PubMed

    Wu, Jingjing; Hao, Yulei; An, Ke; Zhu, Jun

    2016-01-01

    Density functional theory (DFT) calculations were carried out to investigate the stability and aromaticity of metallapentalocyclobutadienes. The results reveal unexpected higher stabilisation achieved with a 4d ruthenium fragment compared to the 5d [corrected] osmium counterpart. Moreover, direct 1-3 metal-carbon bonding in the metallabutadiene unit of these two complexes is negligible. PMID:26505956

  15. DNA-protein noncovalent cross-linking: ruthenium dipyridophenazine biotin complex for the assembly of proteins and gold nanoparticles on DNA templates.

    PubMed

    Slim, Mohamed; Durisic, Nela; Grutter, Peter; Sleiman, Hanadi F

    2007-05-01

    We report the first example of a small molecule that can noncovalently cross-link DNA with streptavidin and streptavidin-labeled materials. Molecule 1 possesses a ruthenium dipyridophenazine DNA-intercalating moiety and a biotin unit; these two units are adequately separated to ensure efficient cross-linking of DNA with protein. Complex 1 is essentially nonemissive in aqueous solution and when bound to streptavidin, however, its luminescence is turned "on" when it binds to DNA. We have used these properties to establish that this complex can simultaneously bind to DNA and streptavidin, and can thus bring these two biomolecules together. We also synthesized a related molecule, 3, in which the biotin and DNA-intercalating moieties are covalently bound. While complex 3 can intercalate into DNA through a threading mechanism, luminescence experiments show that it cannot simultaneously bind DNA and streptavidin, most likely due to the proximity of its two molecular-recognition units. The cross-linking ability of molecule 1 was used to template the assembly of streptavidin molecules on circular plasmid DNA, as visualized by atomic force microscopy. In addition, using 1, we show the organization of discrete groups of gold nanoparticles labeled with streptavidin on a linear DNA template of finite size, with transmission electron microscopy. In these experiments the DNA template acted as a "molecular ruler" that dictated the number of particles in the assembly.

  16. Rolling cycle amplification based single-color quantum dots-ruthenium complex assembling dyads for homogeneous and highly selective detection of DNA.

    PubMed

    Su, Chen; Liu, Yufei; Ye, Tai; Xiang, Xia; Ji, Xinghu; He, Zhike

    2015-01-01

    In this work, a new, label-free, homogeneous, highly sensitive, and selective fluorescent biosensor for DNA detection is developed by using rolling-circle amplification (RCA) based single-color quantum dots-ruthenium complex (QDs-Ru) assembling dyads. This strategy includes three steps: (1) the target DNA initiates RCA reaction and generates linear RCA products; (2) the complementary DNA hybridizes with the RCA products to form long double-strand DNA (dsDNA); (3) [Ru(phen)2(dppx)](2+) (dppx=7,8-dimethyldipyrido [3,2-a:2',3'-c] phenanthroline) intercalates into the long dsDNA with strong fluorescence emission. Due to its strong binding propensity with the long dsDNA, [Ru(phen)2(dppx)](2+) is removed from the surface of the QDs, resulting in restoring the fluorescence of the QDs, which has been quenched by [Ru(phen)2(dppx)](2+) through a photoinduced electron transfer process and is overlaid with the fluorescence of dsDNA bonded Ru(II) polypyridyl complex (Ru-dsDNA). Thus, high fluorescence intensity is observed, and is related to the concentration of target. This sensor exhibits not only high sensitivity for hepatitis B virus (HBV) ssDNA with a low detection limit (0.5 pM), but also excellent selectivity in the complex matrix. Moreover, this strategy applies QDs-Ru assembling dyads to the detection of single-strand DNA (ssDNA) without any functionalization and separation techniques.

  17. Unexpected high photothemal conversion efficiency of gold nanospheres upon grafting with two-photon luminescent ruthenium(II) complexes: A way towards cancer therapy?

    PubMed

    Zhang, Pingyu; Wang, Jinquan; Huang, Huaiyi; Yu, Bole; Qiu, Kangqiang; Huang, Juanjuan; Wang, Shutao; Jiang, Lei; Gasser, Gilles; Ji, Liangnian; Chao, Hui

    2015-09-01

    The design and development of functional hybrid nanomaterials is currently a topic of great interest in biomedicine. Herein we investigated the grafting of Ru(II) polypyridyl complexes onto gold nanospheres (Ru@AuNPs) to improve the particles' near infrared (NIR) absorption, and ultimately allow for application in photothermal cancer therapy. As demonstrated in this article, these ruthenium(II) complexes could indeed significantly enhance gold nanospheres' two-photon luminescence (PTL) intensity and photothermal therapy (PTT) efficiency. The best dual functional nanoparticles of this study were successfully used for real-time luminescent imaging-guided PTT in live cancer cells. Furthermore, in vivo tumor ablation was achieved with excellent treatment efficacy under a diode laser (808 nm) irradiation at the power density of 0.8 W/cm(2) for 5 min. This study demonstrates that the coupling of inert Ru(II) polypyridyl complexes to gold nanospheres allows for the enhancement of two-photon luminescence and for efficient photothermal effect.

  18. Metal encapsulating carbon nanostructures from oligoalkyne metal complexes

    SciTech Connect

    Dosa, P.I.; Erben, C.; Iyer, V.S.; Vollhardt, K.P.C.; Wasser, I.M.

    1999-11-10

    Carbon nanotubes, onions, and related closed-shell carbon particles have commanded extensive recent attention because of their potential applications as unique electronic, magnetic, and mechanically robust materials. When filled with metals, such nanocapsules have additional promise as magnetic particles, contrasting agents, protecting cloaks, and catalysts and in other applications. Among the various methods for their preparation, the transition metal (especially Fe, Co, and Ni) catalyzed pyrolysis of small organic molecules has shown promise for larger scale production and in structural control. While the use of organometallic complexes as solid catalyst precursors or copyrolytic gaseous ingredients has been reported, all of these studies have been limited to gas-phase experiments at relatively high temperatures. There is very little literature that deals with the organic solid-state generation of carbon nanotubes. The latter suffers from extreme conditions, poor yields, or not readily modifiable starting materials. Development of synthetic organic approaches to closed shell large carbon structures is desirable but in its infancy. Here the authors present a significant step in its progress.

  19. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  20. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  1. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  2. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  3. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  4. A novel dual-functioning ruthenium(II)-arene complex of an anti-microbial ciprofloxacin derivative - Anti-proliferative and anti-microbial activity.

    PubMed

    Ude, Ziga; Romero-Canelón, Isolda; Twamley, Brendan; Fitzgerald Hughes, Deirdre; Sadler, Peter J; Marmion, Celine J

    2016-07-01

    7-(4-(Decanoyl)piperazin-1-yl)-ciprofloxacin, CipA, (1) which is an analogue of the antibiotic ciprofloxacin, and its ruthenium(II) complex [Ru(η(6)-p-cymene)(CipA-H)Cl], (2) have been synthesised and the x-ray crystal structures of 1·1.3H2O·0.6CH3OH and 2·CH3OH·0.5H2O determined. The complex adopts a typical pseudo-octahedral 'piano-stool' geometry, with Ru(II) π-bonded to the p-cymene ring and σ-bonded to a chloride and two oxygen atoms of the chelated fluoroquinolone ligand. The complex is highly cytotoxic in the low μM range and is as potent as the clinical drug cisplatin against the human cancer cell lines A2780, A549, HCT116, and PC3. It is also highly cytotoxic against cisplatin- and oxaliplatin-resistant cell lines suggesting a different mechanism of action. The complex also retained low μM cytotoxicity against the human colon cancer cell line HCT116p53 in which the tumour suppressor p53 had been knocked out, suggesting that the potent anti-proliferative properties associated with this complex are independent of the status of p53 (in contrast to cisplatin). The complex also retained moderate anti-bacterial activity in two Escherichia coli, a laboratory strain and a clinical isolate resistant to first, second and third generation β-lactam antibiotics.

  5. Simultaneous realization of Hg2+ sensing, magnetic resonance imaging and upconversion luminescence in vitro and in vivo bioimaging based on hollow mesoporous silica coated UCNPs and ruthenium complex

    NASA Astrophysics Data System (ADS)

    Ge, Xiaoqian; Sun, Lining; Ma, Binbin; Jin, Di; Dong, Liang; Shi, Liyi; Li, Nan; Chen, Haige; Huang, Wei

    2015-08-01

    We have constructed a multifunctional nanoprobe with sensing and imaging properties by using hollow mesoporous silica coated upconversion nanoparticles (UCNPs) and Hg2+ responsive ruthenium (Ru) complex. The Ru complex was loaded into the hollow mesoporous silica and the UCNPs acted as an energy donor, transferring luminescence energy to the Ru complex. Furthermore, polyethylenimine (PEI) was assembled on the surface of mesoporous silica to achieve better hydrophilic and bio-compatibility. Upon addition of Hg2+, a blue shift of the absorption peak of the Ru complex is observed and the energy transfer process between the UCNPs and the Ru complex was blocked, resulting in an increase of the green emission intensity of the UCNPs. The un-changed 801 nm emission of the nanoprobe was used as an internal standard reference and the detection limit of Hg2+ was determined to be 0.16 μM for this nanoprobe in aqueous solution. In addition, based on the low cytotoxicity as studied by CCK-8 assay, the nanoprobe was successfully applied for cell imaging and small animal imaging. Furthermore, when doped with Gd3+ ions, the nanoprobe was successfully applied to in vivo magnetic resonance imaging (MRI) of Kunming mice, which demonstrates its potential as a MRI positive-contrast agent. Therefore, the method and results may provide more exciting opportunities to afford nanoprobes with multimodal bioimaging and multifunctional applications.We have constructed a multifunctional nanoprobe with sensing and imaging properties by using hollow mesoporous silica coated upconversion nanoparticles (UCNPs) and Hg2+ responsive ruthenium (Ru) complex. The Ru complex was loaded into the hollow mesoporous silica and the UCNPs acted as an energy donor, transferring luminescence energy to the Ru complex. Furthermore, polyethylenimine (PEI) was assembled on the surface of mesoporous silica to achieve better hydrophilic and bio-compatibility. Upon addition of Hg2+, a blue shift of the absorption peak

