Sample records for ruthenium complex catalyzed

  1. Dehydrogenative Coupling of Primary Alcohols To Form Esters Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    Sølvhøj, Amanda Birgitte; Madsen, Robert


    The ruthenium complex [RuCl2(IiPr)(p-cymene)] catalyzes the direct condensation of primary alcohols into esters and lactones with the release of hydrogen gas. The reaction is most effective with linear aliphatic alcohols and 1,4-diols and is believed to proceed with a ruthenium dihydride as the c......The ruthenium complex [RuCl2(IiPr)(p-cymene)] catalyzes the direct condensation of primary alcohols into esters and lactones with the release of hydrogen gas. The reaction is most effective with linear aliphatic alcohols and 1,4-diols and is believed to proceed with a ruthenium dihydride...

  2. Dehydrogenative Synthesis of Imines from Alcohols and Amines Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    Maggi, Agnese; Madsen, Robert


    A new method for the direct synthesis of imines from alcohols and amines is described where hydrogen gas is liberated. The reaction is catalyzed by the ruthenium N-heterocyclic carbene complex [RuCl2(IiPr)(p-cymene)] in the presence of the ligand DABCO and molecular sieves. The imination can be a...... to the aldehyde, which stays coordinated to ruthenium. Nucleophilic attack of the amine affords the hemiaminal, which is released from ruthenium and converted into the imine....

  3. Amide Synthesis from Alcohols and Amines Catalyzed by Ruthenium N-Heterocyclic Carbene Complexes

    Dam, Johan Hygum; Osztrovszky, Gyorgyi; Nordstrøm, Lars Ulrik Rubæk


    The direct synthesis of amides from alcohols and amines is described with the simultaneous liberation of dihydrogen. The reaction does not require any stoichiometric additives or hydrogen acceptors and is catalyzed by ruthenium N-heterocyclic carbene complexes. Three different catalyst systems...... chloride and base. A range of different primary alcohols and amines have been coupled in the presence of the three catalyst systems to afford the corresponding amides in moderate to excellent yields. The best results are obtained with sterically unhindered alcohols and amines. The three catalyst systems do...... not show any significant differences in reactivity, which indicates that the same catalytically active species is operating. The reaction is believed to proceed by initial dehydrogenation of the primary alcohol to the aldehyde that stays coordinated to ruthenium and is not released into the reaction...

  4. Highly efficient oxidation of alcohols using Oxone(R) as oxidant catalyzed by ruthenium complex under mild reaction conditions

    Zi Qiang Lei; Jian Qiang Wang; Peng Hua Yan


    Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone (2KHSO5·KHSO4·K2SO4) as oxidant catalyzed by ruthenium complex Quin-Ru-Quin (where Quin = 8-hydroxyquinoline). The reaction time is very short and the preparation of complex is simple. 2008 Zi Qiang Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  5. Transfer hydrogenation reactions catalyzed by chiral half-sandwich Ruthenium complexes derived from Proline



    Chiral ruthenium half-sandwich complexes were prepared using a chelating diamine made from proline with a phenyl, ethyl, or benzyl group, instead of hydrogen on one of the coordinating arms. Three of these complexes were obtained as single diastereoisomers and their configuration identified by X-ray crystallography. The complexes are recyclable catalysts for the reduction of ketones to chiral alcohols in water. A ruthenium hydride species is identified as the active species by NMR spectroscopy and isotopic labelling experiments.Maximum enantio-selectivity was attained when a phenyl group was directly attached to the primary amine on the diamine ligand derived from proline.

  6. Hydrogenation of esters catalyzed by ruthenium PN3-Pincer complexes containing an aminophosphine arm

    Chen, Tao


    Hydrogenation of esters under mild conditions was achieved using air-stable ruthenium PN3-pincer complexes containing an aminophosphine arm. High efficiency was achieved even in the presence of water. DFT studies suggest a bimolecular proton shuttle mechanism which allows H2 to be activated by the relatively stable catalyst with a reasonably low transition state barrier. © 2014 American Chemical Society.

  7. Dialkylamino cyclopentadienyl ruthenium(ii) complex-catalyzed alpha-alkylation of arylacetonitriles with primary alcohols.

    Cheung, Hung Wai; Li, Juan; Zheng, Wenxu; Zhou, Zhongyuan; Chiu, Yu Hin; Lin, Zhenyang; Lau, Chak Po


    Aminocyclopentadienyl ruthenium complexes, [(eta(5)-C(5)H(4)NMe(2))Ru(PPh(3))(2)(CH(3)CN)](+)BF(4)(-) and [(eta(5)-C(5)H(4)NEt(2))Ru(PPh(3))(2)(CH(3)CN)](+)BF(4)(-), are moderately active catalysts for alpha-alkylation of arylacetonitriles with primary alcohols; on the other hand, the analogous unsubstituted cyclopentadienyl ruthenium complex [(eta(5)-C(5)H(5))Ru(PPh(3))(2)(CH(3)CN)](+)BF(4)(-) shows very low catalytic activity. On the basis of experimental results and theoretical calculations, rationalization for the much higher catalytic activity of the aminocyclopentadienyl complexes over that of the unsubstituted Cp complex is provided. In the catalytic systems with the former, it is possible to regenerate the active solvento complexes via protonation of the metal hydride intermediates and subsequent ligand substitution; this process is, however, very nonfacile in the catalytic system with the latter.

  8. Dehydrogenation of Formic Acid Catalyzed by a Ruthenium Complex with an N,N′-Diimine Ligand

    Guan, Chao


    We report a ruthenium complex containing an N,N′-diimine ligand for the selective decomposition of formic acid to H and CO in water in the absence of any organic additives. A turnover frequency of 12000 h and a turnover number of 350 000 at 90 °C were achieved in the HCOOH/HCOONa aqueous solution. Efficient production of high-pressure H and CO (24.0 MPa (3480 psi)) was achieved through the decomposition of formic acid with no formation of CO. Mechanistic studies by NMR and DFT calculations indicate that there may be two competitive pathways for the key hydride transfer rate-determining step in the catalytic process.

  9. Mechanism of Water Oxidation Catalyzed by a Dinuclear Ruthenium Complex Bridged by Anthraquinone

    Tohru Wada


    Full Text Available We synthesized 1,8-bis(2,2′:6′,2″-terpyrid-4′-ylanthraquinone (btpyaq as a new dimerizing ligand and determined its single crystal structure by X-ray analysis. The dinuclear Ruthenium complex [Ru2(µ-Cl(bpy2(btpyaq](BF43 ([3](BF43, bpy = 2,2′-bipyridine was used as a catalyst for water oxidation to oxygen with (NH42[Ce(NO36] as the oxidant (turnover numbers = 248. The initial reaction rate of oxygen evolution was directly proportional to the concentration of the catalyst and independent of the oxidant concentration. The cyclic voltammogram of [3](BF43 in water at pH 1.3 showed an irreversible catalytic current above +1.6 V (vs. SCE, with two quasi-reversible waves and one irreversible wave at E1/2 = +0.62, +0.82 V, and Epa = +1.13 V, respectively. UV-vis and Raman spectra of [3](BF43 with controlled-potential electrolysis at +1.40 V revealed that [Ru(IV=O O=Ru(IV]4+ is stable under electrolysis conditions. [Ru(III, Ru(II] species are recovered after dissociation of an oxygen molecule from the active species in the catalytic cycle. These results clearly indicate that an O–O bond is formed via [Ru(V=O O=Ru(IV]5+.

  10. Alcohol amination with ammonia catalyzed by an acridine-based ruthenium pincer complex: a mechanistic study.

    Ye, Xuan; Plessow, Philipp N; Brinks, Marion K; Schelwies, Mathias; Schaub, Thomas; Rominger, Frank; Paciello, Rocco; Limbach, Michael; Hofmann, Peter


    The mechanistic course of the amination of alcohols with ammonia catalyzed by a structurally modified congener of Milstein's well-defined acridine-based PNP-pincer Ru complex has been investigated both experimentally and by DFT calculations. Several key Ru intermediates have been isolated and characterized. The detailed analysis of a series of possible catalytic pathways (e.g., with and without metal-ligand cooperation, inner- and outer-sphere mechanisms) leads us to conclude that the most favorable pathway for this catalyst does not require metal-ligand cooperation.

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

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


    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.

  12. Iminophosphanes : Synthesis, Rhodium Complexes, and Ruthenium(II)-Catalyzed Hydration of Nitriles

    Rong, Mark K.; Van Duin, Koen; Van Dijk, Tom; De Pater, Jeroen J.M.; Deelman, Berth Jan; Nieger, Martin; Ehlers, A. W.; Slootweg, J. Chris; Lammertsma, Koop


    Highly stable iminophosphanes, obtained from alkylating nitriles and reaction of the resulting nitrilium ions with secondary phosphanes, were explored as tunable P-monodentate and 1,3-P,N bidentate ligands in rhodium complexes. X-ray crystal structures are reported for both κ1 and κ2 complexes with

  13. A Proton-Switchable Bifunctional Ruthenium Complex That Catalyzes Nitrile Hydroboration.

    Geri, Jacob B; Szymczak, Nathaniel K


    A new bifunctional pincer ligand framework bearing pendent proton-responsive hydroxyl groups was prepared and metalated with Ru(II) and subsequently isolated in four discrete protonation states. Stoichiometric reactions with H2 and HBPin showed facile E-H (E = H or BPin) activation across a Ru(II)-O bond, providing access to unusual Ru-H species with strong interactions with neighboring proton and boron atoms. These complexes were found to promote the catalytic hydroboration of ketones and nitriles under mild conditions, and the activity was highly dependent on the ligand's protonation state. Mechanistic experiments revealed a crucial role of the pendent hydroxyl groups for catalytic activity.

  14. Efficient transfer hydrogenation reaction Catalyzed by a dearomatized PN 3P ruthenium pincer complex under base-free Conditions

    He, Lipeng


    A dearomatized complex [RuH(PN 3P)(CO)] (PN 3PN, N′-bis(di-tert-butylphosphino)-2,6-diaminopyridine) (3) was prepared by reaction of the aromatic complex [RuH(Cl)(PN 3P)(CO)] (2) with t-BuOK in THF. Further treatment of 3 with formic acid led to the formation of a rearomatized complex (4). These new complexes were fully characterized and the molecular structure of complex 4 was further confirmed by X-ray crystallography. In complex 4, a distorted square-pyramidal geometry around the ruthenium center was observed, with the CO ligand trans to the pyridinic nitrogen atom and the hydride located in the apical position. The dearomatized complex 3 displays efficient catalytic activity for hydrogen transfer of ketones in isopropanol. © 2011 Elsevier B.V. All rights reserved.

  15. Ruthenium-catalyzed C-H/N-O bond functionalization: green isoquinolone syntheses in water.

    Ackermann, Lutz; Fenner, Sabine


    Ruthenium-catalyzed isoquinolone syntheses with ample scope were accomplished through carboxylate assistance in environmentally benign water as a reaction medium. The high chemoselectivity of the ruthenium(II) carboxylate complex also set the stage for the direct use of free hydroxamic acids for annulations of alkynes.

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

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


    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.

  17. Ruthenium-Catalyzed Ammonia Borane Dehydrogenation: Mechanism and Utility.

    Zhang, Xingyue; Kam, Lisa; Trerise, Ryan; Williams, Travis J


    One of the greatest challenges in using H2 as a fuel source is finding a safe, efficient, and inexpensive method for its storage. Ammonia borane (AB) is a solid hydrogen storage material that has garnered attention for its high hydrogen weight density (19.6 wt %) and ease of handling and transport. Hydrogen release from ammonia borane is mediated by either hydrolysis, thus giving borate products that are difficult to rereduce, or direct dehydrogenation. Catalytic AB dehydrogenation has thus been a popular topic in recent years, motivated both by applications in hydrogen storage and main group synthetic chemistry. This Account is a complete description of work from our laboratory in ruthenium-catalyzed ammonia borane dehydrogenation over the last 6 years, beginning with the Shvo catalyst and resulting ultimately in the development of optimized, leading catalysts for efficient hydrogen release. We have studied AB dehydrogenation with Shvo's catalyst extensively and generated a detailed understanding of the role that borazine, a dehydrogenation product, plays in the reaction: it is a poison for both Shvo's catalyst and PEM fuel cells. Through independent syntheses of Shvo derivatives, we found a protective mechanism wherein catalyst deactivation by borazine is prevented by coordination of a ligand that might otherwise be a catalytic poison. These studies showed how a bidentate N-N ligand can transform the Shvo into a more reactive species for AB dehydrogenation that minimizes accumulation of borazine. Simultaneously, we designed novel ruthenium catalysts that contain a Lewis acidic boron to replace the Shvo -OH proton, thus offering more flexibility to optimize hydrogen release and take on more general problems in hydride abstraction. Our scorpionate-ligated ruthenium species (12) is a best-of-class catalyst for homogeneous dehydrogenation of ammonia borane in terms of its extent of hydrogen release (4.6 wt %), air tolerance, and reusability. Moreover, a synthetically

  18. Mechanistic insights into acetophenone transfer hydrogenation catalyzed by half-sandwich ruthenium(II) complexes containing 2-(diphenylphosphanyl)aniline - a combined experimental and theoretical study

    A. Bacchi; M. Balordi; R. Cammi; L. Elviri; C. Pelizzi; F. Picchioni; V. Verdolino; K. Goubitz; R. Peschar; P. Pelagatti


    Several new half-sandwich ruthenium(II) complexes containing 2-(diphenyphosphanyl)aniline (PNH2) of formula {Ru[(kappa P-2,N)PNH2](p-cymene)Cl}Y [Y = Cl (1a), PF6 (1b), BF4 (1c), BPh4 (1d), TfO (1e)] were synthesized and fully characterized both in solution (H-1 NMR and P-31{H-1) NMR spectroscopy) a

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

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


    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.

  20. Mechanochemical ruthenium-catalyzed olefin metathesis.

    Do, Jean-Louis; Mottillo, Cristina; Tan, Davin; Štrukil, Vjekoslav; Friščić, Tomislav


    We describe the development of a mechanochemical approach for Ru-catalyzed olefin metathesis, including cross-metathesis and ring-closing metathesis. The method uses commercially available catalysts to achieve high-yielding, rapid, room-temperature metathesis of solid or liquid olefins on a multigram scale using either no or only a catalytic amount of a liquid.

  1. Ruthenium-Catalyzed Transformations of Alcohols: Mechanistic Investigations and Methodology Development

    Makarov, Ilya; Madsen, Robert; Fristrup, Peter

    The mechanism of the ruthenium-catalyzed dehydrogenative synthesis of amides from alcohols and amines was studied in detail by employing the combination of experimental and theoretical techniques. The Hammett study revealed that a small positive charge is formed at the benzylic position in the tr......The mechanism of the ruthenium-catalyzed dehydrogenative synthesis of amides from alcohols and amines was studied in detail by employing the combination of experimental and theoretical techniques. The Hammett study revealed that a small positive charge is formed at the benzylic position...... obtained from the calculated energies, it was found that only the trans-dihydride pathway was in agreement with the experimentally determined frequencies. The proposed catalytic cycle was used for an in silico search for more effective carbene ligands. The study showed that the ruthenium complexes...... with dimethoxyisopropylidene and pyridilidene ligands could be more active than RuCl2(IiPr)(p-cymene) used in the mechanistic investigation. Two analogs of the calculated complexes were synthesized but were not isolated in a pure form. The amidation reaction catalyzed by a mixture containing the N-ethyl pyridilidene...

  2. Strongly luminescing ruthenium(II)/ruthenium(II) and ruthenium(II)/platinum(II) binuclear complexes

    Sahai, R.; Baucom, D.A.; Rillema, D.P.


    Two strongly luminescing complexes, ruthenium(II)/ruthenium(II) homobinuclear complex and ruthenium(II)/platinum(II) heterobinuclear complex, have been prepared and characterized. The organic part of the complex is 4,4'-dimethyl-2,2' bipyridine dimer. The luminescence behavior of the homobinuclear and heterobinculear complexes was found to be comparable to that of Ru(bpy)/sub 3//sup 2 +/, although the luminescence maxima were shifted from 615 to 620 nm. These complexes exhibit good stability due to the bidentate chelating capability of the bridging ligand. These new complexes can provide the opportunity for detailed photophysical studies related to donor-acceptor interactions and to the possibility of two simultaneous single-electron transfer events. 17 references, 2 figures.

  3. NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis

    Veronica Paradiso


    Full Text Available The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C2-symmetric and C1-symmetric NHCs is provided.

  4. NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis.

    Paradiso, Veronica; Costabile, Chiara; Grisi, Fabia


    The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C₂-symmetric and C₁-symmetric NHCs is provided.

  5. Light-induced ruthenium-catalyzed nitrene transfer reactions: a photochemical approach towards N-acyl sulfimides and sulfoximines.

    Bizet, Vincent; Buglioni, Laura; Bolm, Carsten


    1,4,2-Dioxazol-5-ones are five-membered heterocycles known to decarboxylate under thermal or photochemical conditions, thus yielding N-acyl nitrenes. Described herein is a light-induced ruthenium-catalyzed N-acyl nitrene transfer to sulfides and sulfoxides by decarboxylation of 1,4,2-dioxazol-5-ones at room temperature, thus providing direct access to N-acyl sulfimides and sulfoximines under mild reaction conditions. In addition, a one-pot sulfur imidation/oxidation sequence catalyzed by a single ruthenium complex is reported. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Recent advances in the ruthenium-catalyzed hydroarylation of alkynes with aromatics: synthesis of trisubstituted alkenes.

    Manikandan, Rajendran; Jeganmohan, Masilamani


    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. Ruthenium(III Chloride Catalyzed Acylation of Alcohols, Phenols, and Thiols in Room Temperature Ionic Liquids

    Mingzhong Cai


    Full Text Available Ruthenium(III chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]. The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.

  8. Ruthenium(II)-Catalyzed Regioselective Ortho Amidation of Imidazo Heterocycles with Isocyanates.

    Shakoor, S M Abdul; Kumari, Santosh; Khullar, Sadhika; Mandal, Sanjay K; Kumar, Anil; Sakhuja, Rajeev


    Direct ortho amidation at the phenyl ring of 2-phenylimidazo heterocycles with aryl isocyanates has been achieved via a chelation-assisted cationic ruthenium(II) complex catalyzed mechanism. The methodology provides a straightforward, high-yielding regioselective approach toward the synthesis of an array of ortho-amidated phenylimidazo heterocycles without prior activation of C(sp(2))-H. This also reports the first method for coupling of aryl isocyanates with the imidazo[1,2-a]pyridine system via a pentacyclometalated intermediate. The methodology is found to be easily scalable and could be applied toward the selective ortho amidation of 2-heteroarylimidazo[1,2-a]pyridine frameworks.

  9. Amine-free reversible hydrogen storage in formate salts catalyzed by ruthenium pincer complex without pH control or solvent change.

    Kothandaraman, Jotheeswari; Czaun, Miklos; Goeppert, Alain; Haiges, Ralf; Jones, John-Paul; May, Robert B; Prakash, G K Surya; Olah, George A


    Due to the intermittent nature of most renewable energy sources, such as solar and wind, energy storage is increasingly required. Since electricity is difficult to store, hydrogen obtained by electrochemical water splitting has been proposed as an energy carrier. However, the handling and transportation of hydrogen in large quantities is in itself a challenge. We therefore present here a method for hydrogen storage based on a CO2 (HCO3 (-) )/H2 and formate equilibrium. This amine-free and efficient reversible system (>90 % yield in both directions) is catalyzed by well-defined and commercially available Ru pincer complexes. The formate dehydrogenation was triggered by simple pressure swing without requiring external pH control or the change of either the solvent or the catalyst. Up to six hydrogenation-dehydrogenation cycles were performed and the catalyst performance remained steady with high selectivity (CO free H2 /CO2 mixture was produced).

  10. Transfer Hydrogenation of Acetophenone Catalyzed by in situ Generated 2,6-Bis(5-thioxo-4,5-dihydro-1,2,4-triazole- 3-yl)pyridine-ruthenium(Ⅱ) Complexes

    CETIN,Ahmet; DAYAN,Osman


    2,6-Bis(5-thioxo-4,5-dihydro-1,2,4-triazole-3-yl)pyridines (3, 4) were used for the first time as ligand in ruthe-nium catalyzed transfer hydrogenation of acetophenone. The in situ prepared three-component system Ru(ll)/tridentate triamine ligands (3a-3d, 4a-4d) and KOH catalysed the transfer hydrogenation reaction of ace-tophenone in good yields under mild conditions.

  11. Ruthenium-catalyzed meta sulfonation of 2-phenylpyridines.

    Saidi, Ourida; Marafie, Jameel; Ledger, Araminta E W; Liu, Po Man; Mahon, Mary F; Kociok-Köhn, Gabriele; Whittlesey, Michael K; Frost, Christopher G


    A selective catalytic meta sulfonation of 2-phenylpyridines was found to occur in the presence of (arene)ruthenium(II) complexes upon reaction with sulfonyl chlorides. The 2-pyridyl group facilitates the formation of a stable Ru-C(aryl) σ bond that induces a strong para-directing effect. Electrophilic aromatic substitution proceeds with the sulfonyl chloride to furnish a sulfone at the position meta to the chelating group. This new catalytic process offers access to atypical regioselectivity for reactions involving chelation-assisted cyclometalation.

  12. Ruthenium-complex catalyzed N-(cyclo)alkylation of aromatic amines with diols. Selective synthesis of N-(n-hydroixyalkyl)anilines of type PhNH(CH2)nOH and of some bioactive arylpiperazines,

    Koten, G. van; Abbenhuis, R.A.T.M.; Boersma, J.


    A new class of well-defined neutral mono-, and dicationic ruthenium(II) complexes containing a neutral terdentate donor system [C5H3N(CH2E)(2)-2,6] (E = PPh2 (PNP) or NMe2 (NN'N)) has been found effective as catalyst precursor in N-(cyclo)alkylation reactions of aromatic amines with diols

  13. Simple and Efficient Ruthenium-Catalyzed Oxidation of Primary Alcohols with Molecular Oxygen.

    Ray, Ritwika; Chandra, Shubhadeep; Maiti, Debabrata; Lahiri, Goutam Kumar


    Oxidative transformations utilizing molecular oxygen (O2 ) as the stoichiometric oxidant are of paramount importance in organic synthesis from ecological and economical perspectives. Alcohol oxidation reactions that employ O2 are scarce in homogeneous catalysis and the efficacy of such systems has been constrained by limited substrate scope (most involve secondary alcohol oxidation) or practical factors, such as the need for an excess of base or an additive. Catalytic systems employing O2 as the "primary" oxidant, in the absence of any additive, are rare. A solution to this longstanding issue is offered by the development of an efficient ruthenium-catalyzed oxidation protocol, which enables smooth oxidation of a wide variety of primary, as well as secondary benzylic, allylic, heterocyclic, and aliphatic, alcohols with molecular oxygen as the primary oxidant and without any base or hydrogen- or electron-transfer agents. Most importantly, a high degree of selectivity during alcohol oxidation has been predicted for complex settings. Preliminary mechanistic studies including (18) O labeling established the in situ formation of an oxo-ruthenium intermediate as the active catalytic species in the cycle and involvement of a two-electron hydride transfer in the rate-limiting step.

  14. Ruthenium-catalyzed C-C coupling of fluorinated alcohols with allenes: dehydrogenation at the energetic limit of β-hydride elimination.

    Sam, Brannon; Luong, Tom; Krische, Michael J


    Ruthenium(II) complexes catalyze the CC coupling of 1,1-disubstituted allenes and fluorinated alcohols to form homoallylic alcohols bearing all-carbon quaternary centers with good to complete levels of diastereoselectivity. Whereas fluorinated alcohols are relatively abundant and tractable, the corresponding aldehydes are often not commercially available because of their instability.

  15. Characteristics and reactivity of ruthenium-oxo complexes.

    Ishizuka, Tomoya; Kotani, Hiroaki; Kojima, Takahiko


    In this perspective, we have surveyed the synthetic procedure, characteristics, and reactivity of high-valent ruthenium-oxo complexes. The ruthenium-oxo complexes have served as ideal species to elucidate the characteristics of metal-oxo complexes in terms of not only geometrical and electronic structures but also oxidation reactivity and mechanisms of oxidation reactions. Due to the high stability and excellent reversibility of redox processes, ruthenium-oxo complexes have provided significant mechanistic insights into the oxidation of organic compounds including alcohols, alkenes, and alkanes and also water on the basis of detailed kinetic analysis.

  16. Iridium and ruthenium catalyzed syntheses, hydroborations, and metathesis reactions of alkenyl-decaboranes.

    Chatterjee, Shahana; Carroll, Patrick J; Sneddon, Larry G


    The selective syntheses of new classes of 6,9-dialkenyl- and 6-alkenyl-decaboranes and 6-alkyl-9-alkenyl-decaboranes have been achieved via iridium and ruthenium catalyzed decaborane and 6-alkyl-decaborane alkyne-hydroborations. Reactions employing [Cp*IrCl2]2 and [RuCl2(p-cymene)]2 precatalysts gave β-E-alkenyl-decaboranes, while the corresponding reactions with [RuI2(p-cymene)]2 gave the α-alkenyl-decaborane isomers, with the differences in product selectivity suggesting quite different mechanistic steps for the catalysts. The alkenyl-decaboranes were easily converted to other useful derivatives, including coupled-cage and functionally substituted compounds, via iridium-catalyzed hydroborations and ruthenium-catalyzed homo and cross olefin-metathesis reactions.

  17. Ruthenium(III) catalyzed oxidation of sugar alcohols by dichloroisocyanuric acid—A kinetic study

    Lakshman Kumar, Y.; Venkata Nadh, R.; Radhakrishnamurti, P. S.


    Kinetics of ruthenium(III) catalyzed oxidation of biologically important sugar alcohols (myo-inositol, D-sorbitol, and D-mannitol) by dichloroisocyanuric acid was carried out in aqueous acetic acid—perchloric medium. The reactions were found to be first order in case of oxidant and ruthenium(III). Zero order was observed with the concentrations of sorbitol and mannitol whereas, a positive fractional order was found in the case of inositol concentration. An inverse fractional order was observed with perchloric acid in oxidation of three substrates. Arrhenius parameters were calculated and a plausible mechanism was proposed.

  18. Ruthenium-catalyzed decarbonylative addition reaction of anhydrides with alkynes: a facile synthesis of isocoumarins and α-pyrones.

    Prakash, Rashmi; Shekarrao, Kommuri; Gogoi, Sanjib; Boruah, Romesh C


    A novel ruthenium catalyzed straightforward and efficient synthesis of isocoumarin and α-pyrone derivatives has been accomplished by the decarbonylative addition reaction of anhydrides with alkynes under thermal conditions.

  19. Design and development of polynuclear ruthenium and platinum polypyridyl complexes in search of new anticancer agents

    Schilden, Karlijn van der


    The research described in this Ph.D. Thesis has been devoted to the design and development of polynuclear polypyridyl ruthenium and ruthenium-platinum complexes in search of new anticancer agents. A variety of polynuclear ruthenium and ruthenium-platinum complexes has been synthesized with a long an

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

    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.

  1. Large-scale ruthenium- and enzyme-catalyzed dynamic kinetic resolution of (rac-1-phenylethanol

    Bäckvall Jan-E


    Full Text Available Abstract The scale-up of the ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR of (rac-1-phenylethanol (2 is addressed. The immobilized lipase Candida antarctica lipase B (CALB was employed for the resolution, which shows high enantioselectivity in the transesterification. The ruthenium catalyst used, (η 5-C5Ph5RuCl(CO2 1, was shown to possess very high reactivity in the "in situ" redox racemization of 1-phenylethanol (2 in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In a successful large-scale DKR of 2, with 0.05 mol% of 1, (R-1-phenylethanol acetate (3 was obtained in 159 g (97% yield in excellent enantiomeric excess (99.8% ee.

  2. Ruthenium-Catalyzed Olefin Metathesis after Tetra-n-butylammonium Fluoride-Mediated Desilylation

    Osman, Sami


    One-pot procedures expedite organic synthesis but pose challenges in that many reagents must be compatible with each other. We discovered that the presence of nBu4NF hindered rutheniumcatalyzed olefin metathesis when nBu4NF-mediated desilylation and olefin metathesis were performed in one pot. This problem could be solved by the addition of (TMS)2O to remove fluoride anions in order to facilitate the ruthenium-catalyzed olefin metathesis. PMID:23269856


    Ren-ren Wang; Jia-qin Wang; Ce Luo; Zhe Zhang; Bi-tao Su; Zi-qiang Lei


    Polymer-supported ruthenium complexes (p)-Phen-Ru-①,(p)-Phen-Ru-②,(P)-Phen-Ru-③,(p)-Phen-Ru-④,morphological structures as supports.A variety of alcohols were oxidized efficiently into the corresponding ketones,carboxylic acids or aldehydes with iodosylbenzene (PhIO) catalyzed by aminomethyl polystyrene-supported ruthenium complexes under mild reaction conditions in acetonitrile.The influences of morphological structure of the polymer supporters on the catalytic properties of these metal complexes were investigated in detail.

  4. Enantioselective olefin metathesis with cyclometalated ruthenium complexes.

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


    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.

  5. Enantioselective Olefin Metathesis with Cyclometalated Ruthenium Complexes


    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

  6. Advances in Photocatalysis: A Microreview of Visible Light Mediated Ruthenium and Iridium Catalyzed Organic Transformations.

    Day, Jon I; Teegardin, Kip; Weaver, Jimmie; Chan, John


    Photocatalytic organic transformations utilizing ruthenium and iridium complexes have garnered significant attention due to the access they provide to new synthetic spaces through new reaction mechanisms. A survey of the photophysical data and the diversity of transformations that may be accomplished utilizing commercially available photocatalysts is contained herein.

  7. Efficient Removal of Ruthenium Byproducts from Olefin Metathesis Products by Simple Aqueous Extraction

    Hong, Soon Hyeok; Grubbs, Robert H.


    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

  8. Binuclear ruthenium(II) complexes for amyloid fibrils recognition

    Hanczyc, Piotr, E-mail:


    Highlights: • Interactions of binuclear ruthenium(II) complexes with amyloid fibrils. • Dimer ruthenium(II) compounds are sensitive amyloid fibrils biomarkers. • Recognition of amyloid-chromophore adducts by two-photon excited emission. - Abstract: Metal–organic compounds represent a unique class of biomarkers with promising photophysical properties useful for imaging. Here interactions of insulin fibrils with two binuclear complexes [μ-(11,11′-bidppz)(phen){sub 4}Ru{sub 2}]{sup 4+} (1) and [μ-C4(cpdppz)(phen){sub 4}Ru{sub 2}]{sup 4+} (2) are studied by linear dichroism (LD) and fluorescence. These ruthenium(II) compounds could provide a new generation of amyloid binding chromophores with long lived lifetimes, good luminescence quantum yields for the bound molecules and photo-stability useful in multiphoton luminescence imaging.

  9. Kinetics of ruthenium(III) catalyzed and uncatalyzed oxidation of monoethanolamine by N-bromosuccinimide

    Venkata Nadh, R.; Syama Sundar, B.; Radhakrishnamurti, P. S.


    Kinetics of uncatalyzed and ruthenium(III) catalyzed oxidation of monoethanolamine by N-bromosuccinimide (NBS) has been studied in an aqueous acetic acid medium in the presence of sodium acetate and perchloric acid, respectively. In the uncatalyzed oxidation the kinetic orders are: the first order in NBS, a fractional order in the substrate. The rate of the reaction increased with an increase in the sodium acetate concentration and decreased with an increase in the perchloric acid concentration. This indicates that free amine molecules are the reactive species. Addition of halide ions results in a decrease in the kinetic rate, which is noteworthy. Both in absence and presence of a catalyst, a decrease in the dielectric constant of the medium decreases the kinetic rate pointing out that these are dipole—dipole reactions. A relatively higher oxidation state of ruthenium i.e., Ru(V) was found to be the active species in Ru(III) catalyzed reactions. A suitable mechanism consistent with the observations has been proposed and a rate law has been derived to explain the kinetic orders.

  10. Topoisomerase II poisoning by indazole and imidazole complexes of ruthenium

    Y N Vashisht Gopal; Anand K Kondapi


    Trans-imidazolium (bis imidazole) tetrachloro ruthenate (RuIm) and trans-indazolium (bis indazole) tetrachloro ruthenate (RuInd) are ruthenium coordination complexes, which were first synthesized and exploited for their anticancer activity. These molecules constitute two of the few most effective anticancer ruthenium compounds. The clinical use of these compounds however was hindered due to toxic side effects on the human body. Our present study on topoisomerase II poisoning by these compounds shows that they effectively poison the activity of topoisomerase II by forming a ternary cleavage complex of DNA, drug and topoisomerase II. The thymidine incorporation assays show that the inhibition of cancer cell proliferation correlates with topoisomerase II poisoning. The present study on topoisomerase II poisoning by these two compounds opens a new avenue for renewing further research on these compounds. This is because they could be effective lead candidates for the development of more potent and less toxic ruthenium containing topoisomerase II poisons. Specificity of action on this molecular target may reduce the toxic effects of these ruthenium-containing molecules and thus improve their therapeutic index.

  11. Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise

    Rapp, Teresa L.; Phillips, Susan R.; Dmochowski, Ivan J.


    The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, lightdriven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes…

  12. Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise

    Rapp, Teresa L.; Phillips, Susan R.; Dmochowski, Ivan J.


    The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, lightdriven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes…

  13. Straightforward synthesis of alpha,beta-unsaturated thioesters via ruthenium-catalyzed olefin cross-metathesis with thioacrylate

    van Zijl, Anthoni W.; Minnaard, Adriaan J.; Feringa, Ben L.


    The cross-metathesis reaction of S-ethyl thioacrylate with a variety of olefins is effectively catalyzed by using a ruthenium benzylidene olefin metathesis catalyst. This reaction provides a convenient and versatile route to substituted alpha,beta-unsaturated thioesters, key building blocks in organ

  14. Mechanistic investigation of the ruthenium-N-heterocyclic-carbene-catalyzed amidation of amines with alcohols.

    Makarov, Ilya S; Fristrup, Peter; Madsen, Robert


    The mechanism of the ruthenium-N-heterocyclic-carbene-catalyzed formation of amides from alcohols and amines was investigated by experimental techniques (Hammett studies, kinetic isotope effects) and by a computational study with dispersion-corrected density functional theory (DFT/M06). The Hammett study indicated that a small positive charge builds-up at the benzylic position in the transition state of the turnover-limiting step. The kinetic isotope effect was determined to be 2.29(±0.15), which suggests that the breakage of the C-H bond is not the rate-limiting step, but that it is one of several slow steps in the catalytic cycle. Rapid scrambling of hydrogen and deuterium at the α position of the alcohol was observed with deuterium-labeled substrates, which implies that the catalytically active species is a ruthenium dihydride. The experimental results were supported by the characterization of a plausible catalytic cycle by using DFT/M06. Both cis-dihydride and trans-dihydride intermediates were considered, but when the theoretical turnover frequencies (TOFs) were derived directly from the calculated DFT/M06 energies, we found that only the trans-dihydride pathway was in agreement with the experimentally determined TOFs. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Ruthenium-catalyzed olefin metathesis accelerated by the steric effect of the backbone substituent in cyclic (alkyl)(amino) carbenes.

    Zhang, Jun; Song, Shangfei; Wang, Xiao; Jiao, Jiajun; Shi, Min


    Three ruthenium complexes bearing backbone-monosubstituted CAACs were prepared and displayed dramatic improvement in catalytic efficiency not only in RCM reaction but also in the ethenolysis of methyl oleate, compared to those bearing backbone-disubstituted CAACs.

  16. Electronic effects of ruthenium-catalyzed [3+2]-cycloaddition of alkynes and azides

    Hou, Duenren


    A combined experimental and theoretical study of ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) reactions is presented and various electronic analyses were conducted to provide a basis in understanding the observed regioselectivity of the 1,2,3-triazole products. Computational studies using density functional theory (DFT) and atoms in molecules quantum theory (AIM) further yield fresh details on the electronic factors that determine the regioselectivity in the RuAAC. It is found that the formation of 1,2,3-triazole products is irreversible and from the Hammett study, the pathway involving a vinyl cationic intermediate is ruled out. The electronic effect favors the formation of 5-electron-donating-group substituted-1,2,3-trizoles. © 2010 Elsevier Ltd. All rights reserved.

  17. Metalloporphyrin-mediated asymmetric nitrogen-atom transfer to hydrocarbons: aziridination of alkenes and amidation of saturated C-H bonds catalyzed by chiral ruthenium and manganese porphyrins.

    Liang, Jiang-Lin; Huang, Jie-Sheng; Yu, Xiao-Qi; Zhu, Nianyong; Che, Chi-Ming


    Chiral metalloporphyrins [Mn(Por*)(OH)(MeOH)] (1) and [Ru(Por*)(CO)(EtOH)] (2) catalyze asymmetric aziridination of aromatic alkenes and asymmetric amidation of benzylic hydrocarbons to give moderate enantiomeric excesses. The mass balance in these nitrogen-atom-transfer processes has been examined. With PhI=NTs as the nitrogen source, the aziridination of styrenes, trans-stilbene, 2-vinylnaphthalene, indene, and 2,2-dimethylchromene catalyzed by complex 1 or 2 resulted in up to 99 % substrate conversions and up to 94 % aziridine selectivities, whereas the amidation of ethylbenzenes, indan, tetralin, 1-, and 2-ethylnaphthalene catalyzed by complex 2 led to substrate conversions of up to 32 % and amide selectivities of up to 91 %. Complex 1 or 2 can also catalyze the asymmetric amidation of 4-methoxyethylbenzene, tetralin, and 2-ethylnaphthalene with "PhI(OAc)(2) + NH(2)SO(2)Me", affording the N-substituted methanesulfonamides in up to 56 % ee with substrate conversions of up to 34 % and amide selectivities of up to 92 %. Extension of the "complex 1 + PhI=NTs" or "complex 1 + PhI(OAc)(2) + NH(2)R (R=Ts, Ns)" amidation protocol to a steroid resulted in diastereoselective amidation of cholesteryl acetate at the allylic C-H bonds at C-7 with substrate conversions of up to 49 % and amide selectivities of up to 90 % (alpha:beta ratio: up to 4.2:1). An aziridination- and amidation-active chiral bis(tosylimido)ruthenium(VI) porphyrin, [Ru(Por*)(NTs)(2)] (3), and a ruthenium porphyrin aziridine adduct, [Ru(Por*)(CO)(TsAz)] (4, TsAz=N-tosyl-2- (4-chlorophenyl)aziridine), have been isolated from the reaction of 2 with PhI=NTs and N-tosyl-2-(4-chlorophenyl)aziridine, respectively. The imidoruthenium porphyrin 3 could be an active species in the aziridination or amidation catalyzed by complex 2 described above. The second-order rate constants for the reactions of 3 with styrenes, 2-vinylnaphthalene, indene, ethylbenzenes, and 2-ethylnaphthalene range from 3.7-42.5x10(-3) dm(3

  18. Complexes of ruthenium and osmium with a 4-amino-2-mercapto-5-nitroso-6-pyrimidinol

    Kushiwaha, V.; Jain, P.; Katyal, M.; Singh, R.P.


    Ruthenium (III) and osmium (VIII) form coloured complexes with 4-amino-2-mercapto-5-nitroso-6-pyrimidinol (ammonium salt). The complexes have been spectrophotometrically studied, and methods for the determination of the metals based on the complexes are reported. The reaction with ruthenium is particularly sensitive (0.006 of ruthenium/cm/sup 3/ for 0.001 absorbance). Many ions do not interfere in the determination.

  19. Tandem amine and ruthenium-catalyzed hydrogenation of CO2 to methanol.

    Rezayee, Nomaan M; Huff, Chelsea A; Sanford, Melanie S


    This Communication describes the hydrogenation of carbon dioxide to methanol via tandem catalysis with dimethylamine and a homogeneous ruthenium complex. Unlike previous examples with homogeneous catalysts, this CO2-to-CH3OH process proceeds under basic reaction conditions. The dimethylamine is proposed to play a dual role in this system. It reacts directly with CO2 to produce dimethylammonium dimethylcarbamate, and it also intercepts the intermediate formic acid to generate dimethylformamide. With the appropriate selection of catalyst and reaction conditions, >95% conversion of CO2 was achieved to form a mixture of CH3OH and dimethylformamide.

  20. Synthesis of cyclopentadienyl ruthenium complexes bearing pendant chelating picolinates through an electrophilic precursor

    Streu, Craig; Carroll, Patrick J.; Kohli, Rakesh K.; Meggers, Eric


    This note reports the facile synthesis of two ruthenium cyclopentadienyl half-sandwich complexes functionalized with coordinating α-picolinates. The synthetic approach involves the (η5-chloromethylcyclopentadienyl)(η6-benzene)ruthenium(II) cation as a useful common building block for cyclopentadienyl complexes bearing anchored ligands.

  1. Structure of ruthenium(II) complexes with coproporphyrin I tetraethyl ester

    Zverev, S. A.; Andreev, S. V.; Zamilatskov, I. A.; Kurochkina, N. M.; Tyurin, V. S.; Senchikhin, I. N.; Ponomarev, G. V.; Erzina, D. R.; Chernyshev, V. V.


    The reaction between coproporphyrin I tetraethyl ester and ruthenium(II) dodecacarbonyl in toluene is investigated. The formation of two different products, complexes 2 and 3 of ruthenium(II) with coproporphyrin I tetraethyl ester, studied by means of mass spectrometry, electronic absorption spectroscopy, NMR, X-ray diffraction, and thermogravimetric analysis, is revealed. Structures are proposed for the products, of which ( 2) is a monocarbonyl complex of ruthenium(II) porphyrin that exists as a coordination polymer formed owing to intermolecular axial bonding between the oxygen atoms of carboethoxyl groups and ruthenium(II). The structure proposed for second product ( 3) is in the form of the corresponding monomer of a monocarbonyl complex of ruthenium(II) porphyrin. It is established that polymeric complex 2 transforms into monomeric complex 3 when it is heating in pyridine.

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

    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


    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.

  3. Mechanistic study on the ruthenium-catalyzed direct amination of alcohols

    Pingen, Dennis; Lutz, Martin; Vogt, Dieter


    The Ru-catalyzed direct amination of alcohols with ammonia was investigated for the RuHCl(CO)(PPh3)3/Xantphos system in order to gain mechanistic insight. For several Ru(II) precursor complexes the influence of different additives on catalytic performance was investigated. NMR studies revealed that

  4. New nitric oxide donors based on ruthenium complexes

    C.N. Lunardi


    Full Text Available Nitric oxide (NO donors produce NO-related activity when applied to biological systems. Among its diverse functions, NO has been implicated in vascular smooth muscle relaxation. Despite the great importance of NO in biological systems, its pharmacological and physiological studies have been limited due to its high reactivity and short half-life. In this review we will focus on our recent investigations of nitrosyl ruthenium complexes as NO-delivery agents and their effects on vascular smooth muscle cell relaxation. The high affinity of ruthenium for NO is a marked feature of its chemistry. The main signaling pathway responsible for the vascular relaxation induced by NO involves the activation of soluble guanylyl-cyclase, with subsequent accumulation of cGMP and activation of cGMP-dependent protein kinase. This in turn can activate several proteins such as K+ channels as well as induce vasodilatation by a decrease in cytosolic Ca2+. Oxidative stress and associated oxidative damage are mediators of vascular damage in several cardiovascular diseases, including hypertension. The increased production of the superoxide anion (O2- by the vascular wall has been observed in different animal models of hypertension. Vascular relaxation to the endogenous NO-related response or to NO released from NO deliverers is impaired in vessels from renal hypertensive (2K-1C rats. A growing amount of evidence supports the possibility that increased NO inactivation by excess O2- may account for the decreased NO bioavailability and vascular dysfunction in hypertension.

  5. Catalytic Activation of Small Molecules. Development and Characterisation of Ruthenium Complexes for Application in Catalysis

    Choi, Jong-Hoo


    In this work, the synthesis, characterisation and catalytic application of ruthenium pincer complexes is presented. In this context, new synthetic strategies are discussed to obtain novel ruthenium pincer dihydrogen complexes. Furthermore, the reactivity of the complexes towards small molecules (e.g. alcohols, boranes, ammonia, amines, nitriles and hydrogen) was observed, delivering fundamental insights into catalytic applications. With the reactivity testing, new borylated B-H-σ-complexes we...

  6. Ruthenium(II)-Catalyzed C-C Arylations and Alkylations: Decarbamoylative C-C Functionalizations.

    Moselage, Marc; Li, Jie; Kramm, Frederik; Ackermann, Lutz


    Ruthenium(II)biscarboxylate catalysis enabled selective C-C functionalizations by means of decarbamoylative C-C arylations. The versatility of the ruthenium(II) catalysis was reflected by widely applicable C-C arylations and C-C alkylations of aryl amides, as well as acids with modifiable pyrazoles, through facile organometallic C-C activation.

  7. Syntheses and NMR characterization of novel ruthenium(II) complexes containing dioxaphospholane

    Matos, Robson Mendes; Costa, Ricardo F.F. da; Passos, Bernadette de F. Trigo [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Quimica. E-mail:


    Synthesis of some ruthenium (III) complexes containing 2-chloro-1,3,2-dioxaphospholane and 2-chloro-4,5-benzo-1,3,2-dioxaphospholane for the first time. The reaction of dichlorotris (triphenylphosphine) ruthenium (II) with these ligands always leads to formation of a product containing two molecules of dioxaphospholane, independently of the stoichiometric proportion employed. On the other hand, complexes derived from chloro (cyclopentadienyl) bis (triphenylphosphane) ruthenium (II) have only one ligand in their structure. The complexes were characterized by {sup 31} P {l_brace}{sup 1}H{r_brace} and {sup -1} H-NMR spectroscopy. (author)

  8. Near infrared electrochromic variable optical attenuator based on ruthenium complex and polycrystalline tungsten oxide

    ZHANG Jidong; WU Xianguo; YU Hongan; YAN Donghang; WANG Zhiyuan


    A near infrared (NIR) electrochromic attenuator based on a dinuclear ruthenium complex and polycrystalline tungsten oxide was fabricated and characterized. The results show that the use of the NIR-absorbing ruthenium complex as a counter electrode material can improve the device performance. By replacing the visible electrochromic ferrocene with the NIR-absorbing ruthenium complex, the optical attenuation at 1550 nm was enhanced from 19.1 to 30.0 dB and color efficiency also increased from 29.2 to 121.2 cm2/C.

  9. Modulating the Anticancer Activity of Ruthenium(II)-Arene Complexes.

    Clavel, Catherine M; Păunescu, Emilia; Nowak-Sliwinska, Patrycja; Griffioen, Arjan W; Scopelliti, Rosario; Dyson, Paul J


    Following the identification of [Ru(η(6)-p-cymene)Cl2(1H,1H,2H,2H-perfluorodecyl-3-(pyridin-3-yl)propanoate)], a ruthenium(II)-arene complex with a perfluoroalkyl-modified ligand that displays remarkable in vitro cancer cell selectivity, a series of structurally related compounds were designed. In the new derivatives, the p-cymene ring and/or the chloride ligands are substituted by other ligands to modulate the steric bulk or aquation kinetics. The new compounds were evaluated in both in vitro (cytotoxicity and migration assays) and in vivo (chicken chorioallantoic membrane) models and were found to exhibit potent antivascular effects.

  10. Synthesis, characterization, and anticancer activity of ruthenium-pyrazole complexes.

    David, Solene; Perkins, Richard S; Fronczek, Frank R; Kasiri, Sahba; Mandal, Subhrangsu S; Srivastava, Radhey S


    A series of new water soluble Ru(III) pyrazole complexes mer-[RuCl(3)(DMSO-S)(pyz)(2)] 1, mer-[RuCl(3)(DMSO-S)(DMSO-O)(pyz)] 2, mer-[RuCl(3)(bpy)(dmpyz)] 3, and mer-[RuCl(3)(DMSO-S)(dmpyz)(2)] 4 (pyz=pyrazole; dmpyz=3,5-dimethylpyrazole, bpy=2,2'-bipyridine) have been synthesized and characterized by use of a combination of spectroscopy (IR and UV-visible), X-ray diffraction, and cyclic voltammetry. The molecular X-ray structure of all reported compounds (1-4) revealed distorted octahedral coordination around ruthenium. The cytotoxicity assay on human breast cancer cells (MCF7) demonstrated that compounds 1 and 4 affect cell viability, whereas compounds 2 and 3 do not show appreciable activity. The IC(50) values for 1 and 4 lie within the range of 71-32μM in MCF7 cells.

  11. Electron Transfer Studies of Ruthenium(II) Complexes with Biologically Important Phenolic Acids and Tyrosine.

    Rajeswari, Angusamy; Ramdass, Arumugam; Muthu Mareeswaran, Paulpandian; Rajagopal, Seenivasan


    The ruthenium(II) complexes having 2,2'-bipyridine and phenanthroline derivatives are synthesized and characterized. The photophysical properties of these complexes at pH 12.5 are studied. The electron transfer reaction of biologically important phenolic acids and tyrosine are studied using absorption, emission and transient absorption spectral techniques. Semiclassical theory is applied to calculate the rate of electron transfer between ruthenium(II) complexes and biologically important phenolic acids.

  12. Ruthenium complexes containing bis-benzimidazole derivatives as a new class of apoptosis inducers.

    Li, Linlin; Wong, Yum-Shing; Chen, Tianfeng; Fan, Cundong; Zheng, Wenjie


    A series of ruthenium complexes containing bis-benzimidazole derivatives have been synthesized and identified as able to target mitochondria and induce caspase-dependent apoptosis in cancer cells through superoxide overproduction.

  13. N-heterocyclic carbene-ruthenium complexes for the racemization of chiral alcohols.

    Bosson, Johann; Nolan, Steven P


    The activity of well-defined 16-electron ruthenium complexes bearing an N-heterocyclic carbene ligand in the racemization of chiral alcohols is reported. Mechanistic considerations are also presented.

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

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


    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

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


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

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


    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.

  17. Coordinatively unsaturated ruthenium complexes as efficient alkyneazide cycloaddition catalysts

    Lamberti, Marina


    The performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azidealkyne cycloaddition reactions that afford the 1,2,3- triazole products. The scope of the Cp*Ru(PiPr 3)Cl precatalyst was investigated for terminal alkynes leading to new 1,5-disubstituted 1,2,3-triazoles in high yields. Mechanistic studies were conducted and revealed a number of proposed intermediates. Cp*Ru- (PiPr3)(2-HCCPh)Cl was observed and characterized by 1H, 13C, and 31P NMR at temperatures between 273 and 213 K. A rare example of N,N-κ2-phosphazide complex, Cp*Ru(κ2- iPr3PN3Bn)Cl, was fully characterized, and a single-crystal X-ray diffraction structure was obtained. DFT calculations describe a complete map of the catalytic reactivity with phenylacetylene and/or benzylazide. © 2012 American Chemical Society.

  18. Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls

    Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D.; Krische, Michael J.


    The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo- and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k and 6m, respectively. Primary alcohols 2a, 2l and 2p were converted to the siloxy-crotylation products 3a, 3l and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes. PMID:26418572

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

    Manikandan, R; Viswanathamurthi, P; Muthukumar, M


    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, (1)H, (13)C and (31)P 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.

  20. Synthesis of Oxacyclic Scaffolds via Dual Ruthenium Hydride/Brønsted Acid‐Catalyzed Isomerization/Cyclization of Allylic Ethers

    Ascic, Erhad; Ohm, Ragnhild Gaard; Petersen, Rico;


    A ruthenium hydride/Brønsted acid‐catalyzed tandem sequence is reported for the synthesis of 1,3,4,9‐tetrahydropyrano[3,4‐b]indoles (THPIs) and related oxacyclic scaffolds. The process was designed on the premise that readily available allylic ethers would undergo sequential isomerization, first ...

  1. Kinetics and Mechanism of Ruthenium(III) Catalyzed Oxidation of Butanone and Uncatalyzed Oxidation of Cychlohexanone by Cerium(IV) in Acid Sulphate Medium

    Sharma, Priyamvada; Hemkar, Shalini; Khandelwal, C. L.; Sharma, P. D. [Univ. of Rajasthan, Jaipur (India)


    The kinetics of ruthenium(III) chloride catalyzed oxidation of butanone and uncatalyzed oxidation of cyclohexanone by cerium(IV) in sulphuric acid medium have been studied. The kinetic rate law(I) in case of butanone conforms to the proposed mechanism. Kinetics and activation parameters have been evaluated conventionally. Kinetically preferred mode of reaction is via ketonic and not the enolic forms.

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

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


    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.

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

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


    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.




    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-}.

  5. Alkene Chemoselectivity in Ruthenium-Catalyzed Z-Selective Olefin Metathesis

    Cannon, Jeffrey S.


    Chelated ruthenium catalysts have achieved highly chemoselective olefin metathesis reactions. Terminal and internal Z olefins were selectively reacted in the presence of internal E olefins. Products were produced in good yield and high stereoselectivity for formation of a new Z olefin. No products of metathesis with the internal E olefin were observed. Chemoselectivity for terminal olefins was also observed over both sterically hindered and electronically deactivated alkenes. PMID:23832646

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

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


    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

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

    Coe, Benjamin J.


    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…

  8. Ligand-controlled reactivity, selectivity, and mechanism of cationic ruthenium-catalyzed hydrosilylations of alkynes, ketones, and nitriles: a theoretical study.

    Yang, Yun-Fang; Chung, Lung Wa; Zhang, Xinhao; Houk, K N; Wu, Yun-Dong


    Density functional theory calculations with the M06 functional have been performed on the reactivity, selectivity, and mechanism of hydrosilylations of alkynes, ketones, and nitriles catalyzed by cationic ruthenium complexes [CpRu(L)(MeCN)2](+), with L = P(i)Pr3 or MeCN. The hydrosilylation of alkynes with L = P(i)Pr3 involves an initial silyl migration mechanism to generate the anti-Markovnikov product, in contrast to the Markovnikov product obtained with L = MeCN. The bulky phosphine ligand directs the silyl group to migrate to Cβ of the alkyne. This explains the anti-Markovnikov selectivity of the catalyst with L = P(i)Pr3. By contrast, the silane additions to either ketone or nitrile proceed through an ionic SN2-Si outer-sphere mechanism, in which the substrate attacks the Si center. The P(i)Pr3 ligand facilitates the activation of the Si-H bond to furnish a η(2)-silane complex, whereas a η(1)-silane complex is formed for the MeCN ligand. This property of the phosphine ligand enables the catalytic hydrosilylation of ketones and nitriles in addition to that of alkynes.

  9. Iridium- and Ruthenium-Catalyzed N-alkylation of Amines with Alcohols and Amines

    Lorentz-Petersen, Linda Luise Reeh

    via folding assisted ligation. One segment was synthesised as the C-terminal thioester by Boc-SPPS and the other segment as a C-terminal acid by Fmoc-SPPS. The sites of mutation were all in the α-helical region of the protein and the mutation choices were alanine and Aib, which both posses a high α...... is environmentally benign as it is performed in the absence of both solvent and additives and the only by-product is ammonia. Additionally, the work-up procedure is a simple distillation of the product directly from the reaction mixture. Synthesis of piperazines In the Madsen group it has previously been...... catalysts have been employed for the N-alkylation of amines with either alcohols or amines. Synthesis of secondary amines Self-condensation of primary amines afforded secondary amines in good to high yields. The reaction is catalyzed by the commercially available [Cp*IrCl2]2 complex. The procedure...

  10. Complexation of DNA with ruthenium organometallic compounds: the high complexation ratio limit.

    Despax, Stéphane; Jia, Fuchao; Pfeffer, Michel; Hébraud, Pascal


    Interactions between DNA and ruthenium organometallic compounds are studied by using visible light absorption and circular dichroism measurements. A titration technique allowing for the absolute determination of the advancement degree of the complexation, without any assumption about the number of complexation modes is developed. When DNA is in excess, complexation involves intercalation of one of the organometallic compound ligands between DNA base pairs. But, in the high complexation ratio limit, where organometallic compounds are in excess relative to the DNA base pairs, a new mode of interaction is observed, in which the organometallic compound interacts weakly with DNA. The weak interaction mode, moreover, develops when all the DNA intercalation sites are occupied. A regime is reached in which one DNA base pair is linked to more than one organometallic compound.

  11. Ruthenium-Catalyzed Selective Hydrogenation of bis-Arylidene Tetramic Acids. Application to the Synthesis of Novel Structurally Diverse Pyrrolidine-2,4-diones

    Olga Igglessi-Markopoulou


    Full Text Available Catalytic hydrogenation of 3,5-bis-arylidenetetramic acids, known for their biological activity, has been developed. The chemoselective ruthenium-catalyzed reduction of the exocyclic carbon-carbon double bonds on pyrrolidine-2,4-dione ring system, containing other reducible functions, has been investigated. Depending on the substrate the yield of the hydrogenation process can reach up to 95%. The structural elucidation has been established using NMR and HRMS spectral data.

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

    Novak, Maria S.


    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.

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

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


    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.

  14. Ruthenium(II) cluster complexes: a series of homooligonuclear complexes based on bidentate bridging ligands

    Sahai, R.; Morgan, L.; Rillema, D.P.


