- Catalytic transfer hydrogenation of ketones catalyzed by orthometalated ruthenium(III) 2-(arylazo)phenolate complexes containing triphenylarsine
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Air-stable, mononuclear orthometalated ruthenium(III) 2-(arylazo)phenolate complexes of the general composition [RuX(AsPh3)2(L)] (X = Cl or Br; L = CNO donor of the 2-(arylazo)phenolate ligands) have been synthesized and characterized by IR, UV-vis, and EPR as well as by elemental analysis. One of the complexes [RuBr(AsPh3)2(azo-OMe)] was structurally characterized by X-ray analysis and was found to be an efficient catalyst for the transfer hydrogenation of ketones with excellent conversion in the presence of isopropanol at 80°C in 1 h.
- Venkatachalam, Galmari,Ramesh, Rengan
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- The Catalytic Reduction of Aldehydes and Ketones with 2-Propanol over Silica-Supported Zirconium Catalyst
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Reduction of aldehydes and ketones with 2-propanol proceeded efficiently over silica-supported zirconium catalyst, and the correspondimg alcohols were obtained in high yields.In the reduction of aldehyde, the acetalization did not occur and the side reaction, the aldol condensation, was inhibited.
- Inada, Kazushige,Shibagaki, Makoto,Nakanishi, Yukio,Matsushita, Hajime
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- Hydroboration. 97. Synthesis of new exceptional chloroborane-Lewis base adducts for hydroboration. Dioxane-monochloroborane as a superior reagent for the selective hydroboration of terminal alkenes
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Several less volatile oxygen-containing Lewis bases, such as tert-butyl methyl ether, dioxane, anisole, ethyl acetate, β-chloroethyl ether, and monoglyme, were examined as prospective mono- and dichloroborane carriers. Dioxane, ethyl acetate, and β-chloroethyl ether form relatively stable boron trichloride adducts, but the boron trichloride adduct of monoglyme is not very stable and must be used immediately. On the other hand, tert-butyl methyl ether and anisole fail to form stable boron trichloride adducts and the corresponding ether-cleaved products are obtained. Among the selected oxygen-containing Lewis bases, only dioxane forms stable and reactive mono- and dichloroborane adducts. Monoglyme and β-chloroethyl ether give stable dichloroborane adducts requiring excess of diborane. Convenient methods for the preparation of mono- and dichloroborane adducts of dioxane from dioxane-BCl3 and NaBH4 in the presence of catalytic amounts of tri- or tetraglyme were developed. The dioxane-monochloroborane adduct hydroborates representative olefins cleanly and rapidly. The corresponding alcohols were obtained in quantitative yields after oxidation. Also, the hydroboration of several terminal olefins with dioxane-monochloroborane were highly regioselective and the primary alcohols were obtained almost exclusively (>99.5%), after oxidation. Accordingly, dioxane-monochloroborane should serve as a reagent of choice for such hydroborations. The dioxane-dichloroborane adduct showed remarkable selectivity toward 2-substituted terminal olefins, such as 2-methyl-1-butene and β-pinene, when compared to simple terminal and hindered olefins, giving a unique tool for selective hydroborations. Dichloroborane adducts of monoglyme and β-chloroethyl ether also showed high reactivity, even at room temperature, toward simple unhindered olefins. However, hydroboration of hindered olefins is slow and requires either higher temperatures or the addition of 1 equiv of boron trichloride to liberate free dichloroborane, as in the case of the previously known dichloroborane adducts of methyl sulfide and diethyl ether.
- Kanth,Brown
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- Mont-K10 Supported Fe(II) Schiff-Base Complex as an Efficient Catalyst for Hydrogenation of Ketones
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Abstract: A new Fe(II) Schiff base complex anchored on mont-K10 (Fe@imine-mont-K10) was synthesized and extensively characterized by FTIR, powder X-ray diffraction, SEM–EDX, TEM, ESR, X-ray photoelectron spectroscopy (XPS), BET surface area measurement, solid state 29Si NMR and ICP-AES analysis. The catalytic activity of the complex was investigated for hydrogenation of ketones. The results indicated that it exhibited good catalytic activity for hydrogenation of aromatic as well as aliphatic ketones in i-PrOH/CH3CN (1:1) using Na-i-OPr as base at 80?°C resulting in moderate to excellent isolated yields (51–99%) of their corresponding products. The catalyst shows good reusability. Graphical Abstract: [Figure not available: see fulltext.].
- Sultana, Samim,Borah, Geetika,Gogoi, Pradip. K.
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- Ruthenium(II) complexes containing quinone based ligands: Synthesis, characterization, catalytic applications and DNA interaction
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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.
- Anitha,Manikandan,Endo,Hashimoto,Viswanathamurthi
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- Stereoselective Oxidative Coupling and Asymmetric Hydride Reduction related to (-)-(S)-10,10'-Dihydroxy-9,9'-biphenanthryl
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Oxidative coupling of 9-phenanthrol (1) with a (-)-(R)-1,2-diphenylethylamine-copper(II) complex yielded (-)-(S)-10,10'-dihydroxy-9,9'-biphenanthryl (2) (98percent optical purity); the chiral aluminium hydride reagent modified by (2) was found to exhibit enantioface selectivity towards a variety of prochiral carbonyl compounds.
- Yamamoto, Koji,Fukushima, Hitoshi,Nakazaki, Masao
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- Ruthenium(III) chalconate complexes containing PPh3/AsPh3 and their use as catalysts
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Ruthenium(III) complexes of the type [RuX(EPh3)(L)2] (X = Cl or Br; E = P or As; L = 2-hydroxychalcone) have been prepared by reacting [RuX3(EPh3)3] with 2-hydroxychalcones in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (infrared, electronic, electron paramagnetic resonance, and mass) methods. Redox potential studies of the complexes have been carried out to elucidate the electronic structure, geometry, and electrochemical features. On the basis of data obtained, an octahedral structure has been assigned for all the complexes. The new complexes exhibit catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide as co-oxidant and they were also found to be efficient catalyst for the transfer hydrogenation of ketones.
- Muthukumar,Viswanathamurthi,Prabhakaran,Natarajan
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- Rhodium(I) complexes of β-diketonates and related ligands as hydrosilylation catalysts
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The complexes (O-O)Rh(CH2CH2)2 ((O-OH)=FcC(O)CH2C(O)CH3, PhC(O)CH2C(O)CH3, 1,2-(CH3CO)(OH)C6H4, 3-benzoyl-(+)-camphor) are catalysts for the hydrosilylation of PhMeCO with Ph2SiH2.The optical yield from the reaction catalyzed by the camphor derivative is too low to measure.Only low optical yields (max 8.7percent e.e.) are obtained from the same reaction by using similar in situ catalysts with ligands prepared from (+)-PhCH(Me)NH2.Bases such as H- and PhCH(Me)NH- catalyze the hydrosilylation reaction in the absence of rhodium salts, but only low optical yields are obtained.Ph2SiH2 reacts with 2-cyclohexen-1-one under these conditions and the mode of reaction depends on the reaction conditions.
- Cullen, William R.,Wickenheiser, Eugene B.
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- Syntheses of enantiopure aliphatic secondary alcohols and acetates by bioresolution with lipase B from candida antarctica
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The lipase B from Candida antarctica (Novozym 435, CALB) efficiently catalyzed the kinetic resolution of some aliphatic secondary alcohols: (±)-4-methylpentan- 2-ol (1), (±)-5-methylhexan-2-ol (3), (±)-octan-2-ol (4), (±)-heptan-3-ol (5) and (±)-oct-1- en-3-ol (6). The lipase showed excellent enantioselectivities in the transesterifications of racemic aliphatic secondary alcohols producing the enantiopure alcohols (>99% ee) and acetates (>99% ee) with good yields. Kinetic resolution of rac-alcohols was successfully achieved with CALB lipase using simple conditions, vinyl acetate as acylating agent, and hexane as non-polar solvent.