  6. Pharmacological Effects of the Ruthenium Complex NAMI-A Given Orally to CBA Mice With MCa Mammary Carcinoma

    PubMed Central

    Zorzet, Sonia; Sorc, Alenka; Casarsa, Claudia; Cocchietto, Moreno

    2001-01-01

    NAMI-A, imidazolium trans-imidazoledimethylsulfoxidetetrachlororuthenate, is a ruthenium based compounds capable of inhibiting the growth of lung metastases of solid tumours in a number of experimental conditions.The aim of this study was to investigate the potential use of NAMI-A by the oral route to treat lung metastases of MCa mammary carcinoma in the CBA mouse. treatment of mice, carrying intramuscular tumours in advanced stage of growth, for 11 consecutive days caused a significant reduction of the weight of lung metastases over the range of doses from 150 to 600 mg/kg/day. No sign of toxicity was observed at the histological analysis in the gut epithelium or in the kidney parenchyma, and NAMI-A concentration in the kidney was more than 10-fold lower than after intraperitoneal treatments. NAMI-A is thus active against metastases also by the oral route, suggesting the use of this way to treat tumour bearing hosts for long periods. PMID:18475970

  7. Chlorambucil conjugates of dinuclear p-cymene ruthenium trithiolato complexes: synthesis, characterization and cytotoxicity study in vitro and in vivo.

    PubMed

    Stíbal, David; Therrien, Bruno; Süss-Fink, Georg; Nowak-Sliwinska, Patrycja; Dyson, Paul J; Čermáková, Eva; Řezáčová, Martina; Tomšík, Pavel

    2016-07-01

    Four diruthenium trithiolato chlorambucil conjugates have been prepared via Steglich esterification from chlorambucil and the corresponding trithiolato precursors. All conjugates are highly cytotoxic towards human ovarian A2780 and A2780cisR cancer cell lines with IC50 values in the nanomolar range. The conjugates exhibit selectivity towards A2780 cells as compared to non-cancerous HEK293 cells, while being only slightly selective for RF24 and A2780cisR cells. In vivo, the conjugate [10]BF4 suppressed the growth of a solid Ehrlich tumor in immunocompetent NMRI mice but did not prolong their overall survival. The reactivity of the chlorambucil conjugates with glutathione, a potential target of the dinuclear ruthenium motive, and with the 2-deoxyguanosine 5'-monophosphate (dGMP-a model target of chlorambucil) was studied by mass spectrometry and NMR spectroscopy. The conjugates did not show catalytic activity for the oxidation of glutathione nor binding to nucleotides, indicating that glutathione oxidation and DNA alkylation are not key mechanisms of action. Four highly cytotoxic diruthenium trithiolato chlorambucil conjugates have been prepared. All conjugates exhibit selectivity towards A2780 cells as compared to HEK293 cells, while being only slightly active in RF24 and A2780cisR cells. In vivo, the best candidate suppressed the growth of a solid Ehrlich tumor in immunocompetent NMRI mice but did not prolong their overall survival. PMID:27040952

  8. A ruthenium dimer complex with a flexible linker slowly threads between DNA bases in two distinct steps.

    PubMed

    Bahira, Meriem; McCauley, Micah J; Almaqwashi, Ali A; Lincoln, Per; Westerlund, Fredrik; Rouzina, Ioulia; Williams, Mark C

    2015-10-15

    Several multi-component DNA intercalating small molecules have been designed around ruthenium-based intercalating monomers to optimize DNA binding properties for therapeutic use. Here we probe the DNA binding ligand [μ-C4(cpdppz)2(phen)4Ru2](4+), which consists of two Ru(phen)2dppz(2+) moieties joined by a flexible linker. To quantify ligand binding, double-stranded DNA is stretched with optical tweezers and exposed to ligand under constant applied force. In contrast to other bis-intercalators, we find that ligand association is described by a two-step process, which consists of fast bimolecular intercalation of the first dppz moiety followed by ∼10-fold slower intercalation of the second dppz moiety. The second step is rate-limited by the requirement for a DNA-ligand conformational change that allows the flexible linker to pass through the DNA duplex. Based on our measured force-dependent binding rates and ligand-induced DNA elongation measurements, we are able to map out the energy landscape and structural dynamics for both ligand binding steps. In addition, we find that at zero force the overall binding process involves fast association (∼10 s), slow dissociation (∼300 s), and very high affinity (Kd ∼10 nM). The methodology developed in this work will be useful for studying the mechanism of DNA binding by other multi-step intercalating ligands and proteins. PMID:26365236

  9. A ruthenium dimer complex with a flexible linker slowly threads between DNA bases in two distinct steps

    PubMed Central

    Bahira, Meriem; McCauley, Micah J.; Almaqwashi, Ali A.; Lincoln, Per; Westerlund, Fredrik; Rouzina, Ioulia; Williams, Mark C.

    2015-01-01

    Several multi-component DNA intercalating small molecules have been designed around ruthenium-based intercalating monomers to optimize DNA binding properties for therapeutic use. Here we probe the DNA binding ligand [μ-C4(cpdppz)2(phen)4Ru2]4+, which consists of two Ru(phen)2dppz2+ moieties joined by a flexible linker. To quantify ligand binding, double-stranded DNA is stretched with optical tweezers and exposed to ligand under constant applied force. In contrast to other bis-intercalators, we find that ligand association is described by a two-step process, which consists of fast bimolecular intercalation of the first dppz moiety followed by ∼10-fold slower intercalation of the second dppz moiety. The second step is rate-limited by the requirement for a DNA-ligand conformational change that allows the flexible linker to pass through the DNA duplex. Based on our measured force-dependent binding rates and ligand-induced DNA elongation measurements, we are able to map out the energy landscape and structural dynamics for both ligand binding steps. In addition, we find that at zero force the overall binding process involves fast association (∼10 s), slow dissociation (∼300 s), and very high affinity (Kd ∼10 nM). The methodology developed in this work will be useful for studying the mechanism of DNA binding by other multi-step intercalating ligands and proteins. PMID:26365236

  10. Bistable molecular switches based on linkage isomerization in ruthenium polypyridyl complexes with a ligand-bound ambidentate motif.

    PubMed

    Johansson, Olof; Johannissen, Linus O; Lomoth, Reiner

    2009-01-01

    Electron-transfer-induced linkage isomerization was investigated in a series of bis-tridentate Ru polypyridyl complexes [Ru(L-X-OH)(Y-tpy)](2+) with ambidentate ligand L-X-OH=bpy-C(R)(OH)-py (bpy=2,2'-bipyridine; py=pyridine; R=H, Me, Ph, or tBu) and spectator ligand Y-tpy (tpy=2,2':6',2''-terpyridine; Y=p-tolyl, p-PhCO(2)Me, Cl, OEt, N-pyrrolidine). The ligand-bound ambidentate motif switches reversibly between N and O coordination in the Ru(II) and Ru(III) state, respectively. The potentials of the Ru(III/II) couple differ by about 0.5 V between the isomers, and this results in a bistable electrochemical response of the molecular switches. The effects of structural modifications in form of substituents on the linking carbon atom of the ambidentate ligand and on the central pyridine moiety of the spectator ligand were investigated by electrochemical and computational methods. Differences in isomerization behavior span six orders of magnitude in rate constants and two orders of magnitude in equilibrium constants. The results can be interpreted in terms of steric and electronic substituent effects and their influence on rotational barriers, ligation geometry, and electron deficiency of the metal center. PMID:19072945

  11. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

    PubMed Central

    Ejidike, Ikechukwu P.; Ajibade, Peter A.

    2016-01-01

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

  12. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent.

    PubMed

    Ejidike, Ikechukwu P; Ajibade, Peter A

    2016-01-04

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2',4'-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl₃·3H₂O lead to the formation of neutral complexes of the type [Ru(L)Cl₂(H₂O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl₂] > [(BZEBOD)RuCl₂] > [(MOABOD)RuCl₂] > [Vit. C] > [rutin] > [(METBOD)RuCl₂], and ABTS radical in the order: [(PAEBOD)RuCl₂] < [(MOABOD)RuCl₂] < [(BZEBOD)RuCl₂] < [(METBOD)RuCl₂]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay.

  13. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent.

    PubMed

    Ejidike, Ikechukwu P; Ajibade, Peter A

    2016-01-01

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2',4'-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl₃·3H₂O lead to the formation of neutral complexes of the type [Ru(L)Cl₂(H₂O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl₂] > [(BZEBOD)RuCl₂] > [(MOABOD)RuCl₂] > [Vit. C] > [rutin] > [(METBOD)RuCl₂], and ABTS radical in the order: [(PAEBOD)RuCl₂] < [(MOABOD)RuCl₂] < [(BZEBOD)RuCl₂] < [(METBOD)RuCl₂]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

  14. Microwave-assisted synthesis of arene ruthenium(II) complexes that induce S-phase arrest in cancer cells by DNA damage-mediated p53 phosphorylation.