    The preparation and properties of trimetallic and tetrametallic cluster complexes containing ruthenium(II) metal centers bridged by 2,2'-bipyrimidine (bpm) and 2,3-bis(2-pyridyl)quinoxaline (bpq) are reported. The tetrametallic clusters are symmetrical complexes containing a central ruthenium(II) coordinated to three (BL)Ru(bpy)/sub 2//sup 2 +/ ligands, where BL is bpm or bpq and bpy is 2,2'-bipyridine. The trimetallic clusters are asymmetric and are of the general formula ((bpy)Ru(BLRu(bpy)/sub 2/)/sub 2/)/sup 6 +/. The complexes exhibit low-energy MLCT transitions assigned as d..pi..(Ru(outer)) ..-->.. ..pi..*(BL). The MLCT maxima of the tetrametallic complexes were at slightly higher energies than those for their trimetallic analogues. For example, lambda/sub max/ for (Ru(bpqRu(bpy)/sub 2/)/sub 3/)/sup 8 +/ was located at 618 nm; that of ((bpy)Ru(bpqRu(bpy)/sub 2/)/sub 2/)/sup 3 +/ was located at 621 nm. The E/sub 1/2/ values were determined by cyclic voltammetry. The first oxidation in the case of ((bpy)Ru(bpqRu(bpy)/sub 2/)/sub 2/)/sup 6 +/ was located at E/sub 1/2/(1) = 1.57 V, and the second, at E/sub 1/2/(2) = 1.83 V vs. SSCE. The wave associated with E/sub 1/2/(1) had about twice the peak current as the wave at E/sub 1/2/(2) and, hence, was assigned to the Ru(III/II) redox couple of the outer ruthenium(II) components. The low-energy MLCT transitions for the mononuclear precursors (Ru(bpy)/sub x/(BL)/sub 3-x/, x = 1-3) and the multimetallic complexes were found to parallel 1/2/, the difference between E/sub 1/2/ values for the first oxidation and the first reduction. The excellent correlation (slope 1, correlation coefficient 0.99) indicates that either the energy of the lowest MLCT transition or 1/2/ can be used to measure the energy gap between the d..pi.. and ..pi..* energy levels. 32 references, 5 figures, 2 tables.

  15. New dyads using (metallo)porphyrins as ancillary ligands in polypyridine ruthenium complexes. Synthesis and electronic properties.

    Lachaud, Fabien; Jeandon, Christophe; Monari, Antonio; Assfeld, Xavier; Beley, Marc; Ruppert, Romain; Gros, Philippe C


    Porphyrins bearing enaminoketones at their periphery have been used as ancillary ligands in ruthenium complexes. Free base, nickel and zinc porphyrins were successfully coordinated to Ru(bpy)(2)Cl(2) under microwave irradiation. The positive contribution of the ruthenium complex was demonstrated by the complexes' wide absorption domains that covered the 500-600 nm region where the parent porphyrins did not absorb. Electrochemical as well as computational data revealed an efficient electronic communication between the porphyrins and the ruthenium cation in the dyads.

  16. ESR ST study of hydroxyl radical generation in wet peroxide system catalyzed by heterogeneous ruthenium

    Rokhina, E.V.; Golovina, E.A.; As, van H.; Virkutyte, J.


    Ru-based catalysts gained popularity because of their applicability for a variety of processes, including carbon monoxide oxidation, wet air catalytic oxidation and wastewater treatment. The focus of a current study was generation of hydroxyl radicals in the wet peroxide system catalyzed by heteroge

  17. Transferrin serves as a mediator to deliver organometallic ruthenium(II) anticancer complexes into cells.

    Guo, Wei; Zheng, Wei; Luo, Qun; Li, Xianchan; Zhao, Yao; Xiong, Shaoxiang; Wang, Fuyi


    We report herein a systematic study on interactions of organometallic ruthenium(II) anticancer complex [(η(6)-arene)Ru(en)Cl](+) (arene = p-cymene (1) or biphenyl (2), en = ethylenediamine) with human transferrin (hTf) and the effects of the hTf-ligation on the bioavailability of these complexes with cisplatin as a reference. Incubated with a 5-fold excess of complex 1, 2, or cisplatin, 1 mol of diferric hTf (holo-hTf) attached 0.62 mol of 1, 1.01 mol of 2, or 2.14 mol of cisplatin. Mass spectrometry revealed that both ruthenium complexes coordinated to N-donors His242, His273, His578, and His606, whereas cisplatin bound to O donors Tyr136 and Tyr317 and S-donor Met256 in addition to His273 and His578 on the surface of both apo- and holo-hTf. Moreover, cisplatin could bind to Thr457 within the C-lobe iron binding cleft of apo-hTf. Neither ruthenium nor platinum binding interfered with the recognition of holo-hTf by the transferrin receptor (TfR). The ruthenated/platinated holo-hTf complexes could be internalized via TfR-mediated endocytosis at a similar rate to that of holo-hTf itself. Moreover, the binding to holo-hTf well preserved the bioavailability of the ruthenium complexes, and the hTf-bound 1 and 2 showed a similar cytotoxicity toward the human breast cancer cell line MCF-7 to those of the complexes themselves. However, the conjugation with holo-hTf significantly reduced the cellular uptake of cisplatin and the amount of platinated DNA adducts formed intracellularly, leading to dramatic reduction of cisplatin cytotoxicity toward MCF-7. These findings suggest that hTf can serve as a mediator for the targeting delivery of Ru(arene) anticancer complexes while deactivating cisplatin.

  18. Ruthenium(II) pincer complexes with oxazoline arms for efficient transfer hydrogenation reactions

    Chen, Tao


    Well-defined P NN CN pincer ruthenium complexes bearing both strong phosphine and weak oxazoline donors were developed. These easily accessible complexes exhibit significantly better catalytic activity in transfer hydrogenation of ketones compared to their PN 3P analogs. These reactions proceed under mild and base-free conditions via protonation- deprotonation of the \\'NH\\' group in the aromatization-dearomatization process. © 2012 Elsevier Ltd. All rights reserved.

  19. The intriguing modeling of cis–trans selectivity in ruthenium-catalyzed olefin metathesis

    Luigi Cavallo


    Full Text Available In this study we have investigated computationally the origin of the cis–trans selectivity in the Ru-catalyzed cross metathesis (CM of a prototype monosubstituted olefin, i.e., propene. Our calculations suggest that the origin of the preferential formation of trans-olefins is in the product release step, which prevents the initially formed cis-olefin from escaping the metal, and returns it to the reaction pool until the trans-olefin is formed.

  20. The intriguing modeling of cis–trans selectivity in ruthenium-catalyzed olefin metathesis

    Bahri-Laleh, Naeimeh; Credendino, Raffaele


    Summary In this study we have investigated computationally the origin of the cis–trans selectivity in the Ru-catalyzed cross metathesis (CM) of a prototype monosubstituted olefin, i.e., propene. Our calculations suggest that the origin of the preferential formation of trans-olefins is in the product release step, which prevents the initially formed cis-olefin from escaping the metal, and returns it to the reaction pool until the trans-olefin is formed. PMID:21286393

  1. Enantiopure C1-symmetric N-Heterocyclic Carbene Ligands from Desymmetrized meso-1,2-Diphenylethylenediamine: Application in Ruthenium-Catalyzed Olefin Metathesis

    Veronica Paradiso


    Full Text Available In order to design improved chiral ruthenium catalysts for asymmetric olefin metathesis, enantiomeric catalysts incorporating C1-symmetric N-Heterocyclic carbenes (NHC ligands with syn-related substituents on the backbone were synthesized starting from meso-1,2-diphenylethylenediamine. The absolute configuration of the enantiomers of the desymmetrized meso diamine was assigned by optical rotation analysis and in silico calculations, and was found to be maintained in their respective ruthenium catalysts by comparison of the relative electronic circular dichroism (ECD spectra. The catalytic behaviour of the enantiomeric ruthenium complexes was investigated in model asymmetric metathesis transformations and compared to that of analogous complexes bearing C1-symmetric NHC ligands with an anti backbone. Modest enantioselectivities were registered and different catalyst properties depending on the nature of stereochemical relationship of substituents on the backbone were observed.

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

    Vadivel, T; Dhamodaran, M


    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.

  3. Photoinduced electron transfer reactions of ruthenium(II)-complexes containing amino acid with quinones.

    Eswaran, Rajkumar; Kalayar, Swarnalatha; Paulpandian, Muthu Mareeswaran; Seenivasan, Rajagopal


    With the aim of mimicking, at basic level the photoinduced electron transfer process in the reaction center of photosystem II, ruthenium(II)-polypyridyl complexes, carrying amino acids were synthesized and studied their photoinduced electron transfer reactions with quinones by steady state and time resolved measurements. The reaction of quinones with excited state of ruthenium(II)-complexes, I-V in acetonitrile has been studied by luminescence quenching technique and the rate constant, k(q), values are close to the diffusion controlled rate. The detection of the semiquinone anion radical in this system using time-resolved transient absorption spectroscopy confirms the electron transfer nature of the reaction. The semiclassical theory of electron transfer has been successfully applied to the photoluminescence quenching of Ru(II)-complexes with quinones.

  4. Transition Metal Catalyzed Reactions for Forming Carbon–Oxygen and Carbon–Carbon Bonds

    Sølvhøj, Amanda Birgitte

    Dehydrogenative ester formation with a ruthenium NHC complex A new atom-economical methodology for synthesizing esters by the dehydrogenative coupling of primary alcohols was developed. The reaction is catalyzed by the ruthenium N-heterocyclic carbene complex RuCl2(IiPr)(p-cymene). By screening t...

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

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


    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, 8.84sorbitol of 57.9% at complete conversion of cellulose, and 97.1% yield in hexitols with a selectivity for sorbitol of 95.1% at complete conversion of cellobiose) were obtained using a Ru-PTA/MIL-100(Cr) catalyst with loadings of 3.2 wt % for Ru and 16.7 wt % for PTA. This research thus opens new perspectives for the rational design of acid/metal bifunctional catalysts for biomass conversion.

  6. Modulation of internuclear communication in multinuclear ruthenium(II) polypyridyl complexes

    Browne, W.R.; Weldon, F.; Guckian, A.; Vos, J.G.


    The syntheses and characterisation of a series of mononuclear and dinuclear ruthenium polypyridyl complexes based on the bridging ligands 1,3-bis-[5-(2-pyridyl)-1H-1,2,4-triazol-3-yl]benzene, 1,4-bis-[5-(2-pyridyl)-1H-1,2,4-triazol-3-yl]benzene, 2,5-bis-[5-(2-pyridyl)-1H-1,2,4-triazol-3-yl] thiophen

  7. Proton controlled intramolecular communication in dinuclear ruthenium(II) polypyridine complexes

    Pietro, Cinzia Di; Serroni, Scolastica; Campagna, Sebastiano; Gandolfi, Maria Teresa; Ballardini, Roberto; Fanni, Stefano; Browne, Wesley R.; Vos, Johannes G.


    The synthesis and characterization of two dinuclear ruthenium polypyridyl complexes based on the bridging ligands 5,5'-bis(pyridin-2"-yl)-3,3'-bis(1H-1,2,4-triazole) and 5,5'-bis(pyrazin-2"-yl)-3,3'-bis(1H-1,2,4-triazole) and of their mononuclear precursors are reported. The dinuclear compounds have

  8. Study of Ruthenium Complex Sensitizer and Gold Nanoparticles Doped Flexible Organic Solar Cells

    Cheng-Chiang Chen


    Full Text Available This work presents a flexible organic solar cell with a structure for ITO/PEDOT:PSS/P3HT:PCBM+ruthenium complex sensitizer and Au nanoparticles on a flexible substrate. The process and thickness of the PEDOT:PSS hole transport layer and P3HT:PCBM active layer were optimized. A ruthenium complex sensitizer and Au nanoparticles were then introduced into the P3HT:PCBM active layer to improve the performance of solar cells. For the ITO/PEDOT:PSS/P3HT:PCBM+ruthenium complex sensitizer and Au nanoparticles structure on a flexible polyimide (PI substrate under 0.1 and 1 sun conditions, the measured short-circuit current density (Jsc, open-circuit voltage (Voc, fill factor (FF, and efficiency (η are 3.89 and 9.67 mA/cm2, 0.45 and 0.45 V, 0.266 and 0.232, and 4.65 and 1.01%, respectively.

  9. Ruthenium Hydride/Brønsted Acid-Catalyzed Tandem Isomerization/N-Acyliminium Cyclization Sequence for the Synthesis of Tetrahydro-β-carbolines

    Hansen, Casper Lykke; Clausen, Janie Regitse Waël; Ohm, Ragnhild Gaard;


    This paper describes an efficient tandem sequence for the synthesis of 1,2,3,4-tetrahydro-β-carbolines (THBCs) relying on a ruthenium hydride/Brønsted acid- catalyzed isomerization of allylic amides to N-acyliminium ion intermediates which are trapped by a tethered indolenucleophile. The methodol...... the Suzuki cross-coupling reaction to the isomerization/N-acyliminium cyclization sequence. Finally, diastereo- and enantioselective versions of the title reaction have been examined using substrate control (with dr >15: 1) and asymmetric catalysis (ee up to 57%), respectively...

  10. Desensitization effects in the ruthenium-catalyzed Belousov-Zhabotinsky reaction.

    Cassidy, Iris; Müller, Stefan C


    The influence of visible light on the velocities of spiral waves in the [Ru(bpy)](3)(2+) -catalyzed Belousov-Zhabotinsky (BZ) reaction is well documented. However, there are only few reports showing the effect of the way a change in the applied intensity is made, or on "desensitization" or "memory" type phenomena. In this paper, we present observations showing significant changes in spiral tip dynamics without varying the light intensity during the course of the experiments. We produce further evidence showing that changes in wave velocity and inhibitory effects are depending on whether the increase in intensity is applied in one large step or in a number of smaller steps. Also, the tip trajectories before and after the spiral waves have been subjected to an increase and subsequent decrease in intensity levels are different, suggesting a change in excitation of the system. The experimental results are separated into two groups depending on the light sensitivity of the system and the behavior of the spiral tip. Simulation results demonstrate that the different tip trajectories observed in the experiments can be modeled by only varying the excitation threshold. Our observations indicate that there must be at least two different competing pathways for the reaction mechanism not only in the oscillatory BZ system but also in excitable media and that intermediates may also play an important part in determining the excitation of the system and not just the initial concentrations of the reactants.

  11. Ruthenium-catalyzed α-(hetero)arylation of saturated cyclic amines: reaction scope and mechanism.

    Peschiulli, Aldo; Smout, Veerle; Storr, Thomas E; Mitchell, Emily A; Eliáš, Zdeněk; Herrebout, Wouter; Berthelot, Didier; Meerpoel, Lieven; Maes, Bert U W


    Transition-metal-catalyzed sp(3) C-H activation has emerged as a powerful approach to functionalize saturated cyclic amines. Our group recently disclosed a direct catalytic arylation reaction of piperidines at the α position to the nitrogen atom. 1-(Pyridin-2-yl)piperidine could be smoothly α-arylated if treated with an arylboronic ester in the presence of a catalytic amount of [Ru3(CO)12] and one equivalent of 3-ethyl-3-pentanol. A systematic study on the substrate and reagent scope of this transformation is disclosed in this paper. The effect of substitution on both the piperidine ring and the arylboronic ester has been investigated. Smaller (pyrrolidine) and larger (azepane) saturated ring systems, as well as benzoannulated derivatives, were found to be compatible substrates with the α-arylation protocol. The successful use of a variety of heteroarylboronic esters as coupling partners further proved the power of this direct functionalization method. Mechanistic studies have allowed for a better understanding of the catalytic cycle of this remarkable transformation featuring an unprecedented direct transmetalation on a Ru(II)-H species.

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

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


    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.

  13. Ruthenium(III Catalysis in Perborate Oxidation of 5-Oxoacids

    S. Shree Devi


    Full Text Available Ruthenium(III catalyzes perborate oxidation of substituted 5-oxoacids in acidic solution. The catalyzed oxidation is first order with respect to the oxidant and catalyst. The rate of ruthenium(III catalyzed oxidation displays the Michaelis-Menten kinetics on the reductant and is independent of [H+] of the medium. Hydrogen peroxide is the reactive species of perborate and the kinetic results reveal formation of ruthenium(III peroxo species-5-oxoacid complex. Electron-releasing substituents accelerate the reaction rate and electron-withdrawing substituents retard it. The order of reactivity among the studied 5-oxoacids is p-methoxy ≫  p-methyl > p-phenyl > −H > p-chloro > p-bromo > m-nitro. Activation parameters are evaluated using Arrhenius and Eyring’s plots. A mechanism consistent with the observed kinetic data is proposed and discussed. A suitable rate law is derived based on the mechanism.

  14. Ruthenium-catalyzed aerobic oxidative decarboxylation of amino acids: a green, zero-waste route to biobased nitriles.

    Claes, Laurens; Verduyckt, Jasper; Stassen, Ivo; Lagrain, Bert; De Vos, Dirk E


    Oxidative decarboxylation of amino acids into nitriles was performed using molecular oxygen as terminal oxidant and a heterogeneous ruthenium hydroxide-based catalyst. A range of amino acids was oxidized in very good yield, using water as the solvent.

  15. Kinetics and mechanism of uncatalyzed and ruthenium(III)-catalyzed oxidation of formamidine derivative by hexacyanoferrate(III) in aqueous alkaline medium



    The catalytic effect of ruthenium(III) on the oxidation of N,N-dimethyl-N-(4H-1,2,4-triazol-3-yl) formamidine (ATF) by hexacyanoferrate(III) (HCF) was studied spectrophotometrically in aqueous alkalinemedium. Both uncatalyzed and catalyzed reactions showed first order kinetics with respect to [HCF],whereas the reaction orders with respect to [ATF] and $[OH^{-}]$ were apparently less than unity over the concentrationrange studied. A first order dependence with respect to $[Ru^{III}]$ was obtained. Increasing ionic strengthincreased the rate of uncatalyzed reaction and decreased the rate of the catalyzed one Plausible mechanisticschemes of oxidation reactions have been proposed. In both cases, the final oxidation products are identifiedas aminotriazole, dimethyl amine and carbon dioxide. The rate laws associated with the reaction mechanismsare derived. The reaction constants involved in the different steps of the mechanisms were calculated. Theactivation and thermodynamic parameters have been computed and discussed.

  16. Arene control over thiolate to sulfinate oxidation in albumin by organometallic ruthenium anticancer complexes.

    Hu, Wenbing; Luo, Qun; Ma, Xiaoyan; Wu, Kui; Liu, Jianan; Chen, Yi; Xiong, Shaoxiang; Wang, Jianping; Sadler, Peter J; Wang, Fuyi


    Interactions of organometallic ruthenium anticancer complexes [Ru(eta6-arene)Cl(en)][PF6] (arene=p-cymene (1) or biphenyl (2), en=ethylenediamine) with human serum albumin were investigated by means of mass spectrometry combined with trypsin digestion, specific sidechain modifications and computational modelling. Both complexes were shown to bind to surface histidine (His128, His247, His510) and methionine (Met298) residues in human albumin, but only the p-cymene complex can gain entry to the crevice containing the free cysteine thiolate (Cys34) and induce oxidation to sulfinate. The two complexes exhibit a similar coordination preference for histidine and methionine residues on the protein surface. His128 binding is favoured both kinetically and thermodynamically. At 310 K, six days of incubation of recombinant human albumin (rHA) with complex 1 (rHA:Ru 50:250 microM) led to about 18 % ruthenation of His128 in the protein. However, the extent of ruthenation of albumin by complex 2 was less than that by 1, due to the steric hindrance from the biphenyl ligand. These results imply that the arene ligand in the organometallic ruthenium anticancer complexes plays a crucial role in interactions with proteins.

  17. Bis(ortho-) chelated Monoanionic Bisphosphinoaryl Ruthenium(Ⅱ) Complexes:Synthesis,Characterization and Reactivity

    van KLINK, Gerard P.M.; DANI, Paulo; van KOTEN, Gerard


    Bisphosphinoaryl ruthenium(Ⅱ) compounds are synthesized using two distinct synthetic routes. One route, direct cycloruthenation, consists of the reaction of the parent arene compound R-PCHP with [R uCl2(PPh)3] in chlorinated solvents. However, this route suffers from major drawbacks because HCl is formed as well as free triphenylphoshine. The other route, the transcyclometalation reaction, involves the interconversion of one cyclometalated ligand metal complex,[RuCl(NCN) (PPh3)], into another complex, [RuCl(RPCP) (PPh3) ], with concomitant consumption and formation of the corresponding arenes R-PCHP and NCHN, respectively.

  18. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    FENG XiaoMing


    @@ Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.

  19. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    FENG; XiaoMing


    Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.  ……

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

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


    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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Photochemical nitric oxide precursors: synthesis, photochemistry, and ligand substitution kinetics of ruthenium salen nitrosyl and ruthenium salophen nitrosyl complexes.

    Works, Carmen F; Jocher, Christoph J; Bart, Gwen D; Bu, Xianhui; Ford, Peter C


    Described are syntheses, characterizations, and photochemical reactions of the nitrosyl complexes Ru(salen)(ONO)(NO) (I, salen = N,N'-ethylenebis(salicylideneiminato) dianion), Ru(salen)(Cl)(NO) (II), Ru((t)Bu(4)salen)(Cl)(NO) (III,(t)Bu(4)salen = N,N'-ethylenebis(3,5-di-tert-butylsalicylideneiminato) dianion), Ru((t)Bu(4)salen)(ONO)(NO) (IV), Ru((t)Bu(2)salophen)(Cl)(NO) (V, (t)Bu(2)salophen = N,N'-1,2-phenylenediaminebis(3-tert-butylsalicylideneiminato) dianion), and Ru((t)Bu(4)salophen)(Cl)(NO) (VI, (t)Bu(4)salophen = N,N'-1,2-phenylenebis(3,5-di-tert-butylsalicylideneiminato) dianion). Upon photolysis, these Ru(L)(X)(NO) compounds undergo NO dissociation to give the ruthenium(III) solvento products Ru(L)(X)(Sol). Quantum yields for 365 nm irradiation in acetonitrile solution fall in a fairly narrow range (0.055-0.13) but decreased at longer lambda(irr). The quantum yield (lambda(irr) = 365 nm) for NO release from the water soluble complex [Ru(salen)(H(2)O)(NO)]Cl (VII) was 0.005 in water. Kinetics of thermal back-reactions to re-form the nitrosyl complexes demonstrated strong solvent dependence with second-order rate constants k(NO) varying from 5 x 10(-4) M(-1) s(-1) for the re-formation of II in acetonitrile to 5 x 10(8) M(-1) s(-1) for re-formation of III in cyclohexane. Pressure and temperature effects on the back-reaction rates were also examined. These results are relevant to possible applications of photochemistry for nitric oxide delivery to biological targets, to the mechanisms by which NO reacts with metal centers to form metal-nitrosyl bonds, and to the role of photochemistry in activating similar compounds as catalysts for several organic transformations. Also described are the X-ray crystal structures of I and V.

  2. Assessing the ligand properties of 1,3-dimesitylbenzimidazol-2-ylidene in ruthenium-catalyzed olefin metathesis.

    Borguet, Yannick; Zaragoza, Guillermo; Demonceau, Albert; Delaude, Lionel


    The deprotonation of 1,3-dimesitylbenzimidazolium tetrafluoroborate with a strong base afforded 1,3-dimesitylbenzimidazol-2-ylidene (BMes), which was further reacted in situ with rhodium or ruthenium complexes to afford three new organometallic products. The compounds [RhCl(COD)(BMes)] (COD is 1,5-cyclooctadiene) and cis-[RhCl(CO)2(BMes)] were used to probe the steric and electronic parameters of BMes. Comparison of the percentage of buried volume (%V(Bur)) and of the Tolman electronic parameter (TEP) of BMes with those determined previously for 1,3-dimesitylimidazol-2-ylidene (IMes) and 1,3-dimesitylimidazolin-2-ylidene (SIMes) revealed that the three N-heterocyclic carbenes (NHCs) had very similar profiles. Nonetheless, changes in the hydrocarbon backbone subtly affected the stereoelectronic properties of these ligands. Accordingly, the corresponding [RuCl2(PCy3)(NHC)(=CHPh)] complexes displayed different catalytic behaviors in the ring-closing metathesis (RCM) of α,ω-dienes. In the benchmark cyclization of diethyl 2,2-diallylmalonate, the new [RuCl2(PCy3)(BMes)(=CHPh)] compound (1d) performed slightly better than the Grubbs second-generation catalyst (1a), which was in turn significantly more active than the related [RuCl2(PCy3)(IMes)(=CHPh)] initiator (1b). For the formation of a model trisubstituted cycloolefin, complex 1d ranked in-between catalyst precursors 1a and 1b, whereas in the RCM of tetrasubstituted cycloalkenes it lost its catalytic efficiency much more rapidly.

  3. Olefin Metathesis in Homogeneous Aqueous Media Catalyzed by Conventional Ruthenium Catalysts

    Binder, Joseph B.; Blank, Jacqueline J.; Raines, Ronald T.


    Olefin metathesis in aqueous solvents is sought for applications in green chemistry and with the hydrophilic substrates of chemical biology, such as proteins and polysaccharides. Most demonstrations of metathesis in water, however, utilize exotic complexes. We have examined the performance of conventional catalysts in homogeneous water–organic mixtures, finding that the second-generation Hoveyda–Grubbs catalyst has extraordinary efficiency in aqueous dimethoxyethane and aqueous acetone. High (71–95%) conversions are achieved for ring-closing and cross metathesis of a variety of substrates in these solvent systems. PMID:17949009

  4. Structural characterization and biological evaluation of a clioquinol-ruthenium complex with copper-independent antileukaemic activity.

    Gobec, Martina; Kljun, Jakob; Sosič, Izidor; Mlinarič-Raščan, Irena; Uršič, Matija; Gobec, Stanislav; Turel, Iztok


    In this study, we present the synthesis, biological characterization, and first crystal structure of an organometallic-clioquinol complex. Combining ruthenium with the established apoptotic agent and 8-hydroxyquinoline derivative, clioquinol, resulted in a complex that induces caspase-dependent cell death in leukaemia cells. This activity is copper independent and is improved compared to the parent compound, clioquinol. The study of the mode of action reveals that this clioquinol-ruthenium complex does not intercalate between DNA base pairs. Additionally, this clioquinol-ruthenium complex shows proteasome-independent inhibition of the NFκB signalling pathway, with no effects on cell-cycle distribution. These data suggest a mechanism of action that involves a target profile that is different from that for clioquinol alone.

  5. Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters.

    Li, Yuehui; Topf, Christoph; Cui, Xinjiang; Junge, Kathrin; Beller, Matthias


    Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

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


    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.

  7. A Ruthenium(III)-Oxyl Complex Bearing Strong Radical Character.

    Shimoyama, Yoshihiro; Ishizuka, Tomoya; Kotani, Hiroaki; Shiota, Yoshihito; Yoshizawa, Kazunari; Mieda, Kaoru; Ogura, Takashi; Okajima, Toshihiro; Nozawa, Shunsuke; Kojima, Takahiko


    Proton-coupled electron-transfer oxidation of a Ru(II) -OH2 complex, having an N-heterocyclic carbene ligand, gives a Ru(III) -O(.) species, which has an electronically equivalent structure of the Ru(IV) =O species, in an acidic aqueous solution. The Ru(III) -O(.) complex was characterized by spectroscopic methods and DFT calculations. The oxidation state of the Ru center was shown to be close to +3; the Ru-O bond showed a lower-energy Raman scattering at 732 cm(-1) and the Ru-O bond length was estimated to be 1.77(1) Å. The Ru(III) -O(.) complex exhibits high reactivity in substrate oxidation under catalytic conditions; particularly, benzaldehyde and the derivatives are oxidized to the corresponding benzoic acid through C-H abstraction from the formyl group by the Ru(III) -O(.) complex bearing a strong radical character as the active species.

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

    Swavey, Shawn; DeBeer, Madeleine; Li, Kaiyu


    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.

  9. The effect of annealing temperature on the optical properties of a ruthenium complex thin film

    Ocakoglu, Kasim, E-mail: [Advanced Technology Research & Application Center, Mersin University, TR-33343, Yenisehir, Mersin (Turkey); Department of Energy Systems Engineering, Faculty of Technology, Mersin University, TR-33480 Mersin (Turkey); Okur, Salih, E-mail: [Department of Materials Science and Engineering, Faculty of Engineering and Architecture, Izmir Katip Celebi University, Izmir (Turkey); Aydin, Hasan [Izmir Institute of Technology, Department of Material Science and Engineering, Gulbahce Campus, 35430, Urla, Izmir (Turkey); Emen, Fatih Mehmet [Faculty of Arts and Sciences, Department of Chemistry, Mehmet Akif Ersoy University, TR-15030 Burdur (Turkey)


    The stability of the optical parameters of a ruthenium polypyridyl complex (Ru-PC K314) film under varying annealing temperatures between 278 K and 673 K was investigated. The ruthenium polypyridyl complex thin film was prepared on a quartz substrate by drop casting technique. The transmission of the film was recorded by using Ultraviolet/Visible/Near Infrared spectrophotometer and the optical band gap energy of the as-deposited film was determined around 2.20 eV. The optical parameters such as refractive index, extinction coefficient, and dielectric constant of the film were determined and the annealing effect on these parameters was investigated. The results show that Ru PC K314 film is quite stable up to 595 K, and the rate of the optical band gap energy change was found to be 5.23 × 10{sup −5} eV/K. Furthermore, the thermal analysis studies were carried out in the range 298–673 K. The Differential Thermal Analysis/Thermal Gravimmetry/Differantial Thermal Gravimmetry curves show that the decomposition is incomplete in the temperature range 298–673 K. Ru-PC K314 is thermally stable up to 387 K. The decomposition starts at 387 K with elimination of functional groups such as CO{sub 2}, CO molecules and SO{sub 3}H group was eliminated between 614 K and 666 K. - Highlights: • Optical parameters of a ruthenium polypyridyl complex film under varying annealing temperatures • The film is quite stable up to 573 K. • The rate of change of optical energy gap was obtained as 5.23 × 10{sup −5} eV/K.

  10. Zeolite-mediated photochemical charge separation using a surface-entrapped ruthenium-polypyridyl complex.

    Kim, Yanghee; Lee, Hyunjung; Dutta, Prabir K; Das, Amitava


    Employing the strategy of quaternization of the 2,2' N atoms of the conjugated bipyridine ligand 1,4-bis[2-(4'-methyl-2,2'-bipyrid-4-yl)ethenyl]benzene (L), a polypyridyl complex of ruthenium(II) was tethered on the surface of zeolite Y. Electrochemical and spectroscopic properties of the complex suggest that, upon visible photoexcitation of the MLCT band, the electron is localized on the conjugated ligand rather than the bipyridines. Electron transfer from the surface complex to bipyridinium ions (methyl viologen) within the zeolite was observed. Visible light photolysis of the ruthenium-zeolite solid ion-exchanged with diquat and suspended in a propyl viologen sulfonate solution led to permanent formation of the blue propyl viologen sulfonate radical ion in solution. The model that is proposed involves intrazeolitic charge transfer to ion-exchanged diquat followed by interfacial (zeolite to solution) electron transfer to propyl viologen sulfonate in solution. Because of the slow intramolecular back-electron-transfer reaction and the forward electron propagation via the ion-exchanged diquat, Ru(III) is formed. This Ru(III) complex formed on the zeolite is proposed to react rapidly with water in the presence of light, followed by reaction with the propyl viologen sulfonate, to form pyridones and regeneration of Ru(II), which then continues the photochemical process.

  11. Ruthenium(II) complexes as apoptosis inducers by stabilizing c-myc G-quadruplex DNA.

    Zhang, Zhao; Wu, Qiong; Wu, Xiao-Hui; Sun, Fen-Yong; Chen, Lan-Mei; Chen, Jin-Chan; Yang, Shu-Ling; Mei, Wen-Jie


    Two ruthenium(II) complexes, [Ru(L)2(p-tFMPIP)](ClO4)2 (L = bpy, 1; phen, 2; p-tFMPIP = 2-(4-(trifluoromethyphenyl)-1H-imidazo[4,5f][1,10] phenanthroline)), were prepared by microwave-assisted synthesis technology. The inhibitory activity evaluated by MTT assay shown that 2 can inhibit the growth of MDA-MB-231 cells with inhibitory activity (IC50) of 16.3 μM, which was related to the induction of apoptosis. Besides, 2 exhibit low toxicity against normal HAcat cells. The inhibitory growth activity of both complexes related to the induction of apoptosis was also confirmed. Furthermore, the studies on the interaction of both complexes with c-myc G4 DNA shown that 1 and 2 can stabilize the conformation of c-myc G4 DNA in groove binding mode, which has been rational explained by using DFT theoretical calculation methods. In a word, this type of ruthenium(II) complexes can act as potential apoptosis inducers with low toxicity in clinic by stabilizing c-myc G4 DNA.

  12. Synthesis and Reactivity of Ruthenium Phosphite Indenylidene Complexes

    Bantreil, Xavier; Poater, Albert; Urbina-Blanco, César A; Bidal, Yannick D.; Falivene, Laura; Randall, Rebecca A. M.; Cavallo, Luigi; Slawin, Alexandra M. Z.; Cazin, Catherine S. J.


    The synthesis of the four olefin metathesis precatalysts Caz-1a-d, featuring the NHC ligand N,N'-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) and four different phosphites (P((OPr)-Pr-i)(3), P(OPh)(3), P(OEt)(3), and P(OMe)(3)), is reported. The complexes are readily synthesized from commercially available [RuCl2(3-phenylinden-1-ylidene)-(pyridine)(SIMes)] (Ind-III) in yields of up to 88%. These complexes adopt an unusual cis configuration between the phosphite and the NHC ligands. ...

  13. Synthesis and photoelectrochemical characterization of a high molar extinction coefficient heteroleptic ruthenium(II) complex

    L Giribabu; Vrun Kumar Singh; M Srinivasu; Ch Vijay Kumar; V Gopal Reddy; Y Soujnya; P Yella Reddy


    A new high molar extinction coefficient heteroleptic ruthenium(II) complex (m-BL-1) that contains a 4,4'4"-tricaboxy-2,2':6’,2”-terpyridine, 4,4’-bis-[3,5-di-tert-butyl-phenyl)-vinyl]-[2,2']bipyridyl and a thiocyanate ligand in its molecular structure has been synthesized and completely characterized by CHN, Mass, 1H-NMR, UV-Vis, and fluorescence spectroscopies as well as cyclic voltammetry. The new sensitizer was tested in dye-sensitized solar cells using three different redox electrolytes and compared its performance to that of standard sensitizer black dye.

  14. Electronic structures of ruthenium complexes encircling non-innocent ligand assembly

    Amit Das; Dipanwita Das; Tanaya Kundu; Goutam Kumar Lahiri


    Electronic structural forms of selected mononuclear and dinuclear ruthenium complexes encompassing redox non-innocent terminal as well as bridging ligands have been addressed. The sensitive valence and spin situations of the complexes have been established in the native and accessible redox states via detailed analysis of their crystal structures, electrochemistry, UV/VIS/NIR spectroelectrochemistry, EPR signatures at the paramagnetic states and DFT calculations. Mononuclear complexes exhibit significant variations in valence and spin distribution processes based on the simple modification of the non-innocent ligand frameworks as well as electronic nature of the co-ligands, -donating or -accepting. Dinuclear complexes with modified pyrazine, -quinone and azo-derived redox-active bridging ligands show complex features including redoxinduced electron-transfer (RIET), remote metal to metal spin-interaction in a three-spin metal-bridge-metal arrangement as well as electron-transfer driven chemical transformation (EC).

  15. Thermodestruction of complex sulfates of iridium and ruthenium in sulfate solutions at 100-180 deg C

    Sinitsyn, N.M.; Godzhiev, S.E.; Blagodatin, Yu.V. (Moskovskij Inst. Tonkoj Khimicheskoj Tekhnologii (USSR))


    Thermodestruction of iridium- and ruthenium complex sulfates in sulfate solutions is studied at 100-180 deg C depending on the solution acidity, hold time, element initial chemical form in the solution, salt background. The complex ruthenium sulfates are shown to be destroyed during high-temperature solution holding with the solid phase formation, the rate of platinum metal transfer into a precipitate increasing with the temperature, hold time and pH of the source solution. Depending on the initial chemical form the thermodestruction proceeds in various ways and leads to the formation of either hydroxides or solid phase ''proper'' of the platinium metal salt. A reduced tendency to high-temperature hydrolysis of complex ruthenium sulfates at the +3 oxidation level is noted.

  16. Antimetastatic activity of novel ruthenium (III) pyridine complexes

    Gu, Liwei; Li, Xiaodong; Ran, Qingsen; Kang, Chen; Lee, Canghai; Shen, Jianying


    Ruthenium‐based complexes have emerged as promising anticancer, especially antimetastatic agents. Among them, NAMI ‐A ( trans ‐[Ru( III )Cl 4 ( DMSO )(Im)][ImH], Im = imidazole, DMSO  = dimethyl sulfoxide) was well studied...

  17. Vibrational energy transfer dynamics in ruthenium polypyridine transition metal complexes.

    Fedoseeva, Marina; Delor, Milan; Parker, Simon C; Sazanovich, Igor V; Towrie, Michael; Parker, Anthony W; Weinstein, Julia A


    Understanding the dynamics of the initial stages of vibrational energy transfer in transition metal complexes is a challenging fundamental question which is also of crucial importance for many applications, such as improving the performance of solar devices or photocatalysis. The present study investigates vibrational energy transport in the ground and the electronic excited state of Ru(4,4'-(COOEt)2-2,2-bpy)2(NCS)2, a close relative of the efficient "N3" dye used in dye-sensitized solar cells. Using the emerging technique of ultrafast two-dimensional infrared spectroscopy, we show that, similarly to other transition-metal complexes, the central Ru heavy atom acts as a "bottleneck" making the energy transfer from small ligands with high energy vibrational stretching frequencies less favorable and thereby affecting the efficiency of vibrational energy flow in the complex. Comparison of the vibrational relaxation times in the electronic ground and excited state of Ru(4,4'-(COOEt)2-2,2-bpy)2(NCS)2 shows that it is dramatically faster in the latter. We propose to explain this observation by the intramolecular electrostatic interactions between the thiocyanate group and partially oxidised Ru metal center, which increase the degree of vibrational coupling between CN and Ru-N modes in the excited state thus reducing structural and thermodynamic barriers that slow down vibrational relaxation and energy transport in the electronic ground state. As a very similar behavior was earlier observed in another transition-metal complex, Re(4,4'-(COOEt)2-2,2'-bpy)(CO)3Cl, we suggest that this effect in vibrational energy dynamics might be common for transition-metal complexes with heavy central atoms.

  18. Bipyrimidine ruthenium(II) arene complexes: structure, reactivity and cytotoxicity.

    Betanzos-Lara, Soledad; Novakova, Olga; Deeth, Robert J; Pizarro, Ana M; Clarkson, Guy J; Liskova, Barbora; Brabec, Viktor; Sadler, Peter J; Habtemariam, Abraha


    The synthesis and characterization of complexes [(η(6)-arene)Ru(N,N')X][PF(6)], where arene is para-cymene (p-cym), biphenyl (bip), ethyl benzoate (etb), hexamethylbenzene (hmb), indane (ind) or 1,2,3,4-tetrahydronaphthalene (thn), N,N' is 2,2'-bipyrimidine (bpm) and X is Cl, Br or I, are reported, including the X-ray crystal structures of [(η(6)-p-cym)Ru(bpm)I][PF(6)], [(η(6)-bip)Ru(bpm)Cl][PF(6)], [(η(6)-bip)Ru(bpm)I][PF(6)] and [(η(6)-etb)Ru(bpm)Cl][PF(6)]. Complexes in which N,N' is 1,10-phenanthroline (phen), 1,10-phenanthroline-5,6-dione or 4,7-diphenyl-1,10-phenanthroline (bathophen) were studied for comparison. The Ru(II) arene complexes undergo ligand-exchange reactions in aqueous solution at 310 K; their half-lives for hydrolysis range from 14 to 715 min. Density functional theory calculations on [(η(6)-p-cym)Ru(bpm)Cl][PF(6)], [(η(6)-p-cym)Ru(bpm)Br][PF(6)], [(η(6)-p-cym)Ru(bpm)I][PF(6)], [(η(6)-bip)Ru(bpm)Cl][PF(6)], [(η(6)-bip)Ru(bpm)Br][PF(6)] and [(η(6)-bip)Ru(bpm)I][PF(6)] suggest that aquation occurs via an associative pathway and that the reaction is thermodynamically favourable when the leaving ligand is I > Br ≈ Cl. pK (a)* values for the aqua adducts of the complexes range from 6.9 to 7.32. A binding preference for 9-ethylguanine (9-EtG) compared with 9-ethyladenine (9-EtA) was observed for [(η(6)-p-cym)Ru(bpm)Cl][PF(6)], [(η(6)-hmb)Ru(bpm)Cl](+), [(η(6)-ind)Ru(bpm)Cl](+), [(η(6)-thn)Ru(bpm)Cl](+), [(η(6)-p-cym)Ru(phen)Cl](+) and [(η(6)-p-cym)Ru(bathophen)Cl](+) in aqueous solution at 310 K. The X-ray crystal structure of the guanine complex [(η(6)-p-cym)Ru(bpm)(9-EtG-N7)][PF(6)](2) shows multiple hydrogen bonding. Density functional theory calculations show that the 9-EtG adducts of all complexes are thermodynamically preferred compared with those of 9-EtA. However, the bmp complexes are inactive towards A2780 human ovarian cancer cells. Calf thymus DNA interactions for [(η(6)-p-cym)Ru(bpm)Cl][PF(6)] and [(η(6)-p

  19. Electronic Spectra of Bare and Solvated Ruthenium Polypyridine Complexes

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


    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.

  20. New Ruthenium Complexes of Fullerene C60&C70


    The new complexes [Ru(NO)(PPh3)]2(η2-Cm)(m=60 1 or 70 2) have been prepared by heating a solution of C60(or C70) with [Ru(NO)2(PPh3)2] in toluene. They have been characterized by elemental analysis, IR, UV/VIS, XPS, 13C and 31P NMR spectroscopy. The photovaltaic effect for the new compounds has been studied.

  1. Enhanced photovoltaic effect of ruthenium complex-modified graphene oxide with P-type conductivity

    Zhang, Wei, E-mail:; Bai, Huicong; Zhang, Yu; Sun, Ying; Lin, Shen; Liu, Jian; Yang, Qi; Song, Xi-Ming, E-mail:


    A graphene oxide nanocomposite with bis(1,10-phenanthroline)(N-(2-aminoethyl)-4-(4-methyl-2,2-bipyridine-4-yl) formamide) ruthenium (Ru(phen){sub 2}(bpy-NH{sub 2})(PF{sub 6}){sub 2}), a ruthenium complex, was synthesized by amidation reaction between amino group of the ruthenium complex and carboxyl group of GO. The as-prepared Ru(II)–GO composite was characterized by infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) absorption spectra, fluorescence spectra, surface photovoltage (SPV) spectrum and transient photovoltage (TPV) technology. This nanocomposite showed a typical p-type character and an enhanced photovoltaic effect at long timescale of about 3 × 10{sup −3} s compared to GO alone. A reversible rise/decay of the photocurrent in response to the on/off illumination step was also observed in a photoelectrochemical cell of the Ru(II)–GO composite. The photocurrent response of the Ru(II)–GO film was remarkably higher than that of GO film. Therefore, this Ru(II)–GO composite is believed to be a promising p-type photoelectric conversion material for further photovoltaic applications. - Highlights: • A new dye-sensitized graphene oxide nanocomposite was reported. • A photo-induced charge transfer process in this nanocomposite was confirmed. • This composite showed a typical p-type conductivity. • This composite showed an enhanced photovoltaic effect at a long timescale.

  2. New carboxy-functionalized terpyridines as precursors for zwitterionic ruthenium complexes for polymer-based solar cells

    Duprez, V.; Krebs, Frederik C


    New carboxy-terpyridines selectively functionalized at the 4-, 4'- and 4"-positions were prepared in a three-step procedure with good yields using, the Krohnke reaction followed by saponification. Their complexation with ruthenium led to symmetric and unsymmetric terpyridinyl zwitterionic complexes...

  3. Ruthenium polypyridyl complexes with anticancer properties : synthesis, characterization and mechanistic studies in search for structure-activity relationships

    Corral Simón, Eva


    The perfect anticancer drug would kill cancer cells without causing any harm to the surrounding healthy tissues. That ideal medicine is searched for in this thesis, in the form of a ruthenium coordination complex. Metal complexes are known to interact with DNA in several different modes, amongst whi

  4. The synthesis, lipophilicity and cytotoxic effects of new ruthenium(II) arene complexes with chromone derivatives.

    Pastuszko, Adam; Majchrzak, Kinga; Czyz, Malgorzata; Kupcewicz, Bogumiła; Budzisz, Elzbieta


    A series of arene ruthenium(II) complexes with the general formula [(η(6)-arene)Ru(L)X2] (where arene=p-cymene, benzene, hexamethylbenzene or mesitylene, L=aminoflavone or aminochromone derivatives and X=Cl, I) were synthesized and characterized by elemental analysis, MS, IR and (1)H NMR spectroscopy. The stability of the selected complexes was assessed by UV-Vis spectroscopy in 24-hour period. The lipophilicity of the synthesized complexes was determined by the shake-flask method, and their cytotoxicity evaluated in vitro on patient-derived melanoma populations. The most active complexes against melanoma cells contain 7-aminoflavone and 6-aminoflavone as a ligand. The relationship between the cytotoxicity of all the obtained compounds and their logP values was determined and briefly analyzed with two different patterns observed. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Half-sandwich ruthenium, rhodium and iridium complexes of triazolopyridine ligand: Synthesis and structural studies



    Triazolopyridine ligand, {3-(2-pyridyl)-[1,2,3]triazolo[1,5-a]-pyridine}, L was synthesized by reaction of p-toulenesulphonyl hydrazine and dipyridyl ketone in the presence of acetic acid. Half-sandwich ruthenium, rhodium and iridium complexes [1–4] have been synthesized by reaction of [{(arene)MCl₂}₂] (arene= p-cymene/benzene/Cp* and M = Ru/Rh/Ir) with ligand L in methanol. The reaction in 1:2 (M:L) ratio has yielded all mononuclear cationic complexes such as [(arene)MLκ²N∩N Cl]PF₆, where {(arene)M} = (p-cym)Ru(1), (benz)Ru (2), Cp*Rh (3) and Cp*Ir (4). All the complexes were characterized by spectral studies and the solid state structures of complexes, 1 and 3 were unambiguously determined by crystallographic studies.

  6. The impact of Metal-Ligand Cooperation in Hydrogenation of Carbon Dioxide Catalyzed by Ruthenium PNP Pincer

    Filonenko, G.A.; Conley, M.P.; Copéret, C.; Lutz, M.; Hensen, E.J.M.; Pidko, E.A.


    The metal–ligand cooperative activation of CO2 with pyridine-based ruthenium PNP pincer catalysts leads to pronounced inhibition of the activity in the catalytic CO2 hydrogenation to formic acid. The addition of water restores catalytic performance by activating alternative reaction pathways and lea

  7. In tandem or alone: a remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts.

    Zieliński, Grzegorz Krzysztof; Samojłowicz, Cezary; Wdowik, Tomasz; Grela, Karol


    A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity.

  8. Ultrasound assisted, ruthenium-exchanged FAU-Y zeolite catalyzed alkylation of indoles with epoxides under solvent free conditions.

    Khorshidi, Alireza


    Ruthenium-exchanged FAU-Y zeolite (RuY) was used as a recyclable catalyst for regioselective ring-opening of epoxides with indoles under irradiation of sonic waves. It was found that a solvent free process, under the above mentioned conditions provides good yields of the desired 3-alkylated indole derivatives.

  9. Solution studies of the antitumor complex dichloro 1,2-propylendiaminetetraacetate ruthenium (III) and of its interactions with proteins.

    Gonzalez Vilchez, F; Vilaplana, R; Blasco, G; Messori, L


    A mixed complex of ruthenium (III) with 1,2-propylendiaminetetraacetate (PDTA) and chloride--RAP hereafter--has been found to exhibit favorable anticancer properties in vivo. To get some insight into the possible mechanism of action of this ruthenium (III) complex, its solution behavior and reactivity with proteins were investigated through absorption, circular dichroism and 1H NMR spectroscopies. Under physiological conditions RAP slowly looses the two coordinated chlorine atoms to produce a number of ruthenium (III) reactive species; a description of the distribution of these species on the dependence of pH has been obtained through 1H NMR studies of the hyperfine shifted signals. Remarkably, through the different solution conditions employed in this study, the ruthenium ion always remains in the 3+ oxidation state and the PDTA ligand is always bound to the metal. Upon reaction with albumin, apotransferrin or diferric transferrin, at a 1:1 ratio, RAP rapidly binds to these proteins to produce substantially equivalent and relatively stable adducts. This behavior is tentatively interpreted in terms of a tight interaction between RAP and surface residues of these proteins. The implications of these findings for the biological action of this novel ruthenium (III) compound are discussed.

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

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


    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

  11. Diene Hydroacylation from the Alcohol or Aldehyde Oxidation Level via Ruthenium Catalyzed C-C Bond Forming Transfer Hydrogenation: Synthesis of β,γ-Unsaturated Ketones

    Shibahara, Fumitoshi; Bower, John F.; Krische, Michael J.


    Under the conditions of ruthenium catalyzed transfer hydrogenation, isoprene couples to benzylic and aliphatic alcohols 1a–1g to deliver β,γ-unsaturated ketones 3a–3g in good to excellent isolated yields. Under identical conditions, aldehydes 2a–2g couple to isoprene to provide an identical set of β,γ-unsaturated ketones 3a–3g in good to excellent isolated yields. As demonstrated by the coupling of butadiene, myrcene and 1,2-dimethylbutadiene to representative alcohols 1b, 1c and 1e, diverse acyclic dienes participate in transfer hydrogenative coupling to form β,γ-unsaturated ketones. In all cases, complete branch-regioselectivity is observed and, with the exception of adduct 3j, isomerization to the conjugated enone is not detected. Thus, formal intermolecular diene hydroacylation is achieved from the alcohol or aldehyde oxidation level. In earlier studies employing a related ruthenium catalyst, acyclic dienes were coupled to carbonyl partners from the alcohol or aldehyde oxidation level to furnish branched homoallylic alcohols. Thus, under transfer hydrogenative coupling conditions, all oxidations levels of substrate (alcohol or aldehyde) and product (homoallyl alcohol or β,γ-unsaturated ketone) are accessible. PMID:18841895

  12. X-Ray structure and cytotoxic activity of a picolinate ruthenium(II–arene complex



    Full Text Available A ruthenium(II–arene complex with picolinic acid, [(η6-p-cymeneRuCl(pico]∙H2O, was prepared by the reaction of [(η6-p-cymeneRuCl2]2 with picolinic acid in a 1:2 molar ratio in 2-propanol. The compound was characterized by elemental analysis, and IR and NMR spectroscopy. X-ray diffraction analysis showed that the molecule adopts a “three-leg piano-stool” geometry, which is common for this type of complexes. The cytotoxic activity of the complex was tested in two human cancer cell lines HeLa (cervix and FemX (melanoma by MTT assay. The IC50 values were at 82.0 and 36.2 µmol dm-3 for HeLa and FemX cells, respectively.

  13. RutheniumII Complexes bearing Fused Polycyclic Ligands: From Fundamental Aspects to Potential Applications

    Ludovic Troian-Gautier


    Full Text Available In this review, we first discuss the photophysics reported in the literature for mononuclear ruthenium complexes bearing ligands with extended aromaticity such as dipyrido[3,2-a:2',3'-c]phenazine (DPPZ, tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]-phenazine (TPPHZ,  tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]acridine (TPAC, 1,10-phenanthrolino[5,6-b]1,4,5,8,9,12-hexaazatriphenylene (PHEHAT 9,11,20,22-tetraaza- tetrapyrido[3,2-a:2',3'-c:3'',2''-l:2''',3'''-n]pentacene (TATPP, etc. Photophysical properties of binuclear and polynuclear complexes based on these extended ligands are then reported. We finally develop the use of binuclear complexes with extended π-systems for applications such as photocatalysis.

  14. Ruthenium(II) complexes containing bidentate Schiff bases and triphenylphosphine or triphenylarsine

    P Viswanathamurthi; R Karvembu; V Tharaneeswaran; K Natarajan


    Reactions of ruthenium(II) complexes [RuHX(CO)(EPh3)2(B)] (X = H or Cl; B = EPh3, pyridine (py) or piperidine (pip); E = P or As) with bidentate Schiff base ligands derived by condensing - hydroxyacetophenone with aniline, - or -methylaniline have been carried out. The products were characterized by analytical, IR, electronic and 1H-NMR spectral studies and are formulated as [Ru(X)(CO) (L)(EPh3)(B)] (L = Schiff base anion; X = H or Cl; B = EPh3, py or pip; E = P or As). An octahedral structure has been tentatively proposed for the new complexes. The new complexes were tested for their catalytic activities in the oxidation of benzyl alcohol to benzaldehyde.

  15. Ruthenium-catalyzed synthesis of 5-amino-1,2,3-triazole-4-carboxylates for triazole-based scaffolds: beyond the dimroth rearrangement.

    Ferrini, Serena; Chandanshive, Jay Zumbar; Lena, Stefano; Comes Franchini, Mauro; Giannini, Giuseppe; Tafi, Andrea; Taddei, Maurizio


    The 5-amino-1,2,3-triazole-4-carboxylic acid is a suitable molecule for the preparation of collections of peptidomimetics or biologically active compounds based on the triazole scaffold. However, its chemistry may be influenced by the possibility of undergoing the Dimroth rearrangement. To overcome this problem, a protocol based on the ruthenium-catalyzed cycloaddition of N-Boc ynamides with azides has been developed to give a protected version of this triazole amino acid. When aryl or alkyl azides are reacted with N-Boc-aminopropiolates or arylynamides, the cycloaddition occurs with complete regiocontrol, while N-Boc-alkyl ynamides yield a mixture of regioisomers. The prepared amino acids were employed for the preparation of triazole-containing dipeptides having the structural motives typical of turn inducers. In addition, triazoles active as HSP90 inhibitors (as compound 41, IC50 = 29 nM) were synthesized.

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

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


    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…

  17. Hydrido-ruthenium cluster complexes as models for reactive surface hydrogen species of ruthenium nanoparticles. Solid-state 2H NMR and quantum chemical calculations.

    Gutmann, Torsten; Walaszek, Bernadeta; Yeping, Xu; Wächtler, Maria; del Rosal, Iker; Grünberg, Anna; Poteau, Romuald; Axet, Rosa; Lavigne, Guy; Chaudret, Bruno; Limbach, Hans-Heinrich; Buntkowsky, Gerd


    The (2)H quadrupolar interaction is a sensitive tool for the characterization of deuterium-metal binding states. In the present study, experimental solid-state (2)H MAS NMR techniques are used in the investigations of two ruthenium clusters, D(4)Ru(4)(CO)(12) (1) and D(2)Ru(6)(CO)(18) (2), which serve as model compounds for typical two-fold, three-fold, and octahedral coordination sites on metal surfaces. By line-shape analysis of the (2)H MAS NMR measurements of sample 1, a quadrupolar coupling constant of 67 +/- 1 kHz, an asymmetry parameter of 0.67 +/- 0.1, and an isotropic chemical shift of -17.4 ppm are obtained. In addition to the neutral complex, sample 2 includes two ionic clusters, identified as anionic [DRu(6)(CO)(18)](-) (2(-)) and cationic [D(3)Ru(6)(CO)(18)](+) (2(+)). By virtue of the very weak quadrupolar interaction (Quantum chemical DFT calculations at different model structures for these ruthenium clusters were arranged in order to help in the interpretation of the experimental results. It is shown that the (2)H nuclear quadrupolar interaction is a sensitive tool for distinguishing the binding state of the deuterons to the transition metal. Combining the data from the polynuclear complexes with the data from mononuclear complexes, a molecular ruler for quadrupolar interactions is created. This ruler now permits the solid-state NMR spectroscopic characterization of deuterium adsorbed on the surfaces of catalytically active metal nanoparticles.

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

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


    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.

  19. Discovery of a highly tumor-selective organometallic ruthenium(II)-arene complex.

    Clavel, Catherine M; Păunescu, Emilia; Nowak-Sliwinska, Patrycja; Griffioen, Arjan W; Scopelliti, Rosario; Dyson, Paul J


    A ruthenium(II)-arene complex with a perfluoroalkyl-ligand was found to display remarkable selectivity toward cancer cells. IC50 values on several cancer cell lines are in the range of 25-45 μM, and no cytotoxic effect was observed on nontumorigenic (HEK-293) cells at concentrations up to 500 μM (the maximum concentration tested). Consequently, this complex was used as the basis for the development of a number of related derivatives, which were screened in cancerous and noncancerous cell lines. The lead compound was then evaluated in vivo for antiangiogenic activity in the CAM model and in a xenografted ovarian carcinoma tumor (A2780) grown on the CAM. A 90% reduction in the tumor growth was observed.

  20. Synthesis of Optically Active Polystyrene Catalyzed by Monophosphine Pd Complexes.

    Jouffroy, Matthieu; Armspach, Dominique; Matt, Dominique; Osakada, Kohtaro; Takeuchi, Daisuke


    Cationic Pd(II) monophosphine complexes derived from α- and β-cyclodextrins (CDs) promote the homopolymerization of styrene under carbon monoxide pressure. Although reversible CO coordination takes place under catalytic conditions according to (13) C NMR studies with (13) C-enriched CO, both complexes catalyze the formation of CO-free styrene polymers. These macromolecules display optical activity as a result of the presence of stereoregular sequences within the overall atactic polymer.