- Ferreira, Hercules V.,Rocha, Lenilson C.,Severino, Richele P.,Porto, Andre L. M.
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- Heterogeneous catalytic conversions with hydrous SnO2
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Hydrous Tin oxide (SnO2) was prepared by the action of conc. HNO3 on tin metal. It was found to catalyse transesterification, amidation and transferhydrogenation in the vapour phase significantly. There was no loss in activity for at least 50 runs of the reactions.
- Waghoo, Gulzar,Jayaram,Joshi
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- Enzymatic kinetic resolution of aliphatic sec-alcohols by LipG9, a metagenomic lipase
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Bioprospection for new enantioselective enzymes for application in organic synthesis is a prominent area of investigation in biocatalysis. In this context, here we present the evaluation of an immobilized lipase isolated from a metagenomic library (LipG9) for the enzymatic kinetic resolution (EKR) of aliphatic sec-alcohols, which are still challenging substrates, since low enantioselectivity values are usually observed for these resolutions. LipG9 was successfully employed in EKR of aliphatic alcohols, which were resolved with satisfactory conversions (19-59%) and enantiomeric excesses for alcohols (26-88%) and esters (30-96%) by transesterification reactions, demonstrating that its performance is equal to or better than commercially available enzymes for the same reaction.
- Bandeira, Pamela T.,Alnoch, Robson C.,De Oliveira, Alfredo R.M.,De Souza, Emanuel M.,De O.P., Fábio,Krieger, Nadia,Piovan, Leandro
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- Transfer hydrogenation of aryl ketones with half-sandwich RuII complexes that contain chelating diamines
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In a comparative study, half-sandwich complexes of RuII (1) with pyridine-based chelating diamine [NN = 2-aminomethylpiperidine (ampi), a; 2-aminomethylpyridine (ampy), b; 8-aminoquaniline (aquan), c; 4,4'-dimethyl-2,2'-bipyridine (dbipy), d; 2,2'-bipyridine (bipy), e] or amine amide (Ts-ampi, 2a) were synthesized by cleavage of [{(η6-p- cymene)Ru(μ-Cl)Cl}2] dimer and the resulting complexes were screened for their efficiency in the transfer hydrogenation (TH) of acetophenone in 2-propanol (IPA) at 82 °C or in water in HCOONa. Among the complexes, cationic 1a, neutral 2a, and 1b, which bear ampi and ampy, were the most effective in terms of catalyst performance (turnover frequency values: 198, 6000, 23 h-1, respectively). Copyright
- Tuerkmen, Hayati,Cetinkaya, Bekir,Kani, Ibrahim
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- Transfer hydrogenation of ketones by ceria-supported Ni catalysts
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Ni-loaded CeO2, prepared by H2-reduction of NiO-loaded CeO2, was found to be an effective and recyclable catalyst for the transfer hydrogenation of aliphatic and aromatic ketones by 2-propanol to the corresponding alcohols under base free conditions with low catalyst loading (1-3 mol%).
- Shimura, Katsuya,Shimizu, Ken-Ichi
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- SODIUM HYDROXIDE-ACTIVATED CATALYST OF COLLOIDAL NICKEL BORIDE FOR ATMOSPHERIC HYDROGENATION OF KETONES AND ALDEHYDES
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Addition of sodium hydroxide to colloidal nickel boride in ethanol resulted in a marked enhancement of its catalytic activity for atmospheric hydrogenation of acetone at 30 deg C by a factor of more than 20.Other ketones and aldehydes with bulky substituents were smoothly hydrogenated by the activated colloidal catalyst.
- Nakao, Yukimichi,Fujishige, Shoei
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- Hydroxyl group effect in novel NNN type pyridine based ruthenium (II) complex for the transfer hydrogenation of ketones
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The new NNN type pyridine ligands were prepared by using low cost and readily available starting materials and metalated with RuCl2(PPh3)3 to obtain ruthenium(II) complexes. All structures were illuminated by NMR, HRMS, and FT-IR spectroscopy. The complexes exhibited good catalytic activity in transfer hydrogen reaction of ketones and it was found that a hydroxyl group on β-position of the pyridine ring had a dramatic effect on the catalyst efficiency.
- Sahin, Irfan,Emir, Sedat,Ispir, Esin,Karakaya, Idris,Gumus, Selcuk,Ulusoy, Mahmut,Karabuga, Semistan
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- Thexylchloroborane-Methyl Sulfide. A Selective Monohydroborating agent with Exceptional regioselectivity
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Thexylchloroborane, readily prepared from 2,3-dimethyl-2-butene and monochloroborane-methyl sulfide in dichloromethane solution, hydroborates representative alkenes with excellent regioselectivity to afford thexylalkylchloroboranes.
- Brown, Herbert C.,Sikorski, James A.,Kulkarni, Surendra U.,Lee, Hsiupu D.
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- Acid-base bifunctional zirconium N-alkyltriphosphate nanohybrid for hydrogen transfer of biomass-derived carboxides
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Catalytic transfer hydrogenation (CTH) reactions are efficient transformation routes to upgrade biobased chemicals. Herein, we report a facile and template-free route to synthesize a series of heterogeneous nitrogen-containing alkyltriphosphonatemetal hybrids with enhancive Lewis acid and base sites, and their catalytic activity in converting biomass-derived carbonyl compounds to corresponding alcohols in 2-propanol. Particularly, a quantitative yield of furfuryl alcohol (FFA) was obtained from furfural (FUR) over organotriphosphate-zirconium hybrid (ZrPN) under mild conditions. The presence of Lewis basic sites adjacent to acid sites with an appropriate base/acid site ratio (1:0.7) in ZrPN significantly improved the yield of FFA. Mechanistic studies for the transformation of FUR to FFA with ZrPN in 2-propanol-d8 evidently indicate CTH reaction proceeding via a direct intermolecular hydrogen transfer route. It was also found that ZrPN could catalyze isomerization of C3-C6 aldoses to ketoses involving intramolecular hydrogen transfer in water.
- Li, Hu,He, Jian,Riisager, Anders,Saravanamurugan, Shunmugavel,Song, Baoan,Yang, Song
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- Montmorillonite supported (-)N-dodecyl-N-methyl ephedrenium borohydride: An efficient reducing agent
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The clay supported reagent reduces ketones under phase transfer conditions efficiently. A two fold activation of the carbonyl group - one by the Lewis acid sites on clay and the other by the β-hydroxy group of ephedreium moiety, ensures facile eductions -maintaining a fair degree of stereoselectivity in reducing some of the cyclic ketones. Asymmetric inductions of 1-9.7% were observed in case of some prochiral ketones.
- Sarkar,Rao
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- Hydroboration. 64. Effect of Structure on the Relative Reactivity of Representative Alkenes and Alkynes toward Hydroboration by Dibromoborane-Methyl Sulfide
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The relative reactivities of 22 alkenes and 5 alkynes toward hydroboration by dibromoborane-methyl sulfide (Br2BH*SMe2) have been determined in CH2Cl2 at 25 deg C by the competitive method.The data are compared and contrasted with those available on 9-borabicyclononane (9-BBN), disiamylborane (Sia2BH), and thexylchloroborane-methyl sulfide (ThxBHCl*SMe2).Br2BH*SMe2 exhibits a uniquely high selectivity toward an internal triple bond compared to a terminal triple or double bond, while the reverse is true with 9-BBN.Consequently, 1-octen-4-yne has been selectively converted to (4Z)-1,4-octadiene by hydroboration with Br2BH*SMe2, followed by protonolysis.The terminal double bond, on the other hand, is selectively hydroborated by 9-BBN.The far higher reactivity of Br2BH*SMe2 toward the C(CH3)=CH2 structure, as compared with the CH=CH2 structure makes possible the selective hydroboration of the 1,2-positions of 2-methyl-1,5-hexadiene; Sia2BH, on the other hand, is known to hydroborate the 5,6-positions selectively.Thus we have at hand several monofunctional hydroborating agents with widely different selectivities, making them highly useful for selective hydroborations for synthesis.