    PubMed

    Wu, Qiong; Fan, Cundong; Chen, Tianfeng; Liu, Chaoran; Mei, Wenjie; Chen, Sidong; Wang, Baoguo; Chen, Yunyun; Zheng, Wenjie

    2013-05-01

    A series of arene ruthenium(II) complexes coordinated by phenanthroimidazole derivates, [(C6H6)Ru(L)Cl]Cl·2H2O (1b L = IP, 2b L = p-NMe2PIP, 3b L = p-MeOPIP, 4b L = p-HOPIP, 5b L = p-COOHPIP, 6b L = p-CF3PIP, 7b L = p-BrPIP) have been synthesized in yields of 89-92% under microwave irradiation in 30 min, and the crystal structure of 1b by XRD gives a typical "piano stool" conformation. The antitumor activity of these complexes against various tumor cells have been evaluated by MTT assay, and the results show that this type of arene Ru(II) complexes exhibit acceptable inhibitory effect against all of these tumor cells, especially osteosarcoma MG-63 cells, but with low toxicity toward HK-2 human normal cells. Studies on the mechanism revealed that cell cycle arrest at S-phase in MG-63 cells induced by the arene Ru(II) complex 2b, which was confirmed by the increase in the percentage of cells at S-phase and down-regulator of cyclin A. The further studies by Comet assay at single cell level indicated that DNA damage in MG-63 cells was triggered by 2b, following with the up-regulation of phosphorylated p53 and histone. The studies by spectroscopy in vitro also indicate that 2b bind to DNA molecule by intercalative mode to disturb the bio-function of tumor cells. In conclusion, the synthetic arene Ru(II) complexes could serve as novel p53 activator with potential application in cancer chemotherapy.

  15. Fighting Cancer with Transition Metal Complexes: From Naked DNA to Protein and Chromatin Targeting Strategies

    PubMed Central

    Palermo, Giulia; Magistrato, Alessandra; Riedel, Tina; von Erlach, Thibaud; Davey, Curt A.; Dyson, Paul J.

    2015-01-01

    Abstract Many transition metal complexes have unique physicochemical properties that can be efficiently exploited in medicinal chemistry for cancer treatment. Traditionally, double‐stranded DNA has been assumed to be the main binding target; however, recent studies have shown that nucleosomal DNA as well as proteins can act as dominant molecular binding partners. This has raised new questions about the molecular determinants that govern DNA versus protein binding selectivity, and has offered new ways to rationalize their biological activity and possible side effects. To address these questions, molecular simulations at an atomistic level of detail have been used to complement, support, and rationalize experimental data. Herein we review some relevant studies—focused on platinum and ruthenium compounds—to illustrate the power of state‐of‐the‐art molecular simulation techniques and to demonstrate how the interplay between molecular simulations and experiments can make important contributions to elucidating the target preferences of some promising transition metal anticancer agents. This contribution aims at providing relevant information that may help in the rational design of novel drug‐discovery strategies. PMID:26634638

  16. Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems

    SciTech Connect

    T. Brent Gunnoe

    2011-02-17

    Catalysts provide foundational technology for the development of new materials and can enhance the efficiency of routes to known materials. New catalyst technologies offer the possibility of reducing energy and raw material consumption as well as enabling chemical processes with a lower environmental impact. The rising demand and expense of fossil resources has strained national and global economies and has increased the importance of accessing more efficient catalytic processes for the conversion of hydrocarbons to useful products. The goals of the research are to develop and understand single-site homogeneous catalysts for the conversion of readily available hydrocarbons into useful materials. A detailed understanding of these catalytic reactions could lead to the development of catalysts with improved activity, longevity and selectivity. Such transformations could reduce the environmental impact of hydrocarbon functionalization, conserve energy and valuable fossil resources and provide new technologies for the production of liquid fuels. This project is a collaborative effort that incorporates both experimental and computational studies to understand the details of transition metal catalyzed C-H activation and C-C bond forming reactions with olefins. Accomplishments of the current funding period include: (1) We have completed and published studies of C-H activation and catalytic olefin hydroarylation by TpRu{l_brace}P(pyr){sub 3}{r_brace}(NCMe)R (pyr = N-pyrrolyl) complexes. While these systems efficiently initiate stoichiometric benzene C-H activation, catalytic olefin hydroarylation is hindered by inhibition of olefin coordination, which is a result of the steric bulk of the P(pyr){sub 3} ligand. (2) We have extended our studies of catalytic olefin hydroarylation by TpRu(L)(NCMe)Ph systems to L = P(OCH{sub 2}){sub 3}CEt. Thus, we have now completed detailed mechanistic studies of four systems with L = CO, PMe{sub 3}, P(pyr){sub 3} and P(OCH{sub 2}){sub 3}CEt

  17. Steric effect for proton, hydrogen-atom, and hydride transfer reactions with geometric isomers of NADH-model ruthenium complexes.

    PubMed

    Cohen, Brian W; Polyansky, Dmitry E; Achord, Patrick; Cabelli, Diane; Muckerman, James T; Tanaka, Koji; Thummel, Randolph P; Zong, Ruifa; Fujita, Etsuko

    2012-01-01

    Two isomers, [Ru(1)]2+ (Ru = Ru(bpy)2, bpy = 2,2'-bipyridine, 1 = 2-(pyrid-2'-yl)-1-azaacridine) and [Ru(2)]2+ (2 = 3-(pyrid-2'-yl)-4-azaacridine), are bioinspired model compounds containing the nicotinamide functionality and can serve as precursors for the photogeneration of C-H hydrides for studying reactions pertinent to the photochemical reduction of metal-C1 complexes and/or carbon dioxide. While it has been shown that the structural differences between the azaacridine ligands of [Ru(1)]2+ and [Ru(2)]2+ have a significant effect on the mechanism of formation of the hydride donors, [Ru(1HH)]2+ and [Ru(2HH)]2+, in aqueous solution, we describe the steric implications for proton, net-hydrogen-atom and net-hydride transfer reactions in this work. Protonation of [Ru(2*-)] in aprotic and even protic media is slow compared to that of [Ru(1*-)]+. The net hydrogen-atom transfer between *[Ru(1)]2+ and hydroquinone (H2Q) proceeds by one-step EPT, rather than stepwise electron-proton transfer. Such a reaction was not observed for *[Ru(2)]2+ because the non-coordinated N atom is not easily available for an interaction with H2Q. Finally, the rate of the net hydride ion transfer from [Ru(1HH)]2+ to [Ph3C]+ is significantly slower than that of [Ru (2HH)]2+ owing to steric congestion at the donor site. PMID:22470971

  18. Ruthenium Complexes Induce HepG2 Human Hepatocellular Carcinoma Cell Apoptosis and Inhibit Cell Migration and Invasion through Regulation of the Nrf2 Pathway

    PubMed Central

    Lu, Yiyu; Shen, Ting; Yang, Hua; Gu, Weiguang

    2016-01-01

    Ruthenium (Ru) complexes are currently the focus of substantial interest because of their potential application as chemotherapeutic agents with broad anticancer activities. This study investigated the in vitro and in vivo anticancer activities and mechanisms of two Ru complexes—2,3,7,8,12,13,17,18-Octaethyl-21H,23H-porphine Ru(II) carbonyl (Ru1) and 5,10,15,20-Tetraphenyl-21H,23H-porphine Ru(II) carbonyl (Ru2)—against human hepatocellular carcinoma (HCC) cells. These Ru complexes effectively inhibited the cellular growth of three human hepatocellular carcinoma (HCC) cells, with IC50 values ranging from 2.7–7.3 μM. In contrast, the complexes exhibited lower toxicity towards L02 human liver normal cells with IC50 values of 20.4 and 24.8 μM, respectively. Moreover, Ru2 significantly inhibited HepG2 cell migration and invasion, and these effects were dose-dependent. The mechanistic studies demonstrated that Ru2 induced HCC cell apoptosis, as evidenced by DNA fragmentation and nuclear condensation, which was predominately triggered via caspase family member activation. Furthermore, HCC cell treatment significantly decreased the expression levels of Nrf2 and its downstream effectors, NAD(P)H: quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO1). Ru2 also exhibited potent in vivo anticancer efficacy in a tumor-bearing nude mouse model, as demonstrated by a time- and dose-dependent inhibition on tumor growth. The results demonstrate the therapeutic potential of Ru complexes against HCC via Nrf2 pathway regulation. PMID:27213353

  19. Mechanism of the formation of carboxylate from alcohols and water catalyzed by a bipyridine-based ruthenium complex: a computational study.

    PubMed

    Li, Haixia; Hall, Michael B

    2014-01-01

    The catalytic mechanism for oxidizing alcohols to carboxylate in basic aqueous solution by the bipyridine-based ruthenium complex 2 (BIPY-PNN)Ru(H)(Cl)(CO) (Nat. Chem. 2013, 5, 122) is investigated by density functional theory (DFT) with the ωB97X-D functional. Using water as the oxygen donor with liberation of dihydrogen represents a safe and clean process for such oxidations. Under NaOH, the active catalyst is 3 (BIPY-PNN)Ru(H)(CO). Four steps are involved: dehydrogenation of alcohol to aldehyde (Step 1); coupling of aldehyde and water to form the gem-diol (Step 2); dehydrogenation of gem-diol to carboxylic acid (Step 3); and deprotonation of carboxylic acid to carboxylate anion under base (Step 4). The dehydrogenations of alcohol (Step 1) and gem-diol (Step 3) prefer the double hydrogen transfer mechanism to the β-H elimination mechanism. The coupling of aldehyde and water (Step 2) proceeds through cleavage of water by catalyst 3 followed by concerted hydroxyl and hydrogen transfer to the aldehyde. The formation of the carboxylate anion occurs via direct deprotonation of the carboxylic acid under base (Step 4), while in the absence of base a stable carboxylic acid-addition complex 6 was formed. Added base was found to play important roles in the generation of catalyst 3 from both the stable carboxylic acid-addition complex 6 and its chloride precursor complex 2. The chemoselectivity for the formation of carboxylic acid rather than ester is ascribed to the favorable cleavage of water and the subsequent generation of the stable carboxylate anion that leads to carboxylic acid upon acidification. PMID:24328295

  20. Synthesis and reactivity of silyl ruthenium complexes: the importance of trans effects in C-H activation, Si-C bond formation, and dehydrogenative coupling of silanes.