  1. Photocatalytic degradation of bromothymol blue with Ruthenium(II) bipyridyl complex in aqueous basic solution

    Fui, Mark Lee Wun; Hang, Ng Kim; Arifin, Khuzaimah; Minggu, Lorna Jeffery; Kassim, Mohammad Bin


    Ru(II) bipyridyl photocatalyst with the formula, [Ru(bpy)2(o-CH3-bzpypz)](PF6)2] (Ru01) and [Ru(bpy)2(o-Cl-bzpypz)](PF6)2] (Ru02), where bpy = 2,2'-bipyridyl, o-CH3-bzpypz = (3-(pyridin-2-yl)-1H-pyrazol-1-yl)(o-tolyl)methanone and o-Cl-bzpypz = (2-chlorophenyl)(3-(pyridin-2-yl)-1H-pyrazol-1-yl)methanone, has been successfully synthesized and characterized on the basis of C, H, N elemental analysis, IR, UV-Vis and NMR spectroscopy. Both Ru(II) complexes showed Infrared stretching frequencies at 1742-1736 cm-1 v(C=O), 1605 cm-1 v(C=N) and 842-837 cm-1 v(PF). Full geometry optimization of the complex structures were carried out using DFT method with B3LYP exchange-correlation functional and 6-31G (d,p) basis-set for H, C, N, O and Cl; and LAN2LDZ basis set as effective core potential for the ruthenium centre. The highest-occupied molecular orbital (HOMO) energy levels of Ru01 and Ru02 are -5.63 and -5.55 eV, respectively. The photocatalytic properties of the Ru(II) complexes were evaluated by studying the degradation of aqueous bromothymol blue (BTB) under light illumination. The mechanisms are presented and discussed to highlight the role of the ruthenium complex in the degradation process.

  2. Selective Catalytic Hydrogenation of Arenols by a Well-Defined Complex of Ruthenium and Phosphorus–Nitrogen PN3–Pincer Ligand Containing a Phenanthroline Backbone

    Li, Huaifeng


    Selective catalytic hydrogenation of aromatic compounds is extremely challenging using transition-metal catalysts. Hydrogenation of arenols to substituted tetrahydronaphthols or cyclohexanols has been reported only with heterogeneous catalysts. Herein, we demonstrate the selective hydrogenation of arenols to the corresponding tetrahydronaphthols or cyclohexanols catalyzed by a phenanthroline-based PN3-ruthenium pincer catalyst.

  3. Formation, Isolation and Characterization of a New Ruthenium Complex in Reaction of Acetone Masked Terminal Alkynone with Transfer Hydrogenation Catalyst

    郭敏捷; 李到; 孙延辉; 成江; 张兆国


    Reaction of [1S,2S-(Ts-diphen)Ru(Ⅱ)(p-cymene)] (1S,2S-Ts-diphen= 1S,2S-N-tosyl-1,2-diphenylethylenediamine) and 2-hydroxy-2-methyl-non-3-yn-5-one under transfer hydrogenation condition gave a ruthenium complex bearing a 2,5-dihydrofuran moiety. The complex was characterized and a possible mechanism for the formation of the complex was proposed.

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

    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


    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

  5. Spectroelectrochemical studies of hole percolation on functionalised nanocrystalline TiO2 films: a comparison of two different ruthenium complexes.

    Li, Xiaoe; Nazeeruddin, Mohammad K; Thelakkat, Mukundan; Barnes, Piers R F; Vilar, Ramón; Durrant, James R


    We report the application of spectroelectrochemical techniques to compare the hole percolation dynamics of molecular networks of two ruthenium bipyridyl complexes adsorbed onto mesoporous, nanocrystalline TiO(2) films. The percolation dynamics of the ruthenium complex cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-tridecyl) ruthenium(II), N621, is compared with those observed for an analogous dye with an additional tri-phenyl amine (TPA) donor moiety, cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-bis(vinyltriphenylamine)) ruthenium(II), HW456. The in situ oxidation of these ruthenium complexes adsorbed to the TiO(2) films is monitored by cyclic voltammetry and voltabsorptometry, whilst the dynamics of hole (cation) percolation between adsorbed ruthenium complexes is monitored by potentiometric spectroelectrochemistry and chronoabsorptometry. The hole diffusion coefficient, D(eff), is shown to be dependent on the dye loading on the nanocrystalline TiO(2) film, with a threshold observed at ∼60% monolayer surface coverage for both dyes. The hole diffusion coefficient of HW456 is estimated to be 2.6 × 10(-8) cm(2)/s, 20-fold higher than that obtained for the control N621, attributed to stronger electronic coupling between the TPA moieties of HW456 accelerating the hole percolation dynamics. The presence of mercuric ions, previously shown to bind to the thiocyanates of analogous ruthenium complexes, resulted in a quenching of the hole percolation for N621/TiO(2) films and an enhancement for HW456/TiO(2) films. These results strongly suggest that the hole percolation pathway is along the overlapped neighbouring -NCS groups for the N621 molecules, whereas in HW456 molecules cation percolation proceeds between intermolecular TPA ligands. These results are discussed in the context of their relevance to the process of dye regeneration in dye sensitised solar cells, and to the molecular wiring of wide

  6. Synthesis, spectroscopic characterization and catalytic oxidation properties of ONO/ONS donor Schiff base ruthenium(III) complexes containing PPh3/AsPh3

    Priyarega; M Muthu Tamizh; R Karvembu; R Prabhakaran; K Natarajan


    Six different ruthenium(III) complexes of Schiff bases derived from 2-hydroxy-1-naphthaldehyde and -aminophenol/-aminothiophenol have been synthesized. The compounds with the general formula [RuX(EPh3)2(L)] (X = Cl or Br; E = P or As; L = bifunctional tridentate ONO/ONS donor Schiff base ligand) were characterized by infrared, electronic, electron paramagnetic resonance spectroscopy and elemental analyses. Spectroscopic investigation reveals coordination of Schiff base ligand through ONO/ONS donor atoms and octahedral geometry around ruthenium metal. Redox property of complexes has been examined by using cyclic voltammetry. The catalytic oxidation property of ruthenium(III) complexes were also investigated.

  7. Organic-Ruthenium(II Polypyridyl Complex Based Sensitizer for Dye-Sensitized Solar Cell Applications

    Lingamallu Giribabu


    Full Text Available A new high molar extinction coefficient organic-ruthenium(II polypyridyl complex sensitizer (RD-Cou that contains 2,2,6,6-tetramethyl-9-thiophene-2-yl-2,3,5,6,6a,11c-hexahydro1H,4H-11oxa-3a-aza-benzoanthracene-10-one as extended -conjugation of ancillary bipyridine ligand, 4,4-dicaboxy-2,26,2-bipyridine, and a thiocyanate ligand in its molecular structure has been synthesized and completely characterized by CHN, Mass, 1H-NMR, UV-Vis, and fluorescence spectroscopies as well as cyclic voltammetry. The new sensitizer was tested in dye-sensitized solar cells using a durable redox electrolyte and compared its performance to that of standard sensitizer Z-907.

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

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


    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.

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

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


    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.

  10. Synthesis, characterization luminiscence studies and microbial activity of ethylenediamine ruthenium (II) complexes with dipyridophenazine ligands.

    Shilpa, Mynam; Nagababu, Penumaka; Kumar, Y Praveen; Latha, J Naveena Lavanya; Reddy, M Rajender; Karthikeyan, K S; Gabra, Nazar Md; Satyanarayana, Sirasani


    Three symmetric ligands 7-methyl dipyrido-[3,2-a;2',3'-c]phenazine (dppz-CH(3)), 7-nitro dipyrido-[3,2-a;2',3'-c]phenazine (dppz-NO(2)) and benzo[i]dipyrido-[3,2-a;2',3'-c]phenazine (dppn) and their ruthenium(II) complexes [Ru(en)(2)(L)][ClO(4)](2) (en= ethylenediamine), L= dppz-CH(3), dppz-NO(2) and dppn have been synthesized and characterized by IR, (1)H, (13)C NMR and Mass spectra. The interactions of these complexes with calf thymus DNA have been investigated by spectrophotometric, spectrofluorimetric, circular dichroism, viscosity and thermal denaturation studies. As the planar extension of the intercalative ligand increases, the interaction of the complex with DNA increases, indicating that the size and shape of the intercalalative ligand has a marked effect on the strength of interaction. The plot of log K versus log [Na(+)] yield a slope of -1.26, -1.53, -1.60 for the complexes 1, 2 and 3 respectively. These three complexes have been found to promote the cleavage of plasmid pBR 322 DNA upon irradiation.

  11. Ruthenium(II) carbonyl complexes containing chalconates and triphenylphosphine/arsine

    P Viswanathamurthi; M Muthukumar


    A series of new hexa-coordinated ruthenium(II) carbonyl complexes of the type [RuCl(CO)(EPh3)(B)(L1−4)] (4-15) (E = P or As; B = PPh3, AsPh3 or Py; L = 2'-hydroxychalcone) were synthesized from the reaction of [RuHCl(CO)(EPh3)2(B)] (1-3) (E = P or As; B = PPh3, AsPh3 or Py) with equimolar chalcone in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (IR, electronic, 1H, 31P{1H}, and 13C NMR) methods. On the basis of data obtained, an octahedral structure has been assigned for all the complexes. The complexes exhibit catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of -methylmorpholine--oxide (NMO) as co-oxidant and were also found to be efficient transfer hydrogenation catalysts. The antifungal properties of the ligands and their complexes have also been examined and compared with standard Bavistin.

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

    Mutter, Shaun T; Platts, James A


    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.

  13. NO Exchange for a Water Molecule Favorably Changes Iontophoretic Release of Ruthenium Complexes to the Skin

    Danielle C. A. S. de Santana


    Full Text Available Ruthenium (Ru complexes have been studied as promising anticancer agents. Ru nitrosyl complex (Ru-NO is one which acts as a pro-drug for the release of nitric oxide (NO. The Ru-aqueous complex formed by the exchange of NO for a water molecule after NO release could also possess therapeutic effects. This study evaluates the influence of iontophoresis on enhancing the skin penetration of Ru-NO and Ru-aqueous and assesses its applicability as a tool in treating diverse skin diseases. Passive and iontophoretic (0.5 mA·cm−2 skin permeation of the complexes were performed for 4 h. The amount of Ru and NO in the stratum corneum (SC, viable epidermis (VE, and receptor solution was quantified while the influence of iontophoresis and irradiation on NO release from Ru-NO complex was also evaluated. Iontophoresis increased the amount of Ru-NO and Ru-aqueous recovered from the receptor solution by 15 and 400 times, respectively, as compared to passive permeation. Iontophoresis produced a higher accumulation of Ru-aqueous in the skin layers as compared to Ru-NO. At least 50% of Ru-NO penetrated the SC was stable after 4 h. The presence of Ru-NO in this skin layer suggests that further controlled release of NO can be achieved by photo-stimulation after iontophoresis.

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

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


    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.

  15. Ruthenium complexes with chiral tetradentate PNNP ligands: asymmetric catalysis from the viewpoint of inorganic chemistry.

    Mezzetti, Antonio


    This is a personal account of the application of ruthenium complexes containing chiral tetradentate ligands with a P(2)N(2) ligand set (PNNP) as catalyst precursors for enantioselective "atom transfer" reactions. Therewith are meant reactions that involve bond formation between a metal-coordinated molecule and a free reagent. The reactive fragment (e.g. carbene) is transferred either from the metal to the non-coordinated substrate (e.g. olefin) or from the free reagent (e.g. F(+)) to the metal-bound substrate (e.g.beta-ketoester), depending on the class of catalyst (monocationic, Class A; or dicationic, Class B). The monocationic five-coordinate species [RuCl(PNNP)](+) and the six-coordinate complexes [RuCl(L)(PNNP)](+) (L = Et(2)O, H(2)O) of Class A catalyse asymmetric epoxidation, cyclopropanation (carbene transfer from the metal to the free olefin), and imine aziridination. Alternatively, the dicationic complexes [Ru(L-L)(PNNP)](2+) (Class B), which contain substrates that act as neutral bidentate ligands L-L (e.g., beta-ketoesters), catalyse Michael addition, electrophilic fluorination, and hydroxylation reactions. Additionally, unsaturated beta-ketoesters form dicationic complexes of Class B that catalyse Diels-Alder reactions with acyclic dienes to produce tetrahydro-1-indanones and estrone derivatives. Excellent enantioselectivity has been achieved in several of the catalytic reactions mentioned above. The study of key reaction intermediates (both in the solid state and in solution) has revealed significant mechanistic aspects of the catalytic reactions.

  16. Ruthenium (II) complexes of thiosemicarbazone: Synthesis, biosensor applications and evaluation as antimicrobial agents

    Yildirim, Hatice [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Buca, Izmir (Turkey); Guler, Emine [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Yavuz, Murat, E-mail: [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Dicle University, Faculty of Science, Department of Chemistry, 21280 Diyarbakir (Turkey); Ozturk, Nurdan; Kose Yaman, Pelin [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Buca, Izmir (Turkey); Subasi, Elif; Sahin, Elif [Dokuz Eylul University, Faculty of Science, Department of Chemistry, 35160 Buca, Izmir (Turkey); Timur, Suna [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Ege University, Institute on Drug Abuse, Toxicology and Pharmaceutical Science (BATI), 35100 Bornova, Izmir (Turkey)


    A conformationally rigid half-sandwich organoruthenium (II) complex [(η{sup 6}-p-cymene)RuClTSC{sup N–S}]Cl, (1) and carbonyl complex [Ru(CO)Cl(PPh{sub 3}){sub 2}TSC{sup N–S}] (2) have been synthesized from the reaction of [{(η"6-p-cymene)RuCl}{sub 2}(μ-Cl){sub 2}] and [Ru(H)(Cl)(CO)(PPh{sub 3}){sub 3}] with thiophene-2-carboxaldehyde thiosemicarbazon (TSC) respectively and both novel ruthenium (II) complexes have been characterized by elemental analysis, FT-IR and NMR spectroscopy. The peripheral TSC in the complexes acts as an electrochemical coupling unit providing the ability to carry out electrochemical deposition (ED) and to form an electro-deposited film on a graphite electrode surface. The biosensing applicability of complexes 1 and 2 was investigated by using glucose oxidase (GOx) as a model enzyme. Electrochemical measurements at − 0.9 V versus Ag/AgCl electrode by following the ED Ru(II) reduction/oxidation due to from the enzyme activity, in the presence of glucose substrate. The designed biosensor showed a very good linearity for 0.01–0.5 mM glucose. The in vitro antimicrobial activities of complexes 1 and 2 were also investigated against nine bacterial strains and one fungus by the disc diffusion test method. No activity was observed against the Gram-negative strains and fungus, whereas complex 1 showed moderate antibacterial activities against Gram-positive bacterial strains. - Highlights: • Novel Ru (II) thiosemicarbazone complexes were synthesized and characterized. • Electrochemical depositions were performed. • Rigid half-sandwich Ru (II) complex showed enhanced antibacterial activity.

  17. Ruthenium complexes of chelating amido-functionalized N-heterocyclic carbene ligands: Synthesis, structure and DFT studies

    Sachin Kumar; Anantha Narayanan; Mitta Nageswar Rao; Mobin M Shaikh; Prasenjit Ghosh


    Synthesis, structure and density functional theory (DFT) studies of a series of new ruthenium complexes, [1-(R)-3--(benzylacetamido)imidazol-2-ylidene]RuCl(-cymene) [R = Me (1c), -Pr (2c), CH2Ph (3c); -cymene = 4--propyltoluene] supported over /-functionalized N-heterocyclic carbene (NHC) ligands are reported. In particular, the ruthenium (1-3)c complexes were synthesized from the respective silver complexes, [1-(R)-3--(benzylacetamido)imidazol-2-ylidene]2Ag+Cl− [R = Me (1b), -Pr (2b), CH2Ph (3b)] by the treatment with [Ru(-cymene)Cl2]2 in 65-76% yields. The molecular structures of (1-3)c revealed the chelation of the N-heterocylic carbene ligand through the carbene center and an amido sidearm of the ligand in all of the three complexes. The density functional theory studies on the ruthenium (1-3)c complexes indicated strong binding of the NHC ligand to the metal center as was observed from the deeply buried NHC-Ru -bonding molecular orbitals.

  18. Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

    Singh, K.S.; Kaminsky, W.

    Synthesis of (η6-arene) ruthenium (II) complexes has attracted considerable attention owing to their anti-cancer [1-3], antiviral [4] and catalytic properties [5-7]. The catalytic activities of these complexes range from hydrogen transfer to ring closing...

  19. Enantioselective Cyclopropanation of a Wide Variety of Olefins Catalyzed by Ru(II)-Pheox Complexes.

    Chanthamath, Soda; Iwasa, Seiji


    The transition-metal-catalyzed asymmetric cyclopropanation of olefins with diazoacetates has become one of the most important methods for the synthesis of optically active cyclopropane derivatives, which are key pharmaceutical building blocks and present in a large number of natural products. To date, significant progress has been made in this area of research, and efficient stereocontrolled synthetic approaches to cyclopropane derivatives have been developed using rhodium, ruthenium, copper, and cobalt catalysts. However, the vast majority of these strategies are limited to electron-rich olefins, such as styrene derivatives, due to the electrophilicity of the metal-carbene intermediates generated from the reaction of the metal with the diazo compound. Recently, the D2-symmetric Co(II)-phophyrin complexes developed by Zhang et al. were shown to be the most efficient catalysts for the asymmetric cyclopropanation of electron-deficient olefins. This catalytic system is mechanistically distinct from the previous rhodium and copper catalytic systems, proceeding via radical intermediates. However, the asymmetric cyclopropanation of vinyl carbamates, allenes, and α,β-unsaturated carbonyl compounds has rarely been reported. Therefore, the development of new powerful catalysts for the asymmetric cyclopropanation of a wide range of olefinic substrates is the next challenge in this field. In this Account, we summarize our recent studies on the Ru(II)-Pheox-catalyzed asymmetric cyclopropanation of various olefins, including vinyl carbamates, allenes, and α,β-unsaturated carbonyl compounds. We demonstrate that the developed catalytic system effectively promotes the asymmetric cyclopropanation of a wide variety of olefins to produce the desired cyclopropane products in high yields with excellent stereocontrol. The use of succinimidyl-, ketone-, and ester-functionalized diazoacetates as carbene sources was found to be crucial for the high stereoselectivity of the

  20. Ruthenium-catalyzed intramolecular metathesis of dienes and its application in the synthesis of bridged and spiro azabicycles

    Kuznetsov, N. Yu; Bubnov, Yu N.


    The review presents a historical excursion into catalytic alkene metathesis, covering the problems of history of the discovery of this process, as well as investigations on the properties, structure and reactivity of the most popular ruthenium catalysts for metathesis, mechanism of their action and decomposition. The main part covers studies devoted to the syntheses of bridged azabicyclic and 1-azaspirocyclic compounds comprising the intramolecular metathesis of dienes as the key step. The formation of a bicyclic skeleton of a series of natural bridged (cocaine, ferruginine, calystegines, and anatoxin-a) and spiro (pinnaic acids, halichlorine, hystrionicotoxin, and cephalotaxine) azabicycles, as well as their analogues and compounds with larger rings is demonstrated. The methods for the synthesis of diene precursors and the conditions for final assembling of the bicyclic compounds are considered in detail. The generalization of the literature data allows one to efficiently carry out the mentioned process taking into account the most important features. The bibliography includes 129 references.

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

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


    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.

  2. Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems

    T. Brent Gunnoe


    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

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

    Kreitner, Christoph; Heinze, Katja


    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.

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

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


    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

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

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


    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.

  6. The Intramolecular Spin-Spin Interactions in Ruthenium Complexes of Pyrazole Derivatives

    Peter A.Aj ibade


    The spin-spin coupling can provide useful information for analysing the structure of a system and the extent of non-covalent bonds interactions.In this study,we present the isotropic NMR properties and spin-spin coupling involving ruthenium-ligand (Ru-L)bonds and other spin-spin interactions obtained from DFT calculations.The proton shift which in close proximity with the Ru and Cl (or O)atoms are characterised with lower and higher chemical shift respectively.Though Ru-Cl bond has longer bond length than all other Ru-L bonds,yet its spin-spin coupling is higher than others because of a very high contribution of PSO which is far higher than the contribution from FC terms.In all other Ru-L bonds,FC is the most significant Ramsey terms that define their spin-spin coupling.Both the isotropic and anisotropic shielding of the Hz of the pyrazole is lower than Hc of the cymene and the spin-spin coupling 3 J(Hz…Hz)of the pyrazole are less than half of the 3 J (Hc…Hc)of the cymene unit in the complexes.There is a little increase in both the 3 J(Hc…Hc)and 3 J(Hz…Hz)spin-spin coupling in the hydrolysed complexes compare to the non-hydrolysed complexes.The isotropic and anisotropic shielding tensor of Ru atoms increases in magnitude as the complexes get hydrolysed that could be ascribed to a more deshielding chemical environments.

  7. Thermodynamic and structural study of phenanthroline derivative ruthenium complex/DNA interactions: probing partial intercalation and binding properties.

    Grueso, E; López-Pérez, G; Castellano, M; Prado-Gotor, R


    The binding of [Ru(PDTA-H(2))(phen)]Cl (PDTA = propylene-1,2-diaminetetra-acetic acid; phen = 1,10 phenanthroline) with ctDNA (=calf thymus DNA) has been investigated through intrinsic and induced circular dichroism, UV-visible absorption and fluorescence spectroscopies, steady-state fluorescence, thermal denaturation technique, viscosity and electrochemical measurements. The latter indicate that the cathodic and anodic peak potentials of the ruthenium complex shift to more positive values on increasing the DNA concentration, this behavior being a direct consequence of the interaction of both the reduced and oxidized form with DNA binding. From spectrophotometric titration experiments, the equilibrium binding constant and the number of monomer units of the polymer involved in the binding of one ruthenium molecule (site size) have been quantified. The intrinsic circular dichroism (CD) spectra show an unwinding and a conformational change of the DNA helix upon interaction of the ruthenium complex. Quenching process, thermal denaturation experiments and induced circular dichroism (ICD) are consistent with a partial intercalative binding mode. Copyright © 2011 Elsevier Inc. All rights reserved.

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


    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

  9. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C


    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested a......',2"] terpyridine-4'-carboxylic acid with a maximum output power similar to 0.016mWcm(-2) under illumination at 100mWcm(-2) AM1.5 and efficiencies 3 times higher than the symmetric complexes. (c) 2006 Elsevier B.V. All rights reserved....

  10. Unravelling The Mechanism of Basic Aqueous Methanol Dehydrogenation Catalyzed By Ru-PNP Pincer Complexes

    Alberico, Elisabetta; Lennox, Alastair J. J.; Vogt, Lydia K.;


    Ruthenium PNP complex 1a (RuH(CO)Cl(HN(C2H4Pi-Pr2)2)) represents a state-of-the-art catalyst for low-temperature (methanol dehydrogenation to H2 and CO2. Herein, we describe an investigation that combines experiment, spectroscopy, and theory to provide a mechanistic rationale...

  11. A tetranuclear ruthenium complex with bridging pyridine-2,4-dicarboxylato ligands forming a square metallamacrocycle

    Xie, Yu-Feng; Jia, Ai-Quan; Zhu, Hang; Shi, Hua-Tian; Zhang, Qian-Feng [Anhui Univ. of Technology (China). Inst. of Molecular Engineering and Applied Chemistry


    Treatment of [RuCl{sub 2}(PPh{sub 3}){sub 3}] with equimolar amounts of 2,4-pyridinedicarboxylic acid (2,4-dipicH{sub 2}) in the presence of Et{sub 3}N afforded a tetranuclear complex [Ru(μ-2,4-dipic)(PPh{sub 3}){sub 2}]{sub 4} (1) as red crystals. The crystal and molecular structure of [Ru(μ-2,4-dipic)(PPh{sub 3}){sub 2}]{sub 4}.CHCl{sub 3}.8H{sub 2}O (1.CHCl{sub 3}.8H{sub 2}O) was determined by single-crystal X-ray diffraction. Each ruthenium center in 1 is six-coordinated with two phosphorus atoms from triphenylphosphine ligands, one nitrogen atom from a pyridyl moiety and three oxygen atoms from two 2,4-dipic{sup 2-} ligands. 2,4-Pyridinedicarboxylate dianions (2,4-dipic{sup 2-}) act as bridging ligands to form the stable tetranuclear metallamacrocyclic compound. The electrochemical properties of 1 were also investigated.

  12. Assemblies composed of oligothiophene–ruthenium complexes bound to CdSe nanoparticles

    Bair, Nathan; Hancock, Jared M.; Simonson, Cameron J. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Thalman, Scott W.; Colton, John S. [Department of Physics and Astronomy,Brigham Young University, Provo, UT 84602 (United States); Asplund, Matthew C. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Harrison, Roger G., E-mail: [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States)


    Molecular conjugates are important to link light sensitized materials to electron acceptors. We have synthesized oligothiophenes and oligothiophene–ruthenium complexes and bound them to CdSe nanoparticles. The absorption and fluorescence properties of the oligothiophenes bound to CdSe were measured. Steady-state luminescence and time correlated single photon counting were used to observe the effects on fluorescence and fluorescence lifetimes before and after binding. It was found that fluorescence of CdSe nanoparticles was quenched when they were bound to the oligothiophenes, and that the fluorescence of the oligothiophenes was also quenched. The fluorescence lifetimes of the quenched species were shortened and suggest electron transfer from oligothiophene to nanoparticle is on the order of one nanosecond. Orbital energy calculations predict that the Ru bound oligothiophenes have HOMO–LUMO energies of correct energy to allow electron and hole transfer. These experiments show that the oligothiophenes efficiently transfer optical energy between CdSe nanoparticles and could potentially be used as charge transfer junctions. - Highlights: • Ru bound thiophenes attached to CdSe nanoparticles. • Luminescence quenching of CdSe nanoparticles. • Molecular conjugates for photosensitized materials.

  13. IRC analysis of methanol carbonylation reaction catalyzed by rhodium complex

    HAO Maorong; FENG Wenlin; JI Yongqiang; LEI Ming


    In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using the energy gradient method at HF/LANL2DZ level, and the changes of their potential profiles have also been calculated. Through IRC analyses of the transition states for each elemental reaction, it is confirmed that the various structure geometries obtained are stationary points on the cycle reaction pathway of methanol carbonylation catalyzed by Rh complex, and the changes are given in energies and structure geometries of the reactant molecules along the reaction pathway of lowest energy. It has been proposed that the geometrical conversions of intermediates play an important role during the cycle reaction. Through analyses of structure geometries, it has been suggested that, in addition to cis- and trans- structure exchange linkage of catalysis reactive species, the two pathways, cis- and trans-cata- lyzed cycle reactions, can also be linked through geometrical conversion of intermediates, of which the activation energy is 49.79 kJ/mol. Moreover, the reductive elimination elemental reaction may be neither cis-cycle nor trans- one, showing that the cycle reaction can be achieved through various pathways. However different the pathway, the oxidative addition elemental reaction of CH3I is the rate-controlling step.

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

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


    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.

  15. High spectral response heteroleptic ruthenium (II) complexes as sensitizers for dye sensitized solar cells

    M Chandrasekharam; Ch Srinivasarao; T Suresh; M Anil Reddy; M Raghavender; G Rajkumar; M Srinivasu; P Yella Reddy


    Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyridyl) (4,4'-dicarboxy-2,2'-bipyridyl) (NCS2) (H112) was synthesized and characterized by 1H-NMR, MASS, Spectrofluorometer and UV-Vis spectroscopes. The photo-voltaic performance of the sensitizer was evaluated in Dye Sensitized Solar Cell (DSSC) under irradiation of AM 1.5 G solar light and the photovoltaic characteristics were compared with those of reference cells of HRS1 and N719 fabricated under comparable conditions. Compared to N719, H112 sensitizer showed enhanced molar extinction coefficient and relatively better monochromatic incident photon-to-current conversion efficiency (IPCE) across the spectral range of 400 to 800 nm with solar energy-to-electrical conversion efficiency () of 2.43% [open circuit photovoltage (VOC) = 0.631V, short-circuit photocurrent density (JSC) = 8.96 mA/cm2, fill factor (ff) = 0.430], while values of 2.51% (VOC = 0.651V, JSC = 9.41 mA/cm2, ff = 0.410) and 2.74% (VOC = 0.705 V, JSC = 8.62 mA/cm2, ff = 0.455) were obtained for HRS1 and N719 sensitized solar cells respectively. The introduction of 4,4'-bis(4-tert-butylstyryl) moieties on one of the bipyridine moieties of N719 complex shows higher light absorption abilities, IPCE and JSC.

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

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


    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.

  17. Evaluation of arene ruthenium(II) N-heterocyclic carbene complexes as organometallics interacting with thiol and selenol containing biomolecules.

    Oehninger, Luciano; Stefanopoulou, Maria; Alborzinia, Hamed; Schur, Julia; Ludewig, Stephanie; Namikawa, Kazuhiko; Muñoz-Castro, Alvaro; Köster, Reinhard W; Baumann, Knut; Wölfl, Stefan; Sheldrick, William S; Ott, Ingo


    Metal complexes with N-heterocyclic carbene (NHC) ligands have been widely used in catalytic chemistry and are now increasingly considered for the development of new chemical tools and metal based drugs. Ruthenium complexes of the type (p-cymene)(NHC)RuCl(2) interacted with biologically relevant thiols and selenols, which resulted in the inhibition of enzymes such as thioredoxin reductase or cathepsin B. Pronounced antiproliferative effects could be obtained provided that an appropriate cellular uptake was achieved. Inhibition of tumor cell growth was accompanied by a perturbation of metabolic parameters such as cellular respiration.

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

    Rouen, Mathieu


    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.

  19. 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.

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


    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.

  20. Ruthenium-ion-catalyzed oxidation of asphaltenes and oil-source correlation of heavy oils from the Lunnan and Tahe oilfields in the Tarim Basin, NW China

    MA Anlai; ZHANG Shuichang; ZHANG Dajiang; JIN Zhijun; MA Xiaojuan; CHEN Qingtang


    The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphaltenes in heavy oils from the Lunnan and Tahe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations. The RICO products included n-alkanoic acids, α, ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid , regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields are different from those of Well TD2. The biomarkers bounded on the asphaltenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C2s sterane and C29 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tahe oilfields.

  1. Cyclometallated ruthenium(II) carbonyl complexes with 1-pyrenaldehyde 4-R-3-thiosemicarbazones: Regioselective ruthenation of the 1-pyrenyl group

    Rupesh Narayana Prabhu; Samudranil Pal


    A facile method for the synthesis of a series of cyclometallated ruthenium(II) carbonyl complexes with 1-pyrenaldehyde 4-R-3-thiosemicarbazones (H2Ln where the two H’s represent the dissociable thioamide and pyrenyl protons; R = H, Me and Ph) has been described. The characterization of the complexes having the general molecular formula trans-[Ru(Ln)(CO)(EPh33)2] (where E = P or As) were accomplished by elemental (CHN) analysis, magnetic susceptibility and spectroscopic (ESI-MS, IR, UV-Vis, emission and 1H-NMR) measurements. Electronic spectra of the complexes display multiple strong absorptions in the range 440–224 nm due to intraligand transitions. All the complexes exhibit emission bands that are characteristic of ligand centred emissive states. X-ray diffraction studies with representative complexes reveal a pincer-like 5,5-membered fused chelate rings forming CNS coordination mode of the thiosemicarbazonate ligand (Ln)2− via regioselective activation of 1-pyrenyl ortho C–H and formation of a distorted octahedral C2NSE2 coordination sphere around the ruthenium(II) centre.

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

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


    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.

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

    Prakash, Govindan; Viswanathamurthi, Periasamy


    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.

  4. A High Molar Extinction Coefficient Mono-Anthracenyl Bipyridyl Heteroleptic Ruthenium(II Complex: Synthesis, Photophysical and Electrochemical Properties

    Peter A. Ajibade


    Full Text Available In our quest to develop good materials as photosensitizers for photovoltaic dye-sensitized solar cells (DSSCs, cis-dithiocyanato-4-(2,3-dimethylacrylic acid-2,2'-bipyridyl-4-(9-anthracenyl-(2,3-dimethylacrylic-2,2'-bipyridyl ruthenium(II complex, a high molar extinction coefficient charge transfer sensitizer, was designed, synthesized and characterized by spectroscopy and electrochemical techniques. Earlier studies on heteroleptic ruthenium(II complex analogues containing functionalized oligo-anthracenyl phenanthroline ligands have been reported and documented. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, herein, we report the photophysical and electrochemical properties of a Ru(II bipyridyl complex analogue with a single functionalized anthracenyl unit. Interestingly, the complex shows better broad and intense metal-to ligand charge transfer (MLCT band absorption with higher molar extinction coefficient (λmax = 518 nm, e = 44900 M−1cm−1, and appreciable photoluminescence spanning the visible region than those containing higher anthracenyl units. It was shown that molar absorption coefficient of the complexes may not be solely depended on the extended π-conjugation but are reduced by molecular aggregation in the molecules.

  5. Outer-sphere 2 e{sup -}/2 H{sup +} transfer reactions of ruthenium(II)-amine and ruthenium(IV)-amido complexes

    Cattaneo, Mauricio [Department of Chemistry, University of Washington (United States); INQUINOA-CONICET, Universidad Nacional de Tucuman, San Miguel de Tucuman (Argentina); Ryken, Scott A. [Department of Chemistry, University of Washington (United States); Mayer, James M. [Department of Chemistry, University of Washington (United States); Department of Chemistry, Yale University, New Haven, CT, 06520 (United States)


    A diverse set of 2 e{sup -}/2 H{sup +} reactions are described that interconvert [Ru{sup II}(bpy)(en*){sub 2}]{sup 2+} and [Ru{sup IV}(bpy)(en-H*){sub 2}]{sup 2+} (bpy=2,2'-bipyridine, en*=H{sub 2}NCMe{sub 2}CMe{sub 2}NH{sub 2}, en*-H=H{sub 2}NCMe{sub 2}CMe{sub 2}NH{sup -}), forming or cleaving different O-H, N-H, S-H, and C-H bonds. The reactions involve quinones, hydrazines, thiols, and 1,3-cyclohexadiene. These proton-coupled electron transfer reactions occur without substrate binding to the ruthenium center, but instead with precursor complex formation by hydrogen bonding. The free energies of the reactions vary over more than 90 kcal mol{sup -1}, but the rates are more dependent on the type of X-H bond involved than the associated ΔG . There is a kinetic preference for substrates that have the transferring hydrogen atoms in close proximity, such as ortho-tetrachlorobenzoquinone over its para-isomer and 1,3-cyclohexadiene over its 1,4-isomer, perhaps hinting at the potential for concerted 2 e{sup -}/2 H{sup +} transfers. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Exploring new generations of ruthenium olefin metathesis catalysts: The reactivity of a bis-ylidene ruthenium complex by DFT

    Poater, Albert


    Density functional theory calculations were used to predict the behaviour of a potential novel architecture of olefin metathesis catalysts, in which one of the neutral ligands of classical Ru-based catalysts, e.g. a phosphine or an N-heterocyclic carbene, is replaced by an alkylidene group. Introduction of a second alkylidene ligand favors dissociation of the remaining phosphine and the overall energy profile for the metathesis using ethylene as the probe substrate reveals that the proposed bis-alkylidene complexes might match the requirements of a good performing olefin metathesis catalyst. © 2013 The Royal Society of Chemistry.

  7. Polycations XX: New Monodentate Cationic Ligands and Their Coordination with Ruthenium for the Construction of Complexes Expressing Enhanced Interaction with DNA

    Leslie Babukutty


    Full Text Available Prior investigations from this laboratory concerned with the preparation of new types of organic cations for a variety of biological and nonbiological applications have been extended to the preparation of cation-bearing ligands with nitrogen coordinating sites for use in complexation reactions with ruthenium cores. The syntheses of new cationic ligands as well as ruthenium complexes bearing them are reported here. The introduction of these new types of ligands is intended to provide to the complexes an enhanced ability to interact with DNA, and thereby to have the potential to be enhanced antitumor agents. Preliminary observations of their interactions with DNA are presented.

  8. Photochemistry between a ruthenium(II) pyridylimidazole complex and benzoquinone: simple electron transfer versus proton-coupled electron transfer.

    Hönes, Roland; Kuss-Petermann, Martin; Wenger, Oliver S


    A ruthenium(II) complex with two 4,4'-bis(trifluoromethyl)-2,2'-bipyridine chelates and a 2-(2'-pyridyl)imidazole ligand was synthesized and characterized by electrochemical and optical spectroscopic means. The respective complex has the potential to act as a combined electron-proton donor when promoted to its long-lived (3)MLCT excited state with visible light. The possibility of proton-coupled electron transfer (PCET) between the ruthenium(II) complex and 1,4-benzoquinone as an electron/proton acceptor was explored by steady-state and time-resolved luminescence spectroscopy, as well as by transient absorption spectroscopy in the nanosecond time regime. Excited-state deactivation is found to occur predominantly via simple oxidative quenching involving no proton motion, but a minor fraction of the photoexcited complex appears to react via PCET since there is spectral evidence for semiquinone as a photoproduct. Presumably, PCET is not kinetically competitive with simple electron transfer because the latter process is sufficiently exergonic and because there is little thermodynamic benefit from coupling proton transfer to the photoinduced electron transfer.

  9. Systematic investigation of the catalytic cycle of a single site ruthenium oxygen evolving complex using density functional theory.

    Hughes, Thomas F; Friesner, Richard A


    The mechanism of water oxidation by a single site ruthenium oxygen evolving complex is investigated using fully unrestricted pseudospectral B3LYP with the effective core potential LACV3P in continuum solvent with some quantum mechanical waters. Guess wave functions have been used that allow greater flexibility in sampling different electronic configurations of the complex. Systematic comparison with experiment is improved using these guesses because they provide a complete analysis of the low energy manifold and help to alleviate the formal disconnect between theory and experiment in assigning Lewis structures for transition metal complexes. In agreement with results from the literature, the challenging 4e(-)and 4H(+) oxidation of water is accomplished using a mechanism that features three proton coupled electron transfers, one electron transfer, one atom proton transfer (APT), and one ligand exchange (LE). Calculations on a large database of ruthenium complexes allows us to benchmark the computation of reduction half potentials and free energies of activation and to investigate systematic ligand variations and their effect on the reaction mechanism. Mean unsigned errors of reduction half potentials in comparison to experiment are generally small (100-200 mV). The APT and LE steps are found to be rate limiting with free energy barriers of 19.27 and 19.53 kcal/mol respectively, which is in excellent agreement with the ∼20 kcal/mol barrier obtained from experimental rate constants using classical transition state theory.

  10. Tunable Electrochemical and Catalytic Features of BIAN- and BIAO-Derived Ruthenium Complexes.

    Hazari, Arijit Singha; Das, Ankita; Ray, Ritwika; Agarwala, Hemlata; Maji, Somnath; Mobin, Shaikh M; Lahiri, Goutam Kumar


    This article deals with a class of ruthenium-BIAN-derived complexes, [Ru(II)(tpm)(R-BIAN)Cl]ClO4 (tpm = tris(1-pyrazolyl)methane, R-BIAN = bis(arylimino)acenaphthene, R = 4-OMe ([1a]ClO4), 4-F ([1b]ClO4), 4-Cl ([1c]ClO4), 4-NO2 ([1d]ClO4)) and [Ru(II)(tpm)(OMe-BIAN)H2O](2+) ([3a](ClO4)2). The R-BIAN framework with R = H, however, leads to the selective formation of partially hydrolyzed BIAO ([N-(phenyl)imino]acenapthenone)-derived complex [Ru(II)(tpm)(BIAO)Cl]ClO4 ([2]ClO4). The redox-sensitive bond parameters involving -N═C-C═N- or -N═C-C═O of BIAN or BIAO in the crystals of representative [1a]ClO4, [3a](PF6)2, or [2]ClO4 establish its unreduced form. The chloro derivatives 1a(+)-1d(+) and 2(+) exhibit one oxidation and successive reduction processes in CH3CN within the potential limit of ±2.0 V versus SCE, and the redox potentials follow the order 1a(+) oxidation and primarily BIAN- or BIAO-based successive reduction processes. The aqua complex 3a(2+) undergoes two proton-coupled redox processes at 0.56 and 0.85 V versus SCE in phosphate buffer (pH 7) corresponding to {Ru(II)-H2O}/{Ru(III)-OH} and {Ru(III)-OH}/{Ru(IV)═O}, respectively. The chloro (1a(+)-1d(+)) and aqua (3a(2+)) derivatives are found to be equally active in functioning as efficient precatalysts toward the epoxidation of a wide variety of alkenes in the presence of PhI(OAc)2 as oxidant in CH2Cl2 at 298 K, though the analogous 2(+) remains virtually inactive. The detailed experimental analysis with the representative precatalyst 1a(+) suggests the involvement of the active {Ru(IV)═O} species in the catalytic cycle, and the reaction proceeds through the radical mechanism, as also supported by the DFT calculations.


    Masahiro Mikuriya


    Full Text Available Mixed-metal chain complexes constructed from lantern-type dinuclear ruthenium(II,III carboxylate unit and tetracyanidonickelate(II, (PPh4n[Ru2(O2CCH34Ni(CN4]n•nH2O (1 and (PPh4n[Ru2{O2CC(CH33}4]3n[Ni(CN4]2n•2nH2O (2, where very weak antiferromagnetic interaction is operating, were synthesized and characterized by elemental analysis and IR and UV-vis spectroscopies and temperature dependence of magnetic susceptibilities (4.5—300K.

  12. Substituents Dependent Capability of bis(ruthenium-dioxolene-terpyridine)Complexes Toward Water Oxidation

    Wada, T.; Muckerman, J.; Fujita, E.; Tanaka, K.


    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

  13. An Electrochemical and Raman Spectroscopy Study of the Surface Behaviour of Mononuclear Ruthenium and Osmium Polypyridyl Complexes Based on Pyridyl- and Thiophene-Based Linkers

    Halpin, Yvonne; Logtenberg, Hella; Cleary, Laura; Schenk, Stephan; Schulz, Martin; Draksharapu, Apparao; Browne, Wesley R.; Vos, Johannes G.


    The utility of a thiophene anchor unit as an alternative for thiols in the immobilisation of ruthenium and osmium complexes on gold and platinum is examined with special attention focused on the relative contributions of physi- and chemisorption of the complexes and the chemical stability of the thi

  14. An Electrochemical and Raman Spectroscopy Study of the Surface Behaviour of Mononuclear Ruthenium and Osmium Polypyridyl Complexes Based on Pyridyl- and Thiophene-Based Linkers

    Halpin, Yvonne; Logtenberg, Hella; Cleary, Laura; Schenk, Stephan; Schulz, Martin; Draksharapu, Apparao; Browne, Wesley R.; Vos, Johannes G.


    The utility of a thiophene anchor unit as an alternative for thiols in the immobilisation of ruthenium and osmium complexes on gold and platinum is examined with special attention focused on the relative contributions of physi- and chemisorption of the complexes and the chemical stability of the

  15. New Class of Half-Sandwich Ruthenium(II) Arene Complexes Bearing the Water-Soluble CAP Ligand as an in Vitro Anticancer Agent.

    Guerriero, Antonella; Oberhauser, Werner; Riedel, Tina; Peruzzini, Maurizio; Dyson, Paul J; Gonsalvi, Luca


    Ruthenium(II) arene complexes of 1,4,7-triaza-9-phosphatricyclo[]tridecane (CAP) were obtained. Cytotoxicity studies against cancer cell lines reveal higher activity than the corresponding PTA analogues and, in comparison to the effects on noncancerous cells, the complexes are endowed with a reasonable degree of cancer cell selectivity.

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

    Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Heng, Lee Yook; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Ahmad, Haslina; Harun, Siti Norain [Chemistry Department, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor (Malaysia)


    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.

  17. A sulfhydryl-reactive ruthenium (II complex and its conjugation to protein G as a universal reagent for fluorescent immunoassays.

    Jing-Tang Lin

    Full Text Available To develop a fluorescent ruthenium complex for biosensing, we synthesized a novel sulfhydryl-reactive compound, 4-bromophenanthroline bis-2,2'-dipyridine Ruthenium bis (hexafluorophosphate. The synthesized Ru(II complex was crosslinked with thiol-modified protein G to form a universal reagent for fluorescent immunoassays. The resulting Ru(II-protein G conjugates were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE. The emission peak wavelength of the Ru(II-protein G conjugate was 602 nm at the excitation of 452 nm which is similar to the spectra of the Ru(II complex, indicating that Ru(II-protein G conjugates still remain the same fluorescence after conjugation. To test the usefulness of the conjugate for biosensing, immunoglobulin G (IgG binding assay was conducted. The result showed that Ru(II-protein G conjugates were capable of binding IgG and the more cross-linkers to modify protein G, the higher conjugation efficiency. To demonstrate the feasibility of Ru(II-protein G conjugates for fluorescent immunoassays, the detection of recombinant histidine-tagged protein using the conjugates and anti-histidine antibody was developed. The results showed that the histidine-tagged protein was successfully detected with dose-response, indicating that Ru(II-protein G conjugate is a useful universal fluorescent reagent for quantitative immunoassays.

  18. Organic Transformations Catalyzed by N-Heterocyclic Carben e-Metal Complexes%以N-杂环卡宾为配体的金属络合物催化有机合成的反应

    李林涛; 麻生明


    Reactions catalyzed by N-heterocyclic carbene-metal complexes, such as ol efin metathesis, coupling reaction, hydrosilylation reaction, etc. were revi ewed.   Ruthenium (II) complexes bearing one or two imidazolin-2-ylidene ligands are h ighly active catalysts for all types of ring closing metathesis reactions. Impor tantly, they even allow the formation of tetrasubstituted alkenes that were not previously achieved by ruthenium-phosphine metathesis catalysts. In addition, f unctionalized olefins were synthesized by intermolecular cross-metathesis and r ing-closing metathesis.   Palladium(0) complexes of imidazolin-2-ylidenes (19) could not catalyze the coupling of p-chlorotoluene and phenylboronic acid. However, a system consists of a Pd(0) precursor and dihydroimidazoline carbene ligand, wh ich is generated in situ, showed high activity for Suzuki cross-coupling re action of aryl chlorides with arylboronic acids, Kumada cross-coupling reaction of aryl chlorides with aryl Grignard reagents and amination of aryl chlorides.   Complexes of the (NHC)Pd(PR3)I2-type with bulky N-heterocyclic carbene s (NHC) are efficient catalysts for the Suzuki and Stille cross-coupling reacti ons, etc.   Imidazolidin-2-ylidene derivatives of rhodium(I) and ruthenium(II) catalyze t he carbon-carbon coupling of terminal alkynes, the cyclopropanation reactions o f diazoalkane derivatives with styrene, hydrosilylation of alkenes, alkynes, keto nes and hydrogenation of olefins.%综述了近几年来以N-杂环卡宾 为配体的金属络合物催化有机合成的反应。

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

    Swarnalatha, Kalaiyar; Kamalesu, Subramaniam; Subramanian, Ramasamy


    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.

  20. A zeolite-supported molecular ruthenium complex with eta6-C6H6 ligands: chemistry elucidated by using spectroscopy and density functional theory.

    Ogino, Isao; Chen, Mingyang; Dyer, Jason; Kletnieks, Philip W; Haw, James F; Dixon, David A; Gates, Bruce C


    An essentially molecular ruthenium-benzene complex anchored at the aluminum sites of dealuminated zeolite Y was formed by treating a zeolite-supported mononuclear ruthenium complex, [Ru(acac)(eta(2)-C(2)H(4))(2)](+) (acac=acetylacetonate, C(5)H(7)O(2)(-)), with (13)C(6)H(6) at 413 K. IR, (13)C NMR, and extended X-ray absorption fine structure (EXAFS) spectra of the sample reveal the replacement of two ethene ligands and one acac ligand in the original complex with one (13)C(6)H(6) ligand and the formation of adsorbed protonated acac (Hacac). The EXAFS results indicate that the supported [Ru(eta(6)-C(6)H(6))](2+) incorporates an oxygen atom of the support to balance the charge, being bonded to the zeolite through three Ru-O bonds. The supported ruthenium-benzene complex is analogous to complexes with polyoxometalate ligands, consistent with the high structural uniformity of the zeolite-supported species, which led to good agreement between the spectra and calculations at the density functional theory level. The calculations show that the interaction of the zeolite with the Hacac formed on treatment of the original complex with (13)C(6)H(6) drives the reaction to form the ruthenium-benzene complex.

  1. Mechanisms in Ruthenium(II) photochemistry and Iron(III) catalyzed oxidations : Photochemical, Electrochemical and Spectroscopic studies

    Unjaroen, Duenpen


    In this thesis, photochemical, electrochemical and spectroscopic studies of Ru(II), Fe(II), and Fe(III) complexes are described. The overall goal in this studies was to understanding process that occur during oxidation catalysis and photo irradiation and especially the changes in the structure that

  2. Photocatalytic water decontamination by the zeolite-y entrapped ruthenium tris-2,2 bipyridine complex

    Szulbinski, W.S.; Malato Rodirguez, S.; Gernjak, W.


    The zeolite-Y entrapped ruthenium tris-2,2-bipyridine complex externally loaded with platinum (Z-[Ru(bpp){sub 3}]''2+/Pt) has been examined as a novel photocatalyst for wastewater treatment in flow reactors of the pilot plant at the Plataforma Solar de Almeria, in Sapin. The catalyst generated by the template synthesis of [Ru(bpy){sub 3}]''2+ within the zeolite-Y supercharges (with the occupancy of one the [Ru(bpy){sub 3}]'' molecule per five the zeolite supercharges), and then platinized (1% wt) of the resulting Z-[Ru(bpy){sub 3}]''2+. The catalytic activity of Z-[u(bpy){sub 3}]''2+/Pt for waste-water treatment has been compared to that of TiO{sub 2} as the standard. For this phenol (PhOH) and pirimicarb ( a pesticide) have been used as models for water pollutants. By kinetics measurements, it has been documented that Z-[Ru(bpy){sub 3}]''2+/Pt decomposes PhOH with the relative photonic efficiency of {zeta}=0.37, assuming that{zeta}=1.0 for TiO{sub 2}, under the same experimental conditions. To improve the Z-[Ru(bpy){sub 3}]''2+/Pt photocatalytic activity, all the zeolite super cages have to be occupied with [Ru(bpy){sub 3}]''2+ modules, since this might increase the rate of the photoinduced electron transfer reaction. Moreover, it has been revealed that Z-[Ru(bpy){sub 3}]''2+/Pt is mostly active at the visible range of the solar radiation, at which TiO{sub 2} is inactive and unable to decompose organic pollutants. This has been supported by the diffuse reflectance spectroscopic measurement exhibiting the electronic absorption of Z-[Ru(bpy){sub 3}]''2*/pt at {lambda}{sub m}ax=454 nm. (Author) 15 refs.

  3. Ruthenium complex with benznidazole and nitric oxide as a new candidate for the treatment of chagas disease.

    Renata Sesti-Costa


    Full Text Available Chagas disease remains a serious medical and social problem in Latin America and is an emerging concern in nonendemic countries as a result of population movement, transfusion of infected blood or organs and congenital transmission. The current treatment of infected patients is unsatisfactory due to strain-specific drug resistance and the side effects of the current medications. For this reason, the discovery of safer and more effective chemotherapy is mandatory for the successful treatment and future eradication of Chagas disease.We investigated the effect of a ruthenium complex with benznidazole and nitric oxide (RuBzNO2 against Trypanosoma cruzi both in vitro and in vivo. Our results demonstrated that RuBzNO2 was more effective than the same concentrations of benznidazole (Bz in eliminating both the extracellular trypomastigote and the intracellular amastigote forms of the parasite, with no cytotoxic effect in mouse cells. In vivo treatment with the compound improved the survival of infected mice, inhibiting heart damage more efficiently than Bz alone. Accordingly, tissue inflammation and parasitism was significantly diminished after treatment with RuBzNO2 in a more effective manner than that with the same concentrations of Bz.The complexation of Bz with ruthenium and nitric oxide (RuBzNO2 increases its effectiveness against T. cruzi and enables treatment with lower concentrations of the compound, which may reduce the side effects of Bz. Our findings provide a new potential candidate for the treatment of Chagas disease.

  4. Ruthenium complex with benznidazole and nitric oxide as a new candidate for the treatment of chagas disease.

    Sesti-Costa, Renata; Carneiro, Zumira A; Silva, Maria C; Santos, Maíta; Silva, Grace K; Milanezi, Cristiane; da Silva, Roberto S; Silva, João S


    Chagas disease remains a serious medical and social problem in Latin America and is an emerging concern in nonendemic countries as a result of population movement, transfusion of infected blood or organs and congenital transmission. The current treatment of infected patients is unsatisfactory due to strain-specific drug resistance and the side effects of the current medications. For this reason, the discovery of safer and more effective chemotherapy is mandatory for the successful treatment and future eradication of Chagas disease. We investigated the effect of a ruthenium complex with benznidazole and nitric oxide (RuBzNO2) against Trypanosoma cruzi both in vitro and in vivo. Our results demonstrated that RuBzNO2 was more effective than the same concentrations of benznidazole (Bz) in eliminating both the extracellular trypomastigote and the intracellular amastigote forms of the parasite, with no cytotoxic effect in mouse cells. In vivo treatment with the compound improved the survival of infected mice, inhibiting heart damage more efficiently than Bz alone. Accordingly, tissue inflammation and parasitism was significantly diminished after treatment with RuBzNO2 in a more effective manner than that with the same concentrations of Bz. The complexation of Bz with ruthenium and nitric oxide (RuBzNO2) increases its effectiveness against T. cruzi and enables treatment with lower concentrations of the compound, which may reduce the side effects of Bz. Our findings provide a new potential candidate for the treatment of Chagas disease.

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

    Inaba, Iku; Kuramitz, Hideki; Sugawara, Kazuharu


    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.

  6. Efficient and versatile catalysis of N-alkylation of heterocyclic amines with alcohols and one-pot synthesis of 2-aryl substituted benzazoles with newly designed ruthenium(II) complexes of PNS thiosemicarbazones.

    Ramachandran, Rangasamy; Prakash, Govindan; Selvamurugan, Sellappan; Viswanathamurthi, Periasamy; Malecki, Jan Grzegorz; Ramkumar, Venkatachalam


    Ruthenium(II) carbonyl complexes with phosphine-functionalized PNS type thiosemicarbazone ligands [RuCl(CO)(EPh3)(L)] (1-6) (E = P or As, L = 2-(2-(diphenylphosphino)benzylidene) thiosemicarbazone (PNS-H), 2-(2-(diphenylphosphino)benzylidene)-N-methylthiosemicarbazone (PNS-Me), 2-(2-(diphenylphosphino)benzylidene)-N-phenylthiosemicarbazone (PNS-Ph)) have been synthesized and characterized by elemental analysis and spectroscopy (IR, UV-Vis, (1)H, (13)C, (31)P-NMR) as well as ESI mass spectrometry. The molecular structures of complexes 1, 2 and 6 were identified by means of single-crystal X-ray diffraction analysis. The analysis revealed that all the complexes possess a distorted octahedral geometry with the ligand coordinating in a uni-negative tridentate PNS fashion. All the ruthenium complexes (1-6) were tested as catalyst for N-alkylation of heteroaromatic amines with alcohols. Notably, complex 2 was found to be a very efficient and versatile catalyst towards N-alkylation of a wide range of heterocyclic amines with alcohols. Complex 2 can also catalyze the direct amination of 2-nitropyridine with benzyl alcohol to the corresponding secondary amine. Furthermore, a preliminary examination of performance for N,N-dialkylation of diamine showed promising results, giving good conversion and high selectivity. In addition, N-alkylation of ortho-substituted anilines (-NH2, -OH and -SH) led to the one-pot synthesis of 2-aryl substituted benzimidazoles, benzoxazoles and benzothiazoles, also revealing the catalytic activity of complex 2.

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

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


    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.

  8. Preparation and Characterization of A New Dinuclear Ruthenium Complex with BDPX Ligand and Its Catalytic Hydrogenation Reactions for Cinnamaldehyde

    TANG,Yuan-You(唐元友); LI,Rui-Xiang(李瑞祥); LI,Xian-Jun(李贤均); WONG,Ning-Bew(黄宁表); TIN,Kim-Chung(田金忠); ZHANG,Zhe-Ying(张哲英); MAK,Thomas C.W.(麦松威)


    A new anionic dinuclear ruthenium complex bearing 1,2-bis(diphenylphosphinomethyl)benzene (BDPX)[NH2Et2][{RuCl (BDPX)}2(μ-Cl)3] (1) was synthesized and its structure was determined by an X-ray crystallographic analysis. This result indicated that complex 1 consisted of an anion dinuclear BDPX-Ru and a cationic diethylammonium. The crystal belonged to monoclinic system, C2/c space group with a=3.3552(7) nm, b= 1.8448(4)nm, c=2.4265(5) nm, β= 101.89(3)° and Z=8. The catalytic hydrogenation activities and selectivities of complex 1 for cinnamaldehyde were investigated.