- Brown, Herbert C.,Chandrasekharan, J.
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- Coordination behavior of ligand based on NNS and NNO donors with ruthenium(III) complexes and their catalytic and DNA interaction studies
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Reactions of 2-acetylpyridine-thiosemicarbazone HL1, 2-acetylpyridine-4-methyl-thiosemicarbazone HL2, 2-acetylpyridine-4- phenyl-thiosemicarbazone HL3 and 2-acetylpyridine-semicarbazone HL4 with ruthenium(III) precursor complexes were studied and the products were characterized by analytical and spectral (FT-IR, electronic, EPR and EI-MS) methods. The ligands coordinated with the ruthenium(III) ion via pyridine nitrogen, azomethine nitrogen and thiolate sulfur/enolate oxygen. An octahedral geometry has been proposed for all the complexes based on the studies. All the complexes are redox active and display an irreversible and quasireversible metal centered redox processes. Further, the catalytic activity of the new complexes has been investigated for the transfer hydrogenation of ketones in the presence of isopropanol/KOH and the Kumada-Corriu coupling of aryl halides with aryl Grignard reagents. The DNA cleavage efficiency of new complexes has also been tested.
- Manikandan,Viswnathamurthi
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- Orderly Layered Zr-Benzylphosphonate Nanohybrids for Efficient Acid–Base-Mediated Bifunctional/Cascade Catalysis
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The development of functional metal–organic materials that are robust and active for bifunctional/cascade catalysis is of great significance. Herein, a series of mesoporous and orderly layered nanohybrids were synthesized for the first time through simple and template-free assembly of ortho-, meta-, or para-xylylenediphosphonates (o-, p-, or m-PhP) containing zirconium. It was found that m-PhPZr nanoparticles (20–50 nm) with mesopores centered at 7.9 nm and high Lewis acid–base site ratio (1:0.7) showed excellent performance under mild conditions (as low as 82 °C) in transfer hydrogenation of carbonyl compounds, including bioaldehydes and alcohols, with near quantitative yields and little Zr leaching. Isotopic labeling studies indicated the occurrence of direct hydrogen transfer rather than metal hydride route by bifunctional catalysis. Lewis acidic (Zr) and basic (PO3) centers of the heterogeneous catalyst were further revealed to play a synergistic role in one-pot cascade transformations, for example, of ethyl levulinate to γ-valerolactone and glucose to 5-hydroxymethylfurfural.
- Li, Hu,Fang, Zhen,He, Jian,Yang, Song
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- Synthesis and catalytic evaluation of ruthenium(II) benzhydrazone complex in transfer hydrogenation of ketones
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Synthesis of new air stable octahedral ruthenium(II) carbonyl complex bearing O, and N-bidentate benzhydrazone ligand is reported. It has been characterized by elemental analysis, spectral methods and single crystal X-ray diffraction method. The new catalyst has been effectively applied to the transfer hydrogenation reaction of various ketones using isopropanol as a solvent and KOH as a base at 82 °C and the maximum conversion is achieved up to 100%.
- Manikandan, Thimma Sambamoorthy,Saranya, Sundar,Ramesh, Rengan
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- ACTIVATION DE REACTIONS PAR LES POLYOXYDES D'ETHYLENE III. REDUCTIONS PAR L'EUTECTIQUE SODIUM-POTASSIUM
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Polyethylene oxides are efficient phase transfer catalysts which promote the reduction of CC, C=C bonds as well as aromatic substrates by the Na-K eutectic.Yields and general conditions of the reaction give it a generally useful synthetic value.
- Gaude, Didier,Goaller, Raymond Le,Luche, Jean-Louis,Pierre, Jean-Louis
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- A porous inorganic zirconyl pyrophosphate as an efficient catalyst for the catalytic transfer hydrogenation of ethyl levulinate to γ-valerolactone
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Catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) to γ-valerolactone (GVL) is an alluring reaction in the field of biomass catalytic conversion, but it normally depends on the consumption of H2. In this study, we report a porous Zr-containing inorganic pyrophosphate catalyst (ZrOPP), which was used as a catalyst for CTH of EL to GVL in the presence of isopropanol and characterized using FT-IR, py-FTIR, TGA, XRD, BET, XPS, ICP-AES, SEM, TEM, NH3-TPD, and CO2-TPD. We achieved a high yield of 94% GVL at 433 K for 11 hr. Furthermore, the ZrOPP has the trait of easy separation and could be reused more than five times without distinct decrease in activity and selectivity. In addition, this catalyst could also be applied to other catalytic hydrogenation reactions, such as those of cyclohexanone, acetophenone, 2-heptanone etc. Its outstanding performance was mainly ascribed to the acid sites from the Zr element and basic sites from phosphate groups interspersing on the surface of the catalyst.
- Wang, Jianjia,Wang, Ruiying,Zi, Huimin,Wang, Haijun,Xia, Yongmei,Liu, Xiang
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- Dioxane-monochloroborane: A new and highly reactive hydroborating reagent with exceptional properties
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(equation presented) Dioxane-monochloroborane was prepared by the reaction of dioxane and dioxane-BCl3 with diborane or NaBH4 in 98% purity. The adduct thus obtained is a liquid, 6.2 M in BH2Cl, stable indefinitely at either 0 or 25°C. The adduct hydroborates simple unhindered olefins to the corresponding dialkylchloroboranes within 0.5 h, while moderately hindered olefins take 1-4 h at room temperature. Hindered tetrasubstituted olefins rapidly hydroborate to the monoalkylchloroborane stage with further hydroboration slow. Regioselectivity studies of representative olefins reveal that this new reagent possesses selectivities similar to those from the monochloroborane-diethyl ether adduct. Consequently, dioxane-monochloroborane can readily substitute for the older hydroborating agents, BH3:THF and BH3:DMS.
- Kanth, Josyula V. B.,Brown, Herbert C.
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- Carbon‐supported Raney nickel catalyst for acetone hydrogenation with high selectivity
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Catalysts with high selectivity play key roles in green chemistry. In this work, a granular Raney Ni catalyst using carbon as support (Raney Ni/C) was developed by mixing phenolic resin with Ni-Al alloy, conducting carbonization at high temperature, and leaching with alkaline liquor. The as-prepared Raney Ni/C catalyst is suitable for use in fix-bed reactors. Moreover, it shows high activity and selectivity for catalytic acetone hydrogenation. For instance, at the reaction temperature of 120°C, the conversion of acetone can reach up to 99.9% and the main byproduct methyl isobutylcarbinol (MIBC) content can be diminished to 0.02 wt%. The Raney Ni/C may represent a new type of shaped Raney metal catalysts, which are important fix-bed catalysts in chemical industry.
- Lu, Shuliang,Wu, Jiajia,Peng, Hui,Chen, Yong
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- The application of tunable tridendate P-based ligands for the Ru(II)-catalysed transfer hydrogenation of various ketones
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Two novel versatile tridendate aminophosphine-phosphinite and phosphinite ligands were prepared and their trinuclear neutral ruthenium(II) dichloro complexes were found to be effective catalysts for the transfer hydrogenation of various ketones in excellent conversions up to 99% in the presence of 2-propanol/NaOH in 0.1M isopropanol solution. Particularly, [Ru3 (PPh2OC2H4)2N-PPh2 (η6-p-cymene)3Cl6] acts as an excellent catalyst giving the corresponding alcohols in excellent conversion up to 99% (turnover frequency ≤ 1176 h-1). A comparison of the catalytic properties of the complexes is also discussed briefly. Furthermore, the structures of these ligands and their corresponding complexes have also been clarified using a combination of multinuclear NMR spectroscopy, infrared spectroscopy and elemental analysis. 1H-13C HETCOR or 1H-1H COSY correlation experiments were used to confirm the spectral assignments.