    PubMed

    Dioumaev, Vladimir K; Procopio, Leo J; Carroll, Patrick J; Berry, Donald H

    2003-07-01

    A series of octahedral ruthenium silyl hydride complexes, cis-(PMe(3))(4)Ru(SiR(3))H (SiR(3) = SiMe(3), 1a; SiMe(2)CH(2)SiMe(3), 1b; SiEt(3), 1c; SiMe(2)H, 1d), has been synthesized by the reaction of hydrosilanes with (PMe(3))(3)Ru(eta(2)-CH(2)PMe(2))H (5), cis-(PMe(3))(4)RuMe(2) (6), or (PMe(3))(4)RuH(2) (9). Reaction with 6 proceeds via an intermediate product, cis-(PMe(3))(4)Ru(SiR(3))Me (SiR(3) = SiMe(3), 7a; SiMe(2)CH(2)SiMe(3), 7b). Alternatively, 1 and 7 have been synthesized via a fast hydrosilane exchange with another cis-(PMe(3))(4)Ru(SiR(3))H or cis-(PMe(3))(4)Ru(SiR(3))Me, which occurs at a rate approaching the NMR time scale. Compounds 1a, 1b, 1d, and 7a adopt octahedral geometries in solution and the solid state with mutually cis silyl and hydride (or silyl and methyl) ligands. The longest Ru-P distance within a complex is always trans to Si, reflecting the strong trans influence of silicon. The aptitude of phosphine dissociation in these complexes has been probed in reactions of 1a, 1c, and 7a with PMe(3)-d(9) and CO. The dissociation is regioselective in the position trans to a silyl ligand (trans effect of Si), and the rate approaches the NMR time scale. A slower secondary process introduces PMe(3)-d(9) and CO in the other octahedral positions, most likely via nondissociative isomerization. The trans effect and trans influence in 7a are so strong that an equilibrium concentration of dissociated phosphine is detectable (approximately 5%) in solution of pure 7a. Compounds 1a-c also react with dihydrogen via regioselective dissociation of phosphine from the site trans to Si, but the final product, fac-(PMe(3))(3)Ru(SiR(3))H(3) (SiR(3) = SiMe(3), 4a; SiMe(2)CH(2)SiMe(3), 4b; SiEt(3), 4c), features hydrides cis to Si. Alternatively, 4a-c have been synthesized by photolysis of (PMe(3))(4)RuH(2) in the presence of a hydrosilane or by exchange of fac-(PMe(3))(3)Ru(SiR(3))H(3) with another HSiR(3). The reverse manifold - HH elimination from 4a and trapping

  1. Synthesis of a ruthenium(II) bipyridyl complex coordinated by a functionalized Schiff base ligand: Characterization, spectroscopic and isothermal titration calorimetry measurements of M 2+ binding and sensing (M 2+ = Ca 2+, Mg 2+)

    NASA Astrophysics Data System (ADS)

    Dixit, Namrata; Mishra, Lallan; Mustafi, Sourajit M.; Chary, Kandala V. R.; Houjou, Hirohiko

    2009-07-01

    Bis-[methylsalicylidine-4'benzoic acid]-ethylene (LH 2) complexed with cis-Ru(bpy) 2Cl 2·2H 2O provides a complex of composition [Ru(bpy) 2L]·2NH 4PF 6 ( 1), which has been characterized spectroscopically. Its binding behaviour towards Mg 2+ and Ca 2+ ions is monitored using 1H NMR titration, isothermal titration calorimetry (ITC) and luminescence microscopy. The luminescent ruthenium complex binds Ca 2+ in a more selective manner as compared to Mg 2+.

  2. Synthesis of a ruthenium(II) bipyridyl complex coordinated by a functionalized Schiff base ligand: characterization, spectroscopic and isothermal titration calorimetry measurements of M2+ binding and sensing (M2+=Ca2+, Mg2+).

    PubMed

    Dixit, Namrata; Mishra, Lallan; Mustafi, Sourajit M; Chary, Kandala V R; Houjou, Hirohiko

    2009-07-01

    Bis-[methylsalicylidine-4'benzoic acid]-ethylene (LH2) complexed with cis-Ru(bpy)2Cl(2).2H2O provides a complex of composition [Ru(bpy)2L].2NH4PF6 (1), which has been characterized spectroscopically. Its binding behaviour towards Mg2+ and Ca2+ ions is monitored using 1H NMR titration, isothermal titration calorimetry (ITC) and luminescence microscopy. The luminescent ruthenium complex binds Ca2+ in a more selective manner as compared to Mg2+.

  3. Electrogenerated chemiluminescence biosensing for the detection of prostate PC-3 cancer cells incorporating antibody as capture probe and ruthenium complex-labelled wheat germ agglutinin as signal probe.

    PubMed

    Yang, Haiying; Li, Zhejian; Shan, Meng; Li, Congcong; Qi, Honglan; Gao, Qiang; Wang, Jinyi; Zhang, Chengxiao

    2015-03-10

    A highly selective and sensitive electrogenerated chemiluminescence (ECL) biosensor for the detection of prostate PC-3 cancer cells was designed using a prostate specific antibody as a capture probe and ruthenium complex-labelled wheat germ agglutinin as a signal probe. The ECL biosensor was fabricated by covalently immobilising the capture probe on a graphene oxide-coated glassy carbon electrode. Target PC-3 cells were selectively captured on the surface of the biosensor, and then, the signal probe was bound with the captured PC-3 cells to form a sandwich. In the presence of tripropylamine, the ECL intensity of the sandwich biosensor was logarithmically directly proportion to the concentration of PC-3 cells over a range from 7.0×10(2) to 3.0×10(4) cells mL(-1), with a detection limit of 2.6×10(2) cells mL(-1). The ECL biosensor was also applied to detect prostate specific antigen with a detection limit of 0.1 ng mL(-1). The high selectivity of the biosensor was demonstrated in comparison with that of a lectin-based biosensor. The strategy developed in this study may be a promising approach and could be extended to the design of ECL biosensors for highly sensitive and selective detection of other cancer-related cells or cancer biomarkers using different probes.

  4. Influence of different ruthenium(II) bipyridyl complex on the photocatalytic H 2 evolution over TiO 2 nanoparticles with mesostructures

    NASA Astrophysics Data System (ADS)

    Peng, Tianyou; Ke, Dingning; Cai, Ping; Dai, Ke; Ma, Liang; Zan, Ling

    H 2 production over dye-sensitized Pt/TiO 2 nanoparticles with mesostructures (m-TiO 2) under visible light (λ > 420 nm) was investigated by using methanol as electron donors. Experimental results indicate that three types of ruthenium(II) bipyridyl complex dyes (one binuclear Ru, two mononuclear Ru), which can be attached to Pt/ m-TiO 2 with different linkage modes, show different photosensitization effects due to their different coordination circumstances and physicochemical properties. The dye tightly linked with m-TiO 2 has better durability but the lowest H 2 evolution efficiency, whereas the loosely attached dyes possess higher H 2 evolution efficiency and preferable durability. It seems that the dynamic equilibrium between the linkage of the ground state dye with TiO 2 and the divorce of the oxidization state dye from the surfaces plays a crucial role in the photochemical behavior during the photocatalyst sensitization process. It is helpful to improve the H 2 evolution efficiency by enhancing the electron injection and hindering the backward transfer. The binuclear Ru(II) dye shows a better photosensitization in comparison with mononuclear Ru(II) dyes due to its large molecular area, conjugation system, and "antenna effect", which, in turn, improve the visible light harvesting and electron transfer between the dye molecules and TiO 2.

  5. Concerted or stepwise hydrogen transfer in the transfer hydrogenation of acetophenone catalyzed by ruthenium-acetamido complex: a theoretical mechanistic investigation.

    PubMed

    Guo, Xiaojia; Tang, Yanhui; Zhang, Xin; Lei, Ming

    2011-11-10

    In this paper, the mechanism of transfer hydrogenation of acetophenone catalyzed by ruthenium-acetamido complex was studied using density function theory (DFT) method. The catalytic cycle of transfer hydrogenation consists of hydrogen transfer (HT) step and dehydrogenation (DH) step of isopropanol (IPA). Inner sphere mechanism (paths 1 and 7) and outer sphere mechanism (paths 2-6) in HT step are fully investigated. Calculated results indicate that DH step of IPA (from (i)1 to (i)2) is the rate-determining step in the whole catalytic cycle, which has a potential energy barrier of 16.2 kcal/mol. On the other hand, the maximum potential energy barriers of paths 1-7 in the HT step are 5.9, 12.7, 24.4, 16.8, 23.7, 7.2, and 6.1 kcal/mol, respectively. The inner sphere pathways (paths 1 and 7) are favorable hydrogen transfer modes compared with outer sphere pathways, and the proton transferred to the oxygen atom of acetophenone comes from the hydroxyl group but not from amino group of acetamido ligand. Those theoretical results are in agreement with experimental report. However, in view of this DFT study in the inner sphere mechanism of HT step, hydride transfer and proton transfer are concerted and asynchronous hydrogen transfer but not a stepwise one, and hydride transfer precedes proton transfer in this case. PMID:21974747

  6. Self-assembly of c-myc DNA promoted by a single enantiomer ruthenium complex as a potential nuclear targeting gene carrier