  9. Nanoformulation improves activity of the (pre)clinical anticancer ruthenium complex KP1019.

    Heffeter, P; Riabtseva, A; Senkiv, Y; Kowol, C R; Körner, W; Jungwith, U; Mitina, N; Keppler, B K; Konstantinova, T; Yanchuk, I; Stoika, R; Zaichenko, A; Berger, W


    Ruthenium anticancer drugs belong to the most promising non-platinum anticancer metal compounds in clinical evaluation. However, although the clinical results are promising regarding both activity and very low adverse effects, the clinical application is currently hampered by the limited solubility and stability of the drug in aqueous solution. Here, we present a new nanoparticle formulation based on polymer-based micelles loaded with the anticancer lead ruthenium compound KP1019. Nanoprepared KP1019 was characterised by enhanced stability in aqueous solutions. Moreover, the nanoparticle formulation facilitated cellular accumulation of KP1019 (determined by ICP-MS measurements) resulting in significantly lowered IC50 values. With regard to the mode of action, increased cell cycle arrest in G2/M phase (PI-staining), DNA damage (Comet assay) as well as enhanced levels of apoptotic cell death (caspase 7 and PARP cleavage) were found in HCT116 cells treated with the new nanoformulation of KP1019. Summarizing, we present for the first time evidence that nanoformulation is a feasible strategy for improving the stability as well as activity of experimental anticancer ruthenium compounds.

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

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


    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

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

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


    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 is

  12. SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

    Bonnet, S.A.; van Lenthe, J.H.; van Dam, H.J.J.; van Koten, G.; Klein Gebbink, R.J.M.


    The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated

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

    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


    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.

  14. SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

    Bonnet, S.A.; van Lenthe, J.H.; van Dam, H.J.J.; van Koten, G.; Klein Gebbink, R.J.M.


    The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated

  15. Ruthenium(II)-catalyzed synthesis of pyrrole- and indole-fused isocoumarins by C-H bond activation in DMF and water

    Singh, K.S.; Sawant, S.G.; Dixneuf, P.H.

    -C-H bond activation offer efficient routes for a fast access to various functional molecules.[12] Initially palladium catalysts were used for the direct C-H functionalization of heterocycles,[13,14] however tremendous progress has been made..., in terms of synthesis efficiency,atom economy and process cost, with the less expensive ruthenium(0)[15] and especially the more stable, even in water, ruthenium(II)catalysts[16--17]for cross C- C bond formation fromsp2C-H bonds.A wide range of N...

  16. Understanding the Excited State Behavior of Cyclometalated Bis(tridentate)ruthenium(II) Complexes: A Combined Experimental and Theoretical Study.

    Kreitner, Christoph; Erdmann, Elisa; Seidel, Wolfram W; Heinze, Katja


    The synthesis and characterization of the donor-acceptor substituted cyclometalated ruthenium(II) polypyridine complex isomers [Ru(dpb-NHCOMe)(tpy-COOEt)](PF6) 1(PF6) and [Ru(dpb-COOEt)(tpy-NHCOMe)](PF6) 2(PF6) (dpbH = 1,3-dipyridin-2-ylbenzene, tpy = 2,2';6,2"-terpyridine) with inverted functional group pattern are described. A combination of resonance Raman spectroscopic and computational techniques shows that all intense visible range absorption bands arise from mixed Ru → tpy/Ru → dpb metal-to-ligand charge transfer (MLCT) excitations. 2(PF6) is weakly phosphorescent at room temperature in fluid solution and strongly emissive at 77 K in solid butyronitrile matrix, which is typical for ruthenium(II) polypyridine complexes. Density functional theory calculations revealed that the weak emission of 2(PF6) arises from a (3)MLCT state that is efficiently thermally depopulated via metal-centered ((3)MC) excited states. The activation barrier for the deactivation process was estimated experimentally from variable-temperature emission spectroscopic measurements as 11 kJ mol(-1). In contrast, 1(PF6) is nonemissive at room temperature in fluid solution and at 77 K in solid butyronitrile matrix. Examination of the electronic excited states of 1(PF6) revealed a ligand-to-ligand charge-transfer ((3)LL'CT) as lowest-energy triplet state due to the very strong push-pull effect across the metal center. Because of the orthogonality of the participating ligands, emission from the (3)LL'CT is symmetry-forbidden. Hence, in this type of complex a stronger push-pull effect does not increase the phosphorescence quantum yields but completely quenches the emission.

  17. Hydroaminomethylation of 1-Dodecene Catalyzed by Water-soluble Rhodium Complex

    Ying Yong WANG; Mei Ming LUO; Yao Zhong LI; Hua CHEN; Xian Jun LI


    The hydroaminomethylation of 1-dodecene catalyzed by water soluble rhodium complex RhCl(CO)(TPPTS)2 in the presence of surfactant CTAB was investigated. High reactivity and selectivity for tertiary amine were achieved under relatively mild conditions.

  18. Population and relaxation kinetics of laser-excitated photofunctional ruthenium-sulfoxide complexes in highly concentrated solutions; Populations- und Relaxationskinetiken laserangeregter photofunktionaler Ruthenium-Sulfoxid-Komplexe in hochkonzentrierten Loesungen

    Eicke, Sebastian


    Photofunctionality of ruthenium sulfoxide complexes offer a distinct photochromy, which results from their light-induced binding isomerization. By this the complexes are suited for the usage in photonic applications like fast optical switches or optical data memories. The present thesis studies the photofunctionality of the complexes by means of laser-excited population and thermally activated relaxation kinetics. In view to photonic applications thereby exclusively highly concentrated sample solutions are considered, which exhibit beside a distinct photochromy a just remarkable photosensitivity. The photochromic kinetics usable in an application are described by means of a model and rate equations, so that a statement on an optimal sample-solution concentration in connection of drived and driving light beam can be met. By means of the characteristics of the photochromic kinetics complex properties, like for instance the thermal stability of the metastable isomers, can be defined. The applicative suitability of the photofunctional ruthenium sulfoxide complexes is finally shown by the selective fitting of their complex properties by diverse structural and environmental modifications.

  19. Ruthenium-catalyzed metathesis reactions of ortho- and meta-dialkenyl-carboranes: efficient ring-closing and acyclic diene polymerization reactions.

    Guron, Marta; Wei, Xiaolan; Carroll, Patrick J; Sneddon, Larry G


    The ruthenium-catalyzed metathesis reactions of dialkenyl-substituted ortho- and meta-carboranes provide excellent routes to both cyclic-substituted o-carboranes and new types of main-chain m-carborane polymers. The adjacent positions of the two olefins in the 1,2-(alkenyl)(2)-o-carboranes strongly favor the formation of ring-closed (RCM) products with the reactions of 1,2-(CH(2)=CHCH(2))(2)-1,2-C(2)B(10)H(10) (1), 1,2-(CH(2)=CH(CH(2))(3)CH(2))(2)-1,2-C(2)B(10)H(10) (2), 1,2-(CH(2)=CHSiMe(2))(2)-1,2-C(2)B(10)H(10) (3), 1,2-(CH(2)=CHCH(2)SiMe(2))(2)-1,2-C(2)B(10)H(10) (4), and 1,2-[CH(2)=CH(CH(2))(4)SiMe(2)](2)-1,2-C(2)B(10)H(10) (5) affording 1,2-(-CH(2)CH=CHCH(2)-)-C(2)B(10)H(10) (10), 1,2-[-CH(2)(CH(2))(3)CH=CH(CH(2))(3)CH(2)-]-1,2-C(2)B(10)H(10) (11), 1,2-[-SiMe(2)CH=CHSiMe(2)-]-1,2-C(2)B(10)H(10) (12), 1,2-[-SiMe(2)CH(2)CH=CHCH(2)SMe(2)-]-C(2)B(10)H(10) (13), and 1,2-[-SiMe(2)(CH(2))(4)CH=CH(CH(2))(4)SiMe(2)-]-C(2)B(10)H(10) (14), respectively, in 72-97% yields. On the other hand, the reaction of 1,2-(CH(2)-CHCH(2)OC(=O))(2)-1,2-C(2)B(10)H(10) (6) gave cyclo-[1,2-(1',8'-C(=O)OCH(2)CH=CHCH(2)OC(=O))-1,2-C(2)B(10)H(10)](2) (15a) and polymer 15b resulting from intermolecular metathesis reactions. The nonadjacent positions of the alkenyl groups in the 1,7-(alkenyl)(2)-m-carboranes, 1,7-(CH(2)=CHCH(2))(2)-1,7-C(2)B(10)H(10) (7), 1,7-(CH(2)=CH(CH(2))(3)CH(2))(2)-1,7-C(2)B(10)H(10) (8), and 1,7-(CH(2)=CHCH(2)SiMe(2))(2)-1,7-C(2)B(10)H(10) (9), disfavor the formation of RCM products, and in these cases, acyclic diene metathesis polymerizations (ADMET) produced new types of main chain m-carborane polymers. The structures of 3, 9, 11, 12, 13, and 15a were crystallographically confirmed.

  20. Thiolate-bridged dinuclear ruthenium and iron complexes as robust and efficient catalysts toward oxidation of molecular dihydrogen in protic solvents.

    Yuki, Masahiro; Sakata, Ken; Hirao, Yoshifumi; Nonoyama, Nobuaki; Nakajima, Kazunari; Nishibayashi, Yoshiaki


    Thiolate-bridged dinuclear ruthenium and iron complexes are found to work as efficient catalysts toward oxidation of molecular dihydrogen in protic solvents such as water and methanol under ambient reaction conditions. Heterolytic cleavage of the coordinated molecular dihydrogen at the dinuclear complexes and the sequential oxidation of the produced hydride complexes are involved as key steps to promote the present catalytic reaction. The catalytic activity of the dinuclear complexes toward the chemical oxidation of molecular dihydrogen achieves up to 10000 TON (turnover number), and electrooxidation of molecular dihydrogen proceeds quite rapidly. The result of the density functional theory (DFT) calculation on the reaction pathway indicates that a synergistic effect between the two ruthenium atoms plays an important role to realize the catalytic oxidation of molecular dihydrogen efficiently. The present dinuclear ruthenium complex is found to work as an efficient organometallic anode catalyst for the fuel cell. It is noteworthy that the present dinuclear complex worked not only as an effective catalyst toward chemical and electrochemical oxidation of molecular dihydrogen but also as a good anode catalyst for the fuel cell. We consider that the result described in this paper provides useful and valuable information to develop highly efficient and low-cost transition metal complexes as anode catalysts in the fuel cell.

  1. Synthesis, Structure, and Anticancer Activity of Arene-Ruthenium(II) Complexes with Acylpyrazolones Bearing Aliphatic Groups in the Acyl Moiety.

    Palmucci, Jessica; Marchetti, Fabio; Pettinari, Riccardo; Pettinari, Claudio; Scopelliti, Rosario; Riedel, Tina; Therrien, Bruno; Galindo, Agustin; Dyson, Paul J


    A series of neutral ruthenium(II) arene complexes [(arene)Ru(Q(R))Cl] (arene = p-cymene (cym) or hexamethylbenzene (hmb)) containing 4-acyl-5-pyrazolonate Q(R) ligands with different electronic and steric substituents (R = 4-cyclohexyl, 4-stearoyl, or 4-adamantyl) and related ionic complexes [(arene)Ru(Q(R))(PTA)][PF6] (PTA = 1,3,5-triaza-7-phosphaadamantane) were synthesized and characterized by spectroscopy (IR, UV-vis, ESI-MS, and (1)H and (13)C NMR), elemental analysis, X-ray crystallography, and density functional theory studies. The cytotoxicity of the proligands and metal complexes was evaluated in vitro against human ovarian carcinoma cells (A2780 and A2780cisR), as well as against nontumorous human embryonic kidney (HEK293) cells. In general the cationic PTA-containing complexes are more cytotoxic than their neutral precursors with a chloride ligand in place of the PTA. Moreover, the complexes do not show cross-resistance and are essentially equally cytotoxic to both the A2780 and A2780cisR cell lines, although they only show limited selectivity toward the cancer cell lines.

  2. New mixed ligand complexes of ruthenium(II) that incorporate a modified phenanthroline ligand: Synthesis, spectral characterization and DNA binding

    S Murali; C V Sastri; Bhaskar G Maiya


    The hexafluorophosphate and chloride salts of two ruthenium(II) complexes, viz. [Ru(phen)(ptzo)2]2+ and [Ru(ptzo)3]2+, where ptzo = 1,10-phenanthrolino[5,6-]1,2,4-triazine-3-one (ptzo) - a new modified phenanthroline (phen) ligand, have been synthesised. These complexes have been characterised by infrared, UV-Vis, steady-state emission and 1H NMR spectroscopic methods. Results of absorption and fluorescence titration as well as thermal denaturation studies reveal that both the bis- and tris-complexes of ptzo show moderately strong affinity for binding with calf thymus (CT) DNA with the binding constants being close to 105M-1 in each case. An intercalative mode of DNA binding has been suggested for both the complexes. Emission studies carried out in non-aqueous solvents and in aqueous media without DNA reveal that both [Ru(phen)(ptzo)2]2+ and [Ru(ptzo)3]2+ are weakly luminescent under these solution conditions. Successive addition of CT DNA to buffered aqueous solutions containing [Ru(phen)(ptzo)2]2+ results in an enhancement of the emission. These results have been discussed in the light of the dependence of the structure-specific deactivation processes of the MLCT state of the metallointercalator with the characteristic features of its DNA interaction. In doing so, attempts have been made to compare and contrast its properties with those of the analogous phenanthroline-based complexes including the ones reported by us previously.

  3. Ruthenium, osmium and rhodium complexes of polypyridyl ligands: Metal-promoted activities, stereochemical aspects and electrochemical properties

    Parimal Paul


    This article presents a brief overview of the reactions of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) in presence of rhodium(III), ruthenium(II) and osmium(II) under various experimental conditions. Under certain experimental conditions tptz exhibits metal-assisted hydrolysis/hydroxylation at the triazine ring. However, synthetic methods have also been developed to prepare complexes with intact tptz. Molecular structures of some of the complexes, especially stereoisomers of the hydroxylated products, are established by single crystal X-ray studies. A critical analysis of all data suggests that the electron-withdrawing effect of the metal ion (L→M donation) is the predominant factor, rather than angular strain, that is responsible for metal-promoted reactivities. Electrochemical properties of all of these complexes have been investigated, Rh(III) complexes are excellent catalysts for electrocatalytic reduction of CO2, and dinuclear Ru(II) and Os(II) complexes exhibit strong electronic communication between the metal centres.

  4. Synthesis and characterization of new TiO{sub 2} sensitizers for photovoltaic cells: bipyridine phosphonic di-acid ruthenium and osmium complexes and dyads composed of an organic chromophore and a ruthenium complex for antenna effect; Synthese et caracterisation de nouveaux sensibilisateurs de TiO{sub 2} pour la photovoltaique: complexes de ruthenium et d'osmium avec la bipyridine diacide phosphonique et diades composees d'un chromophore organique et d'un complexe de ruthenium pour l'effet d'antenne

    Zabri, H.


    The aim of this work is to develop new poly-pyridine transition metals complexes as TiO{sub 2} sensitizers for the design of photovoltaic cells. The first part concerns the preparation and the study of the properties of RuL{sub 2}X{sub 2} complexes (L = 2,2'-bipyridine bis phosphonic acid and X = Cl, CN, NCS). The cis di-thiocyanate bis-(2,2-bipyridine-4,4-phosphonic di-acid) ruthenium (II) sensitizer has the best performances but is nevertheless inferior of 30% to its analog containing the carboxylic acid function (N3) taken as reference in this work. In a second part, the osmium complexes with the 2,2'-bipyridine-4,4'-phosphonic di-acid have been prepared on account of their widest absorbance towards the low energies of the solar spectra. The spectroscopic ({sup 1}H and {sup 13}C NMR, UV-Visible, IR, action spectra, emission and life span of the excited states) and electrochemical properties of these complexes have been studied. This study has shown that 1)the tris-(2,2'-bipyridine-4,4'-phosphonic di-acid) osmium (II) has a photovoltaic efficiency similar to those of N3 2)the phosphonic acid function leads to a bond more stable with TiO{sub 2} compared with those obtained with the carboxylic acid function. At last, dyads composed of an organic pigment (zinc phthalocyanine and boradiazaindacene) grafted on a ruthenium complex have been prepared. The two organic pigments allow to increase the cross section of light collection of the ruthenium complex by antenna effect. The photochemical study in solution shows that the fluorescence of the antennas is trapped by the next ruthenium complex probably by energy transfer. (O.M.)

  5. Ruthenium(II) and osmium(II) polypyridyl complexes of an asymmetric pyrazinyl- and pyridinyl-containing 1,2,4-triazole based ligand. Connectivity and physical properties of mononuclear complexes

    Browne, Wesley R.; O’Connor, Christine M.; Hughes, Helen P.; Hage, Ronald; Walter, Olaf; Doering, Manfred; Gallagher, John F.; Vos, Johannes G.


    The synthesis, purification and characterisation of two coordination isomers of ruthenium(II) and osmium (II) complexes containing the ligand 3-(pyrazin-2'-yl)-5-(pyridin-2"-yl)-1,2,4-triazole (Hppt) are described. The X-ray and molecular structure of the complex [Ru(bipy)(2) (ppt)] PF6.CH3OH (1a) i

  6. Ruthenium(II) and osmium(II) polypyridyl complexes of an asymmetric pyrazinyl- and pyridinyl-containing 1,2,4-triazole based ligand. Connectivity and physical properties of mononuclear complexes

    Browne, Wesley R.; O’Connor, Christine M.; Hughes, Helen P.; Hage, Ronald; Walter, Olaf; Doering, Manfred; Gallagher, John F.; Vos, Johannes G.


    The synthesis, purification and characterisation of two coordination isomers of ruthenium(II) and osmium (II) complexes containing the ligand 3-(pyrazin-2'-yl)-5-(pyridin-2"-yl)-1,2,4-triazole (Hppt) are described. The X-ray and molecular structure of the complex [Ru(bipy)(2) (ppt)] PF6.CH3OH (1a) i

  7. Tuning the cytotoxic properties of new ruthenium(III) and ruthenium(II) complexes with a modified bis(arylimino)pyridine Schiff base ligand using bidentate pyridine-based ligands.

    Garza-Ortiz, Ariadna; Maheswari, Palanisamy Uma; Lutz, Martin; Siegler, Maxime A; Reedijk, Jan


    Synthesis, spectroscopy, characterization, structures, and cytotoxicity studies of 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine (LLL) ruthenium compounds are described. The starting compound [RuCl3(LLL)] has been fully characterized using IR spectroscopy, UV-vis spectroscopy, electrospray ionization mass spectrometry, and NMR spectroscopy. In addition, the crystal structure of the ligand LLL has been determined using single-crystal X-ray diffraction. With the ruthenium(III) trichloride compound as starting material, a new family of Ru(II) complexes with a number of neutral and charged bidentate co-ligands have been synthesized and used for characterization and cytotoxicity studies. The synthesis of the corresponding [Ru(II)LLL(LL)Cl](+/0) complexes with co-ligands- LL is 1,10-phenanthroline, 2,2'-bipyridyl, 2-(phenylazo)pyridine, 2-(phenylazo)-3-methylpyridine, 2-(tolylazo)pyridine, or the anionic 2-picolinate-is reported. Analytical, spectroscopic (IR spectroscopy, UV-vis spectroscopy, (1)H NMR spectroscopy, and electrospray ionization mass spectrometry), and structural characterization of the new compounds is described. Crystal structure analyses of two Ru(II) compounds show a slightly distorted octahedral Ru(II) geometry with tridentate LLL coordinated in a planar meridional fashion, and the chelating co-ligand (LL) and a chloride ion complete the octahedron. The co-ligand plays a significant role in modulating the physicochemical and cytotoxic properties of these new ruthenium complexes. The in vitro cytotoxicity of these new Ru(II) complexes (half-maximal inhibitory concentration, IC50, of 0.5-1.5 μM), in comparison with the parent Ru(III) compound (half-maximal inhibitory concentration of 3.9-4.3 μM) is higher for several of the human cancer cell lines tested. The cytotoxic activity of some of the new ruthenium compounds is even higher than that of cisplatin in the same cancer cell lines. The cytotoxicity of these new anticancer compounds is

  8. Use of ion mobility mass spectrometry and a collision cross-section algorithm to study an organometallic ruthenium anticancer complex and its adducts with a DNA oligonucleotide.

    Williams, Jonathan P; Lough, Julie Ann; Campuzano, Iain; Richardson, Keith; Sadler, Peter J


    We report the development of an enhanced algorithm for the calculation of collision cross-sections in combination with Travelling-Wave ion mobility mass spectrometry technology and its optimisation and evaluation through the analysis of an organoruthenium anticancer complex [(eta6-biphenyl)Ru(II)(en)Cl]+. Excellent agreement was obtained between the experimentally determined and theoretically determined collision cross-sections of the complex and its major product ion formed via collision-induced dissociation. Collision cross-sections were also experimentally determined for adducts of this ruthenium complex with the single-stranded oligonucleotide hexamer d(CACGTG). Ion mobility tandem mass spectrometry measurements have allowed the binding sites for ruthenium on the oligonucleotide to be determined.

  9. Highly efficient and selective photocatalytic oxidation of sulfide by a chromophore-catalyst dyad of ruthenium-based complexes.

    Li, Ting-Ting; Li, Fu-Min; Zhao, Wei-Liang; Tian, Yong-Hua; Chen, Yong; Cai, Rong; Fu, Wen-Fu


    Electronic coupling across a bridging ligand between a chromophore and a catalyst center has an important influence on biological and synthetic photocatalytic processes. Structural and associated electronic modifications of ligands may improve the efficiency of photocatalytic transformations of organic substrates. Two ruthenium-based supramolecular assemblies based on a chromophore-catalyst dyad containing a Ru-aqua complex and its chloro form as the catalytic components were synthesized and structurally characterized, and their spectroscopic and electrochemical properties were investigated. Under visible light irradiation and in the presence of [Co(NH3)5Cl]Cl2 as a sacrificial electron acceptor, both complexes exhibited good photocatalytic activity toward oxidation of sulfide into the corresponding sulfoxide with high efficiency and >99% product selectivity in neutral aqueous solution. The Ru-aqua complex assembly was more efficient than the chloro complex. Isotopic labeling experiments using (18)O-labeled water demonstrated the oxygen atom transfer from the water to the organic substrate, likely through the formation of an active intermediate, Ru(IV)═O.

  10. Nitric oxide binding and photodelivery based on ruthenium(II) complexes of 4-arylazo-3,5-dimethylpyrazole.

    Ortiz, Mayreli; Torréns, Mabel; Mola, José L; Ortiz, Pedro J; Fragoso, Alex; Díaz, Alicia; Cao, Roberto; Prados, Pilar; de Mendoza, Javier; Otero, Antonio; Antiñolo, Antonio; Lara, Agustin


    Two fluorescent ligands, 3,5-dimethyl-4-(6'-sulfonylammonium-1'-azonaphthyl)pyrazole (dmpzn, 1) and 3,5-dimethyl-4-(4'-N,N'-dimethylaminoazophenyl)pyrazole (dmpza, 2) were obtained by condensation of ketoenolic derivatives with hydrazine. 1 and 2 formed the novel dinuclear complexes [(H(2)O)(3)ClRu(micro-L)(2)RuCl(H(2)O)(3)] (3 or 4) and [(H(2)O)(NO)Cl(2)Ru(micro-L)(2)RuCl(2)(NO)(H(2)O)] (6 or 7) (where L 1 = 2 or , respectively) which were characterized by IR, NMR and elemental analysis. The nitrosyl complexes were prepared by bubbling purified nitric oxide through methanol solutions of the corresponding ruthenium(II) chloroderivative or by reaction of the appropriate ligands with Ru(NO)Cl(3). Complexes 3 and 4 were found to bind NO, resulting in an increase in fluorescence. Ligand 1 also formed the mononuclear nitrosyl complex [Ru(NO)(bpy)(2)(dmpzn)]Cl(2) (8) which released NO in water at physiological pH and in the solid state as revealed by fluorescence and IR measurements, respectively.

  11. Bioinspired catalytic nitrile hydration by dithiolato, sulfinato/thiolato, and sulfenato/sulfinato ruthenium complexes.

    Kumar, Davinder; Masitas, César A; Nguyen, Tho N; Grapperhaus, Craig A


    A series of Ru(II) catalysts inspired by the metalloenzyme nitrile hydratase catalyze the hydration of benzonitrile with up to 242 turnovers under neutral conditions with very low catalysts loading. Catalysts with an oxidized sulfur environment are less susceptible to product inhibition increasing the catalytic efficiency at low nitrile : water ratios.

  12. Energy-Storage Applications for a pH Gradient between Two Benzimidazole-Ligated Ruthenium Complexes That Engage in Proton-Coupled Electron-Transfer Reactions in Solution.

    Motoyama, Daisuke; Yoshikawa, Kai; Ozawa, Hiroaki; Tadokoro, Makoto; Haga, Masa-Aki


    The judicious selection of pairs of benzimidazole-ligated ruthenium complexes allowed the construction of a rechargeable proton-coupled electron-transfer (PCET)-type redox battery. A series of ruthenium(II) and -(III) complexes were synthesized that contain substituted benzimidazoles that engage in PCET reactions. The formation of intramolecular Ru-C cyclometalation bonds stabilized the resulting ruthenium(III) complexes, in which pKa values of the imino N-H protons on the benzimidazoles are usually lower than those for the corresponding ruthenium(II) complexes. As a proof-of-concept study for a solution redox battery based on such PCET reactions, the charging/discharging cycles of several pairs of ruthenium complexes were examined by chronopotentiometry in an H-type device with half-cells separated by a Nafion membrane in unbuffered CH3CN/H2O (1/1, v/v) containing 0.1 M NaCl. During the charging/discharging cycles, the pH value of the solution gradually changed accompanied by a change of the open-circuit potential (OCP). The changes for the OCP and pH value of the solution in the anodic and cathodic half-cells were in good agreement with the predicted values from the Pourbaix diagrams for the pairs of ruthenium complexes used. Accordingly, the careful selection of pairs of ruthenium complexes with a sufficient potential gradient and a suitably large pKa difference is crucial: the charge generated between the two ruthenium complexes changes the OCP and the pH difference between the two cells in an unbuffered solution, given that the PCET reactions occur at both electrodes and that discharging leads to the original state. Because the electric energy is stored as a pH gradient between the half-cells, new possibilities for PCET-type rocking-chair redox batteries arise.

  13. Formation of a ruthenium(IV)-oxo complex by electron-transfer oxidation of a coordinatively saturated ruthenium(II) complex and detection of oxygen-rebound intermediates in C-H bond oxygenation.

    Kojima, Takahiko; Nakayama, Kazuya; Ikemura, Kenichiro; Ogura, Takashi; Fukuzumi, Shunichi


    A coordinatively saturated ruthenium(II) complex having tetradentate tris(2-pyridylmethyl)amine (TPA) and bidentate 2,2'-bipyridine (bpy), [Ru(TPA)(bpy)](2+) (1), was oxidized by a Ce(IV) ion in H(2)O to afford a Ru(IV)-oxo complex, [Ru(O)(H(+)TPA)(bpy)](3+) (2). The crystal structure of the Ru(IV)-oxo complex 2 was determined by X-ray crystallography. In 2, the TPA ligand partially dissociates to be in a facial tridentate fashion and the uncoordinated pyridine moiety is protonated. The spin state of 2, which showed paramagnetically shifted NMR signals in the range of 60 to -20 ppm, was determined to be an intermediate spin (S = 1) by the Evans' method with (1)H NMR spectroscopy in acetone-d(6). The reaction of 2 with various oraganic substrates in acetonitrile at room temperature afforded oxidized and oxygenated products and a solvent-bound complex, [Ru(H(+)TPA)(bpy)(CH(3)CN)], which is intact in the presence of alcohols. The oxygenation reaction of saturated C-H bonds with 2 proceeds by two-step processes: the hydrogen abstraction with 2, followed by the dissociation of the alcohol products from the oxygen-rebound complexes, Ru(III)-alkoxo complexes, which were successfully detected by ESI-MS spectrometry. The kinetic isotope effects in the first step for the reaction of dihydroanthrathene (DHA) and cumene with 2 were determined to be 49 and 12, respectively. The second-order rate constants of C-H oxygenation in the first step exhibited a linear correlation with bond dissociation energies of the C-H bond cleavage.

  14. Programmable multimetallic linear nanoassemblies of ruthenium-DNA conjugates

    Irvoas, Joris; Noirot, Arielle; Chouini-Lalanne, Nadia; Reynes, Olivier; Garrigues, Jean-Christophe; Sartor, Valérie


    International audience; A new ruthenium-DNA conjugates family was synthesized, made up of a ruthenium complex bound to one or two identical DNA strands of 14-58 nucleotides. The formation of controlled linear nanoassemblies containing one to seven ruthenium complexes is described.

  15. Photodissociation of a ruthenium(II) arene complex and its subsequent interactions with biomolecules: a density functional theory study.

    Wang, Hanlu; DeYonker, Nathan J; Zhang, Xiting; Zhao, Cunyuan; Ji, Liangnian; Mao, Zong-Wan


    The piano-stool Ru(II) arene complex [(η⁶-benz)Ru(bpm)(py)]²⁺ (benz = benzene, bpm = 2,2'-bipyrimidine, and py = pyridine), which is conventionally nonlabile (on a timescale and under conditions relevant for biological reactivity), can be activated by visible light to selectively photodissociate the monodentate ligand (py). In the present study, the aquation and binding of the photocontrolled ruthenium(II) arene complex [(η⁶-benz)Ru(bpm)(py)]²⁺ to various biomolecules are studied by density functional theory (DFT) and time-dependent DFT (TDDFT). Potential energy curves (PECs) calculated for the Ru-N (py) bonds in [(η⁶-benz)Ru(bpm)(py)]²⁺ in the singlet and triplet state give useful insights into the photodissociation mechanism of py. The binding energies of the various biomolecules are calculated, which allows the order of binding affinities among the considered nuleic-acid- or protein-binding sites to be discerned. The kinetics for the replacement of water in the aqua complex with biomolecules is also considered, and the results demonstrate that guanine is superior to other biomolecules in terms of coordinating with the Ru(II) aqua adduct, which is in reasonable agreement with experimental observations.

  16. New ruthenium(II) complexes with pyridylpyrazole ligands. Photosubstitution and /sup 1/H, /sup 13/C, and /sup 99/Ru NMR structural studies

    Steel, P.J.; LaHousse, F.; Lerner, D.; Marzin, C.


    The preparations and properties of ruthenium (Ru) (II) complexes containing the bidentate ligand (L) 1-(2-pyridyl)-3,5-dimethylpyrazole, are described. The tris complex RuL/sub 3//sup 2 +/ is shown to readily undergo photosubstitution in acetonitrile (CH/sub 3/CN) solution to produce RuL/sub 2/(CH/sub 3/CN)/sub 2//sup 2 +/, which in the presence of other bidentate ligands undergoes thermal substitution of the coordinated acetonitrite. /sup 1/H, /sup 13/C, and /sup 99/Ru NMR spectra are reported for all the complexes. Proton and carbon-13 NMR reveal the CH/sub 3/CN presence of geometrical isomerism, where it exists; proton and ruthenium-99 NMR allow the evaluation of the percentage of these isomers. Ruthenium-99 NMR proves to be an excellent probe of electron density at the metal and is possibly useful to evaluate the amount of ..pi..-back-bonding depending on the ligands. Electronic spectral data and oxidation potential measurements are given for comparison with those of the well-known RU(bipyridine)/sub 3//sup 2 +/ complex but do not lead to consistent results. 4 figures, 3 tables.

  17. Solvent-dependent switch of ligand donor ability and catalytic activity of ruthenium(II) complexes containing pyridinylidene amide (PYA) N-heterocyclic carbene hybrid ligands.

    Leigh, Vivienne; Carleton, Daniel J; Olguin, Juan; Mueller-Bunz, Helge; Wright, L James; Albrecht, Martin


    Chelating ligands incorporating both N-[1-alkylpyridin-4(1H)-ylidene]amide (PYA) and N-heterocyclic carbene (NHC) donor sites were prepared and used for the synthesis of ruthenium(II) complexes. Cyclic voltammetry, NMR, and UV-vis spectroscopy of the complexes indicate a solvent-dependent contribution of the limiting resonance structures associated with the ligand in solution. The neutral pyridylidene imine structure is more pronounced in apolar solvents (CH2Cl2), while the mesoionic pyridinium amide form is predominant in polar solvents (MeOH, DMSO). The distinct electronic properties of these hybrid PYA-NHC ligands in different solvents have a direct influence on the catalytic activity of the ruthenium center, e.g., in the dehydrogenation of benzyl alcohol to benzaldehyde. The activity in different solvents qualitatively correlates with the solvent permittivity.

  18. Photoinduced electron-transfer processes involving covalently linked ruthenium and cobalt polypyridyl complexes. Comparison of electronic coupling in bridged and nonbridged ruthenium and cobalt complexes

    Song, Xiaoqing; Lei, Yabin; Endicott, J.F. (Wayne State Univ., Detroit, MI (United States)); Van Wallendal, S.; Jackman, D.C.; Rillema, D.P. (Univ. of North Carolina, Charlotte (United States)); Perkovic, M.W. (Wayne State Univ., Detroit, MI (United States) Univ. of North Carolina, Charlotte (United States))


    Photoinduced electron-transfer processes have been examined in a heterobimetallic coordination complex with polypyridyl ligands. Three relaxation processes were observed to follow light absorption by (bpy)[sub 2]Ru(bb)Co(bpy)[sub 2][sup 5+] (where bpy = 2,2'-bipyridine and bb 1,2-bis(2,2'-bipyridyl-4'-yl)ethane) with lifetimes in water at 25[degrees]C of 0.18, 1, and 6 ns determined using picosecond flash photolysis techniques. These nearly solvent independent relaxation rates are ascribed to forward electron transfer from ([sup 3]MLCT)Ru(bpy)[sub 2][sup 2+] to Co(bpy)[sub 2][sup 3+], spin relaxation at the Co(II) center and back electron transfer from ([sup 4]T[sub 1])Co(bpy)[sub 2][sub 2+] to Ru(bpy)[sub 2][sup 3+]. Luminescence decay of ([sup 3]MLCT)Ru(bpy)[sub 2][sup 2+] has also been used to monitor the electron-transfer quenching step from 77-150 K, and the quenching rate extrapolated to 25[degrees]C (activation energy of 2.2 [times] 10[sup 3] cm[sup [minus]1]) was compatible with the 180-ps lifetime. It is inferred that the back electron transfer rate is retarded by poor donor-acceptor electronic coupling (k[sub el] [congruent] 10[sup [minus]3]). A Mulliken type of perturbational model is proposed to describe the weak electronic coupling in this complex. Spectroscopic parameters are combined with the perturbational expressions to give a plausible account of the electronic coupling in the back-electron-transfer process. 84 refs., 9 figs., 5 tabs.

  19. Homocoupling of benzyl halides catalyzed by POCOP-nickel pincer complexes

    Chen, Tao


    Two types of POCOP-nickel(II) pincer complexes were prepared by mixing POCOP pincer ligands and NiX 2 in toluene at reflux. The resulting nickel complexes efficiently catalyze the homocoupling reactions of benzyl halides in the presence of zinc. The coupled products were obtained in excellent to quantitative yields. © 2012 Elsevier Ltd. All rights reserved.

  20. Luminescence lifetime standards for the nanosecond to microsecond range and oxygen quenching of ruthenium(II) complexes.

    Morris, Kaleem J; Roach, Michael S; Xu, Wenying; Demas, J N; DeGraff, B A


    A rapid and reproducible method for determining the temperature dependence of luminescence lifetimes has been developed. With the use of this method, a set of standards for the excited-state lifetime oxygen quenching of several ruthenium(II) transition metal complexes was established. With the use of three solvents of different viscosities and two metal complexes with widely different lifetimes, an overlapping range of ca. 100 ns to 6 micros was obtained. The decays are pure single exponentials, which means that they can be used reliably with both phase and pulsed lifetime instruments. For a pure single-exponential decay, a properly operating phase shift instrument will give the same lifetime as a time domain instrument. With the use of a thermal deactivation model and a three-parameter temperature-dependent oxygen quenching constant, the lifetime temperature-dependent data was well fit by a simple six-parameter equation that covers the temperature range of 10-50 degrees C and oxygen pressures from 0 to 1 atm of oxygen with excellent precision (ca. <1%). This permits both laboratory and field calibration of instruments.

  1. Ruthenium(III)/phosphine/pyridine complexes applied in the hydrogenation reactions of polar and apolar double bonds

    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.


    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. Microwave synthesis of mixed ligand diimine-thiosemicarbazone complexes of ruthenium(II): biophysical reactivity and cytotoxicity.

    Beckford, Floyd A; Shaloski, Michael; Leblanc, Gabriel; Thessing, Jeffrey; Lewis-Alleyne, Lesley C; Holder, Alvin A; Li, Liya; Seeram, Navindra P


    A novel microwave-assisted synthetic method has been used to synthesise a series of mixed ligand ruthenium(II) compounds containing diimine as well as bidentate thiosemicarbazone ligands. The compounds contain the diimine 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy) and the thiosemicarbazone is derived from 9-anthraldehyde. Based on elemental analyses and spectroscopic data, the compounds are best formulated as [(phen)(2)Ru(thiosemicarbazone)](PF(6))(2) and [(phen)(2)Ru(thiosemicarbazone)](PF(6))(2) where thiosemicarbazone = 9-anthraldehydethiosemicarbazone, 9-anthraldehyde-N(4)-methylthiosemicarbazone, and 9-anthraldehyde-N(4)-ethylthiosemicarbazone. Fluorescence competition studies with ethidium bromide, along with viscometric measurements suggests that the complexes bind calf thymus DNA (CTDNA) relatively strongly via an intercalative mode possibly involving the aromatic rings of the diimine ligands. The complexes show good cytotoxic profiles against MCF-7 and MDA-MB-231 (breast adenocarcinoma) as well as HCT 116 and HT-29 (colorectal carcinoma) cell lines.

  3. Structural studies on dinuclear ruthenium(II) complexes that bind diastereoselectively to an antiparallel folded human telomere sequence.

    Wilson, Tom; Costa, Paulo J; Félix, Vítor; Williamson, Mike P; Thomas, Jim A


    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.

  4. Synthesis of Highly Stable 1,3-Diaryl-1H-1,2,3-triazol-5-ylidenes and their Applications in Ruthenium-Catalyzed Olefin Metathesis

    Bouffard, Jean; Keitz, Benjamin K.; Tonner, Ralf; Lavallo, Vincent; Guisado-Barrios, Gregorio; Frenking, Gernot


    The formal cycloaddition between 1,3-diaza-2-azoniaallene salts and alkynes or alkyne equivalents provides an efficient synthesis of 1,3-diaryl-1H-1,2,3-triazolium salts, the direct precursors of 1,2,3-triazol-5-ylidenes. These N,N-diarylated mesoionic carbenes (MICs) exhibit enhanced stability in comparison to their alkylated counterparts. Experimental and computational results confirm that these MICs act as strongly electron-donating ligands. Their increased stability allows for the preparation of ruthenium olefin metathesis catalysts that are efficient in both ring-opening and ring-closing reactions. PMID:21572542

  5. Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: synthesis, structure, electrochemistry and DFT calculations.

    Al-Noaimi, Mousa; Awwadi, Firas F; Mansi, Ahmad; Abdel-Rahman, Obadah S; Hammoudeh, Ayman; Warad, Ismail


    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). Copyright © 2014 Elsevier B.V. All rights reserved.

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

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


    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.

  7. Photochemical activation of ruthenium(II)-pyridylamine complexes having a pyridine-N-oxide pendant toward oxygenation of organic substrates.

    Kojima, Takahiko; Nakayama, Kazuya; Sakaguchi, Miyuki; Ogura, Takashi; Ohkubo, Kei; Fukuzumi, Shunichi


    Ruthenium(II)-acetonitrile complexes having η(3)-tris(2-pyridylmethyl)amine (TPA) with an uncoordinated pyridine ring and diimine such as 2,2'-bipyridine (bpy) and 2,2'-bipyrimidine (bpm), [Ru(II)(η(3)-TPA)(diimine)(CH(3)CN)](2+), reacted with m-chloroperbenzoic acid to afford corresponding Ru(II)-acetonitrile complexes having an uncoordinated pyridine-N-oxide arm, [Ru(II)(η(3)-TPA-O)(diimine)(CH(3)CN)](2+), with retention of the coordination environment. Photoirradiation of the acetonitrile complexes having diimine and the η(3)-TPA with the uncoordinated pyridine-N-oxide arm afforded a mixture of [Ru(II)(TPA)(diimine)](2+), intermediate-spin (S = 1) Ru(IV)-oxo complex with uncoordinated pyridine arm, and intermediate-spin Ru(IV)-oxo complex with uncoordinated pyridine-N-oxide arm. A Ru(II) complex bearing an oxygen-bound pyridine-N-oxide as a ligand and bpm as a diimine ligand was also obtained, and its crystal structure was determined by X-ray crystallography. Femtosecond laser flash photolysis of the isolated O-coordinated Ru(II)-pyridine-N-oxide complex has been investigated to reveal the photodynamics. The Ru(IV)-oxo complex with an uncoordinated pyridine moiety was alternatively prepared by reaction of the corresponding acetonitrile complex with 2,6-dichloropyridine-N-oxide (Cl(2)py-O) to identify the Ru(IV)-oxo species. The formation of Ru(IV)-oxo complexes was concluded to proceed via intermolecular oxygen atom transfer from the uncoordinated pyridine-N-oxide to a Ru(II) center on the basis of the results of the reaction with Cl(2)py-O and the concentration dependence of the consumption of the starting Ru(II) complexes having the uncoordinated pyridine-N-oxide moiety. Oxygenation reactions of organic substrates by [Ru(II)(η(3)-TPA-O)(diimine)(CH(3)CN)](2+) were examined under irradiation (at 420 ± 5 nm) and showed selective allylic oxygenation of cyclohexene to give cyclohexen-1-ol and cyclohexen-1-one and cumene oxygenation to afford cumyl alcohol

  8. Organometallic ruthenium(II) complexes: synthesis, structure and influence of substitution at azomethine carbon towards DNA/BSA binding, radical scavenging and cytotoxicity.

    Sathyadevi, Palanisamy; Krishnamoorthy, Paramasivam; Bhuvanesh, Nattamai S P; Kalaiselvi, Palaniswamy; Vijaya Padma, Viswanadha; Dharmaraj, Nallasamy


    Bivalent, ruthenium organometallics containing hydrazone ligands with the composition [RuH(CO)(PPh(3))(2)(L(1-3))] (4-6) have been synthesised from the reactions of [RuH(2)(CO)(PPh(3))(3)] and benzoic acid pyridine-2-ylmethylene-hydrazide (HL(1)) (1) /benzoic acid (1-pyridin-2-yl-ethylidene)-hydrazide (HL(2)) (2)/benzoic acid (phenyl-pyridin-2-yl-methylene)-hydrazide (HL(3)) (3) and characterised by various physico-chemical techniques. The X-ray crystal structure of one of the above complexes, [RuH(CO)(PPh(3))(2)(L(3))] (6) demonstrated a distorted octahedral coordination geometry around the metal centre. Results of our investigation on the effect of substitution (H or CH(3) or C(6)H(5)) at the azomethine carbon of coordinated hydrazone in these ruthenium chelates on the potential binding with DNA/BSA, free radical scavenging and cytotoxicity is presented.

  9. pH luminescence switching, dihydrogen phosphate sensing, and cellular uptake of a heterobimetallic ruthenium(II)-rhenium(I) complex.

    Zheng, Ze-Bao; Wu, Yong-Quan; Wang, Ke-Zhi; Li, Fuyou


    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(-).

  10. Development and characterization of light-emitting diodes (LEDs) based on ruthenium complex single layer for transparent displays

    Santos, G.; Fonseca, F.; Andrade, A.M. [Laboratorio de Microelectronica, Departamento de Engenharia de Sistemas Electronicos, Escola Politecnica da Universidade de Sao Paulo (Brazil); Patrocinio, A.O.T.; Mizoguchi, S.K.; Murakami Iha, N.Y. [Laboratorio de Fotoquimica Inorganica e Conversao de Energia, Instituto de Quimica da Universidade de Sao Paulo (Brazil); Peres, M.; Monteiro, T.; Pereira, L. [Departamento de Fisica e I3N, Universidade de Aveiro (Portugal)


    In this work, two ruthenium complexes,[Ru(bpy){sub 3}](PF{sub 6}){sub 2} and[Ru(ph2phen){sub 3}](PF{sub 6}){sub 2} in poly(methylmethacrylate) matrix were employed to build single-layer light-emitting electrochemical cells by spin coating on indium tin oxide substrate. In both cases the electroluminescence spectra exhibit a relatively broad band with maxima near to 625 nm and CIE (x,y) color coordinates of (0.64,0.36), which are comparable with the photoluminescence data in the same medium. The best result was obtained with the[Ru(bpy){sub 3}](PF{sub 6}){sub 2} device where the optical output power approaches 10{mu}W at the band maximum with a wall-plug efficiency higher than 0.03%. The lowest driving voltage is about 4 V for an electrical current of 20 mA. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. The ruthenium complex cis-(dichloro)tetrammineruthenium(III) chloride induces apoptosis and damages DNA in murine sarcoma 180 cells

    Aliny Pereira De Lima; Flávia De Castro Pereira; Cesar Augusto Sam Tiago Vilanova-Costa; Alessandra De Santana Braga Barbosa Ribeiro; Luiz Alfredo Pavanin; Wagner Batista Dos Santos; Elisângela De Paula Silveira-Lacerda


    Ruthenium(III) complexes are increasingly attracting the interest of researchers due to their promising pharmacological properties. Recently, we reported that the cis-(dichloro)tetrammineruthenium(III) chloride compound has cytotoxic effects on murine sarcoma 180 (S-180) cells. In an effort to understand the mechanism responsible for their cytotoxicity, study we investigated the genotoxicity, cell cycle distribution and induction of apoptosis caused by cis-(dichloro)tetrammineruthenium(III) chloride in S-180 tumour cells. cis-(dichloro)tetrammineruthenium(III) chloride treatment induced significant DNA damage in S-180 cells, as detected by the alkaline comet assay. In the cell cycle analysis, cis-(dichloro)tetrammineruthenium(III) chloride caused an increase in the number of cells in G1 phase, accompanied by a decrease in the S and G2 phases after 24 h of treatment. In contrast, the cell cycle distribution of S-180 cells treated with cis-(dichloro)tetrammineruthenium(III) chloride for 48 h showed a concentration-dependent increase in the sub-G1 phase (indicating apoptosis), with a corresponding decrease in cells in the G1, S and G2 phases. In addition, cis-(dichloro)tetrammineruthenium(III) chloride treatment induced apoptosis in a time-dependent manner, as observed by the increased numbers of annexin V-positive cells. Taken together, these findings strongly demonstrate that DNA damage, cell cycle changes and apoptosis may correlate with the cytotoxic effects of cis-(dichloro)tetrammineruthenium(III) chloride on S-180 cells.

  12. Effects of tethering alkyl chains for amphiphilic ruthenium complex dyes on their adsorption to titanium oxide and photovoltaic properties.

    Ni, Jen-Shyang; Hung, Chun-Yi; Liu, Ken-Yen; Chang, Yu-Hsun; Ho, Kuo-Chuan; Lin, King-Fu


    Ruthenium (II) complex dye, Ru(4,4'-dicarboxyl-2,2'-bipyridine)(4-nonyl-2,2'-bipyridine) (NCS)(2), (denoted as RuC9) tethering single alkyl chain was synthesized and well characterized. Its adsorption behavior onto the mesoporous TiO(2) and photovoltaic properties were compared with Z907 which has similar chemical structure but tethers two alkyl chains. RuC9 dyes tend to aggregate into vesicles in the acetonitrile/t-butanol co-solvent as a result of the amphiphilic structure, whereas Z907 dyes aggregate into lamellae. The dye-sensitized solar cell (DSSC) with RuC9 dye showed higher short-circuit photocurrent than that with Z907, attributing to its higher molar optical extinction coefficient and more adsorption amount onto the mesoporous TiO(2). However, the DSSC with Z907 dye has higher open-circuit photovoltage and power conversion efficiency, presumably due to the fact that Z907 with more alkyl chains formed a molecular layer with higher hydrophobicity. It reduced the charge recombination in the interface between the dye-sensitized mesoporous TiO(2) and electrolyte as verified by the electrochemical impedance spectroscopy and intensity modulated photocurrent and photovoltage spectroscopies.

  13. Polymerization of isoprene catalyzed by neodymium heterocyclic Schiff base complex

    Lei Zhang; Xu Feng Ni; Wei Lin Sun; Zhi Quan Shen


    Neodymium-based heterocyclic Schiff base complex was prepared and applied for the coordination polymerization of isoprene. This complex polymerized isoprene to afford products featuring high cis-1,4 stereospecificity (ca. 95%) and high molecular weight (ca. 105) in the presence of the triisobutyl aluminium (AliBu3) as cocatalyst. The microstructure of obtained polyisoprene was investigated by FTIR, 1H NMR. Two different kinds of active centers in the catalyst system were examined by GPC method.

  14. Troponate/Aminotroponate Ruthenium-Arene Complexes: Synthesis, Structure, and Ligand-Tuned Mechanistic Pathway for Direct C-H Bond Arylation with Aryl Chlorides in Water.

    Dwivedi, Ambikesh D; Binnani, Chinky; Tyagi, Deepika; Rawat, Kuber S; Li, Pei-Zhou; Zhao, Yanli; Mobin, Shaikh M; Pathak, Biswarup; Singh, Sanjay K


    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.

  15. Design and synthesis of ruthenium(II) OCO pincer type NHC complexes and their catalytic role towards the synthesis of amides

    Muthukumaran Nirmala; Periasamy Viswanathamurthi


    The present contribution describes the synthesis and characterization of a family of robust ruthenium complexes, supported by a tridentate pincer ligand of the type bis-phenolate--heterocyclic carbene [Bu(OCO)2−] (NHC). Ruthenium(II) complexes (1-3) bearing bis-phenolate--heterocyclic carbene ligand were synthesized in good yields by the reaction of imidazolinium proligand (HL) with metal precursors [RuHCl(CO)(EPh3)2(B)] (E = P or As; B = PPh3, AsPh3 or Py) by transmetalation from the corresponding silver carbene complex. All the Ru(II)-NHC complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The tridentate nature of the Bu(OCO)2− ligand as well as some level of steric protection provided by the Bu groups may rationalize the excellent stability of the Ru-Ccarbene bond in the present systems. Moreover, for the explorations of catalytic potential of the synthesized compounds, all the three [Ru-NHC] complexes (1-3) were tested as catalysts for amidation of alcohols with amines. Notably, the complex 1 was found to be very efficient and versatile catalyst towards amidation of a wide range of alcohols with amines.

  16. Asymmetric Cyclization of N-Sulfonyl Alkenyl Amides Catalyzed by Iridium/Chiral Diene Complexes.

    Nagamoto, Midori; Yanagi, Tomoyuki; Nishimura, Takahiro; Yorimitsu, Hideki


    Iridium/chiral diene complexes efficiently catalyzed the asymmetric cyclization of N-sulfonyl alkenyl amides to give the corresponding 2-pyrrolidone derivatives with high enantioselectivity. A mechanistic study revealed that the reaction proceeds via nucleophilic attack of the amide on the alkene moiety.

  17. P ' CP '-Pincer palladium complex-catalyzed allylation of N,N-dimethylsulfamoyl-protected aldimines

    Li, Jie; Minnaard, Adriaan J.; Gebbink, Robertus J. M. Klein; van Koten, Gerard


    The P'CP'-pincer palladium complex-catalyzed allylation of N,N-dimethylsulfamoyl-protected aldimines with allyl(tributyl)stannane is investigated for the preparation of N-homoallylic sulfamides. The desired N,N-dimethylsulfamoyl-protected products are obtained in moderate to high yields in DMF under

  18. Enantioselective Conjugate Addition of Grignard Reagents to Enones Catalyzed by Chiral Zinc(II) Complexes

    Jansen, Johan F.G.A.; Feringa, Bernard


    Various chiral zinc(II) complexes catalyze the asymmetric 1,4-addition of Grignard reagents to α,β-unsaturated ketones with high chemoselectivities (yields of 1,4-adducts, 83-99%), high regioselectivities (1,4/1,2 ratios up to 499) and modest enantioselectivities (ee up to 33%). A study of several f

  19. Hydrogen-peroxide epoxidation of natural olefins catalyzed by a dinuclear manganese complex

    Mandelli, D; Voitiski, KB; Schuchardt, U; Shul'pin, GB


    The complex of Mn(IV) with the macrocyclic N-containing ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (L) [L2Mn2O3](PF6)(2) catalyzes epoxidation of (+)-limonene in CH3CN solution at room temperature. Adding CH3COOH accelerates the reaction. The products are isomers of limonene epoxide with

  20. Hydrogen-peroxide epoxidation of natural olefins catalyzed by a dinuclear manganese complex

    Mandelli, D; Voitiski, KB; Schuchardt, U; Shul'pin, GB


    The complex of Mn(IV) with the macrocyclic N-containing ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (L) [L2Mn2O3](PF6)(2) catalyzes epoxidation of (+)-limonene in CH3CN solution at room temperature. Adding CH3COOH accelerates the reaction. The products are isomers of limonene epoxide with predomi

  1. Synthesis and Characterization of Phosphine and Arsine Complexes of Ruthenium (Ii & Iii Ligated With 3-(4-Pyridyl-4-Substituted-Triazoline-5-Thione

    R. N. Pandey


    Full Text Available Organometallic complexes of ruthenium (II & III with the formula [RuH(CO(Ef32L] and [RuCl2(Ef32L] (E = P/As; L = deprotonated mononegative bidentate 3-(4-pyridyl-triazoline-5-thione and its 4-phenyl substituted derivative were synthesized and characterized by elemental analysis, physico-chemical and spectroscopic methods. All new compounds were iso-structural with precursor complexes. Two triphenyl phosphine or triphenylarsine molecules are at trans-disposition and thioamide ligands behaves as bidentate (N, S donor in assigned octahedral structure.

  2. Ruthenium(II) complexes of saccharin with dipyridoquinoxaline and dipyridophenazine: Structures, biological interactions and photoinduced DNA damage activity.

    Kumar, Priyaranjan; Dasari, Srikanth; Patra, Ashis K


    Ruthenium complexes trans-[Ru(sac)2(dpq)2] (1) and trans-[Ru(sac)2(dppz)2] (2) where sac is artificial sweetener saccharin (o-sulfobenzimide; 1,2-benzothiazole-3(2H)-one1,1-dioxide (Hsac)), dpq = dipyrido[3,2-d:2',3'-f]quinoxaline and dppz = dipyrido[3,2-a:2',3'-c]phenazine have been synthesized and thoroughly characterized using various analytical and spectral techniques. Saccharin known to act as carbonic anhydrase IX (CA IX) inhibitor which is a biomarker for highly aggressive and proliferative tumor in hypoxic stress, so inhibition of CA IX is a potential strategy for anticancer chemotherapy. The solid state structures, photophysical properties, photostability, DNA and protein binding affinity, and DNA photocleavage activity were explored. The structural analysis revealed Ru(II) centre is in discrete mononuclear, distorted octahedral {RuN6} coordination geometry with two monoanionic nitrogen donor saccharinate ligands and two neutral bidentate nitrogen donors ligands dpq and dppz. cis-[Ru(sac)2(dppz)2] (cis-2) geometrical isomer was also isolated and structurally characterized by X-ray crystallography. The photo-induced dissociation of monodentate saccharin ligand is observed when irradiated at UV-A light of 365 nm. The complexes show significant binding affinity to the calf thymus DNA (Kb ∼ 10(5) M(-1)) through significant intercalation through planar dpq and dppz ligands. Interaction of complexes 1 and 2 with bovine serum albumin (BSA) showed remarkable tryptophan emission quenching (KBSA ∼10(5) M(-1)). The complexes showed appreciable photoinduced DNA cleavage activity upon irradiation of low power UV-A light of 365 nm from supercoiled (SC) to its nicked circular (NC) form at micromolar complex concentrations. Photocleavage mechanistic studies in presence of O2 reveals involvement of reactive oxygen species (ROS) mediated through ligand-centered (3)ππ* and/or (3)MLCT excited states generated upon photoactivation leads to nicking of

  3. Cellular responses of BRCA1-defective and triple-negative breast cancer cells and in vitro BRCA1 interactions induced by metallo-intercalator ruthenium(II) complexes containing chloro-substituted phenylazopyridine.