- Meri, Nermin,Durap, Feyyaz,Aydemir, Murat,Baysal, Akn
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- Transfer hydrogenation of ketones catalysed by half-sandwich (η6-p-cymene) ruthenium(II) complexes incorporating benzoylhydrazone ligands
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Neutral half-sandwich η6-p-cymene ruthenium(II) complexes of general formula [Ru(η6-p-cymene)Cl(L)] (HL?=?monobasic O, N bidendate benzoylhydrazone ligand) have been synthesized from the reaction of [Ru(η6-p-cymene)(μ-Cl)Cl]2 with acetophenone benzoylhydrazone ligands. All the complexes have been characterized using analytical and spectroscopic (Fourier transform infrared, UV–visible, 1H NMR, 13C NMR) techniques. The molecular structures of three of the complexes have been determined using single-crystal X-ray diffraction, indicating a pseudo-octahedral geometry around the ruthenium(II) ion. All the ruthenium(II) arene complexes were explored as catalysts for transfer hydrogenation of a wide range of aromatic, cyclic and aliphatic ketones with 2-propanol using 0.1?mol% catalyst loading, and conversions of up to 100% were obtained. Further, the influence of other variables on the transfer hydrogenation reaction, such as base, temperature, catalyst loading and substrate scope, was also investigated.
- Mohan, Nanjan,Ramesh, Rengan
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- Half?Sandwich (η6?p?Cymene) Ruthenium(II) complexes bearing 5?Amino?1?Methyl?3?Phenylpyrazole Schiff base ligands: Synthesis, structure and catalytic transfer hydrogenation of ketones
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New (η6?p?cymene) ruthenium(II) complexes containing Schiff base ligands of the general composition [RuCl(η6?p?cymene)(L1?3)] have been synthesized. The complexes were characterized by analytical and spectral (FT?IR, UV–Vis, 1H NMR and 13C NMR) methods. The molecular structure of the representative complex [RuCl(η6?p?cymene)(L3)] 6 was determined by single crystal X?ray diffraction studies, revealing a pseudo-octahedral piano stool geometry around ruthenium(II) ion. Further, one of the complexes 6 was screened for their efficiency as a catalyst in the transfer hydrogenation of various ketones to alcohols in the presence of KOH and 2?propanol showed an excellent conversion up to 99%. Under the optimized conditions, the influence of base, reaction temperature and substrate scope was also reported.
- Ramesh, Madhan,Venkatachalam, Galmari
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- Ruthenium(II) complexes derived from 2-phenylthiazoline-4-carboxylic acid: Structure and catalytic activity for transfer hydrogenation reaction
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Piano-stool ([(p-cymene)Ru(thz)Cl], 2) and six-coordinated ([Ru(thz)2(PPh3)2], 3) ruthenium complexes derived from 2-phenylthiazoline-4-carboxylic acid (Hthz, 1) were synthesized for the first time, and fully characterized using conventional methods. Also, the molecular structure of complex 3 was determined using X-ray analysis. These complexes were evaluated as catalysts for transfer hydrogenation of carbonyl compounds in the presence of isopropyl alcohol and KOtBu. Complex 2 was found to be more active than 3 in transfer hydrogenation.
- Denizalt, Serpil,G?ke, Ayta Gürhan,en, Betül,etinkaya, Bekir
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- Synthesis and characterization of new ruthenium(III) complexes derived from fluoreneamine-based Schiff base ligands and their catalytic activity in transfer hydrogenation of ketones
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An easy and convenient synthesis of a new series of octahedral ruthenium(III) complexes bearing Schiff base ligands of general formula [RuCl2(EPh3)2(L)] (where E = P, As and L = O,N-donor Schiff bases) has been reported. The composition of all complexes has been unequivocally characterized by spectral (IR, UV-vis, EPR) and ESI-MS techniques. The substituted Schiff base ligands behave as bidentate O,N-donors and coordinate to ruthenium via the phenolic oxygen, the azomethine nitrogen. Complexes 1–6 have been proven to catalyze the transfer hydrogenation of linear, cyclic and aromatic ketones to their corresponding secondary alcohols in the presence of i-PrOH/KOH at 80 °C with conversion up to 99%. The effect of other variables on the transfer hydrogenation reaction such as solvent, base, and catalyst loading is also reported.
- Balasubramani, Kasturi,Nagalakshmi, Veerasamy,Nandhini, Raja,Venkatachalam, Galmari
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- Cycloruthenation of N-(naphthyl)salicylaldimine and related ligands: Utilization of the Ru-C bond in catalytic transfer hydrogenation
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Upon reaction with [Ru(PPh3)2(CO)2Cl2], N-(naphthyl)-4-R-salicylaldimines (R = OCH3, H, Cl; H2L1-H2L3) and 2-hydroxy-N-(naphthyl)naphthaldimine (H2L4) readily undergo cycloruthenation by C-H bond activation at the peri position to afford complexes of the type [Ru(PPh3)2(L)(CO)] (L = L1-L4). The crystal structures of the [Ru(PPh3)2(L)(CO)] (L = L1, L2, L4) complexes were determined and the structure of [Ru(PPh3)2(L3)(CO)] optimized by DFT calculations. The thermodynamics for the reaction of [Ru(PPh3)2(CO)2Cl2] with H2L2 to give [Ru(PPh3)2(L2)(CO)] were determined. All the complexes show intense absorptions in the visible and UV regions, which have been analyzed by TDDFT calculations. Cyclic voltammetry of the four cycloruthenated complexes showed two oxidations within the range 0.50-1.35 V versus SCE and a reduction at around -1.75 V versus SCE. The [Ru(PPh3)2(L)(CO)] (L = L1-L4) complexes were found to efficiently catalyze the transfer hydrogenation of carbonyl compounds.
- Dutta, Jayita,Richmond, Michael G.,Bhattacharya, Samaresh
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Read Online
- A ruthenium(II) bipyridine complex containing a 4,5-diazafluorene moiety: Synthesis, characterization and its applications in transfer hydrogenation of ketones and dye sensitized solar cells
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The ruthenium(II) complex [Ru(bpy)2L](PF6)2, where bpy is 2,2′-bipyridine and L is 1,5-dihydro-2-H-cyclopenta[1,2-b:5,4-b′]dipyridine-2-one, was synthesized from the reaction of cis-Ru(bpy)2Cl2·2H2O with L, and isolated as the hexafluorophosphate salt. The structure of L was unequivocally elucidated by single-crystal X-ray diffraction analysis. The new ruthenium(II) complex was thoroughly characterized by 1H and 13C NMR spectroscopy, along with FTIR, UV-Vis and LC MS/MS Triple Quadrupole Mass spectroscopy and elemental analysis. The catalytic activity of [Ru(bpy)2L](PF6)2 was tested in the transfer hydrogenation of various ketones in 2-propanol as both the solvent and hydrogen donor. The usage of [Ru(bpy)2L](PF6)2 for the formation of a dye sensitized solar cell is also presented.
- Baysal, Akin,Aydemir, Murat,Durap, Feyyaz,?zkar, Saim,Yildirim, Leyla Tatar,Ocak, Yusuf Selim
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Read Online
- Synthesis method of antioxidant 6PPD to reduce side reactions
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The present invention belongs to the field of fine chemical technology, relates to a method of continuous synthesis of adhesive antioxidant 6PPD. The patent of the present invention uses a precious metal catalyst to synthesize antioxidant 6PPD on a fixed bed, the precious metal catalyst is loaded into a fixed bed reaction device, nitrogen is filled with 0.1 ~ 0.5MPa pressure and replaces the entire high pressure reactor system, after the reaction system is replaced, the temperature rises, and the flow rate of hydrogen is 0.1 ~ 1L / min. Using 4-aminodiphenylamine and similar organic matter and methyl isobutyl methyl ketone and acetone as raw materials, the synthesis test of the antioxidant 6PPD using a precious metal catalyst was carried out. Compared with the existing precious metal kettle hydrogenation process, it has continuous operation, simple operation, avoids the catalyst loss caused by the use of powder catalyst due to filtration, and can reduce production costs; compared with the existing copper catalyst, due to the improvement of catalyst selectivity, NO MIBC dehydrogenation device can be added, saving energy consumption and having superiority.