    PubMed Central

    Wu, Qiong; Mei, Wenjie; Zheng, Kangdi; Ding, Yang

    2016-01-01

    Gene therapy has long been limited in the clinic, due in part to the lack of safety and efficacy of the gene carrier. Herein, a single enantiomer ruthenium(II) complex, Λ-[Ru(bpy)2(p-BEPIP)](ClO4)2 (Λ-RM0627, bpy = 4,4′-bipyridine, p-BEPIP = 2-(4-phenylacetylenephenyl)imidazole [4,5f][1, 10] phenanthroline), has been synthesized and investigated as a potential gene carrier that targets the nucleus. In this report, it is shown that Λ-RM0627 promotes self-assembly of c-myc DNA to form a nanowire structure. Further studies showed that the nano-assembly of c-myc DNA that induced Λ-RM0627 could be efficiently taken up and enriched in the nuclei of HepG2 cells. After treatment of the nano-assembly of c-myc DNA with Λ-RM0627, over-expression of c-myc in HepG2 cells was observed. In summary, Λ-RM0627 played a key role in the transfer and release of c-myc into cells, which strongly indicates Λ-RM0627 as a potent carrier of c-myc DNA that targets the nucleus of tumor cells. PMID:27381008

  7. Synthesis of PVP-stabilized ruthenium colloids with low boiling point alcohols.

    PubMed

    Zhang, Yuqing; Yu, Jiulong; Niu, Haijun; Liu, Hanfan

    2007-09-15

    A route to the preparation of poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloids by refluxing ruthenium(III) chloride in low boiling point alcohols was developed. Deep purple colloids with shuttle-like ruthenium particles were also synthesized. XPS measurement verified the nanoparticles were in the metallic state. The morphology of metal nanoparticles was characterized by UV-visible absorption spectrophotometry, TEM and XRD.

  8. Identification of the structural determinants for anticancer activity of a ruthenium arene peptide conjugate.

    PubMed

    Meier, Samuel M; Novak, Maria; Kandioller, Wolfgang; Jakupec, Michael A; Arion, Vladimir B; Metzler-Nolte, Nils; Keppler, Bernhard K; Hartinger, Christian G

    2013-07-01

    Organometallic Ru(arene)-peptide bioconjugates with potent in vitro anticancer activity are rare. We have prepared a conjugate of a Ru(arene) complex with the neuropeptide [Leu(5)]-enkephalin. [Chlorido(η(6)-p-cymene)(5-oxo-κO-2-{(4-[(N-tyrosinyl-glycinyl-glycinyl-phenylalanyl-leucinyl-NH2)propanamido]-1H-1,2,3-triazol-1-yl)methyl}-4H-pyronato-κO)ruthenium(II)] (8) shows antiproliferative activity in human ovarian carcinoma cells with an IC50 value as low as 13 μM, whereas the peptide or the Ru moiety alone are hardly cytotoxic. The conjugation strategy for linking the Ru(cym) (cym=η(6)-p-cymene) moiety to the peptide involved N-terminal modification of an alkyne-[Leu(5)]-enkephalin with a 2-(azidomethyl)-5-hydroxy-4H-pyran-4-one linker, using Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC), and subsequent metallation with the Ru(cym) moiety. The ruthenium-bioconjugate was characterized by high resolution top-down electrospray ionization mass spectrometry (ESI-MS) with regard to peptide sequence, linker modification and metallation site. Notably, complete sequence coverage was obtained and the Ru(cym) moiety was confirmed to be coordinated to the pyronato linker. The ruthenium-bioconjugate was analyzed with respect to cytotoxicity-determining constituents, and through the bioconjugate models [{2-(azidomethyl)-5-oxo-κO-4H-pyronato-κO}chloride (η(6)-p-cymene)ruthenium(II)] (5) and [chlorido(η(6)-p-cymene){5-oxo-κO-2-([(4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl]methyl)-4H-pyronato-κO}ruthenium(II)] (6) the Ru(cym) fragment with a triazole-carrying pyronato ligand was identified as the minimal unit required to achieve in vitro anticancer activity.

  9. Sensitization of nanocrystalline TiO2 anchored with pendant catechol functionality using a new tetracyanato ruthenium(II) polypyridyl complex.

    PubMed

    Kar, Prasenjit; Verma, Sandeep; Sen, Anik; Das, Amitava; Ganguly, Bishwajit; Ghosh, Hirendra Nath

    2010-05-01

    We have synthesized a new photoactive ruthenium(II) complex having a pendant catechol functionality (K(2)[Ru(CN)(4)(L)] (1) (L is 4-[2-(4'-methyl-2,2'-bipyridinyl-4-yl)vinyl]benzene-1,2-diol) for studying the dynamics of the interfacial electron transfer between nanoparticulate TiO(2) and the photoexcited states of this Ru(II) complex using femtosecond transient absorption spectroscopy. Steady-state absorption and emission studies revealed that the complex 1 showed a strong solvatochromic behavior in solvents or solvent mixtures of varying polarity. Our steady-state absorption studies further revealed that 1 is bound to TiO(2) surfaces through the catechol functionality, though 1 has two different types of functionalities (catecholate and cyanato) for binding to TiO(2) surfaces. The longer wavelength absorption band tail for 1, bound to TiO(2) through the proposed catecholate functionality, could also be explained on the basis of the DFT calculations. Dynamics of the interfacial electron transfer between 1 and TiO(2) nanoparticles was investigated by studying kinetics at various wavelengths in the visible and near-infrared region. Electron injection to the conduction band of the nanoparticulate TiO(2) was confirmed by detection of the conduction band electron in TiO(2) ([e(-)](TiO(2))(CB)) and cation radical of the adsorbed dye (1(*+)) in real time as monitored by transient absorption spectroscopy. A single exponential and pulse-width limited (<100 fs) electron injection was observed. Back electron transfer dynamics was determined by monitoring the decay kinetics of 1(*+) and [e(-)](TiO(2))(CB). This is the first report on ultrafast ET dynamics on TiO(2) nanoparticle surface using a solvatochromic sensitizer molecule.

  10. Asymmetric reduction of ketones by biocatalysis using clementine mandarin (Citrus reticulata) fruit grown in Annaba or by ruthenium catalysis for access to both enantiomers.

    PubMed

    Bennamane, Manhel; Zeror, Saoussen; Aribi-Zouioueche, Louisa

    2015-03-01

    Biocatalytic reduction of prochiral ketones using freshly ripened clementine mandarin (Citrus reticulata) in aqueous medium is reported. High enantioselectivities were observed, especially for the bioreduction of indanone , tetralone , and thiochromanone with respectively 95%, 99%, and 86% enantiomeric excess (ee). Enantioselective bio- and metal-catalyzed reactions were compared. Chiral ruthenium catalysts afforded good asymmetric inductions (>75% ee) in most cases, enantiomeric excesses depending on the nature of substrate and ligand. N-aminoindanol prolinamide was revealed as the best ligand for most ketones. Interestingly, for several substrates both enantiomers could be obtained using either Citrus reticulata or ruthenium complex.

  11. A Metallacycle Fragmentation Strategy for Vinyl Transfer from Enol Carboxylates to Secondary Alcohol C-H Bonds via Osmium- or Ruthenium-Catalyzed Transfer Hydrogenation.

    PubMed

    Park, Boyoung Y; Luong, Tom; Sato, Hiroki; Krische, Michael J

    2015-06-24

    A strategy for catalytic vinyl transfer from enol carboxylates to activated secondary alcohol C-H bonds is described. Using XPhos-modified ruthenium(0) or osmium(0) complexes, enol carboxylate-carbonyl oxidative coupling forms transient β-acyloxy-oxametallacycles, which eliminate carboxylate to deliver allylic ruthenium(II) or osmium(II) alkoxides. Reduction of the metal(II) salt via hydrogen transfer from the secondary alcohol reactant releases the product of carbinol C-H vinylation and regenerates ketone and zero-valent catalyst.

  12. Asymmetric reduction of ketones by biocatalysis using clementine mandarin (Citrus reticulata) fruit grown in Annaba or by ruthenium catalysis for access to both enantiomers.

    PubMed

    Bennamane, Manhel; Zeror, Saoussen; Aribi-Zouioueche, Louisa

    2015-03-01

    Biocatalytic reduction of prochiral ketones using freshly ripened clementine mandarin (Citrus reticulata) in aqueous medium is reported. High enantioselectivities were observed, especially for the bioreduction of indanone , tetralone , and thiochromanone with respectively 95%, 99%, and 86% enantiomeric excess (ee). Enantioselective bio- and metal-catalyzed reactions were compared. Chiral ruthenium catalysts afforded good asymmetric inductions (>75% ee) in most cases, enantiomeric excesses depending on the nature of substrate and ligand. N-aminoindanol prolinamide was revealed as the best ligand for most ketones. Interestingly, for several substrates both enantiomers could be obtained using either Citrus reticulata or ruthenium complex. PMID:25482318

  13. Cluster synthesis. 39. New platinum-ruthenium carbonyl cluster complexes with bridging hydride ligands. Synthesis and structural characterizations of Ru sub 4 Pt(CO) sub 13 (COD)(. mu. -H) sub 2 , Ru sub 3 Pt(CO) sub 9 (. mu. -CO)(COD)(. mu. -H) sub 2 , Ru sub 4 Pt sub 2 (CO) sub 11 (COD) sub 2 (. mu. sub 3 -H) sub 2 , and Ru sub 5 Pt sub 5 (CO) sub 18 (COD) sub 2 (. mu. -H) sub 2 , COD = Cycloocta-1,5-diene

    SciTech Connect

    Adams, R.D.; Zhaoyang Li; Jauching Lii; Wengan Wu )

    1992-08-05

    The reaction of Ru{sub 4}(CO){sub 13}({mu}-H){sub 2} (1) with Pt(COD){sub 2} at 25 C yielded four new platinum-ruthenium carbonyl cluster complexes Ru{sub 4}Pt(CO){sub 13}(COD)({mu}-H){sub 2} (2) (37%), Ru{sub 3}Pt(CO){sub 9}({mu}-CO)(COD)({mu}-H){sub 2} (3) (10%), Ru{sub 4}Pt{sub 2}-(CO){sub 11}(COD){sub 2}({mu}{sub 3}-H){sub 2} (4) (2.5%), and Ru{sub 5}Pt{sub 5}(CO){sub 18}(COD){sub 2}({mu}{sub 3}-H){sub 2} (5) (1%). All compounds were characterized by IR, {sup 1}H NMR, and single-crystal X-ray diffraction analyses. The cluster of compound 2 consists of a butterfly tetrahedron of four ruthenium atoms with one triangular face capped by a Pt(COD) grouping. Compound 3 consists of a cluster of three ruthenium atoms and one platinum atom in a tetrahedral arrangement. Compound 4 consists of a tetrahedral cluster of four ruthenium atoms with two of the triangular faces capped by Pt(COD) groupings. The other two triangular faces have triply bridging hydride ligands. In the cluster of compound 5, the five ruthenium and four of the platinum atoms are arranged in the form of a face-shared bioctahedron. The shared face consists of three of the platinum atoms. The fifth platinum atom is a cap on one of the Ru{sub 2}Pt triangles. Two hydride ligands are believed to bridge metals of the triangular faces on the opposite ends of the bioctahedron.