    Nhukeaw, Tidarat; Temboot, Pornvichai; Hansongnern, Kanidtha; Ratanaphan, Adisorn


    Triple-negative breast cancer (TNBC) is defined by the absence of expression of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2. Breast cancers with a BRCA1 mutation are also frequently triple-negative. Currently, there is a lack of effective therapies and known specific molecular targets for this aggressive breast cancer subtype. To address this concern, we have explored the cellular responses of BRCA1-defective and triple-negative breast cancer cells, and in vitro BRCA1 interactions induced by the ruthenium(II) complexes containing the bidentate ligand, 5-chloro-2-(phenylazo)pyridine. Triple-negative MDA-MB-231, BRCA1-defective HCC1937 and BRCA1-competent MCF-7 breast cancer cell lines were treated with ruthenium(II) complexes. The cytoxoxicity of ruthenium-induced breast cancer cells was evaluated by a real time cellular analyzer (RTCA). Cellular uptake of ruthenium complexes was determined by ICP-MS. Cell cycle progression and apoptosis were assessed using propidium iodide and Annexin V flow cytometry. The N-terminal BRCA1 RING protein was used for conformational and functional studies using circular dichroism and in vitro ubiquitination. HCC1937 cells were significantly more sensitive to the ruthenium complexes than the MDA-MB-231 and MCF-7 cells. Treatment demonstrated a higher degree of cytotoxicity than cisplatin against all three cell lines. Most ruthenium atoms were retained in the nuclear compartment, particularly in HCC1937 cells, after 24 h of incubation, and produced a significant block at the G2/M phase. An increased induction of apoptotic cells as well as an upregulation of p53 mRNA was observed in all tested breast cancer cells. It was of interest that BRCA1 mRNA and replication of BRCA1-defective cells were downregulated. Changes in the conformation and binding constants of ruthenium-BRCA1 adducts were observed, causing inactivation of the RING heterodimer BRCA1/BARD1-mediated E3 ubiquitin ligase activity

  4. Hydroformylation of Oleyl Alcohol Catalyzed by Rh-OPGPP Complex


    Polyether-tailored phosphite modified rhodium complex formed in situ was highly active in the hydroformylation of oleyl alcohol in nonaqueous phosphite/heptane system where the phosphite acted both as the ligand and the second phase. This catalyst was easily separated by simple decantation and can be used for five times with only a slight decrease in activity.

  5. Cytotoxic, DNA binding, DNA cleavage and antibacterial studies of ruthenium-fluoroquinolone complexes

    Mohan N Patel; Hardik N Joshi; Chintan R Patel


    Six new Ru(II) and Ru(III) complexes have been synthesized and characterized by elemental analysis, LC-MS, electronic spectra, IR spectra and magnetic moment measurements. DNA-binding properties of Ru complexes have been studied by means of absorption spectrophotometry and viscosity measurements as well as their HS DNA cleavage properties by means of agarose gel electrophoresis. The experimental results show that all the complexes can bind to DNA via partial intercalative mode. The b values of complexes were found in the range 2.14 × 104 to 2.70 × 105 M-1. All the complexes show excellent efficiency of cleaving DNA than respective fluoroquinolones. Brine shrimp lethality bioassay has been performed to check the cytotoxic activity. The IC50 values of the complexes are in the range of 6.27 to 16.05 g mL-1.

  6. Ruthenium(II) complexes bearing pyridine-functionalized N-heterocyclic carbene ligands: Synthesis, structure and catalytic application over amide synthesis



    A series of four imidazolium salts was synthesized by the reaction of 2-bromopyridine with 1- substituted imidazoles. These imidazolium salts (1a–d) were successfully employed as ligand precursors for the syntheses of new ruthenium(II) complexes bearing neutral bidentate ligands of N-heterocyclic carbene and pyridine donor moiety. The NHC-ruthenium(II) complexes (3a–d) were synthesized by reacting the appropriately substituted pyridine-functionalized N-heterocyclic carbenes with Ag₂O forming the NHC–silver bromide in situ followed by transmetalation with [RuHCl(CO)(PPh₃)₃]. The new complexes were characterized by elemental analyses and spectroscopy (IR, UV-Vis, ¹H, ¹³C, ³¹P-NMR) as well as ESI mass spectrometry. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The complexes were shown to be efficient catalysts for the one-pot conversion of various aldehydes to their corresponding primary amides with good to excellent isolated yields using NH₂OH.HCl and NaHCO₃. The effects of solvent, base, temperature, time and catalyst loading were also investigated. A broad range of amides were successfully synthesized with excellent isolated yields using the above optimized protocol. Notably, the complex 3a was found to be a very efficient and versatile catalyst towards amidation of a wide range of aldehydes.

  7. Origins of Enantioselectivity during Allylic Substitution Reactions Catalyzed by Metallacyclic Iridium Complexes

    Madrahimov, Sherzod T.; Hartwig, John F.


    In depth mechanistic studies of iridium catalyzed regioselective and enantioselective allylic substitution reactions are presented. A series of cyclometallated allyliridium complexes that are kinetically and chemically competent to be intermediates in the allylic substitution reactions was prepared and characterized by 1D and 2D NMR spectroscopies and solid state structural analysis. The rates of epimerization of the less thermodynamically stable diastereomeric allyliridium complexes to the t...


    金军挺; 黄吉玲; 陶晓春; 钱延龙


    @@ Transition metal vinylidene complexes (M=C=CHR) have attracted a great deal of attention in recent years as a new type of organometallic intermediates that may have unusual reactivity[1]. Their reactivity has been explored and their application to organic synthesis is developed[2]. Recent reports on the ruthenium-vinylidene complexes[3]suggest that the reaction of ruthenium-vinylidene complexes with a base generates the coordinatively unsaturated ruthenium acetylide species, which are involved in a number of catalytic and stoichiometric reactions of alkynes. For example,the coordinatively unsaturated ruthenium acetylide species C5Me5Ru(PPh3)-C≡CPh,formed from the reaction of the vinylidene complex C5Me5Ru(PPh3) (Cl)=C=CHPh with a base was reactive toward a variety of small molecules and active in catalytic dimerization of terminal alkynes[4]. The dimerization of terminal alkyne is an effective method of forming enynes, but its synthetic application in organic synthesis has been limited dueto low selectivity for dimeric products[5]. In this communication, we report that three ruthenium complexes were used as catalysts for the highly selective dimerization of phenylacetylene.

  9. Complex Biotransformations Catalyzed by Radical S-Adenosylmethionine Enzymes*

    Zhang, Qi; Liu, Wen


    The radical S-adenosylmethionine (AdoMet) superfamily currently comprises thousands of proteins that participate in numerous biochemical processes across all kingdoms of life. These proteins share a common mechanism to generate a powerful 5′-deoxyadenosyl radical, which initiates a highly diverse array of biotransformations. Recent studies are beginning to reveal the role of radical AdoMet proteins in the catalysis of highly complex and chemically unusual transformations, e.g. the ThiC-cataly...

  10. Selective Hydrogenation of Avermectin Catalyzed by Iridium-Phosphine Complexes

    MA, Xiao-Yan; WANG, Kun; ZHANG, Lei; LI, Xian-Jun; LI, Rui-Xiang


    A series of new iridium complexes, IrCl(COD)(TMOPP) (1) [COD=1,5-cyclooctadiene, TMOPP=tris(4-methoxyphenyl)phosphine], IrCl(COD)(TFMPP) (2) [TFMPP = tris(4-trifluoromethylphenyl)phosphine], IrCl-(COD)(BDNA) (3) [BDNA=1,8-bis(diphenylphosphinomethyl)naphthalene], IrCl(COD)(BISBI) (4) [BISBI=2,2'-bis(diphenylphosphinomethyl)biphenyl] and IrCl(COD)(BDPB) (5) [BDPB = 1,2-bis(diphenylphosphinomethyl)benzene], were synthesized and characterized by NMR spectra and elemental analyses. In order to obtain the relationships between complex structures and their catalytic properties, IrCl(COD)(DPPM) (6) [DPPM=bis(diphenylphosphino)methane], IrCl(COD)(DPPE) (7) [DPPE= 1,2-bis(diphenylphosphino)ethane], IrCl(COD)-(DPPP) (8) [DPPP=1,3-bis(diphenylphosphino)propane] and IrCl(COD)(TPP) (9) [TPP=triphenylphosphine],were also synthesized according to the reported methods. The hydrogenation results showed that the low electronic density at the central metal was favorable to increase the catalytic activity for the hydrogenation of avermectin, but decrease the selectivity to ivermectin. The complex with a large chelating ring and a bulky chelating backbone would easily cause the cleavage of C-O bond in avermectin to give a byproduct avermectin aglycon.

  11. Radiochemistry of ruthenium

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


    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.

  12. Ruthenium(II) and iridium(III) complexes featuring NHC-sulfonate chelate.

    Rajaraman, A; Sahoo, A R; Hild, F; Fischmeister, C; Achard, M; Bruneau, C


    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.

  13. Ruthenium(II) arene complexes with oligocationic triarylphosphine ligands: synthesis, DNA interactions and in vitro properties

    Snelders, D.J.M.; Casini, A.; Edafe, F.; van Koten, G.; Klein Gebbink, R.J.M.; Dyson, P.J.


    The synthesis, DNA binding properties and cytotoxicity of a series of Ru(II)-arene complexes containing oligocationic ammonium-functionalized triarylphosphines, of the type Ru(p-cymene)Cl2(L) (L ¼ oligocationic phosphine), are reported. The complexes are highly charged (the overall charge states bei

  14. Hydrogen evolution catalyzed by cobalt diimine-dioxime complexes.

    Kaeffer, Nicolas; Chavarot-Kerlidou, Murielle; Artero, Vincent


    Mimicking photosynthesis and producing solar fuels is an appealing way to store the huge amount of renewable energy from the sun in a durable and sustainable way. Hydrogen production through water splitting has been set as a first-ranking target for artificial photosynthesis. Pursuing that goal requires the development of efficient and stable catalytic systems, only based on earth abundant elements, for the reduction of protons from water to molecular hydrogen. Cobalt complexes based on glyoxime ligands, called cobaloximes, emerged 10 years ago as a first generation of such catalysts. They are now widely utilized for the construction of photocatalytic systems for hydrogen evolution. In this Account, we describe our contribution to the development of a second generation of catalysts, cobalt diimine-dioxime complexes. While displaying similar catalytic activities as cobaloximes, these catalysts prove more stable against hydrolysis under strongly acidic conditions thanks to the tetradentate nature of the diimine-dioxime ligand. Importantly, H2 evolution proceeds via proton-coupled electron transfer steps involving the oxime bridge as a protonation site, reproducing the mechanism at play in the active sites of hydrogenase enzymes. This feature allows H2 to be evolved at modest overpotentials, that is, close to the thermodynamic equilibrium over a wide range of acid-base conditions in nonaqueous solutions. Derivatization of the diimine-dioxime ligand at the hydrocarbon chain linking the two imine functions enables the covalent grafting of the complex onto electrode surfaces in a more convenient manner than for the parent bis-bidentate cobaloximes. Accordingly, we attached diimine-dioxime cobalt catalysts onto carbon nanotubes and demonstrated the catalytic activity of the resulting molecular-based electrode for hydrogen evolution from aqueous acetate buffer. The stability of immobilized catalysts was found to be orders of magnitude higher than that of catalysts in the

  15. Recent Advances in Organic Reactions Catalyzed by Lanthanide (Ⅲ) Complexes

    CHEN,Rui-Fang(陈瑞芳); QIAN,Chang-Tao(钱长涛)


    Lanthanide compounds have been attracting much attention in organic synthesis. Chiral Ln-substituted BINOL have been widely studied in several asymmetric organic reactions. LnCl3 and Ln(OTf)3 have been expected to serve as Lewis acids and have been applied to many important synthetic reactions in a one-pot manner. Ln(O-i-Pr)3 exhibits some basic characters,which also can be utilized in some special organic transformation. This article deals with some lanthanides (Ⅲ) complexes promoted organic reactions, which we have recently developed.

  16. Photocatalytic CO2 Reduction by Periodic Mesoporous Organosilica (PMO) Containing Two Different Ruthenium Complexes as Photosensitizing and Catalytic Sites.

    Kuramochi, Yusuke; Sekine, Masato; Kitamura, Kyohei; Maegawa, Yoshifumi; Goto, Yasutomo; Shirai, Soichi; Inagaki, Shinji; Ishida, Hitoshi


    A periodic mesoporous organosilica (PMO) containing 2,2'-bipyridine (bpy) ligands within the framework (BPy-PMO) has great potential for designing novel catalysts by modifying metal complexes. A photosensitizing site (Ru(PS)) was introduced by treating cis-[Ru(bpy)2 (dimethylsulfoxide)Cl]Cl with BPy-PMO. Then a catalytic site (Ru(Cat)) was brought in Ru(PS)x -BPy-PMO by reaction with a ruthenium polymer [Ru(CO)2 Cl2 ]n . The stepwise modification of BPy-PMO successfully affords a novel photocatalyst Ru(PS)x -Ru(Cat)y -BPy-PMO. The molar fractions (x, y) of Ru(PS) and Ru(Cat) were determined by energy dispersive X-ray (EDX) measurement and quantification of the amount of CO emitted in the photo-decarbonylation of Ru(Cat), respectively. Photochemical CO2 reduction (λex >430 nm) by Ru(PS)x -Ru(Cat)y -BPy-PMO in a CO2 -saturated N,N-dimethylacetamide/water solution containing 1-benzyl-1,4-dihydronicotinamide catalytically produced CO and formate. The total turnover frequency of CO and formate reached more than 162 h(-1) on x=0.11 and y=0.0055. The product selectivity (CO/formate) became large when the ratio of Ru(PS)-to-Ru(Cat) (x/y) was increased. The photocatalysts can be recycled at least three times without losing their catalytic activity, demonstrating that the Ru(PS) and Ru(Cat) units were strongly immobilized on the BPy-PMO framework. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Kinetic effects of sulfur oxidation on catalytic nitrile hydration: nitrile hydratase insights from bioinspired ruthenium(II) complexes.

    Kumar, Davinder; Nguyen, Tho N; Grapperhaus, Craig A


    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.

  18. Comparison of the mechanisms underlying the relaxation induced by two nitric oxide donors: sodium nitroprusside and a new ruthenium complex.

    Bonaventura, Daniella; de Lima, Renata Galvão; Vercesi, Juliana A; da Silva, Roberto Santana; Bendhack, Lusiane M


    We studied the mechanisms involved in the relaxation induced by nitric oxide (NO) donors, ruthenium complex ([Ru(terpy)(bdq)NO(+)](3+)-TERPY) and sodium nitroprusside (SNP) in denuded rat aorta. Both NO donors induced vascular relaxation independent of the agonist used in the pre-contraction. [Ru(terpy)(bdq)NO(+)](3+) and SNP activated guanylyl cyclase (GC) and K(+) channels. The production of cGMP induced by [Ru(terpy)(bdq)NO(+)](3+) - was higher than that obtained with SNP. The combination of GC inhibitor with K(+)channels blocker almost abolished the relaxation induced by the NO donors. The extracellular NO scavenger oxyhemoglobin reduced the potency without changing the maximum effect (Emax) of both NO donors. By using specific NO species scavengers, hydroxocobalamin and l-cysteine, we have identified the contribution of free radical NO (NO()) and nytroxil anion (NO(-)), respectively, to the rat aorta relaxation induced by both NO donors. The selective scavengers for NO() and NO(-) reduced the potency but not the Emax of [Ru(terpy)(bdq)NO(+)](3+). However, the NO(-) scavenger had no effect on the relaxation induced by SNP and NO() scavenger reduced only the potency to SNP. The inhibition of sarcoplasmic reticulum Ca(2+)-ATPase reduced only the potency of SNP without effect on the relaxation induced by [Ru(terpy)(bdq)NO(+)](3+). Our results demonstrate that both NO donors induce relaxation by activating the GC and K(+) channels. The NO() is the unique NO specie involved in the SNP-relaxation. On the other hand, the relaxant effect of [Ru(terpy)(bdq)NO(+)](3+) involves both NO() and NO(-), that produce higher concentration of cGMP. The inhibition of sarcoplasmic reticulum Ca(2+)-ATPase reduces the relaxation induced by SNP but it did not alter the relaxation induced by [Ru(terpy)(bdq)NO(+)](3+).

  19. Polymerization of Ethylene Catalyzed by Vanadium(III Complexes

    Hamdi Ali Elagab


    Full Text Available Thirty five  complexes of 1,2- bis(benzimidazole, benzothiazole and benzoxazolebenzene,  1,2-bis(benzimidazole, benzothiazole and benzoxazole-4-methyl-benzene, 1,2-bis  (benzimidazole, benzothiazole and benzoxazole4-bromobenzene, 1, 2-bis(benzimidazole, benzothiazole and benzoxazole 4- chlorobenzene,  and 2, 6-bis(benzimidazole, benzothiazole and benzoxazole pyridine compounds with V (III metal centers were synthesized, characterized, activated with methylalumoxane (MAO and then tested for catalytic ethylene polymerization. The catalysts generally show moderate to good activities compared to the benchmark catalyst Cp2ZrCl2. The activities of the various catalysts were found to be function of the hetero atoms in the ligand frameworks and also strongly influenced by the bridging unit of the ligand. The highest activity was obtained with 36 / MAO (442 kg PE / mol cat. h. The produced polyethylenes showed high molecular weights (up to 2.7 × 106 g/mol and broad molecular weight distributions (PD = 1.4 - 16.6. Thermal analysis of polyethylenes produced with vanadium complexes revealed that the catalyst systems were capable to produce high density polyethylenes with melting temperatures > 135 °C and crystallization temperatures range from 117-120 °C with high degree of crystallinity. DOI: 

  20. Multimetallic ruthenium(II) complexes based on biimidazole and bibenzimidazole: Effect of dianionic bridging ligands on Redox and spectral properties

    Rillema, D.P.; Sahai, R.; Matthews, P.; Edwards, A.K.; Shaver, R.J.; Morgan, L. (Univ. of North Carolina, Charlotte (USA))


    The preparation and properties of ruthenium(II) complexes containing the ligands 2,2{prime}-biimidazole (BiImH{sub 2}), 2,2{prime}-bibenzimidazole (BiBzImH{sub 2}), and 2,2{prime}-bipyridine (bpy) are reported. The complexes described are ((Ru(bpy){sub 2}){sub 2}BiIm){sup 2+} and the series (Ru-(bpy){sub n}(BiImH{sub 2}){sub 3{minus}n}){sup 2+}, (Ru(bpy){sub n}(BiBzImH{sub 2}){sub 3{minus}n}){sup 2+}, and (Ru(bpy){sub n}(BiBzImRu(bpy){sub 2}){sub 3{minus}n}){sup 2+}, n = 0-2. The redox potential for the first Ru{sup 3+/2+} couple shifted negatively from 1.26 to {minus}0.26 V vs SSCE as bpy ligands were replaced by BiImH{sub 2}, BiBzImH{sub 2}, and BiBzImRu(bpy){sub 2} ligands. Reductions were found in the {minus}1.5- to {minus}1.6-V range for complexes containing bypyridine ligands, but none were observed out to {minus}2.0 V for (Ru(BiImH{sub 2}){sub 3}){sup 2+} or (Ru(BiBzImH{sub 2}){sub 3}){sup 2+}. The complexes absorbed energy in the visible and UV regions of the spectrum and emitted radiation, with the exception of the tetrametallic species, in the 600-800-nm region. Estimates of the excited-state redox potentials revealed that the excited-state species were powerful reductants, but were weak oxidants. The (Ru{sup III}-(BiBzImRu{sup II}(bpy){sub 2}){sub 3}){sup 3+} cation absorbed in the near-infrared region at 12.2 {times} 10{sup 3} cm{sup {minus}1} in acetonitrile, but the absorption disappeared upon reduction to (Ru{sup II}(BiBzImRu{sup II}(bpy){sub 2}){sub 3}){sup 2+}. The position of the absorption manifold maximum varied linearly with the static and optical dielectric constant of the solvent. 45 refs., 12 figs., 3 tabs.

  1. New ruthenium nitrosyl pincer complexes bearing an O2 ligand. Mono-oxygen transfer.

    Fogler, Eran; Efremenko, Irena; Gargir, Moti; Leitus, Gregory; Diskin-Posner, Yael; Ben-David, Yehoshoa; Martin, Jan M L; Milstein, David


    We report on Ru((II))(μ(2)-O2) nitrosyl pincer complexes that can return to their original Ru(0) state by reaction with mono-oxygen scavengers. Potential intermediates were calculated by density functional theory (DFT) and a mechanism is proposed, revealing a new type of metal-ligand cooperation consisting of activation of the O2 moiety by both the metal center and the NO ligand. Reaction of the Ru(0) nitrosyl complex 1 with O2 quantitatively yielded the crystallographically characterized Ru((II)) (μ(2)-O2) nitrosyl complex 2. Reaction of 2 with the mono-oxygen scavengers phosphines or CO gave the Ru(0) complex 1 and phosphine oxides, or the carbonyl complex 3 (1 trapped by CO) and CO2, respectively. Reaction of 2 with 1 equiv of phosphine at room temperature or -40 °C resulted in immediate formation of half an equivalent of 1 and 1 equiv of phosphine oxide, while half an equivalent of 2 remained unchanged. Overnight reaction at room temperature of 2 with excess CO (≥3 equiv) resulted in 3 and CO2 gas as the only products. Reaction of 1 with 1 equiv of mono-oxygen source (dioxirane) at -78 °C yielded the Ru((II))(μ(2)-O2) complex 2. Similarly, reaction of the Ru(0) dearomatized complex 4 with O2 led to the crystallographicaly characterized Ru((II))(μ(2)-O2) complex 5. Further reaction of 5 with mono-oxygen scavengers (phosphines or CO) led to the Ru(0) complex 4 and phosphine oxides or complex 6 (4 trapped by CO) and CO2. When instead only 1 equiv of 5 was reacted with 1 equiv of phosphine at room temperature, immediate formation of half an equivalent of 4 and 1 equiv of phosphine oxide took place, while half an equivalent of 5 remained unchanged. When 5 reacted with an excess of CO (≥3 equiv), complex 6 and CO2 gas were the only products obtained. DFT studies indicate a new mode of metal-ligand cooperation involving the nitrosyl ligand in the oxygen transfer process.

  2. Efficient Hydration of Olefins Catalyzed by Wool-Supported Palladium Complex

    Dan-Ni SUI; Si-Qian WANG; Xin WANG; Mei-Yu HUANG; Ying-Yan JIANG


    @@ 1Introduction The hydration of olefins is one of the most important prxesses for the production of alcohols[1]. Both transition metal complexes[2] and enzymes[3] have been reported to catalyze the hydration of alkenes, but their catalysts are usually tither unstable or difficult to prepare, expensive and sometimes can not be easily recovered.In our previous papers, some natural biopolymer-metal complexes[4-6] have been used as effective catalysts in hydration to overcome above disadvantages. Recently, wool-Palladium complex(Wool-Pd) has been prepared and found to be able to effficiently catalyze the hydration of olefins to alcohols, such as cinnamyl alcohol(1a) to 1-phenyl-1,3-propanediol(1b), acrylic acid(2a) to lactic acid(2b), 4-vinyl pyridine(3a) to α-methyl-4-pyridinemethanol (3b) and acrylamide(4a) to 1-hydroxyethylamide(4b) respectively in high yields under mild conditions. See scheme 1.

  3. The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

    Phanopoulos, Andreas; Long, Nicholas; Miller, Philip


    Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the hydroxylmethylene phosphine precursor with ammonia in methanol under a nitrogen atmosphere. The N-triphosPh ligand precipitates from the solution after approximately 1 hr of reflux and can be isolated analytically pure via simple cannula filtration procedure under nitrogen. Reaction of the N-triphosPh ligand with [Ru3(CO)12] under reflux affords a deep red solution that show evolution of CO gas on ligand complexation. Orange crystals of the complex [Ru(CO)2{N(CH2PPh2)3}-κ3P] (2) were isolated on cooling to RT. The 31P{1H} NMR spectrum showed a characteristic single peak at lower frequency compared to the free ligand. Reaction of a toluene solution of complex 2 with oxygen resulted in the instantaneous precipitation of the carbonate complex [Ru(CO3)(CO){N(CH2PPh2)3}-κ3P] (3) as an air stable orange solid. Subsequent hydrogenation of 3 under 15 bar of hydrogen in a high-pressure reactor gave the dihydride complex [RuH2(CO){N(CH2PPh2)3}-κ3P] (4), which was fully characterized by X-ray crystallography and NMR spectroscopy. Complexes 3 and 4 are potentially useful catalyst precursors for a range of hydrogenation reactions, including biomass-derived products such as levulinic acid (LA). Complex 4 was found to cleanly react with LA in the presence of the proton source additive NH4PF6 to give [Ru(CO){N(CH2PPh2)3}-κ3P{CH3CO(CH2)2CO2H}-κ2O](PF6) (6). PMID:25938678

  4. Synthesis, characterization and biological evaluation of ruthenium flavanol complexes against breast cancer

    Singh, Ashok Kumar; Saxena, Gunjan; Sahabjada; Arshad, M.


    Four Ru(II) DMSO complexes (M1R-M4R) having substituted flavones viz. 3-Hydroxy-2-(4-methoxyphenyl)-4H-chromen-4-one (HL1), 3-Hydroxy-2-(4-nitrophenyl)-4H-chromen-4-one (HL2), 3-Hydroxy-2-(4-dimethylaminophenyl)-4H-chromen-4-one (HL3) and 3-Hydroxy-2-(4-chlorophenyl)-4H-chromen-4-one (HL4) were synthesized and characterized by elemental analysis, IR, UV-Vis, 1H NMR spectroscopies and ESI-MS. The molecular structures of the complexes were investigated by integrated spectroscopic and computational techniques (DFT). Both ligands as well as their complexes were screened for anticancer activities against breast cancer cell lines MCF-7. Cytotoxicity was assayed by MTT [3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay. All ligands and their complexes exhibited significant cytotoxic potential of 5-40 μM concentration at incubation period of 24 h. The cell cytotoxicity increased significantly in a concentration-dependent manner. In this series of compounds, HL2 (IC50 17.2 μM) and its complex M2R (IC50 16 μM) induced the highest cytotoxicity.

  5. New ruthenium(II bipyridyl complex: Synthesis, crystal structure and cytotoxicity

    Baroud Afya A.


    Full Text Available A new Ru(II bipyridyl complex with O4-hydrogenpyridine-2,4-dicarboxylate was synthesized and characterized by IR, NMR and mass spectrometry, X-ray diffraction analysis and elemental analysis. The electrochemical characteristics of the complex were investigated by cyclic voltammetry, revealing Ru(II/Ru(III electron transfer in the positive range of potentials. On the opposite potential side, multiple partially reversible peaks were dominant, representing subsequent reductions of the bulky bipyridyl moiety. The cytotoxic activity of the complex was tested in two human cancer cell lines: A549 (lung cancer and K562 (leukemia as well as non-tumor MRC-5 cells, by MTT assays. The IC50 values were > 300 and 177.63±2.28 μM for the A549 and K562 cells, respectively. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172035

  6. Protein-binding, cytotoxicity in vitro and cell cycle arrest of ruthenium(II) polypyridyl complexes

    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


    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.

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

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


    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.

  8. Sequential picosecond isomerizations in a photochromic ruthenium sulfoxide complex triggered by pump-repump-probe spectroscopy.

    King, Albert W; Jin, Yuhuan; Engle, James T; Ziegler, Christopher J; Rack, Jeffrey J


    The complex [Ru(bpy)(2)(bpSO)](PF(6))(2), where bpy is 2,2'-bipydine and bpSO is 1,2-bis(phenylsulfinyl)ethane, exhibits three distinct isomers which are accessible upon metal-to-ligand charge-transfer (MLCT) irradiation. This complex and its parent, [Ru(bpy)(2)(bpte)](PF(6))(2), where bpte is 1,2-bis(phenylthio)ethane, have been synthesized and characterized by UV-visible spectroscopy, NMR, X-ray crystallography, and femtosecond transient absorption spectroscopy. A novel method of 2-color Pump-Repump-Probe spectroscopy has been employed to investigate all three isomers of the bis-sulfoxide complex. This method allows for observation of the isomerization dynamics of sequential isomerizations of each sulfoxide from MLCT irradiation of the S,S-bonded complex to ultimately form the O,O-bonded metastable complex. One-dimensional (1-D) and two-dimensional (2-D) (COSY, NOESY, and TOCSY) (1)H NMR data show the thioether and ground state S,S-bonded sulfoxide complexes to be rigorously C(2) symmetric and are consistent with the crystal structures. Transient absorption spectroscopy reveals that the S,S to S,O isomerization occurs with an observed time constant of 56.8 (±7.4) ps. The S,O to O,O isomerization time constant was found to be 59 (±4) ps by pump-repump-probe spectroscopy. The composite S,S- to O,O-isomer quantum yield is 0.42.

  9. Highly enantioselective asymmetric autocatalysis using chiral ruthenium complex-ion-exchanged synthetic hectorite as a chiral initiator.

    Kawasaki, Tsuneomi; Omine, Toshiki; Suzuki, Kenta; Sato, Hisako; Yamagishi, Akihiko; Soai, Kenso


    The synthetic hectorite containing intercalated chiral Delta- and Lambda-tris(1,10-phenanthroline)ruthenium(II) ions acts as a heterogeneous chiral catalyst in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde to afford, in combination with asymmetric autocatalytic amplification of enantiomeric excess, 5-pyrimidyl alkanol with high enantiomeric excess.

  10. Comparison of physical and photophysical properties of monometallic and bimetallic ruthenium(II) complexes containing structurally altered diimine ligands

    Macatangay, A.; Jackman, D.C.; Merkert, J.W. [Univ. of North Carolina, Charlotte, NC (United States)] [and others


    The physical and photophysical properties of a series of monometallic, [Ru(bpy){sub 2}(dmb)]{sup 2+}, [Ru(bpy){sub 2}(BPY)]{sup 2+}, [Ru(bpy)(Obpy)]{sup 2+} and [Ru(bpy){sub 2}(Obpy)] {sup 2+}, and bimetallic, [(Ru(bpy){sub 2}){sub 2}(BPY)]{sup 4+} and [(Ru(bpy){sub 2}){sub 2}(Obpy)]{sup 4+}, complexes are examined, where bpy is 2,2{prime}-bipyridine, dmb is 4,4{prime}-dimethyl-2,2{prime}-bipyridine, BPY is 1,2-bis(4-methyl-2,2{prime}-bipyridin-4{prime}-yl)ethane, and Obpy is 1,2-bis(2,2{prime}-bipyridin-6-yl)ethane. The complexes display metal-to-ligand charge transfer transitions in the 450 nmn region, intraligand {pi}{yields}{pi}* transitions at energies greater than 300 nm, a reversible oxidation of the ruthenium(II) center in the 1.25-1.40 V vs SSCE region, a series of three reductions associated with each coordinated ligand commencing at {minus}1.3 V and ending at {approximately}{minus}1.9 V, and emission from a {sup 3}MLCT state having energy maxima between 598 and 610 nm. The Ru{sup III}/Ru{sup II} oxidation of the two bimetallic complexes is a single, two one-electron process. Relative to [Ru(bpy){sub 2}(BPY)]{sup 2+}, the Ru{sup III}/Ru{sup II} potential for [Ru-(bpy){sub 2}(Obpy)]{sup 2+} increases from 1.24 to 1.35 V, the room temperature emission lifetime decreases from 740 to 3ns, and the emission quantum yield decreases from 0.078 to 0.000 23. Similarly, relative to [(Ru(bpy){sub 2}){sub 2}(BPY)]{sup 4+}, the Ru{sup III}/Ru{sup II} potential for [(Ru(bpy){sub 2}){sub 2}(Obpy)]{sup 4+} increases from 1.28 to 1.32 V, the room temperature emission lifetime decreases from 770 to 3 ns, and the room temperature emission quantum yield decreases from 0.079 to 0.000 26.

  11. Backbone tuning in indenylidene–ruthenium complexes bearing an unsaturated N-heterocyclic carbene

    César A. Urbina-Blanco


    Full Text Available The steric and electronic influence of backbone substitution in IMes-based (IMes = 1,3-bis(2,4,6-trimethylphenylimidazol-2-ylidene N-heterocyclic carbenes (NHC was probed by synthesizing the [RhCl(CO2(NHC] series of complexes to quantify experimentally the Tolman electronic parameter (electronic and the percent buried volume (%Vbur, steric parameters. The corresponding ruthenium–indenylidene complexes were also synthesized and tested in benchmark metathesis transformations to establish possible correlations between reactivity and NHC electronic and steric parameters.

  12. Structure-function relationships within Keppler-type antitumor ruthenium(III) complexes: the case of 2-aminothiazolium[trans-tetrachlorobis(2-aminothiazole)ruthenate(III)].

    Mura, Pasquale; Piccioli, Francesca; Gabbiani, Chiara; Camalli, Mercedes; Messori, Luigi


    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.

  13. MCM-41 Bound Ruthenium Complex as Heterogeneous Catalyst for Hydrogenation Ⅰ: Effect of Support, Ligand and Solvent on the Catalyst Performance

    YU, Ying-Min; FEI, Jin-Hua; ZHANG, Yi-Ping; ZHENG, Xiao-Ming


    The functionalized MCM-41 mesoporous bound ruthenium complex was synthesized and characterized using elemental analysis, atomic absorption spectrophotometer, BET, XRD and FTIR. Hydrogenation of carbon dioxide to formic acid was investigated over these catalysts under supercritical CO2 condition. The effect of reactant gas partial pressure, supports, solvents and ligands on the synthesis of formic acid was studied. These factors could influence the catalyst activity, stability and reuse performance greatly and no byproduct was detected. These promising catalysts also offered the industrial advantages such as easy separation.

  14. Tuning interaction in dinuclear ruthenium complexes : HOMO versus LUMO mediated superexchange through azole and azine bridges

    Browne, Wesley; Hage, R; Vos, Johannes G.


    In this review the interaction between metal centers in dinuclear complexes based on azole and azine containing bridging ligands is reviewed. The focus of the review is on the manner in which the interaction pathway can be manipulated by variations in the nature of both the direct bridging unit and

  15. η6-Arene complexes of ruthenium and osmium with pendant donor functionalities

    Reiner, Thomas


    Conversion of 4′-(2,5-dihydrophenyl)butanol or N-trifluoroacetyl-2,5- dihydrobenzylamine with MCl3·n H2O (M = Ru, Os) affords the corresponding dimeric η6-arene complexes in good to excellent yields. Under similar reaction conditions, the amine functionalized arene precursor 2,5-dihydrobenzylamine yields the corresponding Ru(II) complex. For osmium, HCl induced oxidation leads to formation of [OsCl6] 2- salts. However, under optimized reaction conditions, conversion of the precursor 2,5-dihydrobenzylamine chloride results in clean formation of η6-arene Os(II) complex. X-ray structures of [(η6- benzyl ammonium)(dmso)RuCl2] and (2,5-dihydrobenzyl ammonium) 4[OsCl6]2confirm the spectroscopic data. High stability towards air and acid as well as enhanced solubility in water is observed for all η6-arene complexes. © 2010 Elsevier B.V. All rights reserved.

  16. A glycine ruthenium trithiacyclononane complex and its molecular encapsulation using cyclodextrins.

    Marques, Joana; Santos, Teresa M; Marques, Maria Paula; Braga, Susana S


    The complex Ru([9]aneS(3))(gly)Cl (gly = glycine) was obtained from the reaction of the precursor Ru([9]aneS(3))dmsoCl(2) with glycine and encapsulated into native beta-CD, a hydroxypropylated derivative HPbetaCD, and the methylated cyclodextrins TRIMEB and CRYSMEB. All four inclusion compounds were obtained with a 1:1 host:guest stoichiometry and characterised in the solid-state by powder X-ray diffraction, thermogravimetric analysis (TGA), and (13)C{(1)H} CP/MAS NMR and FTIR spectroscopies. The cytostatic and antiproliferative activity of the complex Ru([9]aneS(3))(gly)Cl and its four CD inclusion compounds was tested on the human osteosarcoma MG-63 cell line and the results compared to the inhibitory effect exerted by the pure cyclodextrins.


    Page, Norman J; Talkington, Raymond W.


    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.

  18. Hexakis (PCP-Platinum and -Ruthenium) Complexes by the Transcyclometalation Reaction and Their Use in Catalysis

    Koten, G. van; Dijkstra, H.P.; Albrecht, M.; Medici, S.; Klink, G.P.M. van


    Hexakis(PCP-pincer) complexes [C6{PtBr(PCP)}6] (5d) and [C6{RuCl(PCP)(PPh3)}6] (5e) were synthesized via the transcyclometalation (TCM) procedure. Mixing the hexakis(PCHP-arene) ligand 7 with six equivalents of [PtBr(NCN)] (1a) or [RuCl(NCN)(PPh3)] (1b), respectively, resulted in the selective

  19. From ruthenium olefin metathesis catalyst to (η5-3-phenylindenyl)hydrido complex via alcoholysis.

    Manzini, Simone; Nelson, David J; Lebl, Tomas; Poater, Albert; Cavallo, Luigi; Slawin, Alexandra M Z; Nolan, Steven P


    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).

  20. From ruthenium olefin metathesis catalyst to (η5-3- phenylindenyl)hydrido complex via alcoholysis

    Manzini, Simone


    The synthesis and characterisation of [Ru(H)(η5-3- phenylindenyl)(iBu-Phoban)2] 4 is reported ( iBu-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 [RuCl 2(PPh3)2(3-phenylindenylidene)] (M 10). This journal is © The Royal Society of Chemistry.

  1. Ultrafast spectroscopy and structural characterization of a photochromic isomerizing ruthenium bis-sulfoxide complex.

    King, Albert W; Malizia, Jason P; Engle, James T; Ziegler, Christopher J; Rack, Jeffrey J


    Irradiation of [Ru(bpy)2(bpSOp)](PF6)2 (where bpy is 2,2'-bipyridine and bpSOp is 1,3-bis(phenylsulfinyl)propane) results in the formation of two new isomers, namely the S,O- and O,O-bonded species. The crystal structure of the bis-thioether and bis-sulfoxide complexes are reported. NMR spectroscopy of the bis-thioether complex in solution is consistent with the molecular structure determined by diffraction methods. Further, NMR spectroscopy of the bis-sulfoxide complex reveals two conformers in solution, one that is consistent with the solid state structure and a second conformer showing distortion in the aliphatic portion of the chelate ring. Time-resolved visible absorption spectroscopy reveals isomerization time constants of 91 ps in dichloroethane (DCE) and 229 ps in propylene carbonate (PC). Aggregate isomerization quantum yields of 0.57 and 0.42 have been determined in DCE and in PC, respectively. The kinetics of the thermal reversion from the O,O- to S,O-bonded isomer are strongly solvent dependent, occurring with rates of 2.41 × 10(-3) and 4.39 × 10(-5) s(-1) in DCE, and 4.68 × 10(-4) and 9.79 × 10(-6) s(-1) in PC. The two kinetic components are assigned to the two isomers identified in solution.

  2. RutheniumII(η6-arene Complexes of Thiourea Derivatives: Synthesis, Characterization and Urease Inhibition

    Muhammad Hanif


    Full Text Available RuII(arene complexes have emerged as a versatile class of compounds to design metallodrugs as potential treatment for a wide range of diseases including cancer and malaria. They feature modes of action that involve classic DNA binding like platinum anticancer drugs, may covalent binding to proteins, or multimodal biological activity. Herein, we report the synthesis and urease inhibition activity of RuII(arene complexes of the general formula [RuII(η6-p-cymene(LCl2] and [RuII(η6-p-cymene(PPh3(LCl]PF6 with S-donor systems (L based on heterocyclic thiourea derivatives. The compounds were characterized by 1H-, 13C{1H}- and 31P{1H}-NMR spectroscopy, as well as elemental analysis. The crystal structure of [chlorido(η6-p-cymene(imidazolidine-2-thione(triphenylphosphineruthenium(II] hexafluorophosphate 11 was determined by X-ray diffraction analysis. A signal in the range 175–183 ppm in the 13C{1H}-NMR spectrum indicates the presence of a thione rather than a thiolate. This observation was also confirmed in the solid state by X-ray diffraction analysis of 11 which shows a C=S bond length of 1.720 Å. The compounds were tested for urease inhibitory activity and the thiourea-derived ligands exhibited moderate activity, whereas their corresponding Ru(arene complexes were not active.

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

    Pannwitz, Andrea; Wenger, Oliver S


    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.

  4. Dye-Sensitized Nanocrystalline ZnO Solar Cells Based on Ruthenium(II Phendione Complexes

    Hashem Shahroosvand


    Full Text Available The metal complexes (RuII (phen2(phendione(PF62(1, [RuII (phen(bpy(phendione(PF62 (2, and (RuII (bpy2(phendione(PF62 (3 (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine and phendione = 1,10-phenanthroline-5,6-dione have been synthesized as photo sensitizers for ZnO semiconductor in solar cells. FT-IR and absorption spectra showed the favorable interfacial binding between the dye-molecules and ZnO surface. The surface analysis and size of adsorbed dye on nanostructure ZnO were further examined with AFM and SEM. The AFM images clearly show both, the outgrowth of the complexes which are adsorbed on ZnO thin film and the depression of ZnO thin film. We have studied photovoltaic properties of dye-sensitized nanocrystalline semiconductor solar cells based on Ru phendione complexes, which gave power conversion efficiency of (η of 1.54% under the standard AM 1.5 irradiation (100 mW cm−2 with a short-circuit photocurrent density (sc of 3.42 mA cm−2, an open-circuit photovoltage (oc of 0.622 V, and a fill factor (ff of 0.72. Monochromatic incident photon to current conversion efficiency was 38% at 485 nm.

  5. Interaction and Binding Modes of bis-Ruthenium(II Complex to Synthetic DNAs

    Hasi Rani Barai


    Full Text Available [μ-(linkerL2(dipyrido[3,2-a:2′,3′-c]phenazine2(phenanthroline2Ru(II2]2+ with linker: 1,3-bis-(4-pyridyl-propane, L: PF6 (bis-Ru-bpp was synthesized and their binding properties to a various polynucleotides were investigated by spectroscopy, including normal absorption, circular dichroism(CD, linear dichroism(LD, and luminescence techniques in this study. On binding to polynucleotides, the bis-Ru-bpp complex with poly[d(A-T2], and poly[d(I-C2] exhibited a negative LDr signal whose intensity was as large as that in the DNA absorption region, followed by a complicated LDr signal in the metal-to-ligand charge transfer region. Also, the emission intensity and equilibrium constant of the bis-Ru-bpp complex with poly[d(A-T2], and poly[d(I-C2] were enhanced. It was reported that both of dppz ligand of the bis-Ru-bpp complex intercalated between DNA base-pairs when bound to native, mixed sequence DNA. Observed spectral properties resemble to those observed for poly[d(A-T2] and poly[d(I-C2], led us to be concluded that both dppz ligands intercalate between alternated AT and IC bases-pairs In contrast when bis-Ru-bpp complex was bound to poly[d(G-C2], the magnitude of the LDr in the dppz absorption region, as well as the emission intensity, was half in comparison to that of bound to poly[d(A-T2], and poly[d(I-C2]. Therefore the spectral properties of the bis-Ru-bpp-poly[d(G-C2] complex suggested deviation from bis-intercalation model in the poly[d(G-C2] case. These results can be explained by a model whereby one of the dppz ligands is intercalated while the other is exposed to solvent or may exist near to phosphate. Also it is indicative that the amine group of guanine in the minor groove provides the steric hindrance for incoming intercalation binder and it also takes an important role in a difference in binding of bis-Ru-bpp bound to poly[d(A-T2] and poly[d(I-C2].

  6. Electrochemical properties of the hexacyanoferrate(II)–ruthenium(III) complex immobilized on silica gel surface chemically modified with zirconium(IV) oxide

    Panice, Lucimara B.; Oliveira, Elisangela A. de; Filho, Ricardo A.D. Molin; Oliveira, Daniela P. de [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Lazarin, Angélica M., E-mail: [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Andreotti, Elza I.S.; Sernaglia, Rosana L. [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Gushikem, Yoshitaka [Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13084-971 Campinas, São Paulo (Brazil)


    Highlights: • The cyano-bridged mixed valence ruthenium composite material was synthesized. • This newly synthesized compound was incorporated into a carbon paste electrode. • The electrode did not show significant changes in response after six months of use. • The modified electrode is very stable and reproducible. • The electrode sensor was successfully applied for ascorbic acid determination. - Abstract: The chemically modified silica gel with zirconium(IV) oxide was used to immobilize the [Fe(CN){sub 6}]{sup 4−} complex ion initially. The reaction of this material with [Ru(edta)H{sub 2}O]{sup −} complex ion formed the immobilized cyano-bridged mixed valence ruthenium complex, (≡Zr){sub 5}[(edta)RuNCFe(CN){sub 5}]. This material was incorporated into a carbon paste electrode and, its electrochemical properties were investigated. However, for an ascorbic acid solution, an enhancement of the anodic peak current was detected due to electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for ascorbic acid determination in pharmaceutical preparation with success.

  7. Synthesis and characterisation of ruthenium carbonyl complexes with cyclometallated ligands derived from senecialdimine

    Mul, WP; Elsevier, CJ; Vuurman, MA; Smeets, WJJ; Spek, AL; deBoer, JL


    From thermal reactions of Ru-3(CO)(12) with senecialdimine, (CH3)(2)C=CHCH=NR (R = iPr (a), t-Bu (b)), in refluxing heptanes the following complexes have been isolated and characterised: Ru-2(CO)(6)[(CH3)(2)C(H)CC(H)NR] (2a,b), Ru-2(Co)(6)[C(H)C(CH3)C(H)C(H)=NR] (3a,b), [HRu6(CO)(18)][2-(C(H)=C(CH3)

  8. The Combination of 4-Hydroxythiazoles with Azaheterocycles: Efficient bidentate Ligands for novel Ruthenium Complexes

    Beckert, Rainer; Weiss, Dieter


    Abstract We report here on the synthesis of three novel ligands in which an azaheterocycle is connected with a thiazole subunit: 4-methoxy-5-methyl-2-pyridine-2-yl-1,3-thiazole (1), 4-methoxy-5-methyl-2-pyrimidine-2-yl-1,3-thiazole (2) and 4-methoxy-5-phenyl-2-pyridine-2-yl-1,3-thiazole (3). Being cyclic versions of 1,4-diazadienes, they offer good prerequisites for the synthesis of metal complexes and have been employed as chelating ligands. Three novel heteroleptic cationic compl...

  9. The Effect of Dye Density on the Efficiency of Photosensitization of TiO2 Films: Light-Harvesting by Phenothiazine-Labelled Dendritic Ruthenium Complexes

    Lin-Yong Zhu


    Full Text Available A family of dendritic tris-bipyridyl ruthenium coordination complexes incorporating two or four carboxylate groups for binding to a TiO2 surface site and another dendritic linker between the metal complex and highly absorptive dyes were formulated as thin films on TiO2 coated glass. The family included phenothiazine-substituted dendrons of increasing structural complexity and higher optical density. The dye-loaded films were characterized by steady-state emission and absorption measurements and by kinetic studies of luminescence and transient absorption. Upon photoexcitation of the bound dyes, rapid electron injection into the metal oxide film was the dominant observed process, producing oxidized dye that persisted for hundreds of milliseconds. Complex decay profiles for emission, transient absorption, and optical bleaching of the dendritic dyes point to highly heterogeneous behavior for the films, with observed persistence lifetimes related directly to structurally enhance electronic coupling between the metal oxide support and the dendritic dyes.

  10. Crystal structure, physical, and photophysical properties of a ruthenium(II) bipyridine diazafluorenone complex

    Wang, Y.; Jackman, D.C.; Rillema, D.P. [Univ. of North Carolina, Charlotte, NC (United States)] [and others


    The complex [Ru(bpy){sub 2}(dafo)](PF{sub 6}){sub 2}, where bpy is 2,2{prime}-bipyridine and dafo is diazafluorenone crystallizes in the space group P2{sub 1}/n with a = 9.5059(3){angstrom}, b = 14.002(2){angstrom} and c = 25.783(8){angstrom}. The coordination geometry of the Ru atom is that of a distorted octahedron with a RuN{sub 6} core. The two Ru-N bond distances to the dafo ligand are 2.13(1) and 2.15(1) {angstrom}; the four Ru-N bond distances to the bipyridine ligands are 2.03(1), 2.05(1), 2.06(1), and 2.07(1) {angstrom}. The three shortest Ru-N distances are trans to the three longest Ru-N distances. The complex is oxidized and reduced reversibly at 1.41 and -0.65 V vs. SSCE, respectively. It displays absorptions at 438 nm (1.6 x 10{sup 4}), 285 nm (6.2 x 10{sup 4}), and 240 nm (4.1 x 10{sup 4}) and a broad emission centered at 626 nm in water at room temperature. The emission lifetime is 420 ns and the emission quantum yield is 5.3 x 10{sup -4}.

  11. A study on tailor made ruthenium sulfoxide complexes: Synthesis, characterization and application

    Mehrotra Ripul


    Full Text Available In this study, a dinucleating spacer incorporating two 2-aminopyridine units has been used to prepare seven novel dinuclear compounds. These molecules were characterized by elemental analyses, conductivity measurements, magnetic susceptibility, FT-IR, FAB-Mass, electronic, 1H and 13C{1H}NMR spectral studies. The complex [{trans,mer-RuCl2(DMSO3}2(μ-5,5'-methylenebis(2-aminopyridine].2DMSO, 2 was also characterized through 1H-1H COSY NMR. There are mainly three different formulations; [{cis,fac-RuCl2(SO3}2(μ-MBAP].2SO; [{trans,mer-RuCl2(SO3}2(μ-MBAP].2SO and [{trans-RuCl4(SO}2(μ-MBAP]2- [X]2+; where SO = DMSO / TMSO; MBAP = 5,5'-methylenebis(2-aminopyridine and [X]+ = [(DMSO2H]+, Na+ or [(TMSOH]+. The coordination was found through cyclic nitrogen of pyridine ring in octahedral environment for both metal centers. The chemical behivour of [{cis,fac-RuCl2(DMSO3}2(μ-5,5'-methylenebis(2-aminopyridine].2DMSO, 1 and 2 in aqueous solution with respect to time was observed by conductivity measurements and UV-vis spectrophotometer. All complexes were found to possess prominent antibacterial activity against Escherichia coli in comparison to Chloramphenicol and Gatifloxacin.

  12. Complexes of ruthenium(III) with some 2-aminothiazole derivatives/synthesis, properties and pharmacological studies.

    Nikolova, Antonina; Ivanov, Darvin; Bontchev, Panayot; Buyukliev, Rossen; Mehandjiev, Dimitar; Gochev, Georgi; Konstantinov, Spiro; Karaivanova, Margarita


    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.

  13. Ruthenium Complex “Light Switches” that are Selective for Different G-Quadruplex Structures

    Wachter, Erin; Moyá, Diego; Parkin, Sean


    Recognition and regulation of G-quadruplex nucleic acid structures is an important goal for the development of chemical tools and medicinal agents. The addition of a bromo substituent to the dipyridylphenazine (dppz) ligands in the photophysical “light switch”, [Ru(bpy)2dppz]2+, and the photochemical “light switch”, [Ru(bpy)2dmdppz]2+, creates compounds with increased selectivity for an intermolecular parallel G-quadruplex and the mixed-hybrid G-quadruplex, respectively. When [Ru(bpy)2dppz-Br]2+ and [Ru(bpy)2dmdppz-Br]2+ are incubated with the G-quadruplexes, they have a stabilizing effect on the DNA structures. Activation of [Ru(bpy)2dmdppz-Br]2+ with light results in covalent adduct formation with the DNA. These complexes demonstrate that subtle chemical modifications of RuII complexes can alter G-quadruplex selectivity, and could be useful for the rational design of in vivo G-quadruplex probes. PMID:26560887

  14. Bis-heteroleptic ruthenium(II) complex of a triazole ligand as a selective probe for phosphates.

    Chowdhury, Bijit; Khatua, Snehadrinarayan; Dutta, Ranjan; Chakraborty, Sourav; Ghosh, Pradyut


    A new bis-heteroleptic ruthenium(II) complex (1) of 2-(1-methyl-1H-1,2,3-triazol-4-yl) pyridine (L) ligand was extensively explored for anion sensing studies. 1[PF6]2 shows selective sensing of dihydrogen phosphate (H2PO4(-))/hydrogen pyrophosphate (HP2O7(3-)) among halides, HCO3(-), AcO(-), NO3(-), ClO4(-), HSO4(-), OH(-), BzO(-), H2PO4(-), and HP2O7(3-) in acetonitrile. Enhancement of emission intensity of 1[PF6]2 along with a 10 nm red shift of the emission maximum is observed in the presence of H2PO4(-)/HP2O7(3-) selectively. The photoluminescence (PL) titration experiment of 1[PF6]2 results in binding constants (K(a)) of 5.28 × 10(4) M(-1) and 4.67 × 10(4) M(-1) for H2PO4(-) and HP2O7(3-), respectively, which is in good agreement with the Ka values obtained from UV-vis titration experiments (2.97 × 10(4) M(-1) and 2.45 × 10(4) M(-1) for H2PO4(-) and HP2O7(3-), respectively). High selectivity of 1[PF6]2 toward these two anions in acetonitrile is further confirmed by PL intensity measurement of 1[PF6]2 upon addition of these two anions in the presence of a large excess of other competitive anions. Further, considerable changes in the lifetime (τ) as well as in the decay pattern of 1[PF6]2 in the presence of H2PO4(-)/HP2O7(3-) among all tested anions support the selective binding property of 1[PF6]2 toward these two anions. Significant downfield shift of the triazole -CH proton of 1[PF6]2 with 1 equiv of H2PO4(-) (Δδ = 0.26 ppm) and HP2O7(3-) (Δδ = 0.23 ppm) in deuterated dimethyl sulfoxide proclaim binding mechanism via C-H···anion interaction in solution state. Finally, single-crystal X-ray structural analysis confirms the first example of dihydrogen pyrophosphate (H2P2O7(2-)) recognition via solitary C-H···anion interactions.

  15. Characterization of the mechanisms of action and nitric oxide species involved in the relaxation induced by the ruthenium complex.

    Bonaventura, Daniella; Oliveira, Fabiana S; Lunardi, Claure N; Vercesi, Juliana A; da Silva, Roberto S; Bendhack, Lusiane M


    Nitric oxide (NO) plays an important role in the control of vascular tone. NO donors have therapeutic use and the most used NO donors, nitroglycerin and sodium nitroprusside have problems in their use. Thus, new NO donors have been synthesized to minimize these undesirable effects. Nytrosil ruthenium complexes have been studied as a new class of NO donors. trans-[RuCl([15]aneN(4))NO](2+), induces vasorelaxation only in presence of reducing agent. In this study, we characterized the mechanisms of vasorelaxation of trans-[RuCl([15]aneN(4))NO](2+) in denuded rat aorta and identified which NO forms are involved in this relaxation. We also evaluated the effect of this NO donor in decreasing the cytosolic Ca(2+) concentration ([Ca(2+)]c) of the vascular smooth muscle cells. Vasorelaxation to trans-[RuCl([15]aneN(4))NO](2+) (E(max): 101.8 +/- 2.3%, pEC(50): 5.03 +/- 0.15) was almost abolished in the presence of the NO* scavenger hydroxocobalamin (E(max): 4.0 +/- 0.4%; P < 0.001) and it was partially inhibited by the NO(-) scavenger L-cysteine (E(max): 79.9 +/- 6.9%, pEC(50): 4.41 +/- 0.06; P < 0.05). The guanylyl cyclase inhibitor ODQ reduced the E(max) (57.7 +/- 4.0%, P < 0.001) and pEC(50) (4.21 +/- 0.42, P < 0.01) and the combination of ODQ and TEA abolished the response to trans-[RuCl([15]aneN(4))NO](2+). The blockade of voltage-dependent (K(v)), ATP-sensitive (K(ATP)), and Ca(2+)-activated (K(Ca) K(+) channels reduced the vasorelaxation induced by trans-[RuCl([15]aneN(4))NO](2+). This compound significantly reduced [Ca(2+)]c (from 100% to 85.9 +/- 3.5%, n = 4). In conclusion, our data demonstrate that this NO donor induces vascular relaxation involving NO* and NO(-) species, that is associated to a decrease in [Ca(2+)]c. The mechanisms of vasorelaxation involve guanylyl cyclase activation, cGMP production and K(+) channels activation.

  16. Bis-mixed-carbene ruthenium-thiolate-alkylidene complexes: synthesis and olefin metathesis activity.

    Dahcheh, Fatme; Stephan, Douglas W


    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.

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

    Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng


    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.

  18. Origins of enantioselectivity during allylic substitution reactions catalyzed by metallacyclic iridium complexes.

    Madrahimov, Sherzod T; Hartwig, John F


    In depth mechanistic studies of iridium catalyzed regioselective and enantioselective allylic substitution reactions are presented. A series of cyclometalated allyliridium complexes that are kinetically and chemically competent to be intermediates in the allylic substitution reactions was prepared and characterized by 1D and 2D NMR spectroscopies and single-crystal X-ray difraction. The rates of epimerization of the less thermodynamically stable diastereomeric allyliridium complexes to the thermodynamically more stable allyliridium stereoisomers were measured. The rates of nucleophilic attack by aniline and by N-methylaniline on the isolated allyliridium complexes were also measured. Attack on the thermodynamically less stable allyliridium complex was found to be orders of magnitude faster than attack on the thermodynamically more stable complex, yet the major enantiomer of the catalytic reaction is formed from the more stable diastereomer. Comparison of the rates of nucleophilic attack to the rates of epimerization of the diastereomeric allyliridium complexes containing a weakly coordinating counterion showed that nucleophilic attack on the less stable allyliridium species is much faster than conversion of the less stable isomer to the more stable isomer. These observations imply that Curtin-Hammett conditions are not met during iridium catalyzed allylic substitution reactions by η(3)-η(1)-η(3) interconversion. Rather, these data imply that when these conditions exist for this reaction, they are created by reversible oxidative addition, and the high selectivity of this oxidative addition step to form the more stable diastereomeric allyl complex leads to the high enantioselectivity. The stereochemical outcome of the individual steps of allylic substitution was assessed by reactions of deuterium-labeled substrates. The allylic substitution was shown to occur by oxidative addition with inversion of configuration, followed by an outer sphere nucleophilic attack

  19. Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols and Hydroxide Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    Santilli, Carola; Makarov, Ilya; Fristrup, Peter


    reaction is most likely involved in this case. The kinetic isotope effect was determined to be 0.67 using 1-butanol as the substrate. A plausible catalytic cycle was characterized by DFT/B3LYP-D3 and involved coordination of the alcohol to the metal, β-hydride elimination, hydroxide attack...... on the coordinated aldehyde, and a second β-hydride elimination to furnish the carboxylate....