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Paragraph 0016; 0018-0019
(2022/03/02)
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- Reduction of α,β-unsaturated carbonyl compounds and 1,3-diketones in aqueous media, using a raney ni-al alloy
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The treatment of α,β-unsaturated carbonyl compounds and 1,3-diketones with Raney Ni-Al alloy in aqueous media yielded as major reaction products the corresponding saturated alcohols and/or the corresponding hydrocarbons, in a complete transformation of the starting material.
- Simion, Cristian,Mitoma, Yoshiharu,Katayama, Yumi,Simion, Alina Marieta
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- Method for preparing alcohol compound through hydrogenation of carbonyl-containing compound
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The invention provides a method for preparing an alcohol compound through hydrogenation of a carbonyl-containing compound, the method comprises the following steps: firstly, contacting the carbonyl-containing compound with a nickel catalyst precursor to obtain a nickel-containing solution, then carrying out a contact reaction on the nickel-containing solution and hydrogen, converting the contained nickel into a nickel catalyst, and carrying out in-situ catalysis on the hydrogenation reaction of the carbonyl-containing compound, and obtaining the alcohol compound. According to the preparation method provided by the invention, the preparation of the nickel catalyst and the hydrogenation reaction of the carbonyl-containing compound are carried out in the same technological process for the first time, the prepared nickel catalyst is good in catalytic activity and long in service life, and the alcohol compound prepared by in-situ catalysis is high in yield and good in selectivity, so that the production cost of the alcohol compound can be remarkably reduced, the production efficiency is improved, and the method is particularly suitable for large-scale industrial production.
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Paragraph 0056-0058
(2021/07/10)
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- Chemoselective and Site-Selective Reductions Catalyzed by a Supramolecular Host and a Pyridine-Borane Cofactor
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Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.
- Morimoto, Mariko,Cao, Wendy,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
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supporting information
p. 2108 - 2114
(2021/02/06)
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- Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
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The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
- Lambert, Tristan H.,Steiniger, Keri A.
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p. 8013 - 8017
(2021/10/25)
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- Efficient Transfer Hydrogenation of Ketones Catalyzed by a Phosphine-Free Cobalt-NHC Complex
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A simple phosphine-free cobalt-NHC pincer complex has been synthesized and utilized for the transfer hydrogenation of ketones with 2-propanol as hydrogen donor. A broad range of ketones varying from aromatic, aliphatic and heterocyclic were effectively reduced to their corresponding alcohols in moderate to excellent yields with good tolerance of functional groups.
- Ibrahim, Jessica Juweriah,Reddy, C. Bal,Fang, Xiaolong,Yang, Yong
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p. 4429 - 4432
(2020/07/04)
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- Reduction of α,β-Unsaturated carbonyl compounds and 1,3-Diketones in aqueous media, using a raney ni-al alloy
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The treatment of α,β-unsaturated carbonyl compounds and 1,3-diketones with Raney Ni-Al alloy in aqueous media yielded as major reaction products the corresponding saturated alcohols and/or the corresponding hydrocarbons, in a complete transformation of the starting material.
- Katayama, Yumi,Mitoma, Yoshiharu,Simion, Alina Marieta,Simion, Cristian
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- An active and stable multifunctional catalyst with defective UiO-66 as a support for Pd over the continuous catalytic conversion of acetone and hydrogen
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The one-pot synthesis of methyl isobutyl ketone (MIBK) and methyl isobutyl methanol (MIBC) from acetone and hydrogen is a typical cascade reaction comprised of aldol condensation-dehydration-hydrogenation. Pd loss and aggregation during long term operation are typical problems in industrial application. In this paper, an active and stable catalyst was achieved with defective UiO-66 as a support for Pd, which was synthesized with the ratio 15?:?1 of ZrOCl2·8H2O to ZrCl4as Zr-precursors. The resultant Pd catalyst remained active for at least 1000 h with a MIBK + MIBC selectivity of 84.87-93.09% and acetone conversion of 45.26-53.22% in a continuous trickle-bed reactor. Besides the increased Br?nsted acid amount generated by the defect sites was favorable for the activity, the cavity confinement in the UiO-66 (R= 15?:?1) structure also efficiently prevented Pd loss and aggregation during the long term run. The contrast of the characterization of the fresh and used Pd/UiO-66 (R= 15?:?1) indicated that the deactivation of the catalyst was attributed to carbonaceous accumulation on the catalyst surface, which could be easily regenerated by calcination. This work supplied a new alternative for the design and utilization of industrial catalysts for MIBK and MIBC synthesis.
- Hu, Yingjie,Mei, Yuxin,Lin, Baining,Du, Xuhong,Xu, Fan,Xie, Huasheng,Wang, Kang,Zhou, Yonghua
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- Efficient conversion of ethanol to 1-butanol and C5-C9 alcohols over calcium carbide
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Production of 1-butanol or alcohols with 4-9 carbon atoms (C4-C9 alcohols) from widely available bio-ethanol has attracted much interest in recent years in academia and industry of renewable chemicals and liquid fuels. This work discloses for the first time that calcium carbide (CaC2) has a superior catalytic activity in condensation of ethanol to C4-C9 alcohols at 275-300 °C. The 1-butanol yield reached up to 24.5% with ethanol conversion of 62.4% at the optimized conditions. The by-products are mainly alcohols with 5-9 carbons besides 2-butanol, and the total yield of all the alcohols reached up to 56.3%. The reaction route was investigated through controlled experiments and quantitative analysis of the products. Results indicated that two reaction routes, aldol-condensation and self-condensation, took place simultaneously. The aldol-condensation route involves coupling of ethanol with acetaldehyde (formed from ethanol dehydrogenation) to form 2-butenol, which is subsequently hydrogenated to 1-butanol. The alkynyl moiety in CaC2 plays an important role in the catalytic pathways of both routes and affords the good activity of CaC2. CaC2 is converted to acetylene [C2H2] and calcium hydroxide [Ca(OH)2] simultaneously by the H2O that was generated from the condensation of alcohols.
- Wang, Dong,Liu, Zhenyu,Liu, Qingya
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p. 18941 - 18948
(2019/07/04)
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- Efficient and Practical Transfer Hydrogenation of Ketones Catalyzed by a Simple Bidentate Mn?NHC Complex
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Catalytic reductions of carbonyl-containing compounds are highly important for the safe, sustainable, and economical production of alcohols. Herein, we report on the efficient transfer hydrogenation of ketones catalyzed by a highly potent Mn(I)?NHC complex. Mn?NHC 1 is practical at metal concentrations as low as 75 ppm, thus approaching loadings more conventionally reserved for noble metal based systems. With these low Mn concentrations, catalyst deactivation is found to be highly temperature dependent and becomes especially prominent at increased reaction temperature. Ultimately, understanding of deactivation pathways could help close the activity/stability-gap with Ru and Ir catalysts towards the practical implementation of sustainable earth-abundant Mn-complexes.
- van Putten, Robbert,Benschop, Joeri,de Munck, Vincent J.,Weber, Manuela,Müller, Christian,Filonenko, Georgy A.,Pidko, Evgeny A.