  14. VCD Studies on Chiral Characters of Metal Complex Oligomers

    PubMed Central

    Sato, Hisako; Yamagishi, Akihiko

    2013-01-01

    The present article reviews the results on the application of vibrational circular dichroism (VCD) spectroscopy to the study of stereochemical properties of chiral metal complexes in solution. The chiral characters reflecting on the vibrational properties of metal complexes are revealed by measurements of a series of β-diketonato complexes with the help of theoretical calculation. Attention is paid to the effects of electronic properties of a central metal ion on vibrational energy levels or low-lying electronic states. The investigation is further extended to the oligomers of β-diketonato complex units. The induction of chiral structures is confirmed by the VCD spectra when chiral inert moieties are connected with labile metal ions. These results have demonstrated how VCD spectroscopy is efficient in revealing the static and dynamic properties of mononuclear and multinuclear chiral metal complexes, which are difficult to clarify by means of other spectroscopes. PMID:23296273

  15. Development of nitrosyl ruthenium complex-loaded lipid carriers for topical administration: improvement in skin stability and in nitric oxide release by visible light irradiation.

    PubMed

    Marquele-Oliveira, Franciane; Santana, Danielle Cristine de Almeida; Taveira, Stephânia Fleury; Vermeulen, Deise Mirella; de Oliveira, Anderson Rodrigo Moraes; da Silva, Roberto Santana; Lopez, Renata Fonseca Vianna

    2010-12-01

    The prominent nitric oxide (NO) donor [Ru(terpy)(bdqi)NO](PF(6))(3) has been synthesized and evaluated with respect to noteworthy biological effects due to its NO photorelease, including vascular relaxation and melanoma cell culture toxicity. The potential for delivering NO in therapeutic quantities is tenable since the nitrosyl ruthenium complex (NRC) must first reach the "target tissue" and then release the NO upon stimulus. In this context, NRC-loaded lipid carriers were developed and characterized to further explore its topical administration for applications such as skin cancer treatment. NRC-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carriers were prepared via the microemulsification method, with average diameters of 275+/-15 nm and 211+/-31 nm and zeta potentials of -40.7+/-10.4 mV and -50.0+/-7.5 mV, respectively. In vitro kinetic studies of NRC release from nanoparticles showed sustained release of NRC from the lipid carriers and illustrated the influence of the release medium and the lyophilization process. Stability studies showed that NO is released from NRC as a function of temperature and time and due to skin contact. The encapsulation of NRC in SLN followed by its lyophilization, significantly improved the complex stability. Furthermore, of particular interest was the fact that in the NO photorelease study, the NO release from the NRC-loaded SLN was approximately twice that of just NRC in solution. NRC-loaded SLN performs well enough at releasing and protecting NO degradation in vitro that it is a promising carrier for topical delivery of NO.

  16. Tandem isomerization-decarboxylation of unsaturated fatty acids to olefins via ruthenium metal-as-ligand catalysts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new facile Ru-catalyzed route to bio-olefins3 from unsaturated fatty acids via readily accessible metal-as-ligand type catalyst precursors, [Ru(CO)2RCO2]n and Ru3(CO)12, will be described. The catalyst apparently functions in a tandem mode by dynamically isomerizing the positions of double bonds i...

  17. MERCURY-NITRITE-RHODIUM-RUTHENIUM INTERACTIONS IN NOBLE METAL CATALYZED HYDROGEN GENERATION FROM FORMIC ACID DURING NUCLEAR WASTE PROCESSING AT THE SAVANNAH RIVER SITE - 136C

    SciTech Connect

    Koopman, D.; Pickenheim, B.; Lambert, D.; Newell, J; Stone, M.

    2009-09-02

    Chemical pre-treatment of radioactive waste at the Savannah River Site is performed to prepare the waste for vitrification into a stable waste glass form. During pre-treatment, compounds in the waste become catalytically active. Mercury, rhodium, and palladium become active for nitrite destruction by formic acid, while rhodium and ruthenium become active for catalytic conversion of formic acid into hydrogen and carbon dioxide. Nitrite ion is present during the maximum activity of rhodium, but is consumed prior to the activation of ruthenium. Catalytic hydrogen generation during pre-treatment can exceed radiolytic hydrogen generation by several orders of magnitude. Palladium and mercury impact the maximum catalytic hydrogen generation rates of rhodium and ruthenium by altering the kinetics of nitrite ion decomposition. New data are presented that illustrate the interactions of these various species.

  18. A comparative DFT study on aquation and nucleobase binding of ruthenium (II) and osmium (II) arene complexes.

    PubMed

    Wang, Hanlu; Zeng, Xingye; Zhou, Rujin; Zhao, Cunyuan

    2013-11-01

    The potential energy surfaces of the reactions of organometallic arene complexes of the type [(η (6)-arene)M(II)(pic)Cl] (where pic = 2-picolinic acid, M = Ru or Os) were examined by a DFT computational study. Among the seven density functional methods, hybrid exchange functional B3LYP outperforms the others to explain the aquation of the complexes. The reactions and binding energies of Ru(II) and Os(II) arene complexes with both 9EtG and 9EtA were studied to gain insight into the reactivity of these types of organometallic complexes with DNA. The obtained data rationalize experimental observation, contributing to partly understanding the potential biological and medical applications of organometallic complexes.

  19. A comparative DFT study on aquation and nucleobase binding of ruthenium (II) and osmium (II) arene complexes.

    PubMed

    Wang, Hanlu; Zeng, Xingye; Zhou, Rujin; Zhao, Cunyuan

    2013-11-01

    The potential energy surfaces of the reactions of organometallic arene complexes of the type [(η (6)-arene)M(II)(pic)Cl] (where pic = 2-picolinic acid, M = Ru or Os) were examined by a DFT computational study. Among the seven density functional methods, hybrid exchange functional B3LYP outperforms the others to explain the aquation of the complexes. The reactions and binding energies of Ru(II) and Os(II) arene complexes with both 9EtG and 9EtA were studied to gain insight into the reactivity of these types of organometallic complexes with DNA. The obtained data rationalize experimental observation, contributing to partly understanding the potential biological and medical applications of organometallic complexes. PMID:24037457

  20. Effects of Fe cations in ruthenium-complex multilayers fabricated by a layer-by-layer method.

    PubMed

    Oyama, Makiko; Ozawa, Hiroaki; Nagashima, Takumi; Haga, Masa-aki; Ishida, Takao

    2016-04-01

    Molecular multilayers were fabricated using a Ru complex containing Fe cations on an indium tin oxide surface to control the properties of the Ru-complex multilayers such as the multilayer orientation and the electron transport. The Ru-complex multilayer films containing Fe cations were thicker than those containing Zr cations, which have been used previously. The electron transport properties of the multilayers containing Fe cations were evaluated. Solid-state sandwich cell measurements showed that the Ru-complex multilayer films containing Fe cations exhibited increased electron transport with a lower transport coefficient β of 0.01 Å(-1), whereas those that contain Zr cations have β ∼ 0.07 Å(-1). Thus, Fe cations are effective in obtaining thicker Ru-complex layers with increased electron transport abilities.

  1. Building Indenylidene-Ruthenium Catalysts for Metathesis Transformations

    NASA Astrophysics Data System (ADS)

    Clavier, Hervé; Nolan, Steven P.

    Ruthenium-mediated olefin metathesis has emerged as an indispensable tool in organic synthesis for the formation carbon-carbon double bonds, attested by the large number of applications for natural product synthesis. Among the numerous catalysts developed to mediate olefin metathesis transformations, ruthenium-indenylidene complexes are robust and powerful pre-catalysts. The discovery of this catalyst category was slightly muddled due to a first mis-assignment of the compound structure. This report provides an overview of the synthetic routes for the construction of the indenylidene pattern in ruthenium complexes. The parameters relating to the indenylidene moiety construction will be discussed as well as the mechanism of this formation

  2. Simultaneous determination of hydrazine and phenyl hydrazine using 4′-(4-carboxyphenyl)-2,2′:6′,2″ terpyridine diacetonitrile triphenylphosphine ruthenium(II) tetrafluoroborate complex functionalized multiwalled carbon nanotubes modified electrode

    SciTech Connect

    Tiwari, Ida; Gupta, Mandakini; Sinha, Preeti; Banks, Craig E.