  20. Transfer Hydrogenation of C= C Double Bonds Catalyzed by Ruthenium Amido-Complexes:Scopes, Limitation and Enantioselectivity

    XUE,Dong; CHENG,Ying-Chun; CUI,Xin; WANG,Qi-Wei; ZHU,Jin; DENG,Jin-Gen


    @@ The reduction of C = C double bonds is one of the most fundamental synthetic transformations and plays a key role in the manufacturing of a wide variety of bulk and fine chemicals. Hydrogenation of olefinic substrates can be achieved readily with molecular hydrogen in many cases, but transfer hydrogenation methods using suitable donor molecules such as formic acid or alcohols are receiving increasing attention as possible synthetic alternatives because it requires no special equipment and avoids the handling of potentially hazardous gaseous hydrogen.

  1. Determination of Trace Ruthenium(Ⅲ) with Ruthenium Catalyzing Potassium Periodate Oxidizing Methyl Violet Fading Kinetic Spectrophotometric%钌催化甲基紫褪色动力学光度法测定痕量Ru(Ⅲ)

    王洪福; 苏智先; 罗英; 杨森


    On condition of heating to 70℃ in water bath and diluted H2SO4 used as medium,the fading reaction in potassium periodate catalyzing methyl violet can be catalyzed by ruthenium(III),and based on this phenomenon,a new catalytic kinetic spectrphotometry determination of ruthenium(III) has been founded.The optimum experimental conditions of the catalytic reaction was studied,and the absorbance difference between non-catalytic reaction and catalytic reaction remained good linear relationship with mass concentration ρ of ruthenium(III) in the range of 0.02~1.5μg/25mL at wavelength 581nm.The detection limit was 1.933×10-10 g/mL.The kinetic parameters were determined and showed that the reaction was first order to ruthenium(III) and pseudo first order to the whole reaction.The apparent rate constant was 5.967×10-4 /s,and the apparent active energy was 49.36 kJ/mol.The relative standard deviation for the determination of 1.0 μg /25mL ruthenium standard solution was 1.8%(n=11).Applied to the determination of ruthenium in molecular sieve and active carbon samples,the recovery of this method was 98.8%~102.2% which fulfilled the requirement of analysis.%基于稀H2SO4介质中及70℃水浴加热下,Ru(Ⅲ)对高碘酸钾氧化甲基紫褪色反应有明显的催化作用,且催化作用的强弱与钌的加入量成正比,据此建立了催化动力学光度法测定痕量Ru(Ⅲ)的新光度分析方法。研究了反应的最佳条件。非催化反应与催化反应于波长581 nm处的吸光度差值与Ru(Ⅲ)的质量浓度ρ在0.02~1.5μg/25mL范围内呈良好的线性关系,检出限为1.933×10-10g/mL。测定了动力学参数,反应对Ru(Ⅲ)为一级反应,在试验条件下,总反应为准一级反应,表观速率系数为5.967×10-4/s,表观活化能为49.36 kJ/mol。对1.0μg/25mLRu(Ⅲ)标准试液测定的相对标准偏差为1.8%(n=11)。方法用于分子筛和活性炭样品中钌(Ⅲ)的测定,结果满意。

  2. Solution chemistry of a water-soluble eta2-H2 ruthenium complex: evidence for coordinated H2 acting as a hydrogen bond donor.

    Szymczak, Nathaniel K; Zakharov, Lev N; Tyler, David R


    The ability of an eta2-H2 ligand to participate in intermolecular hydrogen bonding in solution has long been an unresolved issue. Such species are proposed to be key intermediates in numerous important reactions such as the proton-transfer pathway of H2 production by hydrogenase enzymes. We present the synthesis of several new water-soluble ruthenium coordination complexes including an eta2-H2 complex that is surprisingly inert to substitution by water. The existence of dihydrogen hydrogen bonding (DHHB) was experimentally probed by monitoring the chemical shift of H-bonded Ru-(H2) complexes using NMR spectroscopy, by UV-visible spectroscopy, and by monitoring the rotational dynamics of a hydrogen-bonding probe molecule. The results provide strong evidence that coordinated H2 can indeed participate in intermolecular hydrogen bonding to bulk solvent and other H-bond acceptors.

  3. Ruthenium ammine/crown ether interactions in solution: Effects of modification of both guest and host on the strength of second-sphere complexation

    Todd, M.D.; Yuhua Dong; Horney, J.; Yoon, D.I.; Hupp, J.T. (Northwestern Univ., Evanston, IL (United States))


    Charge-transfer absorption, electrochemical, and NMR-NOE studies of monomeric and dimeric (ligand-bridged) ruthenium ammine guest interactions with several crown ether hosts show that second-sphere complexation is prevalent in nitromethane as solvent and that complexation or binding constants can be varied by ca. 10[sup 8]-fold by modifying both guest and host properties. For hosts, larger binding constants are obtained with larger macrocycles and with more flexible macrocycles (i.e. dicyclohexano vs dibenzo crowns). For guests, larger binding constants are observed in higher oxidation states and in the presence of strongly electron-withdrawing ancillary ligands. In all cases, binding appears to be driven primarily by ammine hydrogen/ether oxygen (Lewis acid/base) interactions. Evidence is also found, however, for contributions from favorable benzene(crown)/pyridine(complex) interactions and (apparently) benzene(crown) [yields] Ru(III) charge-transfer (donor/acceptor) interactions. 17 refs., 3 figs., 2 tabs.

  4. Assignment of Pre-Edge Features in the Ru K-Edge X-Ray Absorption Spectra of Organometallic Ruthenium Complexes

    Getty, K.; Delgado-Jaime, M.U.; Kennepohl, P.


    The nature of the lowest energy bound-state transition in the Ru K-edge X-ray absorption spectra for a series of Grubbs-type ruthenium complexes was investigated. The pre-edge feature was unambiguously assigned as resulting from formally electric dipole forbidden Ru 4d {l_arrow} 1s transitions. The intensities of these transitions are extremely sensitive to the ligand environment and the symmetry of the metal centre. In centrosymmetric complexes the pre-edge is very weak since it is limited by the weak electric quadrupole intensity mechanism. By contrast, upon breaking centrosymmetry, Ru 5p-4d mixing allows for introduction of electric dipole allowed character resulting in a dramatic increase in the pre-edge intensity. The information content of this approach is explored as it relates to complexes of importance in olefin metathesis and its relevance as a tool for the study of reactive intermediates.


    TANG Liming; HUANG Meiyu; JIANG Yingyan


    A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% selectivity at 70℃ and 1.01325 × 105 Pa mild conditions. N/Pd molar ratio in the complex, temperature and solvents have much influence on the reaction. The reactivity order of reactants was found to be: phenol >m->p->ocresol. The catalyst is stable during the reaction and could be repeatedly used for several times without much decrease in its catalytic activity.

  6. Hydrogenation of Toluidines Catalyzed by Silica-supported Carboxymethylcellulose-platinum Complex

    WANG Xin; YANG Ji-huo; HUANG Mei-yu; JIANG Ying-yan


    The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields,respectively, at 30 C and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.

  7. Amplification of anti-diastereoselectivity via Curtin-Hammett effects in ruthenium-catalyzed hydrohydroxyalkylation of 1,1-disubstituted allenes: diastereoselective formation of all-carbon quaternary centers.

    Zbieg, Jason R; McInturff, Emma L; Leung, Joyce C; Krische, Michael J


    Under the conditions of ruthenium-catalyzed transfer hydrogenation, 1,1-disubstituted allenes 1a-c and alcohols 2a-g engage in redox-triggered generation of allylruthenium-aldehyde pairs to form products of hydrohydroxyalkylation 3a-g, 4a-g, and 5a-g with complete branched regioselectivity. By exploiting Curtin-Hammett effects, good to excellent levels of anti-diastereoselectivity (4:1 to >20:1) are obtained. Thus, all carbon quaternary centers are formed in a diastereoselective fashion upon carbonyl addition from the alcohol oxidation level in the absence of premetalated nucleophiles or stoichiometric byproducts. Exposure of allene 1b to equimolar quantities of alcohol 2a and aldehyde 6b under standard reaction conditions delivers adducts 4a and 4b in a 1:1 ratio. Similarly, exposure of allene 1b to equimolar quantities of aldehyde 6a and alcohol 2b provides adducts 4a and 4b in an identical equimolar ratio. Exposure of allene 1b to d(2)-p-nitrobenzyl alcohol, deuterio-2a, under standard reaction conditions delivers the product of hydrohydroxyalkylation, deuterio-4a, which incorporates deuterium at the carbinol position (>95% (2)H) and the interior vinylic position (34% (2)H). Competition experiments involving exposure of allene 1b to equimolar quantities of benzylic alcohols 2a and deuterio-2a reveal no significant kinetic effect. The collective data corroborate rapid, reversible alcohol dehydrogenation, allene hydrometalation, and (E)-, (Z)-isomerization of the transient allylruthenium in advance of turnover-limiting carbonyl addition. Notably, analogous allene-aldehyde reductive C-C couplings employing 2-propanol as the terminal reductant display poor levels of anti-diastereoselectivity, suggesting that carbonyl addition is not turnover-limiting in reactions conducted from the aldehyde oxidation level.

  8. The role of the alcohol and carboxylic acid in directed ruthenium-catalyzed C(sp3)-H α-alkylation of cyclic amines.

    Bergman, Sheba D; Storr, Thomas E; Prokopcová, Hana; Aelvoet, Karel; Diels, Gaston; Meerpoel, Lieven; Maes, Bert U W


    A general directed Ru-catalyzed C(sp(3))-H α-alkylation protocol for piperidines (less-reactive substrates than the corresponding five-membered cyclic amines) has been developed. The use of a hindered alcohol (2,4-dimethyl-3-pentanol) as the solvent and catalyst activator, and a catalytic amount of trans-1,2-cyclohexanedicarboxylic acid is necessary to achieve a high conversion to product. This protocol was used to effectively synthesize a number of 2-hexyl- and 2,6-dihexyl piperidines, as well as the alkaloid (±)-solenopsin A. Kinetic studies have revealed that the carboxylic acid additive has a significant effect on catalyst initiation, catalyst longevity, and reverses the reaction selectivity compared with the acid-free reaction (promotes alkylation versus competing alkene reduction).

  9. Asymmetric ruthenium(II) and osmium(II) complexes with new bidentate polyquinoline ligands. Synthesis and NMR characterization.

    Mamo, Antonino; Aureliano, Alessandro; Recca, Antonino


    A series of Ru(II) and Os(II) tris-chelate complexes with new bidentate 2-pyridylquinoline ligands have been synthesized and fully characterized by EA,1H-NMR and FAB-MS techniques. The new ligands are: L1 = 4-p-methoxyphenyl-6-bromo-2-(2'- pyridyl)quinoline (mphbr-pq) and L2 = 4-p-hydroxyphenyl-6-bromo-2-(2'-pyridyl)-quinoline (hphbr-pq). The complexes studied are: [Ru(bpy)2L1](PF6)2 (C1), [Ru(bpy)2L2](PF6)2 (C2), [Os(bpy)2L1](PF6)2 (C3), [Os(bpy)2L2](PF6)2 (C4) (bpy = 2,2'-bipyridine), [Ru(dmbpy)2L1](PF6)2 (C5), [Ru(dmbpy)2L2](PF6)2 (C6), [Os(dmbpy)2L1](PF6)2 (C7), and [Os(dmbpy)2L2](PF6)2 (C8) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine). Moreover, new functionalized complexes C9-C12 were obtained by the base-catalyzed direct alkylation of C2, C4, C6, and C8 with 6-bromo-1-hexene. The complete assignment of the 1H-NMR spectra for the two new ligands (L1 and L2), and their Ru(II) or Os(II) complexes has been accomplished using a combination of one- and two-dimensional NMR techniques. The JH,H values have been determined for the majority of the resonances.

  10. Highly efficient redox isomerisation of allylic alcohols catalysed by pyrazole-based ruthenium(IV) complexes in water: mechanisms of bifunctional catalysis in water.

    Bellarosa, Luca; Díez, Josefina; Gimeno, José; Lledós, Agustí; Suárez, Francisco J; Ujaque, Gregori; Vicent, Cristian


    The catalytic activity of ruthenium(IV) ([Ru(η(3):η(3)-C(10)H(16))Cl(2)L]; C(10)H(16) = 2,7-dimethylocta-2,6-diene-1,8-diyl, L = pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, 3-methyl-5-phenylpyrazole, 2-(1H-pyrazol-3-yl)phenol or indazole) and ruthenium(II) complexes ([Ru(η(6)-arene)Cl(2)(3,5-dimethylpyrazole)]; arene = C(6)H(6), p-cymene or C(6)Me(6)) in the redox isomerisation of allylic alcohols into carbonyl compounds in water is reported. The former show much higher catalytic activity than ruthenium(II) complexes. In particular, a variety of allylic alcohols have been quantitatively isomerised by using [Ru(η(3):η(3)-C(10)H(16))Cl(2)(pyrazole)] as a catalyst; the reactions proceeded faster in water than in THF, and in the absence of base. The isomerisations of monosubstituted alcohols take place rapidly (10-60 min, turn-over frequency = 750-3000 h(-1)) and, in some cases, at 35 °C in 60 min. The nature of the aqueous species formed in water by this complex has been analysed by ESI-MS. To analyse how an aqueous medium can influence the mechanism of the bifunctional catalytic process, DFT calculations (B3LYP) including one or two explicit water molecules and using the polarisable continuum model have been carried out and provide a valuable insight into the role of water on the activity of the bifunctional catalyst. Several mechanisms have been considered and imply the formation of aqua complexes and their deprotonated species generated from [Ru(η(3):η(3)-C(10)H(16))Cl(2)(pyrazole)]. Different competitive pathways based on outer-sphere mechanisms, which imply hydrogen-transfer processes, have been analysed. The overall isomerisation implies two hydrogen-transfer steps from the substrate to the catalyst and subsequent transfer back to the substrate. In addition to the conventional Noyori outer-sphere mechanism, which involves the pyrazolide ligand, a new mechanism with a hydroxopyrazole complex as the active species can be at work in water. The

  11. In vitro evaluation of the cyto-genotoxic potential of Ruthenium(II) SCAR complexes: a promising class of antituberculosis agents.

    De Grandis, Rone Aparecido; Resende, Flávia Aparecida; da Silva, Monize Martins; Pavan, Fernando Rogério; Batista, Alzir Azevedo; Varanda, Eliana Aparecida


    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.

  12. [Ru(pipe)(dppb)(bipy)]PF6: A novel ruthenium complex that effectively inhibits ERK activation and cyclin D1 expression in A549 cells.

    Ferreira-Silva, Guilherme A; Ortega, Marina M; Banionis, Marco A; Garavelli, Graciana Y; Martins, Felipe T; Dias, Julia S M; Viegas, Cláudio; Oliveira, Jaqueline C de; Nascimento, Fabio B do; Doriguetto, Antonio C; Barbosa, Marilia I F; Ionta, Marisa


    Lung cancer is the most frequent type of cancer worldwide. In Brazil, only 14% of the patients diagnosed with lung cancer survived 5years in the last decades. Although improvements in the therapeutic approach, it is relevant to identify new chemotherapeutic agents. In this framework, ruthenium metal compounds emerge as a promising alternative to platinum-based compounds once they displayed lower cytotoxicity and more selectivity for tumor cells. The present study aimed to evaluate the antitumor potential of innovative ruthenium(II) complex, [Ru(pipe)(dppb)(bipy)]PF6 (PIPE) on A549 cells, which is derived from non-small cell lung cancer. Results demonstrated that PIPE effectively reduced the viability and proliferation rate of A549 cells. When PIPE was used at 9μM there was increase in G0/G1 cell population with concomitant reduction in frequency of cells in S-phase, indicating cell cycle arrest in G1/S transition. Antiproliferative activity of PIPE was associated to its ability of reducing cyclin D1 expression and ERK phosphorylation levels. Cytotoxic activity of PIPE on A549 cells was observed when PIPE was used at 18μM, which was associated to its ability of inducing apoptosis by intrinsic pathway. Taken together, the data demonstrated that PIPE is a promising antitumor agent and further in vivo studies should be performed. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    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


    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.

  14. A fast-initiating ionically tagged ruthenium complex: a robust supported pre-catalyst for batch-process and continuous-flow olefin metathesis.

    Borré, Etienne; Rouen, Mathieu; Laurent, Isabelle; Magrez, Magaly; Caijo, Fréderic; Crévisy, Christophe; Solodenko, Wladimir; Toupet, Loic; Frankfurter, René; Vogt, Carla; Kirschning, Andreas; Mauduit, Marc


    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.

  15. Computational POM and DFT Evaluation of Experimental in-vitro Cancer Inhibition of Staurosporine-Ruthenium(II) Complexes: the Power Force of Organometallics in Drug Design.

    Hadda, Taibi Ben; Genc, Zuhal K; Masand, Vijay H; Nebbache, Nadia; Warad, Ismail; Jodeh, Shehdeh; Genc, Murat; Mabkhot, Yahia N; Barakat, Assem; Salgado-Zamora, Hector


    A computational Petra/Osiris/Molinspiration/DFT(POM/DFT) based model has been developed for the identification of physico-chemical parameters governing the bioactivity of ruthenium-staurosporine complexes 2-4 containing an antitumoral-kinase (TK) pharmacophore sites. The four compounds 1-4 analyzed here were previously screened for their antitumor activity, compounds 2 and 4 are neutral, whereas analogue compound 3 is a monocation with ruthenium(II) centre. The highest anti- antitumor activity was obtained for compounds 3 and 4, which exhibited low IC(50) values (0.45 and 8 nM, respectively), superior to staurosporine derivative (pyridocarbazole ligand 1, 150 · 10(3) nM). The IC(50) of 3 (0.45 nM), represents 20,000 fold increased activity as compared to staurosporine derivative 1. The increase of bioactivity could be attributed to the existence of pi-charge transfer from metal-staurosporine to its (CO(δ)--NH(δ+)) antitumor pharmacophore site.

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

    Casey, Charles P; Guan, Hairong


    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.

  17. Studies on PNPP Hydrolysis Catalyzed by Schiff Base Cobalt(Ⅱ) Complexes

    HU Wei; LI Jian-Zhang; WANG Ying; LI Ci; DU Juana; MENG Xiang-Guang; HU Chang-Wei; ZENG Xian-Cheng


    Two cobalt(Ⅱ) complexes of the Schiff base with morpholino or aza-crown ether pendants, CoL1 and CoL2, as mimic hydrolytic metalloenzyme, were used in catalytic hydrolysis of carboxylic ester (PNPP). The analysis of specific absorption spectra of the hydrolytic reaction systems indicates that key intermediates, made up of PNPP and Co(Ⅱ)complexes, have been formed in reaction processes of the PNPP catalytic hydrolysis. The mechanism of PNPP catalytic hydrolysis has been proposed based on the analytic result of specific absorption spectrum. A kinetic mathematical model, applied to the calculation of the kinetic parameter of PNPP catalytic hydrolysis, has been established based on the mechanism proposed. The acid effect of buffer solution, structural effect of the complexes,and effect of temperature on the rate of PNPP hydrolysis catalyzed by the complexes have been also discussed.

  18. Selective Hydrogen Generation from Formic Acid with Well-Defined Complexes of Ruthenium and Phosphorus-Nitrogen PN3-Pincer Ligand

    Pan, Yupeng


    An unsymmetrically protonated PN3-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. Grabbing hold: A PN3-pincer complex was employed for the selective hydrogen generation from formic acid. Mechanistic studies suggest 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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthesis, characterization, and DNA-binding studies of ruthenium complexes [Ru(tpy)(ptn)]2+ and Ru(dmtpy)(ptn)]2+.

    Li, Lü-Ying; Jia, Hai-Na; Yu, Hui-Juan; Du, Ke-Jie; Lin, Qi-Tian; Qiu, Kang-Qiang; Chao, Hui; Ji, Liang-Nian


    Two ruthenium(II) polypyridyl complexes [Ru(tpy)(ptn)](2+) (1) and Ru(dmtpy)(ptn)](2+) (2) (ptn=3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]naphthalene, tpy=2,2':6',2"-terpyridine, dmtpy=5,5'-dimethyl-2,2':6',2"-terpyridine) have been synthesized and characterized by elemental analysis, (1)H NMR, mass spectrometry and crystal structure analysis. Spectroscopic studies together with isothermal titration calorimetry (ITC) and viscosity measurements prove that two complexes bind to DNA in an intercalative mode. ITC experiments show that the binding mode for complex 2 is entropically driven, while an entropy-driven initial binding of complex 1 is followed by an entropically and enthalpically favorable process. This difference may be attributed to the ancillary ligand effects on the DNA binding of Ru(II) complexes. Circular dichroism titrations of calf thymus DNA (CT-DNA) with Ru(II) complexes show that complexes 1 and 2 induce B to Z conformational transition of calf thymus DNA at low ionic strength (0.05 M NaCl). The induced Z-DNA conformation can revert to B form when Ru(II) complexes are displaced by ethidium bromide or at high ionic strengths ([NaCl]=0.4 M), but keeps intact with temperature ranged from 25 to 90 °C. The unique structure and characteristics of Ru(II) complexes designed in this investigation will be useful for the study of Z-DNA.

  20. Architecture of Amylose Supramolecules in Form of Inclusion Complexes by Phosphorylase-Catalyzed Enzymatic Polymerization

    Kadokawa, Jun-ichi


    This paper reviews the architecture of amylose supramolecules in form of inclusion complexes with synthetic polymers by phosphorylase-catalyzed enzymatic polymerization. Amylose is known to be synthesized by enzymatic polymerization using α-d-glucose 1-phosphate as a monomer, by phosphorylase catalysis. When the phosphorylase-catalyzed enzymatic polymerization was conducted in the presence of various hydrophobic polymers, such as polyethers, polyesters, poly(ester-ether), and polycarbonates as a guest polymer, such inclusion supramolecules were formed by the hydrophobic interaction in the progress of polymerization. Because the representation of propagation in the polymerization is similar to the way that a vine of a plant grows, twining around a rod, this polymerization method for the formation of amylose-polymer inclusion complexes was proposed to be named “vine-twining polymerization”. To yield an inclusion complex from a strongly hydrophobic polyester, the parallel enzymatic polymerization system was extensively developed. The author found that amylose selectively included one side of the guest polymer from a mixture of two resemblant guest polymers, as well as a specific range in molecular weights of the guest polymers poly(tetrahydrofuran) (PTHF) in the vine-twining polymerization. Selective inclusion behavior of amylose toward stereoisomers of chiral polyesters, poly(lactide)s, also appeared in the vine-twining polymerization. PMID:24970172

  1. Synthesis, Crystal Structure of Ruthenium 1,2-Naphthoquinone-1-oxime Complex and Its Mediated C-C Coupling Reactions of Terminal Alkynes

    SUN, Ke; WONG, Wing-Tak; LIU, Xiao-Xia; ZHANG, Bao-Yan


    Substituted decarbonylation reaction of ruthenium 1,2-naphthoquinone-1-oxime (1-nqo) complex, cis-, cis-[Ru{ η2-N(O)C10-H6O}2(CO)2] (1), with acetonitrile gave cis-, cis-[Ru { η2-N(O)C10H6O}2(CO)(NCMe)] (2). Complex 2 was fully characterized by 1H NMR, FAB MS, IR spectra and single crystal X-ray analysis. Complex 2 maintains the coordination structure of 1 with the two naphthoquinonic oxygen atoms, as well as the two oximato nitrogen atoms located cis to each other, showing that there is no ligand rearrangement of the 1-nqo ligands during the substitution reaction. The carbonyl group originally trans to the naphthoquinonic oxygen in one 1-nqo ligand is left in its original position [O(5)-Ru-C(1), 174.0(6)°], while the other one originally trans to the oximato group of the other 1-nqo llgand is substituted by NCMe [N(1)-Ru-N(3), 170.6(6)°].This shows that the carbonyl trans to oximato group is more labile than the one trans to naphthoquinonic O atom towards substitution. This is probably due to the comparatively stronger π back bonding from ruthenium metal to the carbonyl group trans to naphthoquinonic O atom, than the one trans to oximato group, resulting in the comparatively weaker Ru-CO bond for the latter and consequently easier replacement of this carbonyl. Selected coupling of phenylacetylene mediated by 2 gave a single trans-dimerization product 3, while 2 mediated coupling reaction of methyl propiolate produced three products:one trans-dimerization product 4 and two cyclotrimeric products 5 and 6.

  2. Optimum bifunctionality in a 2-(2-pyridyl-2-ol)-1,10-phenanthroline based ruthenium complex for transfer hydrogenation of ketones and nitriles: impact of the number of 2-hydroxypyridine fragments.

    Paul, Bhaskar; Chakrabarti, Kaushik; Kundu, Sabuj


    Considerable differences in reactivity and selectivity for 2-hydroxypyridine (2-HP) derived ruthenium complexes in transfer hydrogenation are described. Bifunctional Ru(ii)-(phenpy-OH) [phenpy-OH: 2-(2-pyridyl-2-ol)-1,10-phenanthroline] complex () exhibited excellent catalytic activity in transfer hydrogenation (TH) of ketones and nitriles. Notably, in comparison with all the reported 2-hydroxypyridine (2-HP) derived ruthenium complexes in transfer hydrogenation, complex displayed significantly higher activity. Additionally, exploiting the metal-ligand cooperativity in complex , chemoselective TH of ketones was achieved and sterically demanding ketones were readily reduced. An outer-sphere mechanism is proposed for this system as exogenous PPh3 has no significant effect on the rate of this reaction. This is a rare example of a highly active bifunctional Ru(ii) catalyst bearing only one 2-HP unit.

  3. Olefin Metathesis With Ruthenium-Arene Catalysts Bearing N-Heterocyclic Carbene Ligands

    Delaude, Lionel; Demonceau, Albert

    In this chapter, we summarize the main results of our investigations on the ring-opening metathesis polymerization (ROMP) of cyclooctene catalyzed by various ruthenium (Ru)-arene complexes bearing imidazolin-2-ylidene, imidazolidin- 2-ylidene, or triazolin-5-ylidene ligands. Three major findings emerged from this study. First, we underscored the intervention of a photochemical activation step due to visible light illumination. Second, we established that the presence of an endocyclic double bond in the carbene ligand central heterocycle was not crucial to achieve high catalytic efficiencies. Third, we demonstrated that ortho-metallation of the N-heterocyclic carbene (NHC) ligand by the Ru center led to inactive catalysts.

  4. Bis(o-methylserotonin)-containing iridium(III) and ruthenium(II) complexes as new cellular imaging dyes: synthesis, applications, and photophysical and computational studies.

    Núñez, Cristina; Silva López, Carlos; Faza, Olalla Nieto; Fernández-Lodeiro, Javier; Diniz, Mario; Bastida, Rufina; Capelo, Jose Luis; Lodeiro, Carlos


    We report the synthesis, characterization, and scope of a new versatile emissive molecular probe functionalized with a 1,10-phenanthroline moiety containing methylserotonin groups as binding sites for metal ion recognition. The synthesis, characterization, and evaluation of the in vitro imaging capability of the iridium(III) and ruthenium(II) complexes [Ir(ppy)2(N-N)](+) and [Ru(bpy)2(N-N)](2+), in which ppy is 2-phenylpyridine, bpy is 2,2'-bipyridine, and N-N is a 1,10-phenanthroline ligand functionalized with two methylserotonin groups to serve as binding sites for metal ion recognition, is reported. The uptake of these compounds by living freshwater fish (Carassius auratus) was studied by fluorescence microscopy, and the cytotoxicity of ligand N-N and [Ru(bpy)2(N-N)](2+) in this species was also investigated.

  5. Development of a New Class of Thiocyanate-Free Cyclometalated Ruthenium(II Complex for Sensitizing Nanocrystalline TiO2 Solar Cells

    Surya Prakash Singh


    Full Text Available We designed and developed a new class of thiocyanate-free cyclometalated ruthenium sensitizers for sensitizing nanocrystalline TiO2 solar cells. This complex shows appreciably broad absorption range. Anchoring to nanocrystalline TiO2 films for light to electrical energy conversion in regenerative photoelectrochemical cells achieves efficient sensitization to TiO2 electrode. With this new sensitizer, there were a power conversion efficiency of 4.76%, a short-circuit photocurrent density of 11.21 mA/cm2, an open-circuit voltage of 0.62 V, and a fill factor of 0.68 obtained under standard AM 1.5 sunlight.

  6. 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

    Yang, Haiying [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062 (China); Department of Chemistry, Yuncheng University, Yuncheng 044300 (China); Li, Zhejian; Shan, Meng; Li, Congcong; Qi, Honglan; Gao, Qiang [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062 (China); Wang, Jinyi [College of Science and College of Veterinary Medicine, Northwest A& F University, Yangling 712100 (China); Zhang, Chengxiao, E-mail: [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062 (China)


    Highlights: • A novel biosensor was developed for the detection of prostate cancer cells. • The selectivity of the biosensor was improved using antibody as capture probe. • The biosensor showed the low extremely detection limit of 2.6 × 10{sup 2} cells mL{sup −1}. • The ruthenium complex-labelled WGA can be transported in the cell vesicles. - Abstract: 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{sup 2} to 3.0 × 10{sup 4} cells mL{sup −1}, with a detection limit of 2.6 × 10{sup 2} cells mL{sup −1}. The ECL biosensor was also applied to detect prostate specific antigen with a detection limit of 0.1 ng mL{sup −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.

  7. A new ion imprinted polymer based on Ru(III)-thiobarbituric acid complex for solid phase extraction of ruthenium(III) prior to its determination by ETAAS.

    Zambrzycka, Elżbieta; Godlewska-Żyłkiewicz, Beata


    A new ruthenium ion imprinted polymer was prepared from the Ru(III) 2-thiobarbituric acid complex (the template), methacrylic acid or acrylamide (the functional monomers), and ethylene glycol dimethacrylate (the cross-linking agent) using 2,2'-azobisisobutyronitrile as the radical initiator. The ion imprinted polymer was characterized and used as a selective sorbent for the solid phase extraction of Ru(III) ions. The effects of type of functional monomer, sample volume, solution pH and flow rate on the extraction efficiency were studied in the dynamic mode. Ru(III) ion was quantitatively retained on the sorbents in the pH range from 3.5 to 10, and can be eluted with 4 mol L(-1) aqueous ammonia. The affinity of Ru(III) for the ion imprinted polymer based on the acrylamide monomer is weaker than that for the polymer based on the methacrylic acid monomer, which therefore was used in interference studies and in analytical applications. Following extraction of Ru(III) ions with the imprint and their subsequent elution from the polymer with aqueous ammonia, Ru(III) was detected by electrothermal atomic absorption spectrometry with a detection limit of 0.21 ng mL(-1). The method was successfully applied to the determination of trace amounts of Ru(III) in water, waste, road dust and platinum ore (CRM SARM 76) with a reproducibility (expressed as RSD) below 6.4 %. FigureThe new ion imprinted polymer was prepared and used for the separation of ruthenium from water and most complex environmental samples, such as road dust and platinum ore (CRM SARM 76) prior ETAAS determination.

  8. Syntheses, DNA binding and anticancer profiles of L-glutamic acid ligand and its copper(II) and ruthenium(III) complexes.

    Ali, Imran; Wani, Waseem A; Saleem, Kishwar; Wesselinova, Diana


    A new multidentate ligand (L) has been synthesized by the controlled condensation of L-glutamic acid with formaldehyde and ethylenediamine. Cu(II) and Ru(III) metal ion complexes of the synthesized ligand have also been prepared. The ligand and the metal complexes were purified by chromatography and characterized by spectroscopy and other techniques. Molar conductance measurements suggested ionic nature of the complexes. The ligand and the complexes are soluble in water with quite good stabilities; essential requirements for effective anticancer drugs. DNA binding constants (Kbs) for copper and ruthenium complexes were 1.8 x 103 and 2.6 x 103 M-1 while their Ksv values were 7.9 x 103, and 7.3 x 103; revealing strong binding of these complexes with DNA. Hemolytic assays of the reported compounds indicated their significantly less toxicity to RBCs than the standard anticancer drug letrazole. Anticancer profiles of all the compounds were determined on HepG2, HT-29, MDA-MB-231 and HeLa human cancer cell lines. All the compounds have quite good activities on HeLa cell lines but the best results were of CuL on HepG2, HT-29 and MDA-MB-231 cell lines.

  9. 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

    Sampath, K.; Sathiyaraj, S.; Raja, G.; Jayabalakrishnan, C.


    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.

  10. Interplay between Theory and Experiment for Ammonia Synthesis Catalyzed by Transition Metal Complexes.

    Tanaka, Hiromasa; Nishibayashi, Yoshiaki; Yoshizawa, Kazunari


    Nitrogen fixation is an essential chemical process both biologically and industrially. Since the discovery of the first transition-metal-dinitrogen complex in 1965, a great deal of effort has been devoted to the development of artificial nitrogen fixation systems that work under mild reaction conditions. However, the transformation of chemically inert dinitrogen using homogeneous catalysts is still challenging because of the difficulty in breaking the strong triple bond of dinitrogen, and a very limited number of transition metal complexes have exhibited the catalytic activity for the direct transformation of dinitrogen into ammonia with low turnover numbers. To develop more effective nitrogen fixation systems, it is necessary to retrieve as much information as possible from the limited successful examples. Computational chemistry will provide valuable insights in the understanding of the reaction mechanisms involving unstable intermediates that are hard to isolate or characterize. We have been applying it for clarifying detailed mechanisms of dinitrogen activation and functionalization by transition metal complexes as well as for designing new catalysts for more effective nitrogen fixation. This Account summarizes recent progress in the elucidation of catalytic mechanisms of nitrogen fixation by using mono- and dinuclear molybdenum complexes, as well as cubane-type metal-sulfido clusters from a theoretical point of view. First, we briefly introduce experimental and theoretical contributions to the elucidation of the reaction mechanism of nitrogen fixation catalyzed by a mononuclear Mo-triamidoamine complex. Special attention is paid to our recent studies on Mo-catalyzed nitrogen fixation using dinitrogen-bridged dimolybdenum complexes. A possible catalytic mechanism is proposed based on theoretical and experimental investigations. The catalytic mechanism involves the formation of a monuclear molybdenum-nitride (Mo≡N) intermediate, as well as the regeneration of

  11. Evaluation of DNA-binding, DNA cleavage, antioxidant and cytotoxic activity of mononuclear ruthenium(II) carbonyl complexes of benzaldehyde 4-phenyl-3-thiosemicarbazones

    Sampath, Krishnan; Sathiyaraj, Subbaiyan; Jayabalakrishnan, Chinnasamy


    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.

  12. Anthracene-tethered ruthenium(II) arene complexes as tools to visualize the cellular localization of putative organometallic anticancer compounds.

    Nazarov, Alexey A; Risse, Julie; Ang, Wee Han; Schmitt, Frederic; Zava, Olivier; Ruggi, Albert; Groessl, Michael; Scopelitti, Rosario; Juillerat-Jeanneret, Lucienne; Hartinger, Christian G; Dyson, Paul J


    Anthracene derivatives of ruthenium(II) arene compounds with 1,3,5-triaza-7-phosphatricyclo[]decane (pta) or a sugar phosphite ligand, viz., 3,5,6-bicyclophosphite-1,2-O-isopropylidene-α-d-glucofuranoside, were prepared in order to evaluate their anticancer properties compared to the parent compounds and to use them as models for intracellular visualization by fluorescence microscopy. Similar IC(50) values were obtained in cell proliferation assays, and similar levels of uptake and accumulation were also established. The X-ray structure of [{Ru(η(6)-C(6)H(5)CH(2)NHCO-anthracene)Cl(2)(pta)] is also reported.

  13. Synthesis, spectroscopic and DFT structural characterization of two novel ruthenium(III) oxicam complexes. In vivo evaluation of anti-inflammatory and gastric damaging activities.

    Tamasi, Gabriella; Bernini, Caterina; Corbini, Gianfranco; Owens, Natalie F; Messori, Luigi; Scaletti, Federica; Massai, Lara; Giudice, Pietro Lo; Cini, Renzo


    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.

  14. G protein activation by G protein coupled receptors: ternary complex formation or catalyzed reaction?

    Roberts, David J; Waelbroeck, Magali


    G protein coupled receptors catalyze the GDP/GTP exchange on G proteins, thereby activating them. The ternary complex model, designed to describe agonist binding in the absence of GTP, is often extended to G protein activation. This is logically unsatisfactory as the ternary complex does not accumulate when G proteins are activated by GTP. Extended models taking into account nucleotide binding exist, but fail to explain catalytic G protein activation. This review puts forward an enzymatic model of G protein activation and compares its predictions with the ternary complex model and with observed receptor phenomenon. This alternative model does not merely provide a new set of formulae but leads to a new philosophical outlook and more readily accommodates experimental observations. The ternary complex model implies that, HRG being responsible for efficient G protein activation, it should be as stable as possible. In contrast, the enzyme model suggests that although a limited stabilization of HRG facilitates GDP release, HRG should not be "too stable" as this might trap the G protein in an inactive state and actually hinder G protein activation. The two models also differ completely in the definition of the receptor "active state": the ternary complex model implies that the active state corresponds to a single active receptor conformation (HRG); in contrast, the catalytic model predicts that the active receptor state is mobile, switching smoothly through various conformations with high and low affinities for agonists (HR, HRG, HRGGDP, HRGGTP, etc.).

  15. Theoretical and experimental studies of phenol oxidation by ruthenium complex with N,N,N-tris(benzimidazol-2yl-methyl)amine.

    Hernandez, J Guadalupe; Silva, Antonio Romero; Thangarasu, Pandiyan; Najera, Rafael Herrera; Moreno, Alfonso Duran; Ledesma, M Teresa Orta; Cruz-Borbolla, Julian; Singh, Narinder


    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.

  16. Ruthenium Sensitizers and Their Applications in Dye-Sensitized Solar Cells

    Yuancheng Qin


    Full Text Available Dye-sensitized solar cells (DSSCs have attracted considerable attention in recent years due to the possibility of low-cost conversion of photovoltaic energy. The DSSCs-based ruthenium complexes as sensitizers show high efficiency and excellent stability, implying potential practical applications. This review focuses on recent advances in design and preparation of efficient ruthenium sensitizers and their applications in DSSCs, including thiocyanate ruthenium sensitizers and thiocyanate-free ruthenium sensitizers.

  17. Synthesis of ruthenium hydride

    Kuzovnikov, M. A.; Tkacz, M.


    Ruthenium hydride was synthesized at a hydrogen pressure of about 14 GPa in a diamond-anvil cell. Energy-dispersive x-ray diffraction was used to monitor the ruthenium crystal structure as a function of hydrogen pressure up to 30 GPa. The hydride formation was accompanied by phase transition from the original hcp structure of the pristine metal to the fcc structure. Our results confirmed the theoretical prediction of ruthenium hydride formation under hydrogen pressure. The standard Gibbs free energy of the ruthenium hydride formation reaction was calculated assuming the pressure of decomposition as the equilibrium pressure.

  18. CO2 Hydrogenation Catalyzed by Iridium Complexes with a Proton-Responsive Ligand.

    Onishi, Naoya; Xu, Shaoan; Manaka, Yuichi; Suna, Yuki; Wang, Wan-Hui; Muckerman, James T; Fujita, Etsuko; Himeda, Yuichiro


    The catalytic cycle for the production of formic acid by CO2 hydrogenation and the reverse reaction have received renewed attention because they are viewed as offering a viable scheme for hydrogen storage and release. In this Forum Article, CO2 hydrogenation catalyzed by iridium complexes bearing sophisticated N^N-bidentate ligands is reported. We describe how a ligand containing hydroxy groups as proton-responsive substituents enhances the catalytic performance by an electronic effect of the oxyanions and a pendent-base effect through secondary coordination sphere interactions. In particular, [(Cp*IrCl)2(TH2BPM)]Cl2 (Cp* = pentamethylcyclopentadienyl; TH2BPM = 4,4',6,6'-tetrahydroxy-2,2'-bipyrimidine) enormously promotes the catalytic hydrogenation of CO2 in basic water by these synergistic effects under atmospheric pressure and at room temperature. Additionally, newly designed complexes with azole-type ligands were applied to CO2 hydrogenation. The catalytic efficiencies of the azole-type complexes were much higher than that of the unsubstituted bipyridine complex [Cp*Ir(bpy)(OH2)]SO4. Furthermore, the introduction of one or more hydroxy groups into ligands such as 2-pyrazolyl-6-hydroxypyridine, 2-pyrazolyl-4,6-dihydroxypyrimidine, and 4-pyrazolyl-2,6-dihydroxypyrimidine enhanced the catalytic activity. It is clear that the incorporation of additional electron-donating functionalities into proton-responsive azole-type ligands is effective for promoting further enhanced hydrogenation of CO2.

  19. Copolymerization of Ethylene and Vinyl Amino Acidic Ester Catalyzed by Titanium and Zirconium Complexes

    Jing Wang


    Full Text Available A series of titanium and zirconium complexes with ligands based on di-isopropyl phosphorus-phenylamine and their derivatives were synthesized and characterized. These catalysts were utilized to catalyze the copolymerization of ethylene with N-acetyl-O-(dec-9-enyl-L-tyrosine ethyl ester with high catalytic activity of 6.63 × 104 g P (mol Ti−1 h−1 after activation by methylaluminoxane (MAO. The effects of ligand structure, metal atoms (Ti, Zr and polymerization conditions were investigated in detail. The obtained polymers were characterized by 13C-NMR, DSC, FT-IR, and GPC. The results showed that the obtained copolymer had a high comonomer incorporation rate of 2.56 mol % within the copolymer chain. The melting temperature of the copolymer was up to 138.9 °C, higher than that of the obtained homopolyethylene.

  20. Rolling cycle amplification based single-color quantum dots–ruthenium complex assembling dyads for homogeneous and highly selective detection of DNA

    Su, Chen; Liu, Yufei; Ye, Tai; Xiang, Xia; Ji, Xinghu; He, Zhike, E-mail:


    Graphical abstract: A universal, 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. - Highlights: • The single-color QDs–Ru assembling dyads were applied in homogeneous DNA assay. • This biosensor exhibited high selectivity against base mismatched sequences. • This biosensor could be severed as universal platform for the detection of ssDNA. • This sensor could be used to detect the target in human serum samples. • This DNA sensor had a good selectivity under the interference of other dsDNA. - Abstract: 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){sub 2}(dppx)]{sup 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){sub 2}(dppx)]{sup 2+} is removed from the surface of the QDs, resulting in restoring the fluorescence of the QDs, which has been quenched by [Ru(phen){sub 2}(dppx)]{sup 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

  1. Microwave-assisted synthesis of ruthenium(II) complexes with alkynes as potential inhibitor by selectively recognizing c-myc G-quadruplex DNA.

    Zhang, Shuangyan; Wu, Qiong; Zhang, Hao; Wang, Qi; Wang, Xicheng; Mei, Wenjie; Wu, Xiaohui; Zheng, Wenjie


    Herein, two polypyridyl ruthenium(II) complexes with alkynes, [Ru(bpy)2L](ClO4)2 (L=p-TEPIP (1) and p-BEPIP (2); bpy=2,2'-bipyridine; p-TEPIP=2-(4-trimethylsilylpropargyl)-1H-imidazo[4,5f][1,10]phenanthroline; p-BEPIP=2-(4-phenyacetylenephenyl)-1H-imidazo[4,5f][1,10]phenanthroline) have been successfully achieved in yields of 32%-89% by a Sonogashira coupling reaction under microwave irradiation. We studied these complexes as potential stabilizers of c-myc G-quadruplex DNA. Observations revealed that both complexes could selectively bind to and stabilize c-myc G-quadruplex DNA with a constant of approximately 1.61±0.78 and 9.47±4.20×10(3)M(-1), respectively, as determined from ITC (isothermal ttitration calorimetry) experiments, FRET (fluorescence resonance energy ttransfer) assay and competitive FRET assay. Moreover, the melting point (Tm) of the c-myc G-quadruplex DNA increased in the presence of 1 and 2 ([Ru]=0.2μM) by approximately 9 and 19.9°C, respectively. It is noteworthy that the conformation of the c-myc G-quadruplex DNA appeared to change when titrated with 1 and 2, which was accompanied by a negative-induced CD (circular dichroism) signal that appeared at a wavelength of 295nm. Furthermore, the conformational change in c-myc G-quadruplex DNA induced by 1 and 2have also been confirmed by TEM (transmission electron microscopy) and AFM (atomic force microscopy). Consequently, the replication of c-myc DNA was blocked by 1 and 2, and especially by 2, as verified by PCR (polymerase chain reaction) -stop assay and Western-blot assay. Thus, these ruthenium(II) complexes can be developed as potential inhibitors in chemotherapy through their binding and stabilization of c-myc G-quadruplex DNA. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Cytotoxic activity, DNA damage, cellular uptake, apoptosis and western blot analysis of ruthenium(II) polypyridyl complex against human lung decarcinoma A549 cell.

    Lai, Shang-Hai; Jiang, Guang-Bin; Yao, Jun-Hua; Li, Wei; Han, Bing-Jie; Zhang, Cheng; Zeng, Chuan-Chuan; Liu, Yun-Jun


    A new ruthenium(II) polypyridyl complex [Ru(dmp)2(pddppn)](ClO4)2Ru1 was synthesized and characterized. The cytotoxic activity in vitro of the complex was evaluated by MTT method. Ru1 shows high effect on the inhibition of the cell growth against BEL-7402, HeLa, MG-63 and A549 cells with low IC50 values of 1.6±0.4, 9.0±0.8, 1.5±0.2 and 1.5±0.3 μM, respectively. The cellular uptake indicates that Ru1 can enter into the cytoplasm and accumulate in the cell nuclei. Ru1 can induce apoptosis in A549 cells and enhance the levels of reactive oxygen species (ROS) and induce the decrease of mitochondrial membrane potential. In addition, Ru1 can down-regulate the levels of Bcl-2, Bcl-x, Bak, and Bim expression and up-regulate the expression of Bag-1 and Bad. The complex induces apoptosis of A549 cells through an intrinsic ROS-mediated mitochondrial dysfunction pathway, which was accompanied by regulating the expression of caspases and Bcl-2 family proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Photodegradation of methyl orange and photoinactivation of bacteria by visible light activation of persulphate using a tris(2,2'-bipyridyl)ruthenium(II) complex.

    Subramanian, Gokulakrishnan; Parakh, Priyadarshini; Prakash, Halan


    Persulphate is an emerging oxidant in the field of advanced oxidation processes for the degradation of environmentally persistent organic compounds. The present study shows that visible light activation of persulphate (2 mM) using tris(2,2'-bipyridyl)ruthenium(II) (complex 1) (1 μM) caused rapid degradation (98%) of model azo dye methyl orange (MO) (12 mg L(-1)) with significant mineralization (76%), and also complete inactivation of both Gram negative and positive bacteria (∼10(7) CFU mL(-1)). BacLight LIVE/DEAD assay, scanning electron microscopy and genomic DNA analysis revealed cell membrane damage and loss of chromosomal DNA, indicating oxidative stress caused to E. coli during photoinactivation. The effect of concentration of complex 1 : persulphate ratio and presence of inorganic ions (0.1 M), such as sodium hydrogen phosphate, sodium sulphate, and sodium hydrogen carbonate, on the photodegradation of MO and photoinactivation of E. coli were studied. In addition, the effect of the presence of the organic contaminant resorcinol on the photoinactivation of E. coli was also studied. Significant degradation of MO and complete inactivation of bacteria were observed in simulated ground water. The present study is the first to reveal that activation of persulphate using a visible light absorbing metal complex in aqueous media has the ability to cause degradation of organic contaminants as well as complete inactivation of bacteria.

  4. Rolling cycle amplification based single-color quantum dots-ruthenium complex assembling dyads for homogeneous and highly selective detection of DNA.

    Su, Chen; Liu, Yufei; Ye, Tai; Xiang, Xia; Ji, Xinghu; He, Zhike


    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.

  5. Mass spectrometry and UV-VIS spectrophotometry of ruthenium(II) [RuClCp(mPTA)2](OSO2CF3)2 complex in solution.

    Peña-Méndez, Eladia María; González, Beatriz; Lorenzo, Pablo; Romerosa, Antonio; Havel, Josef


    Ruthenium(II) complexes are of great interest as a new class of cancerostatics with advantages over classical platinum compounds including lower toxicity. The stability of the [RuClCp(mPTA)2](OSO2CF3)2 complex (I) (Cp cyclopentadienyl, mPTA N-methyl 1,3,5-triaza-7-phosphaadamantane) in aqueous solution was studied using spectrophotometry, matrix-assisted laser desorption/ionization (MALDI) and laser desorption/ionization (LDI) time-of-flight (TOF) mass spectrometry (MS). Spectrophotometry proves that at least three different reactions take place in water. Dissolution of I leads to fast coordination of water molecules to the Ru(II) cation and then slow hydrolysis and ligand exchange of chloride and mPTA with water, hydroxide or with trifluoromethane sulfonate itself. Via MALDI and LDI of the hydrolyzed solutions the formation of singly positively charged ions of general formula RuCl(p)(Cp)(q)(mPTA)(r)(H2O)(s)(OH)(t) (p = 0-1, q = 0-1, r = 0-2, s = 0-5, t = 0-2) and of some fragment ions was shown. The stoichiometry was determined by analyzing the isotopic envelopes and computer modelling. The [RuClCp(mPTA)2](OSO2CF3)2 complex can be stabilized in dilute hydrochloric acid or in neutral 0.15 M isotonic sodium chloride solution. Copyright 2009 John Wiley & Sons, Ltd.

  6. Stereoselective Alkane Oxidation with meta-Chloroperoxybenzoic Acid (MCPBA) Catalyzed by Organometallic Cobalt Complexes.

    Shul'pin, Georgiy B; Loginov, Dmitriy A; Shul'pina, Lidia S; Ikonnikov, Nikolay S; Idrisov, Vladislav O; Vinogradov, Mikhail M; Osipov, Sergey N; Nelyubina, Yulia V; Tyubaeva, Polina M


    Cobalt pi-complexes, previously described in the literature and specially synthesized and characterized in this work, were used as catalysts in homogeneous oxidation of organic compounds with peroxides. These complexes contain pi-butadienyl and pi-cyclopentadienyl ligands: [(tetramethylcyclobutadiene)(benzene)cobalt] hexafluorophosphate, [(C₄Me₄)Co(C₆H₆)]PF₆ (1); diiodo(carbonyl)(pentamethylcyclopentadienyl)cobalt, Cp*Co(CO)I₂ (2); diiodo(carbonyl)(cyclopentadienyl)cobalt, CpCo(CO)I₂ (3); (tetramethylcyclobutadiene)(dicarbonyl)(iodo)cobalt, (C₄Me₄)Co(CO)₂I (4); [(tetramethylcyclobutadiene)(acetonitrile)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [(C₄Me₄)Co(bipy)(MeCN)]PF₆ (5); bis[dicarbonyl(B-cyclohexylborole)]cobalt, [(C₄H₄BCy)Co(CO)₂]₂ (6); [(pentamethylcyclopentadienyl)(iodo)(1,10-phenanthroline)cobalt] hexafluorophosphate, [Cp*Co(phen)I]PF₆ (7); diiodo(cyclopentadienyl)cobalt, [CpCoI₂]₂ (8); [(cyclopentadienyl)(iodo)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [CpCo(bipy)I]PF₆ (9); and [(pentamethylcyclopentadienyl)(iodo)(2,2'-bipyridyl)cobalt] hexafluorophosphate, [Cp*Co(bipy)I]PF₆ (10). Complexes 1 and 2 catalyze very efficient and stereoselective oxygenation of tertiary C-H bonds in isomeric dimethylcyclohexanes with MCBA: cyclohexanols are produced in 39 and 53% yields and with the trans/cis ratio (of isomers with mutual trans- or cis-configuration of two methyl groups) 0.05 and 0.06, respectively. Addition of nitric acid as co-catalyst dramatically enhances both the yield of oxygenates and stereoselectivity parameter. In contrast to compounds 1 and 2, complexes 9 and 10 turned out to be very poor catalysts (the yields of oxygenates in the reaction with cis-1,2-dimethylcyclohexane were only 5%-7% and trans/cis ratio 0.8 indicated that the oxidation is not stereoselective). The chromatograms of the reaction mixture obtained before and after reduction with PPh₃ are very similar, which testifies that alkyl

  7. Synthesis and characterization of mixed-ligand diimine-piperonal thiosemicarbazone complexes of ruthenium(II): Biophysical investigations and biological evaluation as anticancer and antibacterial agents.

    Beckford, Floyd A; Thessing, Jeffrey; Shaloski, Michael; Mbarushimana, P Canisius; Brock, Alyssa; Didion, Jacob; Woods, Jason; Gonzalez-Sarrías, Antonio; Seeram, Navindra P


    We have used a novel microwave-assisted method developed in our laboratories to synthesize a series of ruthenium-thiosemicarbazone complexes. The new thiosemicarbazone ligands are derived from benzo[d][1,3]dioxole-5-carbaldehyde (piperonal) and the complexes are formulated as [(diimine)(2)Ru(TSC)](PF(6))(2) (where the TSC is the bidentate thiosemicarbazone ligand). The diimine in the complexes is either 2,2'-bipyridine or 1,10-phenanthroline. The complexes have been characterized by spectroscopic means (NMR, IR and UV-Vis) as well as by elemental analysis. We have studied the biophysical characteristics of the complexes by investigating their anti-oxidant ability as well as their ability to disrupt the function of the human topoisomerase II enzyme. The complexes are moderately strong binders of DNA with binding constants of 10(4) M(-1). They are also strong binders of human serum albumin having binding constants on the order of 10(4) M(-1). The complexes show good in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116 and indeed show some cytotoxic selectivity for cancer cells. The IC(50) values range from 7 - 159 μM (after 72 h drug incubation). They also have antibacterial activity against Gram-positive strains of pathogenic bacteria with IC(50) values as low as 10 μM; little activity was seen against Gram-negative strains. It has been established that all the compounds are catalytic inhibitors of human topoisomerase II.

  8. Ruthenium Complexes are pH-Activated Metallo Prodrugs (pHAMPs) with Light-Triggered Selective Toxicity Toward Cancer Cells.

    Qu, Fengrui; Park, Seungjo; Martinez, Kristina; Gray, Jessica L; Thowfeik, Fathima Shazna; Lundeen, John A; Kuhn, Ashley E; Charboneau, David J; Gerlach, Deidra L; Lockart, Molly M; Law, James A; Jernigan, Katherine L; Chambers, Nicole; Zeller, Matthias; Piro, Nicholas A; Kassel, W Scott; Schmehl, Russell H; Paul, Jared J; Merino, Edward J; Kim, Yonghyun; Papish, Elizabeth T


    Metallo prodrugs that take advantage of the inherent acidity surrounding cancer cells have yet to be developed. We report a new class of pH-activated metallo prodrugs (pHAMPs) that are activated by light- and pH-triggered ligand dissociation. These ruthenium complexes take advantage of a key characteristic of cancer cells and hypoxic solid tumors (acidity) that can be exploited to lessen the side effects of chemotherapy. Five ruthenium complexes of the type [(N,N)2Ru(PL)](2+) were synthesized, fully characterized, and tested for cytotoxicity in cell culture (1A: N,N = 2,2'-bipyridine (bipy) and PL, the photolabile ligand, = 6,6'-dihydroxybipyridine (6,6'-dhbp); 2A: N,N = 1,10-phenanthroline (phen) and PL = 6,6'-dhbp; 3A: N,N = 2,3-dihydro-[1,4]dioxino[2,3-f][1,10]phenanthroline (dop) and PL = 6,6'-dhbp; 4A: N,N = bipy and PL = 4,4'-dimethyl-6,6'-dihydroxybipyridine (dmdhbp); 5A: N,N = 1,10-phenanthroline (phen) and PL = 4,4'-dihydroxybipyridine (4,4'-dhbp). The thermodynamic acidity of these complexes was measured in terms of two pKa values for conversion from the acidic form (XA) to the basic form (XB) by removal of two protons. Single-crystal X-ray diffraction data is discussed for 2A, 2B, 3A, 4B, and 5A. All complexes except 5A showed measurable photodissociation with blue light (λ = 450 nm). For complexes 1A-4A and their deprotonated analogues (1B-4B), the protonated form (at pH 5) consistently gave faster rates of photodissociation and larger quantum yields for the photoproduct, [(N,N)2Ru(H2O)2](2+). This shows that low pH can lead to greater rates of photodissociation. Cytotoxicity studies with 1A-5A showed that complex 3A is the most cytotoxic complex of this series with IC50 values as low as 4 μM (with blue light) versus two breast cancer cell lines. Complex 3A is also selectively cytotoxic, with sevenfold higher toxicity toward cancerous versus normal breast cells. Phototoxicity indices with 3A were as high as 120, which shows that dark toxicity is

  9. Chlorambucil conjugates of dinuclear p-cymene ruthenium trithiolato complexes: synthesis, characterization and cytotoxicity study in vitro and in vivo.