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p. 5232 - 5235
(2019/07/18)
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- METAL OXIDE CATALYST, METHOD OF PREPARING THE CATALYST, AND METHOD OF ALCOHOL USING THE SAME
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A metal oxide catalyst involved in a hydrogenation reaction in which a ketone is converted into an alcohol, a method of preparing the metal oxide catalyst, and a method of preparing an alcohol using the same are provided. The metal oxide catalyst has a spinel structure represented by the following Formula 1: [in-line-formulae]XAl2O4, ??[/in-line-formulae] wherein X represents nickel or copper.
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Paragraph 0076-0085
(2018/10/24)
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- Chiral C2-symmetric η6-p-cymene-Ru(II)-phosphinite complexes: Synthesis and catalytic activity in asymmetric reduction of aromatic, methyl alkyl and alkyl/aryl ketones
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Chiral C2-symmetric bis(phosphinite) ligands and their binuclear ruthenium(II) complexes have been synthesized and used as catalysts in the ruthenium-catalyzed asymmetric transfer hydrogenation of aromatic, methyl alkyl and alkyl/aryl ketones using 2-propanol as both the hydrogen source and solvent in the presence of KOH. Under optimized conditions, all complexes showed high catalytic activity as catalysts in the reduction of various ketones to corresponding chiral secondary alcohols. Products were obtained with high conversions (99%) and moderate to good enantioselectivities (82% ee). Furthermore, C2-symmetric bis(phosphinite) ligands and their binuclear ruthenium(II) complexes were characterized by multinuclear NMR spectroscopy, FT-IR spectroscopy, LC/MS-MS and elemental analysis.
- Karaka?, Duygu Elma,Aydemir, Murat,Durap, Feyyaz,Baysal, Ak?n
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p. 430 - 439
(2017/12/06)
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- Iridium-catalyzed efficient reduction of ketones in water with formic acid as a hydride donor at low catalyst loading
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A highly efficient and chemoselective transfer hydrogenation of ketones in water has been successfully achieved with our newly developed catalyst. Simple ketones, as well as α- or β-functionalized ketones, are readily reduced. Formic acid is used as a traceless hydride source. At very low catalyst loading (S/C = 10:000 in most cases; S/C = 50:000 or 100:000 in some cases), the iridium catalyst is impressively efficient at reducing ketones in good to excellent yields. The TOF value can be as high as up to 26:000 mol mol-1 h-1. A variety of functional groups are well tolerated, for example, heteroaryl, aryloxy, alkyloxy, halogen, cyano, nitro, ester, especially acidic methylene, phenol and carboxylic acid groups.
- Liu, Ji-Tian,Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
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supporting information
p. 2118 - 2124
(2018/05/24)
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- Hydrogen Sulfide: A Reagent for pH-Driven Bioinspired 1,2-Diol Mono-deoxygenation and Carbonyl Reduction in Water
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Hydrogen sulfide (H2S) was evaluated for its peculiar sulfur radical species generated at different pHs and was used under photolytical conditions in aqueous medium for the reduction of 1,2-diols to alcohols. The conversion steps of 1,2-cyclopentanediol to cyclopentanol via cyclopentanone were analyzed, and it was proven that the reaction proceeds via a dual catalytic/radical chain mechanism. This approach was successfully adapted to the reduction of a variety of carbonyl compounds using H2S at pH 9 in water. This work opens up the field of environmental friendly synthetic processes using the pH-driven modulation of reactivity of this simple reagent in water.
- Barata-Vallejo, Sebastián,Ferreri, Carla,Golding, Bernard T.,Chatgilialoglu, Chryssostomos
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supporting information
p. 4290 - 4294
(2018/07/29)
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- Transfer-hydrogenation process
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A transfer-hydrogenation process for preparing a carbonyl compound and an alcohol compound comprises the steps of (a) contacting a first carbonyl compound with a first alcohol compound in the presence of a transfer-hydrogenation catalyst in a first reaction zone at conditions effective to form a second carbonyl compound from the first alcohol compound and a second alcohol compound from the first carbonyl compound, and (b) removing the second carbonyl compound from the first reaction zone during step (a). The first carbonyl compound is a saturated aldehyde or ketone, or an α,β-unsaturated aldehyde or ketone. The first alcohol compound is a primary or secondary alcohol. The second alcohol compound is α,β-saturated. The transfer-hydrogenation catalyst includes a Group 8 to 11 metal. This process is useful for preparing and higher value alcohols, such as butanol or 2-ethylhexanol, from the corresponding carbonyl compounds by engaging lower alcohol (C2-C4) feedstocks instead of hydrogen (H2).
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Page/Page column 30; 31
(2018/06/19)
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- AN ECO-FRIENDLY PROCESS FOR HYDROGENATION OR/AND HYDRODEOXYGENATION OF ORGANIC COMPOUND USING HYDROUS RUTHENIUM OXIDE CATALYST
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The invention discloses aneco-friendly process for hydrogenation (alkenealkene, carbonyl compound and aromatic) and hydrodeoxygenation (methoxy phenols) of organic compound using hydrous ruthenium oxide (HRO) and its supported form as a recyclable heterogeneous catalyst in aqueous medium with good yield of desired compounds (70-100%) under mild reaction conditions. The invention also discloses hydrogenation of organic compound such as alkene, carbonyl compound and substituted aromatic and also for the processes that involve hydrodeoxygenation, for example, lignin derived aromatic (methoxy phenols).
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Page/Page column 12; 19
(2017/08/01)
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- Direct Synthesis of Renewable Dodecanol and Dodecane with Methyl Isobutyl Ketone over Dual-Bed Catalyst Systems
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For the first time, we demonstrated two integrated processes for the direct synthesis of dodecanol or 2,4,8-trimethylnonane (a jet fuel range C12-branched alkane) using methyl isobutyl ketone (MIBK) that can be derived from lignocellulose. The reactions were carried out in dual-bed continuous flow reactors. In the first bed, MIBK was selectively converted to a mixture of C12 alcohol and ketone. Over the Pd-modified magnesium– aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C12 oxygenates can be achieved under mild conditions. In the second bed, the C12 oxygenates generated in the first bed were hydrogenated to dodecanol over a Ru/C catalyst or hydrodeoxygenated to 2,4,8-trimethylnonane over a Cu/SiO2 catalyst. The as-obtained dodecanol can be used as feedstock in the production of sodium dodecylsulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), which are widely used as surfactants or detergents. The asobtained 2,4,8-trimethylnonane can be blended into conventional jet fuel without hydroisomerization.
- Sheng, Xueru,Li, Ning,Li, Guangyi,Wang, Wentao,Wang, Aiqin,Cong, Yu,Wang, Xiaodong,Zhang, Tao
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p. 825 - 829
(2017/03/17)
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- Synthesis of Acetone-Derived C6, C9, and C12Carbon Scaffolds for Chemical and Fuel Applications
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A simple, inexpensive catalyst system (Amberlyst 15 and Ni/SiO2–Al2O3) is described for the upgrading of acetone to a range of chemicals and potential fuels. Stepwise hydrodeoxygenation of the produced ketones can yield branched alcohols, alkenes, and alkanes. An analysis of these products is provided, which demonstrates that this approach can provide a product profile of valuable bioproducts and potential biofuels.
- Moore, Cameron M.,Jenkins, Rhodri W.,Janicke, Michael T.,Kubic, William L.,Polikarpov, Evgueni,Semelsberger, Troy A.,Sutton, Andrew D.