    2014-12-15

    Highlights: • A nanocomposite of ruthenium(II) terpyridine, triphenylphosphine based complex and multiwalled carbon nanotubes have been used first time for simultaneous detection of hydrazine and phenyl hydrazine. • The detection limit reported is lower as compared to other reported works. • The paper also focuses towards effect of ligand variation attached to ruthenium(II) terpyridine based complexes complex for the hydrazine and phenyl hydrazine detection. • Nanocomposite does not involve any biological entity hence high stability. - Abstract: A nanocomposite based on the incorporation of the complex 4′-(4-carboxyphenyl)-2,2′:6′,2″ terpyridine triphenylphosphine diacetonitrile ruthenium(II) tetrafluoroborate with multiwalled carbon nanotubes and ionomer supported upon a glassy carbon electrode substrate is reported and characterized with scanning electron microscopy, transmission electron microscopy and infrared spectroscopy. The electrochemical behavior and stability of the composite electrode was investigated via cyclic voltammetry. The modified electrode exhibits an electro-catalytic activity towards the oxidation of both hydrazine and phenyl hydrazine in 0.1 M phosphate buffer solution (PBS, pH 7.4). The oxidation of hydrazine and phenyl hydrazine occurs at 0.81 V and 0.32 V with limit of detection found to be 3.7 × 10{sup −7} M and 1.15 × 10{sup −7} M and having a linear range from 5 × 10{sup −6} M to 6.5 × 10{sup −3} M, and 5 × 10{sup −6} M to 0.2 × 10{sup −3} M, respectively.

  3. Ferrocene and (arene)ruthenium(II) complexes of the natural anticancer naphthoquinone plumbagin with enhanced efficacy against resistant cancer cells and a genuine mode of action.

    PubMed

    Spoerlein-Guettler, Cornelia; Mahal, Katharina; Schobert, Rainer; Biersack, Bernhard

    2014-09-01

    A series of ferrocene and (arene)ruthenium(II) complexes attached to the naturally occurring anticancer naphthoquinones plumbagin and juglone was tested for efficacy against various cancer cell lines and for alterations in the mode of action. The plumbagin ferrocene and (p-cymene)Ru(II) conjugates 1c and 2a overcame the multi-drug drug resistance of KB-V1/Vbl cervix carcinoma cells and showed IC50 (72 h) values around 1 μM in growth inhibition assays using 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT). They were further investigated for their influence on the cell cycle of KB-V1/Vbl and HCT-116 colon carcinoma cells, on the generation of reactive oxygen species (ROS) by the latter cell line, for their substrate character for the P-glycoprotein drug eflux pump via the calcein-AM efflux assays, and for DNA affinity by the electrophoretic mobility shift assay (EMSA). The derivatives 1c and 2a increased the number of dead cancer cells (sub-G0/G1 fraction) in a dose- and time-dependent manner. ROS levels were significantly increased upon treatment with 1c and 2a. These compounds also showed a greater affinity to linear DNA than plumbagin. While plumbagin did not affect calcein-AM transport by P-glycoprotein the derivatives 1c and 2a exhibited a 50% or 80% inhibition of the P-glycoprotein-mediated calcein-AM efflux relative to the clinically established sensitizer verapamil.

  4. Analytical gradients of complete active space self-consistent field energies using Cholesky decomposition: Geometry optimization and spin-state energetics of a ruthenium nitrosyl complex

    SciTech Connect

    Delcey, Mickaël G.; Freitag, Leon; González, Leticia; Pedersen, Thomas Bondo; Aquilante, Francesco; Lindh, Roland

    2014-05-07

    We present a formulation of analytical energy gradients at the complete active space self-consistent field (CASSCF) level of theory employing density fitting (DF) techniques to enable efficient geometry optimizations of large systems. As an example, the ground and lowest triplet state geometries of a ruthenium nitrosyl complex are computed at the DF-CASSCF level of theory and compared with structures obtained from density functional theory (DFT) using the B3LYP, BP86, and M06L functionals. The average deviation of all bond lengths compared to the crystal structure is 0.042 Å at the DF-CASSCF level of theory, which is slightly larger but still comparable with the deviations obtained by the tested DFT functionals, e.g., 0.032 Å with M06L. Specifically, the root-mean-square deviation between the DF-CASSCF and best DFT coordinates, delivered by BP86, is only 0.08 Å for S{sub 0} and 0.11 Å for T{sub 1}, indicating that the geometries are very similar. While keeping the mean energy gradient errors below 0.25%, the DF technique results in a 13-fold speedup compared to the conventional CASSCF geometry optimization algorithm. Additionally, we assess the singlet-triplet energy vertical and adiabatic differences with multiconfigurational second-order perturbation theory (CASPT2) using the DF-CASSCF and DFT optimized geometries. It is found that the vertical CASPT2 energies are relatively similar regardless of the geometry employed whereas the adiabatic singlet-triplet gaps are more sensitive to the chosen triplet geometry.

  5. Infrared study of CO adsorption on magnesia-supported ruthenium, gold, and bimetallic ruthenium-gold clusters

    SciTech Connect

    Schwank, J.; Parravano, G.; Gruber, H.L.

    1980-01-01

    An infrared study of CO adsorption on magnesia-supported ruthenium, gold, and bimetallic ruthenium-gold clusters provided evidence for metal-support interaction in the single-metal catalysts and for metal-metal interaction in the bimetallic catalysts which indicated that all the metal present existed as bimetallic clusters and that gold did not form separate clusters or segregate at the surface. The IR study was made at various degrees of coverage with CO of catalysts containing 2.1-4.7% metal (0, 11, 36, 90, and 100Vertical Bar3< gold) on magnesia and pretreated in hydrogen, helium or oxygen, and a comparison sample of 5% ruthenium on silica.

  6. Recent advances in the ruthenium-catalyzed hydroarylation of alkynes with aromatics: synthesis of trisubstituted alkenes.

    PubMed

    Manikandan, Rajendran; Jeganmohan, Masilamani

    2015-11-14

    The hydroarylation of alkynes with substituted aromatics in the presence of a metal catalyst via chelation-assisted C-H bond activation is a powerful method to synthesize trisubstituted alkenes. Chelation-assisted C-H bond activation can be done by two ways: (a) an oxidative addition pathway and (b) a deprotonation pathway. Generally, a mixture of cis and trans stereoisomeric as well as regioisomeric trisubstituted alkenes was observed in an oxidative addition pathway. In the deprotonation pathway, the hydroarylation reaction can be done in a highly regio- and stereoselective manner, and enables preparation of the expected trisubstituted alkenes in a highly selective manner. Generally, ruthenium, rhodium and cobalt complexes are used as catalysts in the reaction. In this review, a ruthenium-catalyzed hydroarylation of alkynes with substituted aromatics is covered completely. The hydroarylation reaction of alkynes with amide, azole, carbamate, phosphine oxide, amine, acetyl, sulfoxide and sulphur directed aromatics is discussed.

  7. Transition Metal and Vacancy Defect Complexes in Phosphorene

    NASA Astrophysics Data System (ADS)

    Kabir, Mukul; Babar, Rohit

    Inducing magnetic moment in otherwise nonmagnetic two-dimensional semiconducting materials is the first step to design spintronic material. Here, we study the adsorption of transition-metals on pristine and defected phosphorene, within density functional theory. We predict that increased transition-meal diffusivity on the pristine phosphorene would hinder controlled magnetism. In contrast, point-defects anchor the transiton-metal to reduce metal diffusivity. The di-vacancy complex is more important in this context due to their increased thermodynamic stability over the mono-vacancy. For most cases, the defect-transition metal complexes retain the intrinsic semiconducting properties, and induce a local moment. We provide a simple microscopic model which describe the local moment of these transition metal and defect complexes.

  8. Nickel/ruthenium catalyst and method for aqueous phase reactions

    DOEpatents

    Elliott, D.C.; Sealock, J.L.

    1998-09-29

    A method of hydrogenation is described using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions. 2 figs.

  9. Antischistosomal Activity of Oxindolimine-Metal Complexes

    PubMed Central

    Dario, Bruno S.; Couto, Ricardo A. A.; Pinto, Pedro L. S.; da Costa Ferreira, Ana M.

    2015-01-01

    In recent years, a class of oxindole-copper and -zinc complex derivatives have been reported as compounds with efficient proapoptotic activity toward different tumor cells (e.g., neuroblastomas, melanomas, monocytes). Here we assessed the efficacy of synthesized oxindole-copper(II), -zinc(II), and -vanadyl (VO2+) complexes against adult Schistosoma mansoni worms. The copper(II) complexes (50% inhibitory concentrations of 30 to 45 μM) demonstrated greater antischistosomal properties than the analogous zinc and vanadyl complexes regarding lethality, reduction of motor activity, and oviposition. PMID:26239976

  10. Facile η5-η3 hapticity interconversion in pentamethylcyclopentadienyl ruthenium(II) complexes containing a phenylmethallyl ("open indenyl") ligand.

    PubMed

    Glöckner, Andreas; Àrias, Òscar; Bannenberg, Thomas; Daniliuc, Constantin G; Jones, Peter G; Tamm, Matthias

    2011-11-21

    The indenyl effect has been introduced to pentadienyl ("open cyclopentadienyl") chemistry by preparation of the phenylmethallyl ("open indenyl") ligand oInd(Me). The reaction of its potassium salt K(oInd(Me)) with [(η(5)-C(5)Me(5))RuCl](4) afforded the sandwich complex [(η(5)-C(5)Me(5))Ru(η(5)-oInd(Me))] (1), which, upon treatment with PMe(3), CO, and 2,6-dimethylphenyl isocyanide (CN-o-Xy), easily underwent η(5)-η(3) hapticity interconversion and formed the complexes [(η(5)-C(5)Me(5))Ru(η(3)-oInd(Me))(L)] (2, L = PMe(3); 3, L = CO; 4, L = CN-o-Xy). In these complexes, the η(3)-bound phenylmethallyl ligand adopts an anti-conformation with regard to the relative positions of the phenyl and methyl substituents. For the PMe(3) complex anti-2, slow conversion to the syn-isomer was observed, and this equilibrium reaction was monitored by NMR spectroscopy at 50 °C to determine a first order rate constant of k(323 K) = 6.57 × 10(-6) (± 0.02 × 10(-6)) s(-1) and an activation barrier of ΔG° = 26.8 kcal mol(-1). DFT calculations afforded a stabilization of syn-2 and syn-3 by ΔG(298) = -1.54 and -1.74 kcal mol(-1) over the respective anti-isomer.