    Stíbal, David; Therrien, Bruno; Süss-Fink, Georg; Nowak-Sliwinska, Patrycja; Dyson, Paul J; Čermáková, Eva; Řezáčová, Martina; Tomšík, Pavel


    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.

  10. A novel dual-functioning ruthenium(II)-arene complex of an anti-microbial ciprofloxacin derivative - Anti-proliferative and anti-microbial activity.

    Ude, Ziga; Romero-Canelón, Isolda; Twamley, Brendan; Fitzgerald Hughes, Deirdre; Sadler, Peter J; Marmion, Celine J


    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.

  11. Non-bridging ligand effects on the kinetics of reduction of chloro- and azido-pentaamminecobalt(III by some polypyridyl complexes of ruthenium(II

    Olayinka A. Oyetunji


    Full Text Available Pentaamminecobalt(III complexes, [Co(NH35X]2+ (X = Cl-, N3-, are reduced by [Ru(bipy3]2+ and [Ru(terpy(bipyCl] + in aqueous media at a constant ionic strength of 0.5 M (HCl/LiCl. At 308 K, the second order rate constants (M-1 s-1 are as follows: 17.9 for the reduction of the azidocobalt(III complex by [Ru(bipy3]2+, and 1.41 and 2.63 for the [Ru(terpy(bipyCl]+ reduction of the azido- and chlorocobalt(III complexes, respectively. Activation enthalpies (ΔH‡ and entropies (ΔS‡ were determined from temperature dependence measurements with the following results: ΔH‡= 72.1 kJ mol-1 and ΔS‡ = 13.3 J mol-1 K-1 for the [Ru(bipy3]2+ reduction of the azidocobalt(III complex, while for the reduction of the cobalt(III complexes by [Ru(terpy(bipyCl] +, ΔH‡ (N3- = 20.3 kJ mol-1, ΔH‡ (Cl- = 40.6 kJ mol-1, ΔS‡(N3- = -177 J mol-1 K-1, and ΔS‡ (Cl- = -106 J mol-1 K-1. The relative rates of electron transfer in the different reactions and the influence of π-acceptor ligands on the ruthenium(II reduction of the cobalt(III complexes are discussed.

  12. 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

    Ge, Xiaoqian; Sun, Lining; Ma, Binbin; Jin, Di; Dong, Liang; Shi, Liyi; Li, Nan; Chen, Haige; Huang, Wei


    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

  13. Iron and ruthenium nanoparticles in carbon prepared by thermolysis of buckymetallocenes.

    Nakae, Takahiro; Matsuo, Yutaka; Takagi, Masatoshi; Sato, Yuta; Suenaga, Kazu; Nakamura, Eiichi


    Thermolysis of fullerene iron and ruthenium complexes (buckymetallocene M(C(60)R(5))Cp (M = Fe; R = Ph (1) and Me (2), M = Ru; R = Ph (3), Me (4)) under a nitrogen atmosphere produced metal nanoparticles dispersed in carbon materials. The thermal degradation processes of the buckymetallocenes were studied by TG-DTA, TEM with a heating sample stage, and VT-XRD. Variation of the thermolysis temperature led to a change in the size of the nanoparticles and the morphology of the carbon materials. Thermolysis of buckyferrocene at 700 degrees C gave highly dispersed iron nanoparticles (average diameter of 7.4 nm). After thermal treatment at 900 degrees C, graphite structures such as carbon nanocapsules and carbon nanotubes formed because of the catalytic activity of the iron nanoparticles. Ruthenium nanoparticles prepared from buckyruthenocene were much smaller than the iron counterparts, and did not catalyze the formation of graphite structures. When buckyruthenocene absorbed on silica gel was heated at 500 degrees C under a hydrogen atmosphere, the resulting ruthenium nanoparticles showed high activity in catalytic hydrogenation.

  14. Hydroformylation of methyl oleate catalyzed by rhodium complexes; Hidroformilacao do oleato de metila catalisada por complexos de rodio

    Mendes, Ana Nery Furlan [Universidade Federal do Espirito Santo (UFES), Sao Mateus, ES (Brazil). Centro Universitario Norte do Espirito Santo. Dept. de Ciencias Naturais; Rosa, Ricardo Gomes da; Gregorio, Jose Ribeiro, E-mail: [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica


    In this work, we describe the hydroformylation of methyl oleate catalyzed by several rhodium complexes. Parameters including total pressure, phosphorous/rhodium and CO/H{sub 2} ratio, temperature and phosphorous ligands were scanned. Total conversion of the starting double bonds was achieved while maintaining excellent selectivity in aldehydes. (author)

  15. A facile synthesis of terminal arylacetylenes via Sonogashira coupling reactions catalyzed by MCM-41-supported mercapto palladium(0) complex

    Ya Ping Xu; Rong Hua Hu; Ramesh C.Kamboj


    A variety of terminal arylacetylenes have been conveniently synthesized in good to high yields via Sonogashira coupling of aryl iodides with (trimethylsilyl)acetylene catalyzed by MCM-41-supported mercapto palladium(0) complex,followed by desilylation under mild conditions.This polymeric palladium catalyst can be reused many times without any decrease in activity.

  16. Asymmetric Cyclopropanation Catalyzed by Four Stereoisomers of a Copper-(Schiff-base) Complex with Double Chiral Centers


    Four stereoisomers of a copper-(Schiff-base) complex with double chiral centers were applied to catalyze the asymmetric cyclopropanation. Two of the stereoisomers were also efficient catalysts affording high enantiomeric excess of up to 91.8%. A mechanism that predicts the observed results accurately was proposed.

  17. Robust binding between carbon nitride nanosheets and a binuclear ruthenium(II) complex enabling durable, selective CO{sub 2} reduction under visible light in aqueous solution

    Kuriki, Ryo; Ishitani, Osamu; Maeda, Kazuhiko [Department of Chemistry, School of Science, Tokyo Institute of Technology (Japan); Yamamoto, Muneaki; Yoshida, Tomoko [Advanced Research Institute for Natural Science and Technology, Osaka City University (Japan); Higuchi, Kimitaka; Yamamoto, Yuta; Akatsuka, Masato; Yagi, Shinya [Institute of Materials and Systems for Sustainability, Nagoya University (Japan); Lu, Daling [Suzukakedai Materials Analysis Division, Technical Department, Tokyo Institute of Technology, Yokohama (Japan)


    Carbon nitride nanosheets (NS-C{sub 3}N{sub 4}) were found to undergo robust binding with a binuclear ruthenium(II) complex (RuRu') even in basic aqueous solution. A hybrid material consisting of NS-C{sub 3}N{sub 4} (further modified with nanoparticulate Ag) and RuRu' promoted the photocatalytic reduction of CO{sub 2} to formate in aqueous media, in conjunction with high selectivity (approximately 98 %) and a good turnover number (>2000 with respect to the loaded Ru complex). These represent the highest values yet reported for a powder-based photocatalytic system during CO{sub 2} reduction under visible light in an aqueous environment. We also assessed the desorption of RuRu' from the Ag/C{sub 3}N{sub 4} surface, a factor that can contribute to a loss of activity. It was determined that desorption is not induced by salt additives, pH changes, or photoirradiation, which partly explains the high photocatalytic performance of this material. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

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


    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.

  19. Microwave-assisted synthesis of arene ruthenium(II) complexes that induce S-phase arrest in cancer cells by DNA damage-mediated p53 phosphorylation.

    Wu, Qiong; Fan, Cundong; Chen, Tianfeng; Liu, Chaoran; Mei, Wenjie; Chen, Sidong; Wang, Baoguo; Chen, Yunyun; Zheng, Wenjie


    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.

  20. Polymerization of Dimethylaminoethyl Methacrylate Catalyzed by Substituted Indenyl Lanthanide(Ⅱ) Complexes


    The polymerization of dimethylaminoethyl methacrylate (DMAEMA) catalyzed by the 1-cyclopentylindenyl lanthanide (Ⅱ) complex (1-C5H9C9H6)2Yb (THF)2 was investigated.The results indicated that the complex (1-C5H9C9H6)2Yb (THF)2 as a single component catalyst showed high activity.The conversion of the polymerization and the molecular weight of the polymer were affected by temperature, time, amount of catalyst and solvent in the polymerization process.The catalytic activity of (1-C5H9C9H6)2Yb (THF)2 enhanced significantly when a small amount of polar solvent THF was added into the polymerization system in which toluene was selected as the solvent.The optimal temperature of polymerization was about 0 ℃.Other modified substituted indenyl lanthanide (Ⅱ) complexes also showed good catalytic activity.The order of catalytic activity of the complexes was as follows: (1-C5H9C9H6)2Sm(THF)≈(1-C2H5C9H6)2Sm(THF)2>(1-C5H9C9H6)2Yb(THF)2>(1-PhCH2C9H6)2Sm(THF)2.The steric regularity of poly (dimethylaminoethyl methacrylate) (PDMAEMA) was characterized by 1H NMR spectra.The polymerization provided syndiotacticity-rich PDMAEMA.The molecular weight and the molecular weight distribution of PDMAEMA were measured by gel permeation chromatography.

  1. Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls

    McCarthy, Thomas J.; Shih, Yen-Shiang; Whitesides, George M.


    Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

  2. C-H functionalization of phenols using combined ruthenium and photoredox catalysis: in situ generation of the oxidant.

    Fabry, David C; Ronge, Meria A; Zoller, Jochen; Rueping, Magnus


    A combination of ruthenium and photoredox catalysis allowed the ortho olefination of phenols. Using visible light, the direct C-H functionalization of o-(2-pyridyl)phenols occurred, and diverse phenol ethers were obtained in good yields. The regeneration of the ruthenium catalyst was accomplished by a photoredox-catalyzed oxidative process.

  3. Facile concerted proton-electron transfers in a ruthenium terpyridine-4'-carboxylate complex with a long distance between the redox and basic sites.

    Manner, Virginia W; Dipasquale, Antonio G; Mayer, James M


    We have designed and prepared ruthenium complexes with terpyridine-4'-carboxylate (tpyCOO) ligands, in which there are six bonds between the redox-active Ru and the basic carboxylate. The protonated Ru(II) complex, RuII(dipic)(tpyCOOH) (Ru(II)COOH), is prepared in one-pot from [(p-cymene)RuCl2]2, tpyCOONa, and then sodium pyridine-2,6-dicarboxylate [Na(dipic)]. A crystal structure of the deprotonated Ru(II) complex, Ru(II)COO-, shows a distance of 6.9 A between the metal and basic sites. The Ru(III) complex (Ru(III)COO) has been isolated by one-electron oxidation of Ru(II)COO- with triarylaminium radical cations (NAr3*+). Ru(III)COO has a bond dissociation free energy (BDFE) of 81 +/- 1 kcal mol(-1), from pKa and E1/2 measurements. It oxidizes 2,4,6-tri-tert-butylphenol (BDFE = 77 +/- 1 kcal mol(-1)) by removal of e- and H+ (triple bond H*) to form 2,4,6-tri-tert-butylphenoxyl radical and Ru(II)COOH, with a second-order rate constant of (2.3 0.2) x 10(4) M(-1) s(-1) and a kH/kD of 7.7 1.2. Thermochemical analysis suggests a concerted proton-electron transfer (CPET) mechanism for this reaction, despite the 6.9 A distance between the redox-active Ru and the H+-accepting oxygen. Ru(III)COO also oxidizes the hydroxylamine TEMPOH to the stable free radical TEMPO and xanthene to bixanthyl. These reactions appear to be similar to processes that have been previously termed hydrogen atom transfer.

  4. Post-synthetic modification of mesoporous zinc-adeninate framework with tris(2,2′-biprydine) ruthenium(II) complex and its electrochemiluminescence

    Park, Ji Eun; Shin, Ik Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of); Oh, Hye Jae; An, Ji Hyun [Dept. of Chemistry Education, Seoul National University, Seoul (Korea, Republic of)


    Herein we report a redox-active metal-organic framework (MOF) via post-synthetic cation exchange with tris(2,2′-biprydine) ruthenium(II) complex (Ru(bpy){sub 3}{sup 2+}). A porous anionic zinc-adeninate framework (bMOF-100) is spacious enough to easily entrap 2.43 of Ru(bpy){sub 3}{sup 2+} cations within the mesopore. The encapsulation supported the framework structure preventing any distortion from a rapid solvent evaporation under SEM observation. Ru(bpy){sub 3}{sup 2+}@bMOF-100 was then immobilized on the surface of glassy carbon electrode, and its electrocatalytic and electrochemiluminescent (ECL) properties were investigated in aqueous and organic solution. Especially, Ru(bpy){sub 3}{sup 2+}@bMOF-100 showed the excellent electrochemical properties of Ru(bpy){sub 3}{sup 2+}, but gradual decomposition of the MOF structure was observed under electrochemical measurements because of the sluggish oxidation of adeninate ligand.

  5. Design and Characterization of Heteroleptic Ruthenium Complexes Containing Benzimidazole Ligands for Dye-Sensitized Solar Cells: The Effect of Fluorine Substituents on Photovoltaic Performance.

    Huang, Wei-Kai; Wu, Hui-Ping; Lin, Pi-Lun; Lee, Yuan-Pern; Diau, Eric Wei-Guang


    We designed heteroleptic ruthenium complexes (RD12-RD15) containing fluoro-substituted benzimidazole ligands for dye-sensitized solar cells (DSSCs). These dyes were synthesized according to a typical one-pot procedure with the corresponding ancillary ligands produced in two simple steps; they were prepared into DSSC devices according to the same conditions of fabrication. The eventual devices show a systematic trend of increasing VOC and decreasing JSC with fluorine atoms of increasing number substituted on the ligand. The charge-extraction results show that upward shifts of the TiO2 potential occurred when the fluoro-substituted dyes were sensitized on TiO2 with a systematic trend of shift N719 > RD15 (with 5 F) > RD12 (with 2 F) >RD5 (no F); the intensity-modulated photovoltage spectra indicate that those fluoro substituents retard charge recombination with the electron lifetimes (τR) in the order RD15 > RD12 > RD5 > N719, consistent with the variation of VOC for the systems.

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

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


    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.

  7. Influence of different ruthenium(II) bipyridyl complex on the photocatalytic H{sub 2} evolution over TiO{sub 2} nanoparticles with mesostructures

    Peng, Tianyou [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South-Central University for Nationalities, Wuhan 430074 (China); Ke, Dingning; Cai, Ping; Dai, Ke; Ma, Liang; Zan, Ling [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China)


    H{sub 2} production over dye-sensitized Pt/TiO{sub 2} nanoparticles with mesostructures (m-TiO{sub 2}) under visible light ({lambda} > 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{sub 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{sub 2} has better durability but the lowest H{sub 2} evolution efficiency, whereas the loosely attached dyes possess higher H{sub 2} evolution efficiency and preferable durability. It seems that the dynamic equilibrium between the linkage of the ground state dye with TiO{sub 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{sub 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{sub 2}. (author)

  8. Interactions of the "piano-stool" [ruthenium(II) (eta6-arene)(en)CL]+ complexes with water and nucleobases; ab initio and DFT study.

    Futera, Zdenek; Klenko, Julia; Sponer, Judit E; Sponer, Jirí; Burda, Jaroslav V


    Piano stool ruthenium complexes of the composition [Ru(II)(eta6-arene)(en)Cl](+/2+) (en = ethylenediamine) represent an emerging class of cisplatin-analogue anticancer drug candidates. In this study, we use computational quantum chemistry to characterize the structure, stability and reactivity of these compounds. All these structures were optimized at DFT(B3LYP)/6-31G(d) level and their single point properties were determined by the MP2/6-31++G(2df,2pd) method. Thermodynamic parameters and rate constants were determined for the aquation process, as a replacement of the initial chloro ligand by water and subsequent exchange reaction of aqua ligand by nucleobases. The computations were carried out at several levels of DFT and ab initio theories (B3LYP, MP2 and CCSD) utilizing a range of bases sets (from 6-31G(d) to aug-cc-pVQZ). Excellent agreement with experimental results for aquation process was obtained at the CCSD level and reasonable match was achieved also with the B3LYP/6-31++G(2df,2pd) method. This level was used also for nucleobase-water exchange reaction where a smaller rate constant for guanine exchange was found in comparison with adenine. Although adenine follows a simple replacement mechanism, guanine complex passes by a two-step mechanism. At first, Ru-O6(G) adduct is formed, which is transformed through a chelate TS2 to the Ru-N7(G) final complex. In case of guanine, the exchange reaction is more favorable thermodynamically (releasing in total by about 8 kcal/mol) but according to our results, the rate constant for guanine substitution is slightly smaller than the analogous constant in adenine case when reaction course from local minimum is considered. Copyright 2008 Wiley Periodicals, Inc.

  9. Theoretical Study of Phosphodiester Hydrolysis and Transesterification Catalyzed by an Unsymmetric Biomimetic Dizinc Complex.

    Daver, Henrik; Das, Biswanath; Nordlander, Ebbe; Himo, Fahmi


    Density functional theory calculations have been used to investigate the reaction mechanisms of phosphodiester hydrolysis and transesterification catalyzed by a dinuclear zinc complex of the 2-(N-isopropyl-N-((2-pyridyl)methyl)aminomethyl)-6-(N-(carboxylmethyl)-N-((2-pyridyl)methyl)amino-methyl)-4-methylphenol (IPCPMP) ligand, mimicking the active site of zinc phosphotriesterase. The substrates bis(2,4)-dinitrophenyl phosphate (BDNPP) and 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) were employed as analogues of DNA and RNA, respectively. A number of different mechanistic proposals were considered, with the active catalyst harboring either one or two hydroxide ions. It is concluded that for both reactions the catalyst has only one hydroxide bound, as this option yields lower overall energy barriers. For BDNPP hydrolysis, it is suggested that the hydroxide acts as the nucleophile in the reaction, attacking the phosphorus center of the substrate. For HPNP transesterification, on the other hand, the hydroxide is proposed to act as a Brønsted base, deprotonating the alcohol moiety of the substrate, which in turn performs the nucleophilic attack. The calculated overall barriers are in good agreement with measured rates. Both reactions are found to proceed by essentially concerted associative mechanisms, and it is demonstrated that two consecutive catalytic cycles need to be considered in order to determine the rate-determining free energy barrier.

  10. Synthesis, spectroscopic characterization, photochemical and photophysical properties and biological activities of ruthenium complexes with mono- and bi-dentate histamine ligand.

    Cardoso, Carolina R; de Aguiar, Inara; Camilo, Mariana R; Lima, Márcia V S; Ito, Amando S; Baptista, Maurício S; Pavani, Christiane; Venâncio, Tiago; Carlos, Rose M


    The monodentate cis-[Ru(phen)(2)(hist)(2)](2+)1R and the bidentate cis-[Ru(phen)(2)(hist)](2+)2A complexes were prepared and characterized using spectroscopic ((1)H, ((1)H-(1)H)COSY and ((1)H-(13)C)HSQC NMR, UV-vis, luminescence) techniques. The complexes presented absorption and emission in the visible region, as well as a tri-exponential emission decay. The complexes are soluble in aqueous and non-aqueous solution with solubility in a buffer solution of pH 7.4 of 1.14 × 10(-3) mol L(-1) for (1R + 2A) and 6.43 × 10(-4) mol L(-1) for 2A and lipophilicity measured in an aqueous-octanol solution of -1.14 and -0.96, respectively. Photolysis in the visible region in CH(3)CN converted the starting complexes into cis-[Ru(phen)(2)(CH(3)CN)(2)](2+). Histamine photorelease was also observed in pure water and in the presence of BSA (1.0 × 10(-6) mol L(-1)). The bidentate coordination of the histamine to the ruthenium center in relation to the monodentate coordination increased the photosubstitution quantum yield by a factor of 3. Pharmacological studies showed that the complexes present a moderate inhibition of AChE with an IC(50) of 21 μmol L(-1) (referred to risvagtini, IC(50) 181 μmol L(-1) and galantamine IC(50) 0.006 μmol L(-1)) with no appreciable cytotoxicity toward to the HeLa cells (50% cell viability at 925 μmol L(-1)). Cell uptake of the complexes into HeLa cells was detected by fluorescence confocal microscopy. Overall, the observation of a luminescent complex that penetrates the cell wall and has low cytotoxicity, but is reactive photochemically, releasing histamine when irradiated with visible light, are interesting features for application of these complexes as phototherapeutic agents.

  11. Preparation, spectrochemical, and computational analysis of L-carnosine (2-[(3-aminopropanoyl)amino]-3-(1H-imidazol-5-yl)propanoic acid) and its ruthenium (II) coordination complexes in aqueous solution.

    Branham, Michael Lee; Singh, Parvesh; Bisetty, Krishna; Sabela, Myalo; Govender, Thirumala


    This study reports the synthesis and characterization of novel ruthenium (II) complexes with the polydentate dipeptide, L-carnosine (2-[(3-aminopropanoyl)amino]-3-(1H-imidazol-5-yl)propanoic acid). Mixed-ligand complexes with the general composition [ML(p)(Cl)(q)(H₂O)(r)]·xH₂O (M = Ru(II); L = L-carnosine; p = 3 - q; r = 0-1; and x = 1-3) were prepared by refluxing aqueous solutions of the ligand with equimolar amounts of ruthenium chloride (black-alpha form) at 60 °C for 36 h. Physical properties of the complexes were characterized by elemental analysis, DSC/TGA, and cyclic voltammetry. The molecular structures of the complexes were elucidated using UV-Vis, ATR-IR, and heteronuclear NMR spectroscopy, then confirmed by density function theory (DFT) calculations at the B3LYP/LANL2DZ level. Two-dimensional NMR experiments (¹H COSY, ¹³C gHMBC, and ¹⁵N gHMBC) were also conducted for the assignment of chemical shifts and calculation of relative coordination-induced shifts (RCIS) by the complex formed. According to our results, the most probable coordination geometries of ruthenium in these compounds involve nitrogen (N1) from the imidazole ring and an oxygen atom from the carboxylic acid group of the ligand as donor atoms. Additional thermogravimetric and electrochemical data suggest that while the tetrahedral-monomer or octahedral-dimer are both possible structures of the formed complexes, the metal in either structure occurs in the ²⁺ oxidation state. Resulting RCIS values indicate that the amide-carbonyl, and the amino-terminus of the dipeptide are not involved in chelation and these observations correlate well with theoretical shift predictions by DFT.

  12. Preparation, Spectrochemical, and Computational Analysis of L-Carnosine (2-[(3-Aminopropanoylamino]-3-(1H-imidazol-5-ylpropanoic Acid and Its Ruthenium (II Coordination Complexes in Aqueous Solution

    Myalo Sabela


    Full Text Available This study reports the synthesis and characterization of novel ruthenium (II complexes with the polydentate dipeptide, L-carnosine (2-[(3-aminopropanoylamino]-3-(1H-imidazol-5-ylpropanoic acid. Mixed-ligand complexes with the general composition [MLp(Clq(H2Or]·xH2O (M = Ru(II; L = L-carnosine; p = 3 − q; r = 0–1; and x = 1–3 were prepared by refluxing aqueous solutions of the ligand with equimolar amounts of ruthenium chloride (black-alpha form at 60 °C for 36 h. Physical properties of the complexes were characterized by elemental analysis, DSC/TGA, and cyclic voltammetry. The molecular structures of the complexes were elucidated using UV-Vis, ATR-IR, and heteronuclear NMR spectroscopy, then confirmed by density function theory (DFT calculations at the B3LYP/LANL2DZ level. Two-dimensional NMR experiments (1H COSY, 13C gHMBC, and 15N gHMBC were also conducted for the assignment of chemical shifts and calculation of relative coordination-induced shifts (RCIS by the complex formed. According to our results, the most probable coordination geometries of ruthenium in these compounds involve nitrogen (N1 from the imidazole ring and an oxygen atom from the carboxylic acid group of the ligand as donor atoms. Additional thermogravimetric and electrochemical data suggest that while the tetrahedral-monomer or octahedral-dimer are both possible structures of the formed complexes, the metal in either structure occurs in the (2+ oxidation state. Resulting RCIS values indicate that the amide-carbonyl, and the amino-terminus of the dipeptide are not involved in chelation and these observations correlate well with theoretical shift predictions by DFT.

  13. Building Indenylidene-Ruthenium Catalysts for Metathesis Transformations

    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

  14. Charge mediation by ruthenium poly(pyridine) complexes in 'second-generation' glucose biosensors based on carboxymethylated beta-cyclodextrin polymer membranes.

    Kosela, Edyta; Elzanowska, Hanna; Kutner, Wlodzimierz


    Four different poly(pyridine) complexes of ruthenium, viz. Ru(II)(trpy)(phen)(OH(2))](2+) (1), trans-[Ru(III)(2,2'bpy)(2)(OH(2))(OH)](2+) (2), [(2,2'bpy)(2)(OH)Ru(III)ORu(III)(OH)(2,2'bpy)(2)](4+) (3), and [Ru(II)(4,4'bpy)(NH(3))(5)](2+) (4) (2,2'bpy=2,2'-bipyridine, 4,4'bpy=4,4'-bipyridine, trpy=2,2',2"-terpyridine, phen=1,10-phenanthroline), were tested as non-physiological charge mediators of 'second-generation' glucose biosensors. The membranes for these biosensors were prepared by casting anionic carboxymethylated beta-cyclodextrin polymer films (beta-CDPA) directly onto the Pt or glassy carbon (GC) disk electrodes. Simultaneously, glucose oxidase (GOD) was immobilized in the films by covalent bonding and the Ru complexes were incorporated both by inclusion in the beta-CD molecular cavities and by ion exchange at the fixed carboxymethyl cation-exchange sites. The leakage of the mediator from the polymer has been minimized by adopting a suitable pre-treatment procedure. The biosensors catalytic activities increased in the order 1inclusion complex with beta-CD, the biosensor sensitivity was the highest and equal to 7.2 micro A mM(-1) cm(-2), detectability was as low as 1 mM, but the linear concentration range was limited only to 4 mM. In contrast, for complexes 2 and 3 the sensitivity was 0.4 and 3.2 micro A mM(-1) cm(-2), while the linear concentration range extended up to at least 24 and 14 mM glucose, respectively. Even though some common interfering substances, such as ascorbate, paracetamol or urea, are oxidized at potentials close to those of the Ru complex redox couples, their electro-oxidation currents at physiological concentrations are insignificant compared to those due to the biocatalytic oxidation of glucose. The biosensor response to glucose is reversible as demonstrated by the inhibition of GOD activity by Cu(II). That is, the Cu(II) concentration required to inhibit by half the response to glucose of the biosensor containing complex 2 was 1.0 m

  15. Reactivity studies of eta sup (6)-p-cymene ruthenium(II) carboxylato complexes towards azide some neutral ligands

    Singh, K.S.; Kollipara, M.R.

    complexes with NaN sub (3) yielded azido complex [{(eta sup (6)-p-cymene)Ru(mu-N sub (3))Cl} sub (2)] whereas halide scavengers such as silver acetate, silvertrifluroacetate leads to the substitution of chlorine to give neutral complexes of formulation...

  16. Porous protein crystals as catalytic vessels for organometallic complexes.

    Tabe, Hiroyasu; Abe, Satoshi; Hikage, Tatsuo; Kitagawa, Susumu; Ueno, Takafumi


    Porous protein crystals, which are protein assemblies in the solid state, have been engineered to form catalytic vessels by the incorporation of organometallic complexes. Ruthenium complexes in cross-linked porous hen egg white lysozyme (HEWL) crystals catalyzed the enantioselective hydrogen-transfer reduction of acetophenone derivatives. The crystals accelerated the catalytic reaction and gave different enantiomers based on the crystal form (tetragonal or orthorhombic). This method represents a new approach for the construction of bioinorganic catalysts from protein crystals.

  17. Sequential Functionalization of Alkynes and Alkenes Catalyzed by Gold(I) and Palladium(II) N-Heterocyclic Carbene Complexes

    Gómez-Herrera, Alberto


    The iodination of terminal alkynes for the synthesis of 1-iodoalkynes using N-iodosuccinimide in the presence of a AuI-NHC (NHC=N-heterocyclic carbene) catalyst is reported. A series of aromatic alkynes was transformed successfully into the corresponding 1-iodoalkynes in good to excellent yields under mild reaction conditions. The further use of these compounds as organic building blocks and the advantageous choice of metal-NHC complexes as catalysts for alkyne functionalization were further demonstrated by performing selective AuI-catalyzed hydrofluorination to yield (Z)-2-fluoro-1-iodoalkenes, followed by a Suzuki–Miyaura cross-coupling with aryl boronic acids catalyzed by a PdII-NHC complex to access trisubstituted (Z)-fluoroalkenes. All methodologies can be performed sequentially with only minor variations in the optimized individual reaction conditions, maintaining high efficiency and selectivity in all cases, which therefore, provides straightforward access to valuable fluorinated alkenes from commercially available terminal alkynes.

  18. Synthesis of isocoumarins through three-component couplings of arynes, terminal alkynes, and carbon dioxide catalyzed by an NHC-copper complex.

    Yoo, Woo-Jin; Nguyen, Thanh V Q; Kobayashi, Shū


    A copper-catalyzed multicomponent coupling reaction between in situ generated ortho-arynes, terminal alkynes, and carbon dioxide was developed to access isocoumarins in moderate to good yields. The key to this CO2-incorporating reaction was the use of a versatile N-heterocyclic carbene/copper complex that was able to catalyze multiple transformations within the three-component reaction.

  19. Synthesis, characterization, DNA binding properties, fluorescence studies and toxic activity of cobalt(III) and ruthenium(II) polypyridyl complexes.

    Nagababu, Penumaka; Shilpa, Mynam; Latha, J Naveena Lavanya; Bhatnagar, Ira; Srinivas, P N B S; Kumar, Yata Praveen; Reddy, Kotha Laxma; Satyanarayana, Sirasani


    The new ligand 4-(isopropylbenzaldehyde)imidazo[4,5-f ][1,10]phenanthroline (ippip) and its complexes [Ru(phen)(2)(ippip)](2+)(1),[Co(phen)(2)(ippip)](3+)(2),[Ru(bpy)(2)(ippip)](2+)(3),[Co(bpy)(2)(ippip)](3+)(4)(bpy=2,2-bipyridine) and (phen=1,10-phenanthroline) were synthesized and characterized by ES(+)-MS, (1)H and (13)C NMR. The DNA binding properties of the four complexes were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that complexes bind to calf thymus DNA (CT-DNA) through intercalation. When irradiated at 365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than 2, 3, 4 complexes under comparable experimental conditions. Furthermore, photocleavage studies reveal that singlet oxygen ((1)O(2)) plays a significant role in the photocleavage.

  20. Immobilized Ruthenium Catalyst for Carbon Dioxide Hydrogenation

    Ying Min YU; Jin Hua FEI; Yi Ping ZHANG; Xiao Ming ZHENG


    Three kinds of cross linked polystyrene resin (PS) supported ruthenium complexes were developed as catalysts for the synthesis of formic acid from carbon dioxide hydrogenation. Many factors, such as the functionalized supports, solvents and ligands, could influence their activities and reuse performances greatly. These immobilized catalysts also offer the industrial advantages such as easy separation.

  1. Arene ruthenium(II) complexes with 2-acetamidothiazole derived ligands: Synthesis, structural studies, antifouling and antibacterial properties

    Singh, K.S.; PrabhaDevi; Sawant, S.G.; Kaminsky, W.

    -acetamidothiazole ligands (L) have been prepared by the reaction of precursor complex [RuCl2(η6-arene)]2 with 2 fold excess of ligand in methanol at room temperature (Scheme 1). All these new complexes 1-4 are neutral and adopted piano stool structure... or NH4PF6also gave the neutral complexes 1-4was unsuccessful even by increasing reaction time and in refluxing condition instead the reactionalso gave the identical neutral complexes1-4. The above results indicated that the reaction of [RuCl2(η6-arene...

  2. Enantioselective Direct Mannich-Type Reactions Catalyzed by Frustrated Lewis Acid/Brønsted Base Complexes.

    Shang, Ming; Cao, Min; Wang, Qifan; Wasa, Masayuki


    An enantioselective direct Mannich-type reaction catalyzed by a sterically frustrated Lewis acid/Brønsted base complex is disclosed. Cooperative functioning of the chiral Lewis acid and achiral Brønsted base components gives rise to in situ enolate generation from monocarbonyl compounds. Subsequent reaction with hydrogen-bond-activated aldimines delivers β-aminocarbonyl compounds with high enantiomeric purity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis of hybrid transition-metalloproteins via thiol-selective covalent anchoring of Rh-phosphine and Ru-phenanthroline complexes.

    den Heeten, René; Muñoz, Bianca K; Popa, Gina; Laan, Wouter; Kamer, Paul C J


    The preparation of hybrid transition metalloproteins by thiol-selective incorporation of organometallic rhodium- and ruthenium complexes is described. Phosphine ligands and two rhodium-diphosphine complexes bearing a carboxylic acid group were coupled to the cysteine of PYP R52G, yielding a metalloenzyme active in the rhodium catalyzed hydrogenation of dimethyl itaconate. The successful coupling was shown by (31)P NMR spectroscopy and ESI mass spectroscopy. In addition wild-type PYP (PYP WT), PYP R52G and ALBP were successfully modified with a (eta(6)-arene) ruthenium(II) phenanthroline complex via a maleimide linker.

  4. Domino Cyclization of 1,n-Enynes (n = 7, 8, 9) Giving Derivatives of Pyrane, Chromene, Fluorene, Phenanthrene and Dibenzo[7]annulene by Ruthenium Complexes.

    Ma, Hao-Wei; Chen, Pei-Min; Lo, Ji-Xian; Lin, Ying-Chih; Huang, Shou-Ling; Chen, Chi-Ren; Chia, Pi-Yeh


    Cyclization of the ether enyne 1 catalyzed by [Ru]NCCH3(+) ([Ru] = Cp(PPh3)2Ru) in CHCl3 generates a diastereomeric mixture of the substituted tetrahydropyran 11. Presumably, formation of an allenylidene complex is followed by a cyclization by nucleophilic addition of the olefinic group to Cγ of the ligand giving a boat-like six-membered ring. The diastereoselectivity is controlled by the 1,3-diaxial interaction. The vinylidene complex 7, a precursor of 11, is obtained from 1 and [Ru]Cl. In a mixture of MeOH/CHCl3, the domino cyclization of 1 further affords 14a, a chromene product catalytically. The second cyclization proceeds via nucleophilic addition of the resulting olefinic unit to Cα of 7. But the ether enyne 3 with a cyclopentyl ring on the olefinic unit undergoes only single cyclization due to steric effect. The propargyl alcohol and the two terminal methyl groups on the olefinic unit shape the cyclization. Thus, similar all-carbon 1,n-enynes (n = 7, 8, 9) 4-6 each with an aromatic linker undergo direct domino cyclization catalyzed by [Ru]NCCH3(+), to give derivatives of tricyclic fluorene, phenanthrene and dibenzo[7]annulene, respectively, with no intermediate observed.

  5. Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

    YANG XiongFa; NI XuFeng; SHEN ZhiQuan


    The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H_2salen)_2Cl_3·2C_2H_7OH/Al(i-Bu)_3) at room temperature was investigated.The influences of ligand structure,catalyst composition,polymerization temperature,polymerization time,the concentration of catalyst and monomer,and the polymerization solvent on the polymerization of isocyanates were studied.It was found that under the polymerization conditions,examined La(H_2salen_A)_2Cl_3·2C_(2-)H_7OH/Al(i-Bu)_3 (H_2salen_A=N,N'-disalicylideneethylene diamine) is a fairly high efficient catalyst for the polymerization of n-hexyl isocyanate (n-HexNCO) to prepare high molecular weight poly(n-hexyl isocyanate) (PHNCO) with narrower molecular weight distribution at room temperature.PHNCO could be prepared with yield of 74.0%,number-average molecular weight (M_n) of 40.20×10~4 and MWD of 1.79 under the following optimum conditions:[Al]/[La]=30 (molar ratio),[n-HexNCO]/[La]=100 (molar ratio),[n-HexNCO]=3.43 mol/L polymerization at 20℃ for 12 h in toluene.In the same polymerization conditions,poly (n-octyl isocyanate) (PONCO) with yield of 67.3%,and poly(n-butyl isocyanate) (PBNCO) with yield of 45.5%,could be prepared respectively.The kinetics of the polymerization of n-HexNCO was also investigated and found to be first-order with respect to both monomer and catalyst concentrations.

  6. Metal-ligand cooperative activation of nitriles by a ruthenium complex with a de-aromatized PNN pincer ligand

    Eijsink, Linda E; Perdriau, Sébastien C P; de Vries, Johannes G; Otten, Edwin


    The pincer complex (PNN)RuH(CO), with a de-aromatized pyridine in the ligand backbone, is shown to react with nitriles in a metal-ligand cooperative manner. This leads to the formation of a series of complexes with new Ru-N(nitrile) and C(ligand)-C(nitrile) bonds. The initial nitrile cycloaddition

  7. Metal-ligand cooperative activation of nitriles by a ruthenium complex with a de-aromatized PNN pincer ligand

    Eijsink, Linda E; Perdriau, Sébastien C P; de Vries, Johannes G; Otten, Edwin


    The pincer complex (PNN)RuH(CO), with a de-aromatized pyridine in the ligand backbone, is shown to react with nitriles in a metal-ligand cooperative manner. This leads to the formation of a series of complexes with new Ru-N(nitrile) and C(ligand)-C(nitrile) bonds. The initial nitrile cycloaddition p

  8. Mixed-ligand complexes of ruthenium(II) incorporating a diazo ligand: Synthesis, characterization and DNA binding

    Megha S Deshpande; Avinash S Kumbhar


    Mixed-ligand complexes of the type [Ru(N-N)2(dzdf)]Cl2, where N-N is 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen) and 9-diazo-4,5-diazafluorene (dzdf), have been synthesized and characterized by elemental analysis, UV-Vis, IR and NMR spectroscopy. Binding of these complexes with calf thymus DNA (CT-DNA) has been investigated by absorption spectroscopy, steady-state emission spectroscopy and viscosity measurements. The experimental results indicate that the size and shape of the intercalating ligands have marked effect on the binding affinity of the complexes to CT-DNA. The complex [Ru(phen)2(dzdf)]Cl2 binds with CT-DNA through an intercalative binding mode, while the complex [Ru(bpy)2(dzdf)]Cl2 binds electrostatically.

  9. 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

    Tiwari, Ida, E-mail: [Department of Chemistry (Center of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi (India); Gupta, Mandakini; Sinha, Preeti [Department of Chemistry (Center of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi (India); Banks, Craig E. [Faculty of Science and Engineering, School of Science and the Environment, Division of Chemistry and Environmental Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom)


    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.

  10. Light-Sensitive Ruthenium Complex-Loaded Cross-linked Polymeric Nanoassemblies for the Treatment of Cancer.

    Dickerson, M; Howerton, B; Bae, Y; Glazer, E


    This work focuses on improving the efficacy of photoactivatable Ru complexes for photodynamic therapy by employing cross-linked nanoassemblies (CNAs) as a delivery approach. The effects of complex photoactivation, hydrophobicity, and solution ionic strength and pH on complex loading and release from CNAs were analyzed. The cell cytotoxicity of CNA formulations was similar to free Ru complexes despite reduced or eliminated DNA interactions. The release rate and the amount of each Ru complex released (%) varied inversely with complex hydrophobicity, while the effect of solution ionic strength was dependent on complex hydrophobicity. Premature release of two photoactivatable prodrugs prior to irradiation was believed to account for higher activity in cells studies compared to DNA interaction studies; however, for photostable (1)O2 generator-loaded CNAs this cannot explain the high cytotoxicity and lack of DNA interactions because release was incomplete after 48 hrs. The cause remains unclear, but among other possibilities, accelerated release in a cell culture environment may be responsible.

  11. Analytical gradients of complete active space self-consistent field energies using Cholesky decomposition: Geometry optimization and spin-state energetics of a ruthenium nitrosyl complex

    Delcey, Mickaël G. [Department of Chemistry – Ångström, The Theoretical Chemistry Programme, Uppsala University, Box 518, 751 20 Uppsala (Sweden); Freitag, Leon; González, Leticia, E-mail: [Institut für Theoretische Chemie, Universität Wien, Währinger Straße 17, 1090 Vienna (Austria); Pedersen, Thomas Bondo [Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo (Norway); Aquilante, Francesco [Department of Chemistry – Ångström, The Theoretical Chemistry Programme, Uppsala University, Box 518, 751 20 Uppsala (Sweden); Dipartimento di Chimica “G. Ciamician,” Università di Bologna, V. F. Selmi 2, 40126 Bologna (Italy); Lindh, Roland, E-mail: [Department of Chemistry – Ångström, The Theoretical Chemistry Programme, Uppsala University, Box 518, 751 20 Uppsala (Sweden); Uppsala Center for Computational Chemistry - UC3, Uppsala University, Box 518, 751 20 Uppsala (Sweden)


    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.

  12. A solid-state sensor based on ruthenium (II) complex immobilized on polytyramine film for the simultaneous determination of dopamine, ascorbic acid and uric acid

    Khudaish, Emad A., E-mail: [Sultan Qaboos University, College of Science, Chemistry Department, PO Box 36, PC 123 Muscat (Oman); Al-Ajmi, Khawla Y. [Sultan Qaboos University, College of Science, Chemistry Department, PO Box 36, PC 123 Muscat (Oman); Al-Harthi, Salim H. [Sultan Qaboos University, College of Science, Department of Physics, PO Box 36, PC 123 Muscat (Oman)


    A solid-state sensor based on a polytyramine (Pty) film deposited on a glassy carbon electrode doped with a tris(2,2′-bipyridyl)Ru(II) complex (Ru/Pty/GCE) was constructed electrochemically. The surface morphology of the film modified electrode was characterized using electrochemical and surface scanning techniques. A redox property represented by a [Ru(bpy){sub 3}]{sup 3+/2+} couple immobilized at the Pty moiety was characterized using typical voltammetric techniques. A distinct Ru 3d peak obtained at 280.9 eV confirms doping of the Ru species onto the Pty moiety characterized by X-ray photoelectron (XPS). Atomic force microscopy (AFM) images demonstrate that incorporation of Ru decreases the surface roughness of the native Pty film modified electrode. The Ru/Pty/GCE exhibits efficient electrochemical sensing toward the oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) in their mixture. Three well-defined peaks were resolved with a large peak to peak separation and the detection limits of AA, DA and UA are brought down to 0.31, 0.08 and 0.58 μM, respectively. Interference studies and application for DA determination in real samples were conducted with satisfactory results. - Highlights: • XPS data confirm doping of ruthenium onto the polytyramine moiety. • The voltammetric signals of ascorbic acid, dopamine and uric acid are well defined. • The sensor is stable and offers a large adsorption facility for all species. • The sensor is highly sensitive to dopamine oxidation. • The sensor is applied to a real sample with a satisfactory recovery percentage.

  13. Carborane complexes of ruthenium(III): studies on thermal reaction chemistry and the catalyst design for atom transfer radical polymerization of methyl methacrylate.

    Grishin, Ivan D; D'yachihin, Dmitrii I; Piskunov, Alexander V; Dolgushin, Fedor M; Smol'yakov, Alexander F; Il'in, Mikhail M; Davankov, Vadim A; Chizhevsky, Igor T; Grishin, Dmitry F


    The heating of the 18-electron complex [3,3-(dppb)-3-H-3-Cl-closo-3,1,2-RuC(2)B(9)H(11)] (3) in benzene at 80 °C in the presence of a small amount of CCl(4) as initiator afforded paramagnetic 17-electron species [3,3-(dppb)-3-Cl-closo-3,1,2-RuC(2)B(9)H(11)] (4) along with minor amounts of two P-phenylene ortho-cycloboronated derivatives [3-Cl-3,3,8-{Ph(2)P(CH(2))(4)PPh-μ-(C(6)H(4)-ortho)}-closo-3,1,2-RuC(2)B(9)H(10)] (5) and [3,7-Cl(2)-3,3,8-{Ph(2)P(CH(2))(4)PPh-μ-(C(6)H(4)-ortho)}-closo-3,1,2-RuC(2)B(9)H(10)] (6) in total yield of ca. 80%. The heating of either 3 or 4 in toluene at 95 °C in the absence of CCl(4) led to the selective formation of 5, which was isolated in 64% and 46% yield, respectively. Thermolysis of 3 at higher temperatures (boiling toluene, 110 °C) gives novel paramagnetic species [3-Cl-3,3,7,8-{Ph(2)P(CH(2))(4)P-μ-(C(6)H(4)-ortho)(2)}-closo-3,1,2-RuC(2)B(9)H(9)] (7) featuring bis(ortho-cycloboronation) of both P-phenyl groups at the same phosphorus atom of the ruthenium-bound dppb ligand. All new paramagnetic complexes 4-7, as well as starting diamagnetic species 3, were characterized by single-crystal X-ray diffraction and, in addition, by EPR spectroscopic studies of odd-electron complexes. Ruthenacarboranes 3-5 and 7 all display high efficiency as catalysts for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). Complex 5 gave the best catalyst performance in terms of polydispersity; the PDI (M(w)/M(n)) of the polymer samples is as low as 1.15.

  14. Assessment of intercomponent interaction in phenylene bridged dinuclear ruthenium(II) and osmium(II) polypyridyl complexes

    Guckian, Adrian L.; Doering, Manfred; Ciesielski, Michael; Walter, Olaf; Hjelm, Johan; O’Boyle, Noel M.; Henry, William; Browne, Wesley R.; McGarvey, John J.; Vos, Johannes G.


    The synthesis and characterisation of [Ru(bipy)(2)(L1)](2+) and the homodinuclear complexes [M(bipy)(2)(L1)M(bipy)(2)](4+) (where M=Ru or Os), employing the ditopic ligand, 1,4-phenylene-bis(1-pyridin-2-ylimidazo [1,5-a] pyridine) (L1), are reported. The complexes are identified by elemental analysi

  15. Synthesis, crystal structure and cytotoxic activity of ruthenium(II) piano-stool complex with N,N-chelating ligand

    Rogala, Patrycja; Jabłońska-Wawrzycka, Agnieszka; Kazimierczuk, Katarzyna; Borek, Agnieszka; Błażejczyk, Agnieszka; Wietrzyk, Joanna; Barszcz, Barbara


    A mononuclear compound of the general formula [(η6-p-cymene)RuIICl(2,2‧-PyBIm)]PF6 has been synthesized from a bidentate N,N-donor ligand, viz. 2,-(2‧-pyridyl)benzimidazole (2,2‧-PyBIm) and the corresponding chloro-complex [(η6-p-cymene)Ru(μ-Cl)Cl]2 (precursor). The isolated coordination compound was characterized by IR, UV-vis and 1H, 13C NMR spectroscopies. The single crystal X-ray analysis of the complex reveals that the asymmetric part of the unit cell consists of two symmetrically independent, [(η6-p-cymene)RuCl(2,2‧-PyBIm)]+ cationic complexes. Each cation exhibits a pseudo-octahedral three-legged piano-stool geometry, in which three "legs" are occupied by one chloride ion and two nitrogen donor atoms of the chelating ligand 2,2‧-PyBIm. The Hirshfeld surface analysis of obtained complex was determined, too. The ionic nature of the compound is identified by a strong band at around 830 cm-1 due to the νP-F stretching mode of the PF6- counter ion. The electronic spectrum of this monomeric complex displays high intensity bands in the ultraviolet region assignable to π→π*/n→π* transitions, as well as a band attributable to the metal-to-ligand charge transfer (MLCT) dπ(Ru)→π*(L) transition. Additionally, the complex has been screened for its cytotoxicity against three human cancer lines: non-small cell lung carcinoma (A549), colon adenocarcinoma (HT29) and breast adenocarcinoma (MCF-7) as well as normal mice fibroblast cells (BALB/3T3). The complex demonstrated a moderate antiproliferative activity against the cell lines tested.

  16. Synthesis of cyano-bridged bimetallic complexes of 5-indenyl ruthenium(II): Characterization and spectroscopic studies

    K Mohan Rao; E K Rymmai


    Reactions of the cyanide complexes of the type [(Ind)Ru(PPh3)2CN] (1), [(Ind)Ru(dppe)CN] (2), [(Cp)Ru(PPh3)2CN] (3), with the corresponding chloro complexes [(Ind)Ru(PPh3)2Cl] (4), [(Ind)Ru(dppe)Cl] (5), [(Cp)Ru(PPh3)2Cl] (6), in the presence of NH4PF6 salt give homometallic cyano-bridged compounds of the type [(Ind)(PPh3)2Ru-CN-Ru(PPh3)2(Cp)]PF6 (7), [(Ind)(PPh3)2Ru-CN-Ru(PPh3)2(Ind)] PF6 where Ind = indenyl, 5-C9H7, (8), [(Cp)(PPh3)2Ru-CN-Ru(dppe)(Ind)]PF6, dppe = (Ph2PCH2CH2PPh2) (9), [(Ind(dppe)Ru-CN-Ru(PPh3)2(Ind)PF6 (10) and [(Ind)(dppe)Ru-CN-Ru(PPh3)2(Cp)]PF6 (11) respectively. Reaction of complex 3 with [(p-cymene)RuCl2]2 dimer gave a mixed dimeric complex [(Cp)Ru(PPh3)2-CN-RuCl2(-cymene)] (12). All these complexes have been characterized by IR, 1H, 13C and 31 P NMR spectroscopy and C, H, N analyses.

  17. Influence of complexing agents on the preparation of bimetallic platinum-ruthenium catalysts supported on O-functionalized graphite cloths

    Sieben, J.M., E-mail: [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur., Av. Alem 1253, (B8000CPB) Bahia Blanca (Argentina); Duarte, M.M.E.; Mayer, C.E. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur., Av. Alem 1253, (B8000CPB) Bahia Blanca (Argentina)


    Electrodeposition of bimetallic Pt-Ru catalysts on O-functionalized graphite cloths from H{sub 2}PtCl{sub 6} and RuCl{sub 3} solutions containing trisodium citrate (Cit) and disodium dihydrogen ethylenediaminetetraacetate (Na{sub 2}H{sub 2}EDTA) was investigated. SEM analysis of the electrode prepared without complexant showed a relatively compact and rough deposit displaying a 'tree cortex' structure, whereas uniform size and globular shape particles regularly distributed over the support surface were obtained using citrate and Na{sub 2}H{sub 2}EDTA as complexants. In addition, XRD diffraction and EDX analysis revealed that the catalysts prepared using the complexants showed smaller size particles and lower Ru content. Electrocatalytic activity measurements indicated that the most active electrode for methanol oxidation was obtained with Na{sub 2}H{sub 2}EDTA as additive.

  18. Study of 6- cyclic -perimeter hydrocarbon ruthenium complexes bearing functionalized pyridyl diketones: Isolation of complexes with 2-N∩O and 4-N∩O bonding modes of ligands

    Saphidabha L Nongbri; Babulal Das; Mohan Rao Kollipara


    Chelating mono- and di-pyridyl functionalized -diketones, viz. 1-phenyl-3-(2-pyridyl) propane-1,3-dione (pppdH) and 1,3-di(2-pyridyl)propane-1,3-dione (dppdH) ligands yielded new water soluble 6-arene ruthenium(II) complexes of the formulation [(6-arene)Ru(2-N-O-pppdH)Cl]+ (arene = C6H6 1, pPrC6H4Me 2, C6Me6 3) and [(6-arene)2Ru2(4-N-O-dppd)Cl2]+ (arene = C6H6 4, -PrC6H4Me 5, C6Me6 6), as their (complexes 1-4, 6) PF6 salt or (complex 5) BF4 salt. The complexes were obtained by treatment of respective precursors, [(6-arene)Ru(-Cl)Cl]2 (arene = C6H6, -PrC6H4Me, C6Me6) in 1:2 and 1:1 molar ratio with pppdH and dppdH in the presence of NH4PF6/NH4BF4. All the complexes have been characterized on the basis of FT-IR and NMR spectroscopic data as well as by elemental analysis. Molecular structures of representative complexes 2, 5 and 6 have been confirmed by single crystal X-ray diffraction studies. The `O-C-C-C-O' fragment of the coordinated ligand (pppdH) is neutral in complexes 1-3 and that of the dppdH ligand existed as a neutral as well as concomitantly uninegative fashion in complexes 4-6 due to the delocalization of -electrons.

  19. Ruthenium(II) Complexes Containing Lutidine-Derived Pincer CNC Ligands: Synthesis, Structure, and Catalytic Hydrogenation of C-N bonds.

    Hernández-Juárez, Martín; López-Serrano, Joaquín; Lara, Patricia; Morales-Cerón, Judith P; Vaquero, Mónica; Álvarez, Eleuterio; Salazar, Verónica; Suárez, Andrés


    A series of Ru complexes containing lutidine-derived pincer CNC ligands have been prepared by transmetalation with the corresponding silver-carbene derivatives. Characterization of these derivatives shows both mer and fac coordination of the CNC ligands depending on the wingtips of the N-heterocyclic carbene fragments. In the presence of tBuOK, the Ru-CNC complexes are active in the hydrogenation of a series of imines. In addition, these complexes catalyze the reversible hydrogenation of phenantridine. Detailed NMR spectroscopic studies have shown the capability of the CNC ligand to be deprotonated and get involved in ligand-assisted activation of dihydrogen. More interestingly, upon deprotonation, the Ru-CNC complex 5 e(BF4 ) is able to add aldimines to the metal-ligand framework to yield an amido complex. Finally, investigation of the mechanism of the hydrogenation of imines has been carried out by means of DFT calculations. The calculated mechanism involves outer-sphere stepwise hydrogen transfer to the C-N bond assisted either by the pincer ligand or a second coordinated H2 molecule.

  20. Synthesis, structural, spectral, thermal and antimicrobial studies of palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes derived from N,N,N,N-tetradentate macrocyclic ligand.

    Rani, Soni; Kumar, Sumit; Chandra, Sulekh


    Palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes of general stoichiometry [PdL]Cl(2), [PtL]Cl(2), [Ru(L)Cl(2)]Cl and [Ir(L)Cl(2)]Cl are synthesized with a tetradentate macrocyclic ligand, derived from 2,6-diaminopyridine with 3-ethyl 2,4-pentanedione. Ligand was characterized on the basis of elemental analyses, IR, mass, and (1)H NMR and (13)C NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, electronic spectral techniques and thermal studies. The value of magnetic moments indicates that all the complexes are diamagnetic except Ru(III) complex which shows magnetic moments corresponding its one unpaired electron. The macrocyclic ligand and all its metal complexes were also evaluated in vitro against some plant pathogenic fungi and bacteria to assess their biocidal properties.

  1. Kinetic, mechanistic and spectral investigation of ruthenium (III)-catalysed oxidation of atenolol by alkaline permanganate (stopped-flow technique)

    Rahamatalla M Mulla; Gurubasavaraj C Hiremath; Sharanappa T Nandibewoor


    Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength of 0.30 mol dm3 has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline medium exhibits 1 : 8 stoichiometry (atenolol : KMnO4). The reaction shows first-order dependence on [permanganate] and [ruthenium (III)] and apparently less than unit order on both atenolol and alkali concentrations. Reaction rate decreases with increase in ionic strength and increases with decreasing dielectric constant of the medium. Initial addition of reaction products does not affect the rate significantly. A mechanism involving the formation of a complex between catalyst and substrate has been proposed. The active species of ruthenium (III) is understood as [Ru(H2O)5OH]2+. The reaction constants involved in the different steps of mechanism are calculated. Activation parameters with respect to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated.

  2. Teaching Inorganic Photophysics and Photochemistry with Three Ruthenium(II) Polypyridyl Complexes: A Computer-Based Exercise

    Garino, Claudio; Terenzi, Alessio; Barone, Giampaolo; Salassa, Luca


    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…

  3. Hydrogenation of imines catalysed by ruthenium(II) complexes based on lutidine-derived CNC pincer ligands.

    Hernández-Juárez, Martín; Vaquero, Mónica; Álvarez, Eleuterio; Salazar, Verónica; Suárez, Andrés


    The preparation of new Ru(II) complexes incorporating fac-coordinated lutidine-derived CNC ligands is reported. These derivatives are selectively deprotonated by (t)BuOK at one of the methylene arms of the pincer, leading to catalytically active species in the hydrogenation of imines.

  4. Influence of the π-coordinated arene on the anticancer activity of ruthenium(II) carbohydrate organometallic complexes

    Hanif, Muhammad; Meier, Samuel M; Nazarov, Alexey A; Risse, Julie; Legin, Anton; Casini, Angela; Jakupec, Michael A; Keppler, Bernhard K; Hartinger, Christian G


    The synthesis and in vitro cytotoxicity of a series of Ru(II)(arene) complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well

  5. Synthesis, spectroscopic, DFT calculations and biological activity studies of ruthenium carbonyl complexes with 2-picolinic acid and a secondary ligand

    Shohayeb, Shahera M.; Mohamed, Rania G.; Moustafa, H.; El-Medani, Samir M.


    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.

  6. Influence of the π-coordinated arene on the anticancer activity of ruthenium(II) carbohydrate organometallic complexes

    Hanif, Muhammad; Meier, Samuel M; Nazarov, Alexey A; Risse, Julie; Legin, Anton; Casini, Angela; Jakupec, Michael A; Keppler, Bernhard K; Hartinger, Christian G


    The synthesis and in vitro cytotoxicity of a series of Ru(II)(arene) complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well

  7. Water soluble (Eta sup (6) - arene) ruthenium (II) complexes incorporating marine derived bioligand: Synthesis, spectral and structural studies

    Singh, K.S.; Svitlyk, V.; PrabhaDevi; Mozharivskyj, Y.