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p. 3382 - 3386
(2016/12/27)
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- Base-Free Transfer Hydrogenation of Ketones Using Cp?Ir(pyridinesulfonamide)Cl Precatalysts
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N-(2-(Pyridin-2-yl)ethyl)benzenesulfonamide derivatives and 1,1,1-trifluoro-N-(2-(pyridin-2-yl)ethyl)methanesulfonamide (1-4), along with three-legged piano stool Cp?IrIIICl complexes (5-11) (Cp? = pentamethylcyclopentadienyl) bearing pyridinesulfonamide ligands with varying electronic parameters, were synthesized. These ligands and air-stable complexes were characterized by 1H and 13C{1H} NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Precatalysts, 5-11, were assessed for transfer hydrogenation of aryl, diaryl, dialkyl, linear, cycloaliphatic, and α,β-unsaturated ketones, diones, β-ketoesters, and a biomass-derived substrate with 2-propanol, using 1 mol % precatalyst. Catalysis was also efficient using a 0.1 mol % loading. Remarkably, all catalysis experiments can be conducted in air without dried and degassed substrates, and basic additives and halide abstractors are not required for high activity in transfer hydrogenation. Control experiments and a mercury poisoning experiment support a homogeneous catalyzed pathway. Overall, the fastest reactions are observed using electron-poor substrates and precatalysts bearing electron-rich ligands.
- Ruff, Andrew,Kirby, Christopher,Chan, Benny C.,O'Connor, Abby R.
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p. 327 - 335
(2016/02/19)
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- Alcohol oxidation with H2O2 catalyzed by a cheap and promptly available imine based iron complex
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We previously reported that the iminopyridine iron(II) complex 1, easily and quantitatively obtainable in situ, can activate H2O2 to form a powerful oxidant, capable of aliphatic C-H bond hydroxylation. In the present study we expand the application of this catalyst to the oxidation of a series of alcohols to the corresponding carbonyl compounds. The oxidation of aliphatic alcohols proceeds smoothly, while that of benzylic alcohols is shown to be challenging. Some collected pieces of evidence suggest a preference of the oxidizing species for the aromatic ring instead for the alcoholic moiety. The decrease of the electron density in the aromatic ring shifts the oxidation from the aromatic towards the alcoholic moiety. Quite surprisingly, preferential oxidation of cyclohexanol versus benzylic alcohol was achieved, showing unprecedented selectivity.
- Olivo, Giorgio,Giosia, Simone,Barbieri, Alessia,Lanzalunga, Osvaldo,Di Stefano, Stefano
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supporting information
p. 10630 - 10635
(2016/11/21)
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- Transfer hydrogenation reaction using novel ionic liquid based Rh(I) and Ir(III)-phosphinite complexes as catalyst
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Hydrogen transfer reduction methods are attracting increasing interest from synthetic chemists in view of their operational simplicity. Thus, interaction of [Rh(μ-Cl)(cod)]2and Ir(η5-C5Me5)(μ-Cl)Cl]2with phosphinite ligand [(Ph2PO)-C7H11N2Cl]Cl, 1 gave new monodendate (1-chloro-3-(3-methylimidazolidin-1-yl)propan-2-yl diphenylphosphinite chloride) (chloro ?4-1,5-cyclooctadiene rhodium(I))], 2 and (1-chloro-3-(3-methylimidazolidin-1-yl)propan-2-yl diphenylphosphinite chloride) (dichloro ?5-pentamethylcyclopentadienyl iridium(III))], 3 complexes, which were characterized by a combination of multinuclear NMR spectroscopy, IR spectroscopy, and elemental analysis.1H-{31P} NMR,1H-13C HETCOR or1H-1H COSY correlation experiments were used to confirm the spectral assignments. The novel catalysts were applied to transfer hydrogenation of acetophenone derivatives using 2-propanol as a hydrogen source. The results showed that the corresponding alcohols could be obtained with high activity (up to 99%) under mild conditions. Notably, (1-chloro-3-(3-methylimidazolidin-1-yl)propan-2-yl diphenylphosphinite chloride) (chloro ?4-1,5-cyclooctadiene rhodium(I))], 2 complex is much more active than the other analogous complex, 3 in the transfer hydrogenation. Furthermore, compound, 2 acts as excellent catalysts, giving the corresponding alcohols in 97–99% conversions in 5?min (TOF?≤?1176?h?1).
- Elma Karaka?, Duygu,Durap, Feyyaz,Baysal, Ak?n,Ocak, Yusuf Selim,Rafikova, Khadichakhan,Kaya, Eda ?avu?,Zazybin, Alexey,Temel, Hamdi,Kayan, Cezmi,Meri?, Nermin,Aydemir, Murat
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- Towards understanding the hydrodeoxygenation pathways of furfural-acetone aldol condensation products over supported Pt catalysts
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Aiming at the valorisation of furfural-derived compounds, the hydrodeoxygenation of furfural-acetone condensation products has been studied using supported platinum catalysts. The influence of the catalytic properties of different supports, such as SiO2, Al2O3, TiO2, hydrotalcite (HTC), Beta zeolite, Al-SBA-15 and WO3-ZrO2, was evaluated in a batch reactor for 480 min at 200 °C and 50 bar of H2. The used feed consisted of a mixture of furfural-acetone adducts (C8-C19), obtained in previous experiments using a continuous flow reactor and hydrotalcite as a catalyst. Except for Pt/SiO2, all catalysts showed high conversion of the reactants, especially due to the hydrogenation of all the aliphatic CC bonds. However, the extent of further hydrogenation (furan CC and ketone CO bonds) was limited, particularly when HTC and Al2O3 were used as supports. The higher accessibility of Pt/TiO2 and the smaller Pt particle size shown by Pt/Al-SBA-15, Pt/WO3-ZrO2 and Pt/Beta in comparison with the other catalysts led to an improvement in the hydrogenation of furanic and ketonic groups, likely due to lower adsorption constraints. The higher acid character of the latter group of catalysts promotes dehydration and ring opening steps, thus enhancing the selectivity towards linear alcohols. Likewise, a significant increase in the extent of aldol condensation reactions was also observed with these catalysts, yielding longer carbon chain compounds. Based on this study, a reaction scheme for the transformation of 4-(2-furyl)-3-buten-2-one (C8) into octane has been proposed in order to establish a valuable correlation between the main conversion pathways and the catalytic properties of the employed heterogeneous catalyst, thus contributing to further development of efficient deoxygenation catalysts.
- Ramos,Ti?ler,Kikhtyanin,Kubi?ka
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p. 1829 - 1841
(2016/04/05)
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- Chiral Cyclopentadienone iron complexes for the catalytic asymmetric hydrogenation of ketones
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Three chiral (cyclopentadienone)iron complexes derived from (R)-BINOL (CK1-3) were synthesized and their structures unambiguously confirmed by X-ray analysis (CK3). Under suitable conditions for the in situ conversion into the corresponding (hydroxycyclopentadienyl)iron hydrides (Me3NO, H2), the new chiral complexes were tested in the catalytic asymmetric hydrogenation of ketones, showing moderate to good enantioselectivity. In particular, the complex bearing methoxy substituents at the 3,3-positions of the binaphthyl moiety (CK2) proved remarkably more enantioselective than the unsubstituted one (CK1) and reached the highest level of enantioselectivity (up to 77% ee) ever obtained with chiral (cyclopentadienone)iron complexes. Reducto! Chiral (cyclopentadienone)iron complexes were synthesized and tested, after in situ activation, in the catalytic asymmetric hydrogenation of ketones leading to the highest enantiomeric excesses ever obtained with this type of catalysts.