  11. Synthesis, spectroscopic, DFT calculations and biological activity studies of ruthenium carbonyl complexes with 2-picolinic acid and a secondary ligand

    NASA Astrophysics Data System (ADS)

    Shohayeb, Shahera M.; Mohamed, Rania G.; Moustafa, H.; El-Medani, Samir M.

    2016-09-01

    Thermal reaction of [Ru3(CO)12] with 2-picolinic acid (Hpic) in the absence and presence of a secondary ligand (pyridine, Py, bipyridine, Bipy, or thiourea, Tu) was investigated. Four complexes with molecular formulae: [Ru(CO)3(Hpic)], 1, [Ru2(CO)5(Hpic)(Py)], 2, [Ru2(CO)5(Hpic)(Tu)], 3 and [Ru2(CO)4(Hpic)(Bipy)], 4, were isolated. All complexes were characterized based on elemental analyses, IR, 1H NMR, magnetic studies, mass spectrometry and thermal analysis. The ligand and its complexes have been screened for antibacterial activities. Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligands. The optimized geometry parameters of the complexes were evaluated using B3LYP method and LANL2DZ basis set. The extent of natural charge population (core, valence and rydberg), exact electronic configuration, total Lewis and total non-Lewis are estimated and discussed in terms of natural bond orbitals (NBO) analysis.

  12. Langmuir-Blodgett films of a clay mineral and ruthenium(II) complexes with a noncentrosymmetric structure.

    PubMed

    Umemura, Yasushi; Yamagishi, Akihiko; Schoonheydt, Robert; Persoons, André; De Schryver, Frans

    2002-02-13

    Mono- and multilayers of amphiphilic [Ru(phen)(2)(dcC12bpy)](2+) (phen = 1,10-phenanthroline, dcC12bpy = 4,4'-caboxyl-2,2'-bipyridyl didodecyl ester) hybridized with a clay mineral have been prepared by a modified Langmuir-Blodgett method, and their structures and properties have been investigated. Formation of a hybrid monolayer of the Ru(II) complex cations and the clay platelets at an air-clay suspension interface was confirmed by surface pressure-molecular area (pi-A) isotherm measurement and atomic force microscopic (AFM) observation. Multilayers were fabricated by depositing the hybrid monolayers onto glass substrates. The absorbance at 492 nm due to the Ru(II) complex cation in the multilayer increased linearly with the increase in the layer number, indicating layer-by-layer deposition of the hybrid monolayers. Because no increase in the second-harmonic generation (SHG) signal from the multilayers against the layer number was observed, the orientation of the Ru(II) complex cations in the layer would be disturbed. The hydrophilic surface of the transferred hybrid monolayer can be converted to a hydrophobic surface by dipping it in an aqueous solution of octadecylammonium chloride (ODAH(+)Cl(-)). The multilayers modified with ODAH(+) showed a quadratic relation between the SHG intensity and the layer number. This means that the Ru(II) complex cations in the multilayer are successfully oriented in a noncentrosymmetric way by the conversion of the surface property. Both a racemic mixture and an enantiomer of the Ru(II) complex cations were employed to examine the chiral effect on the film properties. The chiral contribution to the SHG signal was enhanced in the multilayer modified with ODAH(+).

  13. System with potential dual modes of metal-ligand cooperation: highly catalytically active pyridine-based PNNH-Ru pincer complexes.

    PubMed

    Fogler, Eran; Garg, Jai Anand; Hu, Peng; Leitus, Gregory; Shimon, Linda J W; Milstein, David

    2014-11-24

    Metal-ligand cooperation (MLC) plays an important role in catalysis. Systems reported so far are generally based on a single mode of MLC. We report here a system with potential for MLC by both amine-amide and aromatization-dearomatization ligand transformations, based on a new class of phosphino-pyridyl ruthenium pincer complexes, bearing sec-amine coordination. These pincer complexes are effective catalysts under unprecedented mild conditions for acceptorless dehydrogenative coupling of alcohols to esters at 35 °C and hydrogenation of esters at room temperature and 5 atm H2. The likely actual catalyst, a novel, crystallographically characterized monoanionic de-aromatized enamido-Ru(II) complex, was obtained by deprotonation of both the N-H and the methylene proton of the N-arm of the pincer ligand. PMID:25331061

  14. Porphyrins and metal complexes thereof having haloalkyl side chains

    DOEpatents

    Wijesekera, Tilak; Lyons, James E.; Ellis, Jr., Paul E.; Bhinde, Manoj V.

    1997-01-01

    Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.

  15. Porphyrins and metal complexes thereof having haloalkyl side chains

    DOEpatents

    Wijesekera, T.; Lyons, J.E.; Ellis, P.E. Jr.; Bhinde, M.V.

    1997-03-04

    Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. 7 figs.

  16. A Simple Method for Drawing Chiral Mononuclear Octahedral Metal Complexes

    ERIC Educational Resources Information Center

    Mohamadou, Aminou; Haudrechy, Arnaud

    2008-01-01

    Octahedral transition-metal complexes are involved in a number of reactions and octahedral coordination geometry, frequently observed for metallic centers, includes important topographical stereochemistry. Depending on the number and nature of different ligands, octahedral coordination units with at least two different monodentate ligands give…

  17. Electron Capture Dissociation of Trivalent Metal Ion-Peptide Complexes

    PubMed Central

    Flick, Tawnya G.; Donald, William A.; Williams, Evan R.

    2013-01-01

    With electrospray ionization from aqueous solutions, trivalent metal ions readily adduct to small peptides resulting in formation of predominantly (peptide + MT – H)2+, where MT = La, Tm, Lu, Sm, Ho, Yb, Pm, Tb, or Eu, for peptides with molecular weights below ~1000 Da, and predominantly (peptide + MT)3+ for larger peptides. ECD of (peptide + MT – H)2+ results in extensive fragmentation from which nearly complete sequence information can be obtained, even for peptides for which only singly protonated ions are formed in the absence of the metal ions. ECD of these doubly charged complexes containing MT results in significantly higher electron capture efficiency and sequence coverage than peptide-divalent metal ion complexes that have the same net charge. Formation of salt-bridge structures in which the metal ion coordinates to a carboxylate group are favored even for (peptide + MT)3+. ECD of these latter complexes for large peptides results in electron capture by the protonation site located remotely from the metal ion and predominantly c/z fragments for all metals, except Eu3+, which undergoes a one electron reduction and only loss of small neutral molecules and b/y fragments are formed. These results indicate that solvation of the metal ion in these complexes is extensive, resulting in similar electrochemical properties of these metal ions both in the peptide environment and in water. PMID:23283726

  18. Voltammetry and in situ scanning tunnelling spectroscopy of osmium, iron, and ruthenium complexes of 2,2':6',2''-terpyridine covalently linked to Au(111)-electrodes.

    PubMed

    Salvatore, Princia; Hansen, Allan Glargaard; Moth-Poulsen, Kasper; Bjørnholm, Thomas; Nichols, Richard John; Ulstrup, Jens

    2011-08-28

    We have studied self-assembled molecular monolayers (SAMs) of complexes between Os(II)/(III), Fe(II)/(III), and Ru(II)/(III) and a 2,2',6',2''-terpyridine (terpy) derivative linked to Au(111)-electrode surfaces via a 6-acetylthiohexyloxy substituent at the 4'-position of terpy. The complexes were prepared in situ by first linking the terpy ligand to the surface via the S-atom, followed by addition of suitable metal compounds. The metal-terpy SAMs were studied by cyclic voltammetry (CV), and in situ scanning tunnelling microscopy with full electrochemical potential control of substrate and tip (in situ STM). Sharp CV peaks were observed for the Os- and Fe complexes, with interfacial electrochemical electron transfer rate constants of 6-50 s(-1). Well-defined but significantly broader peaks (up to 300 mV) were observed for the Ru-complex. Addition of 2,2'-bipyridine (bipy) towards completion of the metal coordination spheres induced voltammetric sharpening. In situ STM images of single molecular scale strong structural features were observed for the osmium and iron complexes. As expected from the voltammetric patterns, the surface coverage was by far the highest for the Ru-complex which was therefore selected for scanning tunnelling spectroscopy. These correlations displayed a strong peak around the equilibrium potential with systematic shifts with increasing bias voltage, as expected for a sequential two-step in situ ET mechanism.

  19. Preparation of porphyrins and their metal complexes

    DOEpatents

    Ellis, Jr., Paul E.; Langdale, Wayne A.

    1997-01-01

    A hydroxyl-containing pyrrolic compound having a hydroxyl group or a hydroxyl-containing group in the 2-position, optionally substituted in the beta positions, is condensed in an acidified two immiscible phase solvent system to produce excellent yields of the corresponding porphyrin or metal porphyrin.

  20. Preparation of porphyrins and their metal complexes

    DOEpatents

    Ellis, P.E. Jr.; Langdale, W.A.

    1997-08-19

    A hydroxyl-containing pyrrolic compound having a hydroxyl group or a hydroxyl-containing group in the 2-position, optionally substituted in the beta positions, is condensed in an acidified two immiscible phase solvent system to produce excellent yields of the corresponding porphyrin or metal porphyrin.