    ) or L sub(2) in the presence of AgBF sub(4) (L sub(1) = PyCN, DMAP; L sub(2) = 4,4`-bipy, pyrazine). The complexes are characterized on the basis of spectroscopic data and molecular structures of three representative compounds have been determined...

  8. ReBr(CO)5-Catalyzed Knoevenagel Condensation

    ZUO Wei-xiong; HUA Rui-mao; SUN Hong-bin


    Knoevenagel condensations are especially important reactions for the synthesis of alkene compounds having electron-withdrawing groups such as COR,CN,COOR,NO2 etc. Recently,transition metal hydride ruthenium1, hydride and polyhydride rhenium2, and polyhydride iridium complexes have been found to be the efficient catalysts for Knoevenagle condensation. However the mentioned-above transition metal hydride complexes are not easily prepared. In addition, all of them are oxygen and H2O-sensitive, unstable compands. Therefor the catalytic reactions are required to be carried out under an inert atmosphere, and using the prepurified reagent.In the paper, We wish to report the development of Knoevenagel condensation catalyzed by ReBr(CO)5 under an air atmosphere in the absence of solvent.All the experiments were carried out under 1atm, without solvent.The resuIts of the representative Knoevenagel condensations are summarized in Table 1.The Knoevenagel reaction with diethyl malonate can be catalyzed by ReBr(CO)5, while the present Knoevenagel reactions catalyzed by transition metal have at least one cyano group in active methylene compouds.A propose mechanism for present catalytic coupling dehydration reactions is also illustrated in the paper.Briefly, this paper reports the ReBr(CO)5-catalyzed Knoevenagel reaction. The reaction is a new method for the Konevenagel condensation.

  9. Asymmetric hydrogenation of quinolines catalyzed by iridium complexes of monodentate BINOL-derived phosphoramidites

    Mrsic, Natasa; Lefort, Laurent; Boogers, Jeroen A. F.; Minnaard, Adriaan J.; Feringa, Ben L.; de Vries, Johannes G.; Mršić, Nataša

    The monodentate BINOL-derived phosphoramidite PipPhos is used as ligand for the iridium-catalyzed asymmetric hydrogenation of 2- and 2,6-substituted quinolines. If tri-ortho-tolylphosphine and/or chloride salts are used as additives enantioselectivities are strongly enhanced up to 89%. NMR indicates

  10. Asymmetric epoxidation of α,β-unsaturated ketones catalyzed by chiral ytterbium complexes

    Chen, Ruifang; Qian, Changtao; Vries, Johannes G. de


    Several derivatives of (S)-(−)-BINOL ligands with 6,6'-substitutents were synthesized and applied as chiral ligands in the Yb(O-i-Pr)3-catalyzed asymmetric epoxidation of α,β-unsaturated ketones. Superior results were obtained with 6,6'-diphenyl-BINOL, exemplified in the asymmetric epoxidation of

  11. Microwave-Assisted Olefination Reaction of Alkylzinc with Aromatic Aldehyde Catalyzed by Nickel Complex

    MEN Xiu-Qin; WANG Jin-Xian; SHI Xiao-Ning; WANG Ke-Hu


    @@ Carbon-carbon double bond-forming reactions have always been great importance in organic synthesis. Manymethods have been described for C =C bond formation. We[1] have reported the new method of C =C bond formation of nickel catalyzed organozinc with aromatic aldehydes in the presence of Me3SiC1.

  12. Is the ruthenium analogue of compound I of cytochrome p450 an efficient oxidant? A theoretical investigation of the methane hydroxylation reaction.

    Sharma, Pankaz K; De Visser, Sam P; Ogliaro, François; Shaik, Sason


    High-valent metal-oxo complexes catalyze C-H bond activation by oxygen insertion, with an efficiency that depends on the identity of the transition metal and its oxidation state. Our study uses density functional calculations and theoretical analysis to derive fundamental factors of catalytic activity, by comparison of a ruthenium-oxo catalyst with its iron-oxo analogue toward methane hydroxylation. The study focuses on the ruthenium analogue of the active species of the enzyme cytochrome P450, which is known to be among the most potent catalysts for C-H activation. The computed reaction pathways reveal one high-spin (HS) and two low-spin (LS) mechanisms, all nascent from the low-lying states of the ruthenium-oxo catalyst (Ogliaro, F.; de Visser, S. P.; Groves, J. T.; Shaik, S. Angew. Chem. Int. Ed. 2001, 40, 2874-2878). These mechanisms involve a bond activation phase, in which the transition states (TS's) appear as hydrogen abstraction species, followed by a C-O bond making phase, through a rebound of the methyl radical on the metal-hydroxo complex. However, while the HS mechanism has a significant rebound barrier, and hence a long lifetime of the radical intermediate, by contrast, the LS ones are effectively concerted with small barriers to rebound, if at all. Unlike the iron catalyst, the hydroxylation reaction for the ruthenium analogue is expected to follow largely a single-state reactivity on the LS surface, due to a very large rebound barrier of the HS process and to the more efficient spin crossover expected for ruthenium. As such, ruthenium-oxo catalysts (Groves, J. T.; Shalyaev, K.; Lee, J. In The Porphyrin Handbook; Biochemistry and Binding: Activation of Small Molecules, Vol. 4; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: New York, 2000; pp 17-40) are expected to lead to more stereoselective hydroxylations compared with the corresponding iron-oxo reactions. It is reasoned that the ruthenium-oxo catalyst should have larger turnover

  13. Rhodium-catalyzed double [2 + 2 + 2] cycloaddition of 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne with tethered diynes: a modular, highly versatile single-pot synthesis of NU-BIPHEP biaryl diphosphines.

    Doherty, Simon; Knight, Julian G; Smyth, Catherine H; Harrington, Ross W; Clegg, William


    Rhodium-catalyzed double [2 + 2 + 2] cycloaddition of 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne with tethered diynes provides a straightforward, single-pot procedure for the synthesis of a new class of tropos biaryl diphosphine, NU-BIPHEP. This methodology represents a significant improvement on existing multistep procedures. Enantiopure Lewis acid platinum complexes of these diphosphines are highly efficient catalysts for carbonyl-ene and Diels-Alder reactions, and ruthenium diphosphine-diamine complexes catalyze the asymmetric reduction of ketones to give ee's that rival those obtained with their BINAP counterpart.

  14. Asymmetric Ruthenium(II and Osmium(II Complexes with New Bidentate Polyquinoline Ligands. Synthesis and NMR Characterization

    Antonino Mamo


    Full Text Available A series of Ru(II and Os(II tris-chelate complexes with new bidentate 2-pyridylquinoline ligands have been synthesized and fully characterized by EA,1H-NMR and FAB-MS techniques. The new ligands are: L1 = 4-p-methoxyphenyl-6-bromo-2-(2′- pyridylquinoline (mphbr-pq and L2 = 4-p-hydroxyphenyl-6-bromo-2-(2′-pyridyl-quinoline (hphbr-pq. The complexes studied are: [Ru(bpy2L1](PF62 (C1, [Ru(bpy2L2](PF62 (C2, [Os(bpy2L1](PF62 (C3, [Os(bpy2L2](PF62 (C4 (bpy = 2,2′-bipyridine, [Ru(dmbpy2L1](PF62 (C5, [Ru(dmbpy2L2](PF62 (C6, [Os(dmbpy2L1](PF62 (C7, and [Os(dmbpy2L2](PF62 (C8 (dmbpy = 4,4′-dimethyl-2,2′-bipyridine. Moreover, new functionalized complexes C9-C12 were obtained by the basecatalyzed direct alkylation of C2, C4, C6, and C8 with 6-bromo-1-hexene. The complete assignment of the 1H-NMR spectra for the two new ligands (L1 and L2, and their Ru(II or Os(II complexes has been accomplished using a combination of one- and two-dimensional NMR techniques. The JH,H values have been determined for the majority of the resonances.

  15. Selective conversion of polyenes to monoenes by RuCl(3) -catalyzed transfer hydrogenation: the case of cashew nutshell liquid.

    Perdriau, Sébastien; Harder, Sjoerd; Heeres, Hero J; de Vries, Johannes G


    Cardanol, a constituent of cashew nutshell liquid (CNSL), was subjected to transfer hydrogenation catalyzed by RuCl(3) using isopropanol as a reductant. The side chain of cardanol, which is a mixture of a triene, a diene, and a monoene, was selectively reduced to the monoene. Surprisingly, it is the C8-C9 double bond that is retained with high selectivity. A similar transfer hydrogenation of linoleic acid derivatives succeeded only if the substrate contained an aromatic ring, such as a benzyl ester. TEM and a negative mercury test showed that the catalyst was homogeneous. By using ESI-MS, ruthenium complexes were identified that contained one, two, or even three molecules of substrate, most likely as allyl complexes. The interaction between ruthenium and the aromatic ring determines selectivity in the hydrogenation reaction.

  16. Accelerated Hydrolysis of p-Nitrophenyl Picolinate Catalyzed by Metallomicelle Made from a Novel Macrocyclic Polyamine Copper(Ⅱ) Complex

    KOU,Xing-Ming; ZHAO,Guo-Po; HUANG,Zhong; TIAN,Yu-Hua; MENG,Xiang-Guang; ZENG Xian-Cheng


    A copper(Ⅱ) complex 1 of a novel macrocyclic polyamine ligand with hydroxylethyl pendant groups, 4,ll-bis(hydroxylethyl)-5,7,7,12,14,14-hexamethyl-l,4,8,11-tetraazacyclotetradecane (L) has been synthesized and characterized. Rate enhancement for hydrolysis of p-nitrophenyl picolinate (PNPP) catalyzed by 1 was studied kinetically under Brij35 micellar condition. For comparision, the catalytic activity of corresponding copper(Ⅱ) complex 2 of non-substituted macrocyclic polyamine ligand, 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraaza-cyclote-tradecane (L1) toward the hydrolysis of PNPP was also investigated. The results indicate that the macrocyclic polyamine copper(Ⅱ) complex 1 effectively catalyzed the hydrolysis of PNPP, and the pendant ligand hydroxyl group or deprotonated pendant ligand hydroxyl group can act as catalytically active species in the reaction. A ternary complex kinetic model involving metal ion, ligand and substrate has been proposed, and the results confirmed the reasonability of such kinetic model.

  17. Tuning excited state isomerization dynamics through ground state structural changes in analogous ruthenium and osmium sulfoxide complexes.

    Garg, Komal; Engle, James T; Ziegler, Christopher J; Rack, Jeffrey J


    The complexes [Ru(bpy)2(pyESO)](PF6)2 and [Os(bpy)2(pyESO)](PF6)2, in which bpy is 2,2'-bipyridine and pyESO is 2-((isopropylsulfinyl)ethyl)pyridine, were prepared and studied by (1)H NMR, UV-visible and ultrafast transient absorption spectroscopy, as well as by electrochemical methods. Crystals suitable for X-ray structural analysis were grown for [Ru(bpy)2(pyESO)](PF6)2. Cyclic voltammograms of both complexes provide evidence for S→O and O→S isomerization as these voltammograms are described by an ECEC (electrochemical-chemical electrochemical-chemical) mechanism in which isomerization follows Ru(2+) oxidation and Ru(3+) reduction. The S- and O-bonded Ru(3+/2+) couples appear at 1.30 and 0.76 V versus Ag/AgCl in propylene carbonate. For [Os(bpy)2(pyESO)](PF6)2, these couples appear at 0.97 and 0.32 V versus Ag/AgCl in acetonitrile, respectively. Charge-transfer excitation of [Ru(bpy)2(pyESO)](PF6)2 results in a significant change in the absorption spectrum. The S-bonded isomer of [Ru(bpy)2(pyESO)](2+) features a lowest energy absorption maximum at 390 nm and the O-bonded isomer absorbs at 480 nm. The quantum yield of isomerization in [Ru(bpy)2(pyESO)](2+) was found to be 0.58 in propylene carbonate and 0.86 in dichloroethane solution. Femtosecond transient absorption spectroscopic measurements were collected for both complexes, revealing time constants of isomerizations of 81 ps (propylene carbonate) and 47 ps (dichloroethane) in [Ru(bpy)2(pyESO)](2+). These data and a model for the isomerizing complex are presented. A striking conclusion from this analysis is that expansion of the chelate ring by a single methylene leads to an increase in the isomerization time constant by nearly two orders of magnitude.

  18. Hydrogen bonding and proton transfer to ruthenium hydride complex CpRuH(dppe): metal and hydride dichotomy.

    Silantyev, Gleb A; Filippov, Oleg A; Tolstoy, Peter M; Belkova, Natalia V; Epstein, Lina M; Weisz, Klaus; Shubina, Elena S


    The combination of variable temperature (190-297 K) IR and NMR spectroscopy studies with quantum-chemical calculations at the DFT/B3PW91 and AIM level had the aim to determine the mechanism of proton transfer to CpRuH(dppe) (1, dppe = Ph(2)P(CH(2))(2)PPh(2)) and the structures of intermediates. Dihydrogen bond (DHB) formation was established in the case of interaction with weak proton donors like CF(3)CH(2)OH. Low-temperature protonation (at about 200 K) by stronger proton donors leads via DHB complex to the cationic nonclassical complex [CpRu(η(2)-H(2))(dppe)](+) (2). Thermodynamic parameters of DHB formation (for CF(3)CH(2)OH: ΔH°(HB) = -4.9 ± 0.2 kcal·mol(-1), ΔS°(HB) = -17.8 ± 0.7 cal·mol(-1)·K(-1)) and proton transfer (for (CF(3))(2)CHOH: ΔH°(PT) = -5.2 ± 0.3 kcal·mol(-1), ΔS°(PT) = -23 ± 1 cal·mol(-1)·K(-1)) were determined. Above 240 K 2 transforms into trans-[CpRu(H)(2)(dppe)](+) (3) yielding a mixture of 2 and 3 in 1:2 ratio. Kinetic analysis and activation parameters for the "[Ru(η(2)-H(2))](+) → trans-[Ru(H)(2)](+)" transformation indicate reversibility of this process in contrast to irreversible intramolecular isomerization of the Cp* analogue. Calculations show that the driving force of this process is greater stability (by 1.5 kcal·mol(-1) in ΔE scale) of the dihydride cation in comparison with the dihydrogen complex. The calculations of the potential energy profile indicate the low barrier for deprotonation of 2 suggesting that the formation of trans-[CpRu(H)(2)(dppe)](+) proceeds via deprotonation of [Ru(η(2)-H(2))](+) to DHB complex, formation of hydrogen bond with Ru atom and subsequent proton transfer to the metal site.

  19. Reactivity Studies on a Binuclear Ruthenium(0) Complex Equipped with a Bridging κ(2)N,Ge-Amidinatogermylene Ligand.

    Cabeza, Javier A; Fernández-Colinas, José M; García-Álvarez, Pablo; Pérez-Carreño, Enrique; Polo, Diego


    The amidinatogermylene-bridged diruthenium(0) complex [Ru2{μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}(CO)7] (2; (i)Pr2bzam = N,N'-bis(iso-propyl)benzamidinate; HMDS = N(SiMe3)2) reacted at room temperature with (t)BuNC and PMe3 to give [Ru2{μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}(L)(CO)6] (L = (t)BuNC, 3; PMe3, 4), which contain the new ligand in an axial position on the Ru atom that is not attached to the amidinato fragment. At 70 °C, 2 reacted with PPh3, PMe3, dppm, and dppe to give the equatorially substituted derivatives [Ru2{μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}(L)(CO)6] (L = PPh3, 5; PMe3, 6) and [Ru2{μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}(μ-κ(2)P,P'-L2)(CO)5] (L2 = dppm, 7; dppe, 8). HSiEt3 and HSnPh3 were oxidatively added to complex 2 at 70 °C, leading to the coordinatively unsaturated products [Ru2(ER3)(μ-H){μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}(CO)5] (ER3 = SiEt3, 9; SnPh3, 10), which easily reacted with (t)BuNC and CO to give the saturated derivatives [Ru2(ER3)(μ-H){μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}((t)BuNC)(CO)5] (ER3 = SiEt3, 11; SnPh3, 12) and [Ru2(ER3)(μ-H){μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}(CO)6] (ER3 = SiEt3, 13; SnPh3, 14), respectively. Compounds 9-14 have their ER3 group on the Ru atom that is not attached to the amidinato fragment. In contrast, the reaction of 2 with H2 at 70 °C led to the unsaturated tetranuclear complex [Ru4(μ-H)2{μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}2(CO)10] (15), which also reacted with (t)BuNC and CO to give the saturated derivatives [Ru4(μ-H)2{μ-κ(2)Ge,N-Ge((i)Pr2bzam)(HMDS)}2(L)2(CO)10] (L = (t)BuNC, 16; CO, 17). All tetraruthenium complexes contain an unbridged metal-metal connecting two germylene-bridged diruthenium units. Under CO atmosphere, complex 17 reverted to compound 2. All of the coordinatively unsaturated products (9, 10, and 15) have their unsaturation(s) located on the Ru atom(s) that is(are) attached to the amidinato fragment(s). In the absence of added reagents, the thermolysis of 2 in refluxing toluene led to [Ru4{

  20. Structural analysis of ruthenium-arene complexes using ion mobility mass spectrometry, collision-induced dissociation, and DFT.

    Czerwinska, Izabella; Far, Johann; Kune, Christopher; Larriba-Andaluz, Carlos; Delaude, Lionel; De Pauw, Edwin


    Ion mobility mass spectrometry (IM-MS) and collision-induced dissociation (CID) techniques were used to investigate the influence of the phosphine ligand on the physicochemical properties of [RuCl2(p-cymene)(PCy3)] (), [RuCl2(p-cymene)(PPh3)] (), and [RuCl2(p-cymene)(PTA)] () in the gas phase (PTA is 1,3,5-triaza-7-phosphaadamantane). Electrospray ionization of complexes and led to the corresponding [RuCl(p-cymene)(PR3)](+) ions via the dissociation of a chlorido ligand, whereas RAPTA-C () afforded two molecular ions by in-source oxidation ([Ru(III)Cl2(p-cymene)(PTA)](+)) or protonation ([RuCl2(p-cymene)(PTA+H)](+)). Control experiments showed that the balance between these two ionization paths was strongly influenced by the nature of the solvent used for infusion. Collision cross sections (CCSs) of the four molecular ions accurately reflected the variations of steric bulk inferred from the Tolman steric parameters (θ) of the phosphine ligands. Moreover, DFT calculations combined with a model based on the kinetic theory of gases (the trajectory method of the IMoS software) afforded reliable CCS predictions. The almost two times higher dipole moment of [RuCl2(p-cymene)(PTA+H)](+) (μ = 13.75 D) compared to [Ru(III)Cl2(p-cymene)(PTA)](+) (μ = 7.18 D) was held responsible for increased ion-induced dipole interactions with a polarizable drift gas such as N2. Further experiments with He and CO2 confirmed that increasing the polarizability of the buffer gas improved the separation between the two molecular ions derived from complex . The fragmentation patterns of complexes were determined by CID. The sequence of collision voltages at which 50% of a precursor ion dissociates (V50) recorded for the molecular ions derived from compounds was in good agreement with simple electronic considerations based on the donor strength of the phosphine ligand. Thus, the CCS and V50 parameters used to determine the shape and stability of ionic species in the gas phase are complementary

  1. Influence of the π-coordinated arene on the anticancer activity of ruthenium(II carbohydrate organometallic complexes

    Muhammad eHanif


    Full Text Available The synthesis and in vitro cytotoxicity of a series of RuII(arene complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well with cellular accumulation. The most lipophilic compound bearing a biphenyl moiety and a cyclohexylidene-protected carbohydrate is the most cytotoxic with unprecedented IC50 values for the compound class in three human cancer cell lines. This compound shows reactivity to the DNA model nucleobase 9-ethylguanine, but does not alter the secondary structure of plasmid DNA indicating that other biological targets are responsible for its cytotoxic effect.

  2. A Long-Lived Mononuclear Cyclopentadienyl Ruthenium Complex Grafted onto Anatase TiO2 for Efficient CO2 Photoreduction.

    Huang, Haowei; Lin, Jinjin; Zhu, Gangbei; Weng, Yuxiang; Wang, Xuxu; Fu, Xianzhi; Long, Jinlin


    This work shows a novel artificial donor-catalyst-acceptor triad photosystem based on a mononuclear C5 H5 -RuH complex oxo-bridged TiO2 hybrid for efficient CO2 photoreduction. An impressive quantum efficiency of 0.56 % for CH4 under visible-light irradiation was achieved over the triad photocatalyst, in which TiO2 and C5 H5 -RuH serve as the electron collector and CO2 -reduction site and the photon-harvester and water-oxidation site, respectively. The fast electron injection from the excited Ru(2+) cation to TiO2 in ca. 0.5 ps and the slow backward charge recombination in half-life of ca. 9.8 μs result in a long-lived D(+) -C-A(-) charge-separated state responsible for the solar-fuel production.

  3. Supported ruthenium-carbene catalyst on ionic magnetic nanoparticles for olefin metathesis.

    Chen, Shu-Wei; Zhang, Zhi-Cheng; Ma, Miaofeng; Zhong, Chong-Min; Lee, Sang-gi


    The Grubbs-Hoveyda ruthenium-carbene complex has been covalently immobilized on ionic magnetic nanoparticles utilizing an imidazolium salt linker. The supported catalyst exhibited excellent catalytic activity for ring-closing metathesis (RCM) and cross-metathesis (CM) in the presence of less than 1 mol % of ruthenium. The catalysts can easily be recovered magnetically and reused up to seven times with minimal leaching of ruthenium species.

  4. Relaxation of rabbit corpus cavernosum smooth muscle and aortic vascular endothelium induced by new nitric oxide donor substances of the nitrosyl-ruthenium complex

    Joao B. G. Cerqueira


    Full Text Available INTRODUCTION: Endothelial dysfunction characterized by endogenous nitric oxide (NO deficiency made 56% of patients affected with erectile dysfunction decline treatment with PDE-5 inhibitors. New forms of treatment are currently being developed for this group of patients. MATERIALS AND METHODS: The study compared the effect of sodium nitroprusside (SNP and two substances of the nitrosyl-ruthenium complex, cis-[Ru(bpy2(SO3(NO]PF-6-9 ("FONO1” and trans-[Ru(NH34(caffeine(NO]C13 ("LLNO1” on relaxation of rabbit corpus cavernosum smooth muscle and aortic vascular endothelium. The samples were immersed in isolated baths and precontracted with 0.1 µM phenylephrine (PE and the corresponding relaxation concentration/response curves were plotted. In order to investigate the relaxation mechanisms involved, 100 µM ODQ (a soluble guanylate cyclase-specific inhibitor, 3 µM or 10 µM oxyhemoglobin (an extracellular NO scavenger or 1 mM L-cysteine (a nitrosyl anion-specific scavenger was added to the samples. RESULTS: All the NO donors tested produced a significant level of relaxation in the vascular endothelium. In corpus cavernosum samples, FONO1 produced no significant effect, but LLNO1 and SNP induced dose-dependent relaxation with comparable potency (pEC50 = 6.14 ± 0.08 and 6.4 ± 0.14, respectively and maximum effect (Emax = 82% vs. 100%, respectively. All NO donors were found to activate soluble guanylate cyclase, since the addition of the corresponding inhibitor (100 µM ODQ completely neutralized the relaxation effect observed. The addition of oxyhemoglobin reduced the relaxation effect, but did not inhibit it completely. In aortic vascular endothelium 3 µM oxyhemoglobin decreased the relaxation effect by 26% on the average, while 10 µM oxyhemoglobin reduced it by over 52%. The addition of 100 µM L-cysteine produced no significant inhibiting effect. CONCLUSIONS: These results suggest that LLNO1 and FONO1 are potent vasodilators. LLNO1 was

  5. Photophysical characterization of the interactions among tris(2,2'-bipyridyl)ruthenium(II) complexes ion-exchanged within zirconium phosphate.

    Martí, Angel A; Colón, Jorge L


    We studied the structures, luminescence, and self-quenching properties of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) two-dimensional arrangements within the layers of zirconium phosphate (ZrP). The intercalation of Ru(bpy)(3)(2+) was accomplished using a hydrated form of zirconium phosphate ZrP. Varying the Ru(bpy)(3)(2+)/ZrP intercalation ratio, different Ru(bpy)(3)(2+)-exchanged ZrP loading levels were achieved. The ion exchange of Ru(bpy)(3)(2+) within ZrP produces a red shift in the metal-to-ligand charge-transfer (MLCT) absorption band of the complex from 452 nm in aqueous solution to 460 nm in ZrP. Steady state luminescence spectra of the Ru(bpy)(3)(2+)-exchanged ZrP materials show an increase in the luminescence intensity with an increase in the Ru(bpy)(3)(2+) loading level until about 0.77 M, where subsequent increases in the loading level produce a decrease in the luminescence (self-quenching region). Time-resolved luminescence measurements are consistent with the steady state luminescence measurements. Analysis of the time domain luminescence measurements in loadings higher than 0.77 M leads to the determination of a collisional quenching rate constant of (1.67 +/- 0.05) x 10(6) M(-1) s(-1). Stern-Volmer analysis of the luminescence quantum yield of Ru(bpy)(3)(2+)-exchanged ZrP materials indicates that static quenching is also involved in the Ru(bpy)(3)(2+) self-quenching mechanism. The quantum yield data behavior might be explained by a model that takes into account collisional quenching and the quasi-static Perrin mechanism. The calculation yields a quenching sphere of action of 14.8 A, which is slightly larger than the collisional radii of two Ru(bpy)(3)(2+) ions (12.2 A), as predicted by the model.

  6. Ruthenium and osmium complexes of hemilabile chiral monophosphinite ligands derived from 1D-pinitol or 1D-chiro-inositol as catalysts for asymmetric hydrogenation reactions.

    Slade, Angela T; Lensink, Cornelis; Falshaw, Andrew; Clark, George R; Wright, L James


    The monophosphinite ligands, 1D-1,2;5,6-di-O-cyclopentylidene-3-O-methyl-4-O-diphenylphosphino-chiro-inositol (D-P1), 1D-1,2;5,6-di-O-isopropylidene-3-O-methyl-4-O-diphenylphosphino-chiro-inositol (D-P2), 1D-1,2;5,6-di-O-cyclohexylidene-3-O-methyl-4-O-diphenylphosphino-chiro-inositol (D-P3), and 1D-1,2;5,6-di-O-cyclopentylidene-3-O-ethyl-4-O-diphenylphosphino-chiro-inositol (D-P4), can be conveniently prepared from the chiral natural products 1D-pinitol or 1D-chiro-inositol. On treatment of toluene solutions of RuCl2(PPh3)3 with two mole equivalents of the ligands D-PY (Y = 1-4) the complexes RuCl2(D-P1)2 (1), RuCl2(D-P2)2 (4), RuCl2(D-P3)2 (5), or RuCl2(D-P4)2 (6), respectively, are formed. Similarly, treatment of OsCl2(PPh3)3 with D-P1 gives OsCl2(D-P1)2 (7). The single crystal X-ray structure determination of 1 reveals that each D-P1 ligand coordinates to ruthenium through phosphorus and the oxygen atom of the methoxyl group. Treatment of 1 with excess LiBr or LiI results in metathesis of the chloride ligands and RuBr2(D-P1)2 (2) or RuI2(D-P1)2 (3), respectively, are formed. Exposure of a solution of 1 to carbon monoxide results in the very rapid formation of RuCl2(CO)2(D-P1)2 (8), thereby demonstrating the ease with which the oxygen donors are displaced from the metal and hence the hemilabile nature of the two bidentate D-P1 ligands in 1. Preliminary studies indicate that 1-7 act as catalysts for the asymmetric hydrogenation reactions of acetophenone and 3-quinuclidinone to give the corresponding alcohols in generally high conversions but low enantiomeric excesses.

  7. The Use of Differential EXAFS Analysis for the determination of Small Structural Differences between two closely-related Ruthenium Complexes

    Gianolio, D.; Borfecchia, E.; Garino, C.; Ruiu, T.; Lamberti, C.; Salassa, L.


    X-ray Absorption Spectroscopy (XAS) is a sensitive and powerful technique in revealing the structure of a material, providing as well high accuracy on interatomic distances. Nevertheless, when dealing with systems that differ only by small structural features, a standard data analysis might be unable of discriminating between such differences. A differential approach was proposed by Bressler, Chergui, and co-workers [2003, Phys. Rev. Lett. 90, 047403][2006, J. Phys. Chem B, 110, 14035][2009 Angew. Chem., Int. Ed. 48 2711] to solve this problem and differentiate between excited and unexcited state structures during pump-and-probe transient XAS experiments. In this contribution, we apply the differential data analysis procedure to the study of two closely-related molecular complexes, namely cis-[Ru(bpy)2(py)2]2+ and cis-[Ru(bpy)2(py)(H2O)]2+, characterized under static conditions. It is herein demonstrated that the method, based on a direct fit of differential curves, is able to reveal the small differences present between the two structures which, conversely, could not be resolved by standard EXAFS fitting of full spectra.

  8. Electron-deficient ruthenium and osmium complexes: From 14-electron species to C-F bond cleavage reactions

    Huang, Dejian


    Stepwise removal of the fluoride from RuRF(CO)L2 gives [RuR(CO)L 2]BAr'4 (L = PtBu 2Me, R = H, CH3, Ph, Ar' = 3,5- bis(trifluoromethyl)phenyl). This 14-electron cation has a saw-horse shape with two bulky L trans and CO and R cis. The two vacant sites are in fact occupied weakly by C-H bonds from the phosphines. [RuH(CO)L2] + has a strong Lewis acidic but weakened π- basic Ru center as it is illustrated by its reactivity pattern towards olefins and alkynes. While organic fluorocarbon is notorious for its inertness due to the strong C-F bond, the α-C-F bond of a transition metal fluorocarbyl complex is activated. The chemistry in Chapter 3 illustrates this argument. Attempts to replace fluoride of MHF(CO)L2 with CF3 using Me 3SiCF3 do not give MH(CF3)(CO)L2, instead, M[HF(CF2)(CO)L2 is isolated. Fast equilibrium exists between RuHF(CF2)(CO)L2 and RuH(CF3)(CO)L 2 but not for OsHF(CF2)(CO)L2, which is converted to OsF2(CFH)(CO)L2 upon heating. In contrast, isomerization of RuHF(CF2)(CO)L2 gives RUF(CF2H)(CO)L 2.

  9. Highly sensitive and selective difunctional ruthenium(II) complex-based chemosensor for dihydrogen phosphate anion and ferrous cation.

    Zheng, Ze-Bao; Duan, Zhi-Ming; Ma, Ying-Ying; Wang, Ke-Zhi


    The anion-interaction properties of a Ru(II) complex of [Ru(bpy)2(Htppip)](ClO4)2·H2O·DMF (RuL) {bpy =2,2'-bipyridine and Htppip =2-(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} were thoroughly investigated in CH3CN and CH3CN/H2O (50:1, v/v) solutions by UV-visible absorption, emission, and (1)H NMR spectra. These analyses revealed that RuL acts as an efficient "turn on" emission sensor for H2PO4(-), and a "turn off" sensor for F(-) and OAc(-); in addition, RuL exhibited slightly disturbed emission spectra in the presence of the other anions studied (Cl(-), Br(-), I(-), NO3(-), and ClO4(-)). The cation-sensing properties of RuL were also studied in both neat CH3CN and aqueous 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer (pH = 7.2)/CH3CN (71/1, v/v) solutions. RuL was found to exhibit a colorimetric sensing ability that was highly selective for Fe(2+), as evidenced by an obvious color change from pale yellow to light red-purple to the naked eye over the other cations studied (Na(+), Mg(2+), Ba(2+), Mn(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), and Ag(+)). To obtain insights into the possible binding modes and the sensing mechanisms, (1)H NMR spectral analysis, luminescence lifetime measurements, and density functional theoretical calculations were also performed.

  10. Assessment of the. pi. -acceptor capability of selected ligands based on the photoelectron spectra of ruthenium ammine complexes

    Shepherd, R. E.; Proctor, A.; Henderson, W.W.; Myser, T.K.


    ESCA spectra have been recorded for a series of Ru/sup II/ and Ru/sup III/ ammine complexes of general formula ((NH/sub 3/)/sub 5/RuL)X/sub n/ (X/sup -/ = PF/sub 6//sup -/, Cl/sup -/). Binding energy regions of the C/sub 1s/, Ru/sub 3d3/s/, and Ru/sub 3d5/s/, and Ru/sub 3p3/2/ photopeaks were studied. Binding energies were determined by using nonlinear-least-squares curve fitting. equal to the binding energy difference for (C/sub 1s/ - Ru/sub 3d5/2/) has been used to assign a fractional increase in charge at the Ru/sup II/ center when L = a series of ..pi..-acceptor ligands: N-methylpyrazinium (CH/sub 3/pz/sup +/), CO dimethyl acetylenedicarboxylate ester (dmad), CO, pyrazine (pz), pyridine (py), and CH/sub 3/CN. Authentic Ru/sup II/ and Ru/sup III/ oxidation states were assumed for (Ru(en)/sub 3/)ZnCl/sub 4/, = 5.1 eV, and (Ru(NH/sub 3/)/sub 6/)Cl/sub 3/, = 2.5 eV, respectively. The ..pi..-acceptor order and effective Ru oxidation state were determined to be as follows: CH/sub 3/pz/sup +/, 3.01 > CO, 2.88 > dmad, 2.73 > pz, 2.51 > CH/sub 3/CN, 2.31 > py, 2.20. was also found to be linear in the value of E/sub 1/2/ for the (NH/sub 3/)/sub 5/RuL/sup 3+/2+/ couple. ..pi..-Donor ligands exhibit little influence on for Ru/sup III/ derivatives; = 2.4 +/- 0.1 eV for 3,5-dimethylpyrazole, 4-(dimethylamino)pyridine, and 4-aminopyridine.

  11. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    Endo, Koji; Grubbs, Robert H.


    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis. PMID:21563826

  12. 铁络合物催化类Fenton氧化研究进展%Progress in the research on iron complex catalyzed Fenton-like oxidation

    郗丽娟; 曹天静; 李大鹏; 杨榕; 徐淑芬; 廖霞; 张瑛洁


    The progress in iron complex catalyzed Fenton-like oxidation is reviewed. Compared with iron,the iron complex has a higher catalytic activity to improve the removal rate of organic matter from water. The homogeneous Fenton-like catalyzed by iron complex may bring a problem of removing metallic ions in subsequent process, so the heterogeneous Fenton-like catalyzed by iron complex has a better future. The current research situation of the Fenton-like catalyzed by iron complex loaded on resin is introduced emphatically and the reactive species in the Fenton-like catalyzed by iron complex is discussed.%综述了铁络合物催化类Fenton氧化的研究进展.铁络合物与铁相比具有更高的催化活性,可提高水中有机物的去除效果.均相类Fenton存在后续金属离子的去除问题,因此铁络合物作为催化剂的多相催化类Fenton氧化具有更好的应用前景.重点介绍了高分子负载铁络合物催化类Fenton氧化降解水中有机物的研究现状及铁络合物催化类Fenton氧化的反应活性物种.

  13. Ab Initio MO Studies on the Reaction Mechanism for Carbonyl Insertion Catalyzed by Carbonyl Cobalt Complex


    Ab initio method, under the effective core potential(ECP) approximation at HF/LANL2DZ level, has been employed to study the reaction mechanism of the carbonyl insertion of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)3. The two reaction paths have been discussed. The calculated potential energy barriers for the carbonyl migration and the ethyl group migration are 105.0 kJ/mol and 39.17 kJ/mol, respectively. The results indicate that the reaction path via ethyl migration is more energetically favorable than that via carbonyl insertion.

  14. Bis(ortho)-Chelated Bis(phosphanyl)aryl Ruthenium(II).Complexes Containing an h1 -P-Monodentate or m -BridgingP,h1-P' Bonded R—PCHP Arene Ligand, 1-R-3,5(CH2PPh2)2C2H2 [R= H, Br, or, Si(n-CH2CH2C2F17)3]—Cyclometalation Reaction Intermediates and Potential Catalysts for Use in Fluorinated Biphasic Systems

    Koten, G. van; Dani, P.; Richter, B.; Klink, G.P.M. van


    Mono- and binuclear ruthenium(II) complexes containing ligands derived from the meta-bis(phosphanyl)arene ligand 1-R-3,5-(CH2PPh2)2C6H3 [R-PCHP: R = H (5), Br (3), or Si(n-CH2CH2C8F17)3 (4)] have been synthesized and fully characterized. On reaction of equimolar amounts of the ruthenium starting mat

  15. Synthesis, interaction with double-helical DNA and biological activity of the water soluble complex cis-dichloro-1,2-propylenediamine-N,N,N',N'-tetraacetato ruthenium (III) (RAP).

    Vilaplana, Rosario A; Delmani, Fátima; Manteca, Consolación; Torreblanca, José; Moreno, Javier; García-Herdugo, Gregorio; González-Vílchez, Francisco


    The effects exerted by the new complex cis-dichloro-1,2-propylenediaminetetraacetato ruthenium (III), H[RuCl(2)(PDTA-H(2))] [1, RAP], on DNA and cultured tumor cells (ovarian carcinoma TG cell line) were studied. The comparative study of circular dichroism (CD) spectra obtained from DNA and RAP-DNA system evidences the interaction of the complex with DNA. Compound 1 also interacted with tumor TG cells to slow their proliferation rate. BrdU incorporation was enhanced in cells treated with compound 1, as evidenced by a single-cell electrophoresis method (comet assay), in accordance with RAP-induced DNA damage. DNA migration of compound 1-treated cells was similar to that induced by noxious agents other than cross-linking chemicals. The stability of [RuCl(2)(PDTA-H(2))]-DNA binding is suggested by the high degree of damage that persisted after removal of compound 1 from the culture medium.

  16. Complexes of ruthenium(II) with bpmRe(CO) sub 3 Cl and HAT(Re(CO) sub 3 Cl) sub 2 as ligands: Syntheses and redox and luminescence properties

    Sahai, R.; Rillema, D.P.; Shaver, R.; Van Wallendael, S.; Jackman, D.C.; Boldaji, M. (Univ. of North Carolina, Charlotte (USA))


    A series of mixed-metal complexes containing ruthenium and rhenium are reported. The new complexes are ((bpy)Ru-(bpmRe(CO){sub 3}Cl){sub 2})(PF{sub 6}){sub 2}, ((bpy){sub 2}RuHAT(Re(CO){sub 3}Cl){sub 2})(PF{sub 6}){sub 2}, and (Ru(bpmRe(CO){sub 3}Cl){sub 3})(PF{sub 6}){sub 2}. Optical transitions in the visible-uv spectrum are dominated by the presence of the ruthenium heterocycles that have absorption coefficients for the low-energy transition 1 order of magnitude greater than that of the rhenium chromophore. The low-energy transition blue-shifts in the series ((bpy){sub 2}Ru(bpmRe(CO){sub 3}Cl)){sup 2+} (558 nm) < ((bpy)Ru(bpmRe(CO){sub 3}Cl){sub 2}){sup 2+} (531 nm) < (Ru(bpmRe(CO){sub 3}Cl){sub 3}){sup 2+} (501 nm). Polarographic half-wave potentials of the metal-centered oxidations and the bridging-ligand reductions shift positively as the number of Re(CO){sub 3}Cl units increase. The E{sub {1/2}} values for the ((bpy){sub n}Ru(bpmRe(CO){sub 3}Cl){sub 3-n}){sup 2+/+} couple in the series with n = 0-2 were -0.1, -0.33, and -0.41 V vs SSCE, respectively. Two complexes ((bpy)Ru(bpmRe(CO){sub 3}Cl){sub 2}){sup 2+} and ((Ru-(bpmRe(CO){sub 3}Cl){sub 3})){sup 2+}, were found to luminesce weakly at room temperature in acetonitrile with lifetimes of 942 and 847 ns, respectively. In many respects, the mixed-metal complexes are shown to behave as if the bpmRe(CO){sub 3}Cl and HAT(Re(CO){sub 3}Cl){sub 2} chromophores are ligands coordinated to ruthenium(II). 17 refs., 8 figs., 4 tabs.

  17. Photocatalytic splitting of CS2 to S8 and a carbon-sulfur polymer catalyzed by a bimetallic ruthenium(II) compound with a tertiary amine binding site: toward photocatalytic splitting of CO2?

    Livanov, Konstantin; Madhu, Vedichi; Balaraman, Ekambaram; Shimon, Linda J W; Diskin-Posner, Yael; Neumann, Ronny


    The catalytic photocleavage of CS(2) to S(8) and a (C(x)S(y))(n) polymer with visible light using a dinuclear ruthenium(II) compound with a bipyridine units for photoactivity and a vicinal tertiary amine binding site for CS(2) activation was studied. The catalyst was characterized by X-ray diffraction, (1)H NMR, and (13)C NMR, ESI-MS and elemental analysis. CS(2) photocleavage was significant (240 turnovers, 20 h) to yield isolable S(8) and a (C(x)S(y))(n) polymer. A mononuclear catalyst or one without an amine binding site showed significantly less activity. XPS of the (C(x)S(y))(n) polymer showed a carbon/sulfur ratio ∼1.5-1.6 indicating that in part both C-S bonds of CS(2) had been cleaved. Catalyst was also included within the polymer. The absence of peaks in the (1)H NMR verified the (C(x)S(y))(n) nature of the polymer, while (13)C NMR and IR indicated that the polymer had multiple types of C-S and C-C bonds.

  18. Synthesis and characterization of novel heteroleptic ruthenium sensitizer for nanocrystalline dye-sensitized solar cells

    Sivakumar, R.; Marcelis, A.T.M.; Anandan, S.


    A novel heteroleptic ruthenium complex of the type [Ru(bpin)(dcbpyH2)Cl]Cl (where bpin is 2,6-bis(pyrazol-1-yl)isonicotinic acid and dcbpyH2 is 4,4'-dicarboxy-2,2'-bipyridine) was synthesized and characterized for tuning the LUMO level of the ruthenium sensitizer to achieve greater stabilization in

  19. Studies on the Displacement Reaction of Trialkylaluminum with Ethylene Catalyzed by Nitrogen Chelate Cobalt Complexes


    The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature and cobalt complexes containing different ligand on catalyst performance has been investigated.

  20. Baeyer-Villiger oxidation of ketones with hydrogen peroxide catalyzed by Sn-aniline complex

    Qing Hua Zhang; Shou Feng Wang; Zi Qiang Lei


    Sn-aniline complex was prepared by a simple procedure. Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.

  1. Chiral-at-Metal Rh(III) Complex-Catalyzed Decarboxylative Michael Addition of β-Keto Acids with α,β-Unsaturated 2-Acyl Imidazoles or Pyridine.

    Li, Shi-Wu; Gong, Jun; Kang, Qiang


    A newly prepared chiral-at-metal Rh(III) complex-catalyzed, highly efficient enantioselective decarboxylative Michael addition of β-keto acids with α,β-unsaturated 2-acyl imidazoles or pyridine has been developed, affording the corresponding adducts in 94-98% yield with up to 96% enantioselectivity. This protocol exhibits remarkable reactivity, as the complex with a Rh(III) loading as low as 0.05 mol % can catalyze the decarboxylative Michael addition on a gram scale without loss of enantioselectivity.

  2. Studies on the Epoxidation of Styrene with Hydrogen Peroxide Catalyzed by MCM-41 Supported Co(II) Phenanthroline Complex


    @@ The epoxide is a kind of versatile intermediate for manufacture of a wide variety of fine chemicals. The goal of modem efficient catalytic methods is to produce desired compounds with high yield, selectivity, low cost, safety, operational simplicity and more importantly environmentally benign manner. However, there are various oxidants, which are often hazardous or expensive, being used for both laboratory and industrial epoxidation. Hydrogen peroxide (30 wt%) solution is thought as one of the ideal oxidants because water is a sole theoretical side product. Meanwhile the epoxidation of styrene is a typical one among olefins. Here, the performance of styrene epoxidation was studied with hydrogen peroxide solution catalyzed by Co(Ⅱ) phenanthroline complex encapsulated in supercages of MCM-41.

  3. Studies on the Epoxidation of Styrene with Hydrogen Peroxide Catalyzed by MCM-41 Supported Co(II) Phenanthroline Complex

    LOU; JianFang


    The epoxide is a kind of versatile intermediate for manufacture of a wide variety of fine chemicals. The goal of modem efficient catalytic methods is to produce desired compounds with high yield, selectivity, low cost, safety, operational simplicity and more importantly environmentally benign manner. However, there are various oxidants, which are often hazardous or expensive, being used for both laboratory and industrial epoxidation. Hydrogen peroxide (30 wt%) solution is thought as one of the ideal oxidants because water is a sole theoretical side product. Meanwhile the epoxidation of styrene is a typical one among olefins. Here, the performance of styrene epoxidation was studied with hydrogen peroxide solution catalyzed by Co(Ⅱ) phenanthroline complex encapsulated in supercages of MCM-41.  ……

  4. Z-Selective Olefin Metathesis Processes Catalyzed by a Molybdenum Hexaisopropylterphenoxide Monopyrrolide Complex

    Flook, Margaret M.; Jiang, Annie J.; Schrock, Richard R.; Müller, Peter; Hoveyda, Amir H.


    The molybdenum-based monoaryloxide monopyrrolide (MAP) species, Mo(NAd)(CHCMe2Ph)(C4H4N)(HIPTO) (2a), which contains “small” imido (Ad = 1-adamantyl) and “large” aryloxide (HIPTO = O-2,6(2,4,6-i-Pr3C6H2)C6H3) ligands, catalyzes Z-selective metathesis reactions as a consequence of intermediate metallacyclobutane species not being able to have a (anti) substituent pointing toward the HIPTO group. ROMP of dicarbomethoxynorbornadiene (DCMNBD) with 2% 2a in toluene leads to >99% cis and >99% syndiotactic poly(DCMNBD), while ROMP of cyclooctene and 1,5-cyclooctadiene (300 equiv)with initiator 2a leads to poly(cyclooctene) and poly(cyclooctadiene) that have cis contents of >99%; all are previously unknown microstructures. Z-selectivity is also observed in the metathesis of cis-4-octene and cis-3-hexene by initiator 2a to give cis-3-heptene. PMID:19462947

  5. Local bonding and atomic environments in Ni-catalyzed complex hydrides.

    Graetz, J; Chaudhuri, S; Salguero, T T; Vajo, J J; Meyer, M S; Pinkerton, F E


    The local bonding and atomic environments in the Ni-catalyzed destabilized system LiBH4/MgH2 and the quaternary borohydride-amide phase Li3BN2H8, were studied by x-ray absorption spectroscopy. In both cases the Ni catalyst was introduced as NiCl2 and a qualitative comparison of the Ni K-edge near-edge structure suggests the Ni2+ is reduced to primarily Ni0 after ball milling. The extended fine structure of the Ni K edge indicates that the Ni is coordinated by approximately 3 boron atoms with an interatomic distance of approximately 2.1 A and approximately 11 Ni atoms in a split shell at around 2.5 and 2.8 A. These results, and the lack of long-range order, suggest that the Ni is present as a disordered nanocluster with a local structure similar to that of Ni3B. In the fully hydrogenated phase of LiBH4/MgH2 a small amount Mg2NiHx was also present. Surface calculations performed using density functional theory suggest that the lowest kinetic barrier for H2 chemisorption occurs on the Ni3B(100) surface.

  6. Enantioselective reduction of ketones and imines catalyzed by (CN-box)Re(V)-oxo complexes.

    Nolin, Kristine A; Ahn, Richard W; Kobayashi, Yusuke; Kennedy-Smith, Joshua J; Toste, F Dean


    The development and application of chiral, non-racemic Re(V)-oxo complexes to the enantioselective reduction of prochiral ketones is described. In addition to the enantioselective reduction of prochiral ketones, we report the application of these complexes to 1) a tandem Meyer-Schuster rearrangement/reduction to access enantioenriched allylic alcohols and 2) the enantioselective reduction of imines.

  7. Olefin Ring Closing Metathesis and Hydrosilylation Reaction in Aqueous Medium by Grubbs Second Generation Ruthenium Catalyst

    The Grubbs second generation ruthenium catalyst was shown to catalyze various olefin ring closing metathesis and hydrosilylation reactions in aqueous medium. Reactions proceeded in pure water without any additives or co-solvents, in a short period of time. We found that inhomogen...

  8. Metal-catalyzed cycloisomerization as a powerful tool in the synthesis of complex sesquiterpenoids.

    Stathakis, Christos I; Gkizis, Petros L; Zografos, Alexandros L


    Covering: up to 2015Sesquiterpenoids are consistently attracting the interest of the scientific community due to their promising clinical profile as therapeutic agents. Cycloisomerization of enynes and dienes is a powerful tool in the hands of organic chemists to access them. In the last 20 years the field has witnessed remarkable advances, especially by revealing the capability of platinum and gold complexes to initiate such reactions. Nowadays, cycloisomerizations continue to enrich our knowledge with atom-economical routes and impressive cascades to reach more complex molecules. The current review covers the basic mechanistic aspects of metal catalysis in cycloisomerization reactions and their progress to the synthesis of selected complex sesquiterpenoids.

  9. Synthesis, crystal structures and reactivity of copper(I) amidate complexes with aryl halides: insight into copper(I)-catalyzed Goldberg reaction.

    Liu, Xinfang; Zhang, Songlin; Ding, Yuqiang


    In this paper, copper(I) amidate complexes (2-3), proposed intermediates in copper-catalyzed Goldberg reaction, have been prepared and characterized by elemental analysis, IR, (1)H NMR and X-ray crystallography. Ancillary ligand bis(diphenylphosphino)ferrocene (dppf) has contributed greatly to the stability of the copper-amidate complexes due to its strong chelating ability and weak intermolecular interactions. Thermal gravimetric analyses are carried out to determine the thermal competency of complexes 2-3 as the intermediates of the high-temperature Goldberg reactions. Reaction of complexes 2 and 3 with aryl halides generates the N-arylation products 5-8, accompanied by the formation of a copper(I) complex Cu(dppf)X (X = I or Br) 4, which has been determined by LC-MS analysis. These results provide new evidence for the mechanism of copper(I)-catalyzed Goldberg reaction.

  10. Synthesis of bis(indolyl) methanes catalyzed by Schiffbase-Cu(Ⅱ) complex

    Yong Lei Yang; Ning Ning Wan; Wen Ping Wang; Zheng Feng Xie; Ji De Wang


    Schiff base-Cu(Ⅱ) complex is found to be an effective catalyst for the condensation reaction of indole with aldehydes using ethanol as the solvent. The characterization of the catalysts was carried out using XRD and FT-IR.

  11. Nickel-catalyzed proton-deuterium exchange (HDX) procedures for glycosidic linkage analysis of complex carbohydrates

    The structural analysis of complex carbohydrates typically requires the assignment of three parameters: monosaccharide composition, the position of glycosidic linkages between monosaccharides, and the position and nature of non-carbohydrate substituents. The glycosidic linkage positions are often de...

  12. Octahedral Complexes with Predetermined Helical Chirality: Xylene-Bridged Bis([4,5]-pineno-2,2'-bipyridine) Ligands (Chiragen[o-, m-, p-xyl]) with Ruthenium(II).

    Mürner, Hansruedi; von Zelewsky, Alex; Stoeckli-Evans, Helen


    Tetradentate ligands are obtained by joining two optically active [4,5]-pineno-2,2'-bipyridine molecules in a stereoselective reaction, where two new stereogenic centers are created. These ligands are new members of the chiragen family that form OC-6 complexes with predetermined helical chirality. Ru(II) complexes with 4,4'-dimethyl-2,2'-bipyridine occupying the remaining coordination sites have been synthesized with all three new ligands. Characterization of the ruthenium complexes by NMR spectroscopy confirm C(2)-symmetric structures in solution. CD spectra show that the complexes are composed of only one helical diastereomer with the expected absolute configurations. In addition, a strong chiral amplification is observed, if precursors of low enantiomeric purity are used. This is due to the inability of ligands that are heterochiral in the two bpy moieties to coordinate to one center. X-ray structural data were obtained for the complex Delta-[RuCG[o-xyl](4,4'-DMbpy)](PF(6))(2). Crystal data (Mo Kalpha, 298 K): trigonal, space group R3, a = 52.986(4) Å, c = 10.545(1) Å, V = 25639(4) Å(3), Z = 18, R1 = 0.087, and wR2 = 0.0986 for 2609 observed reflections.

  13. Theoretical studies on N-O or N-N bond formation from aryl azide catalyzed by iron(II) bromide complex.

    Li, Juan; Zhang, Qi; Zhou, Lixin


    DFT calculations have been carried out to study the reaction mechanism on N-O or N-N bond formation from aryl azide catalyzed by iron(II) bromide complex. A favorable reaction pathway is proposed to account for the construction of the core structure of 2H-indazoles or 2,1-benzisoxazoles.

  14. Potassium ferro-cyanide trihydrate complex catalyzed one-pot synthesis of 2-phenylimidazo [4,5-f] [1,10] phenanthroline

    Syed Shahed Ali


    Various 2-phenylimidazo [4,5-f] [1,10] phenanthrolines were synthesized from potassium ferro-cyanide trihydrate (KFCT) complex catalyzed three component reaction of 1,10-phenanthroline-5,6-dione, aromatic aldehydes and ammonium acetate at room temperature in excellent isolated yield. This is a simple and straight forward, high yielding, not involving any hazardous or expensive catalyst method.

  15. Synthesis of Mixed-ring Zirconocene Complexes Containing Alkenyl Group and Ethylene Polymerization Catalyzed with Them

    钱延龙; 孙俊全; 等


    Four new mixed-ring zirconium complexes,[CH2=CH(CH2)n·C5H4](RC5H4)ZrCl2[n=1,R=CH3OCH2CH2(3);n=2,R=CH3OCH2CH2(4);n=2,R=Me3Si(5);n=2,R=allyl(6)],have been prepared by the reaction of CH2=CH(CH2)nC5H4ZrCl3·DME[n=1(1);n=2(2)] with RC5H4Li.When activated with methylaluminoxane(MAO),the catalytic activities of the above complexes in ethylene polymerization were tested.Complexes 5 and 6 show high activities similar to Cp2ZrCl2.Introduction of methoxyethyl group into Cp-ligand dramatically decreases the catalytic activities of complexes 3 and 4,which can be overcome by increasing the amount of MAO.For complex 5,the dependence of activity and molecular weight(Mη) on the Al/Zr ratio,the polymerization time(tp).polymerization temperature(Tp) and the polymerization solvent volume(V) was investigated.

  16. Ruthenium-Aryloxide Catalysts for Olefin Metathesis

    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.

  17. Catalytic Asymmetric Carbon-Carbon Forming Reactions Catalyzed Chiral Schiff Base-Metal Complexes

    Takanori; Tanaka; Masahiko; Hayashi


    1 Results In 1991, we disclosed the novel asymmetric catalysts prepared from chiral Schiff base and titanium alkoxide in the reaction of asymmetric silylcyanation of aldehydes (eq.1)[1]. Since our first report, chiral Schiff base-metal complex was proven to be efficient in a variety of asymmetric reactions. We reported the first example of enantioselective addition of diketene to aldehydes promoted by chiral Schiff base-titanium alkoxide complexes (eq.2)[2]. The products of this reaction have been cove...

  18. Nickel-catalyzed proton-deuterium exchange (HDX) for linkage analysis of complex carbohydrates

    The structural assignment of complex carbohydrates typically requires the analysis of at least three parameters: 1. composition; 2. linkage; and 3. substituents. These are often assigned on a small scale by gas chromatography/mass spectrometry (GC/MS). Linkage positions are determined by permethylat...

  19. Asymmetric Michael Reaction of Malononitrile Catalyzed by Chiral Ru(Ⅱ) Complex and Achiral Base

    MA Ya-Ping; XING Zhi-Kui; ZHU Jin; CUI Xin; CUN Lin-Feng; DENG Jin-Gen


    @@ Michael addition reactions represent one of the most important carbon-carbon bond forming reactions in modern synthetic organic chemistry. [1 ~3] We achieved catalytic enantioselective Michael addition reactions of malononitrile with chiral vicinal diamine-Ru(Ⅱ) complex in the presence of achiral base. High yields and moderate ee were observed.


    Bijayashree Samal; Prafulla K.Sahoo


    Nano-sized polyacrylonitrile (PAN) particles were prepared under the catalytic effect of in situ developed CoCl2/EDTA complex with ammonium persulfate as the initiator in the absence of any added emulsifier.The emulsion polymerization was studied at varying concentrations of the initiator,monomer,complex and solvent over a temperature range of 30-70℃.The overall activation energy(Ea,49.79 kJ/mol),energy of dissociation of initiator(Ed,82.68kJ/mol),number of micelles(0.163 × 1018)and the viscosity average molecular weight of the polymer were computed.The distribution of particle sizes was determined by transmission electron microscopy(TEM).It was found that the oil-in-water polymerization was stabilized by the presence of the CoCl2/EDTA in situ complex reducing the particle size into the nano order.The average diameters of PAN nano particles,obtained by TEM,were in the range of 50-150 nm at the maximum conversion.The experimental particle size was mainly dependent on the concentration of the complex and temperature.