- Gajewski, Piotr,Renom-Carrasco, Marc,Facchini, Sofia Vailati,Pignataro, Luca,Lefort, Laurent,De Vries, Johannes G.,Ferraccioli, Raffaella,Forni, Alessandra,Piarulli, Umberto,Gennari, Cesare
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supporting information
p. 1887 - 1893
(2015/03/18)
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- Synthesis and molecular structure of ruthenium(III) benzoylhydrazone complexes: Substituents effect on transfer hydrogenation of ketones
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An easy and convenient synthesis of a new series of octahedral ruthenium(III) complexes bearing benzoylhydrazone of general formula [Ru(L)Cl(PPh3)2] (where L = 2-hydroxy-1-naphthaldehyde benzoylhydrazone) has been reported. The composition of all the complexes has been unequivocally characterized by microanalysis, IR, electronic, magnetic and EPR spectroscopic techniques. The substituted benzoylhydrazone ligands behave as a dianionic tridentate O, N and O donors and coordinate to ruthenium via the phenolic oxygen, the azomethine nitrogen and the deprotonated amide oxygen. The complexes exhibit moderately strong ligand-to-metal charge transfer transitions in the visible region and intraligand transition in the UV region. Magnetic moment of the complexes (298 K) lies in the range 1.72-1.97 μB reveals the presence of one unpaired electron in the metal centre. The low spin mononuclear Ru(III) benzoylhydrazone complexes display rhombic EPR spectral pattern in frozen solution. The molecular structure of two of the complexes has been established by single crystal X-ray crystallography and indicates the presence of a distorted octahedral geometry in these complexes. Further, the complexes 1-5 have been proven to catalyse the transfer hydrogenation of linear, cyclic and aromatic ketones to their corresponding secondary alcohols in the presence of i-PrOH/KOH at 82 °C and the maximum conversion is up to 99%. The effect of other variables on the transfer hydrogenation reaction such as solvent, base, temperature, time and catalyst loading is also reported.
- Kanchanadevi, Appukutti,Ramesh, Rengan,Bhuvanesh, Nattamai
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- Synthesis of (R)-BINOL-Derived (Cyclopentadienone)iron Complexes and Their Application in the Catalytic Asymmetric Hydrogenation of Ketones
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A family of chiral (cyclopentadienone)iron complexes, featuring an (R)-BINOL-derived backbone, and their application in the asymmetric hydrogenation of ketones are described. The complexes differ from each other in the substituents at the 3,3′-positions of the binaphthyl residue (H, OH, OR, OCOR, OSO2R) or at the 2,5-positions of the cyclopentadienone ring [trimethylsilyl (TMS) or Ph]. Remarkably, eight precatalysts with different 3,3′-binaphthyl substitution [(R)-1c-1j] were synthesized from a common parent complex [(R)-1b] through direct functional group interconversion reactions of the complexes. The 3,3′-(bis)methoxy-substituted precatalyst (R)-1b gave the best catalytic performance, and its application scope was assessed in the hydrogenation of several ketones. The observed ee values (up to 77%) are much higher than those previously reported for other chiral (cyclopentadienone)iron complexes.
- Gajewski, Piotr,Renom-Carrasco, Marc,Facchini, Sofia Vailati,Pignataro, Luca,Lefort, Laurent,De Vries, Johannes G.,Ferraccioli, Raffaella,Piarulli, Umberto,Gennari, Cesare
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supporting information
p. 5526 - 5536
(2015/09/01)
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- Selective synthesis of primary amines by reductive amination of ketones with ammonia over supported Pt catalysts
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Supported platinum catalysts are studied for the reductive amination of ketones under ammonia and hydrogen. For a model reaction with 2-adamantanone, Pt-loaded MoOx/TiO2 (Pt-MoOx/TiO2) shows the highest yield of primary amine. The catalyst is effective for the selective transformation of various aliphatic and aromatic ketones to the corresponding primary amines, which demonstrates the first example of the selective synthesis of primary amines by this reaction. The yield of the amine increases with increase in the negative shift of the C£O stretching band in the infrared spectra of adsorbed acetone on the catalysts, suggesting that Lewis acid sites on the support material play an important role in this catalytic system.
- Nakamura, Yoichi,Kon, Kenichi,Touchy, Abeda Sultana,Shimizu, Ken-Ichi,Ueda, Wataru
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p. 921 - 924
(2015/03/18)
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- Hydrogenation of ketones over bifunctional Pt-heteropoly acid catalyst in the gas phase
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Gas-phase hydrogenation of a wide range of ketones to alkanes, including hydrogenation of aliphatic ketones and acetophenone, was investigated using bifunctional metal-acid catalysis. The catalysts were comprised of a metal (Pt, Ru, Ni, and Cu) supported on acidic caesium salt of tungstophosphoric heteropoly acid Cs2.5H0.5PW12O40 (CsPW). The reaction occurred via a sequence of steps involving hydrogenation of ketone to alcohol on metal sites followed by dehydration of alcohol to alkene on acid sites and finally hydrogenation of alkene to alkane on metal sites. Catalyst activity decreased in the order: Pt > Ru >> Ni > Cu. Pt/CsPW showed the highest catalytic activity, giving almost 100% alkane yield at 100 °C and 1 bar pressure. Evidence is provided that the reaction with Pt/CsPW at 100 °C is limited by ketone-to-alcohol hydrogenation, whereas at lower temperatures (≤60 °C) by alcohol dehydration yielding alcohol as themain product. The catalyst comprised of a physical mixture of Pt/C + CsPW was found to be highly efficientas well, which indicates that the reaction is not limited by migration of intermediates between metal andacid sites in the bifunctional catalyst.
- Alharbi,Kozhevnikova,Kozhevnikov
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p. 457 - 462
(2015/10/05)
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- Novel cyclohexyl-based aminophosphine ligands and use of their Ru(II) complexes in transfer hydrogenation of ketones
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Two new aminophosphines - furfuryl-(N-dicyclohexylphosphino)amine, [Cy 2PNHCH2-C4H3O] (1) and thiophene-(N-dicyclohexylphosphino)amine, [Cy2PNHCH 2-C4H3S] (2) - were prepared by the reaction of chlorodicyclohexylphosphine with furfurylamine and thiophene-2-methylamine. Reaction of the aminophosphines with [Ru(η6-p-cymene)(μ-Cl)Cl] 2 or [Ru(η6-benzene)(μ-Cl)Cl]2 gave corresponding complexes [Ru(Cy2PNHCH2-C4H 3O)(η6-p-cymene)Cl2] (1a), [Ru(Cy 2PNHCH2-C4H3O)(η6- benzene)Cl2] (1b), [Ru(Cy2PNHCH2-C 4H3S)(η6-p-cymene)Cl2] (2a) and [Ru(Cy2PNHCH2-C4H3S) (η6-benzene)Cl2] (2b), respectively, which are suitable catalyst precursors for the transfer hydrogenation of ketones. In particular, [Ru(Cy2PNHCH2-C4H 3S)(η6-benzene)Cl2] acts as a good catalyst, giving the corresponding alcohols in 98-99% yield in 30 min at 82 °C (up to time of flight ≤ 588 h-1).
- Kayan, Cezmi,Meric, Nermin,Aydemir, Murat,Ocak, Yusuf Selim,Temel, Hamdi
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p. 127 - 133
(2014/02/14)
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- Transfer hydrogenation of ketones catalyzed by new rhodium and iridium complexes of aminophosphine containing cyclohexyl moiety and photosensing behaviors of rhodium and iridium based devices
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The reaction of [Rh(μ-Cl)(cod)]2 and Ir(η5- C5Me5)(μ-Cl)Cl]2 with aminophosphine ligands Cy2PNHCH2-C4H3X (X: O; S) gave a range of new monodendate [Rh(Cy2PNHCH2-C4H 3O)(cod)Cl], (1), [Rh(Cy2PNHCH2-C 4H3S)(cod)Cl], (2), [Ir(Cy2PNHCH 2-C4H3O)(η5-C5Me 5)Cl2], (3) and [Ir(Cy2PNHCH2-C 4H3S)(η5-C5Me 5)Cl2], (4) complexes, which were characterized by analytical and spectroscopic methods. The new rhodium(I) and iridium(III) catalysts were applied to transfer hydrogenation of acetophenone derivatives using 2-propanol as a hydrogen source. The results showed that the corresponding alcohols could be obtained with high activity (up to 99%) under mild conditions. Notably, [Rh(Cy2PNHCH2-C4H 3O)(cod)Cl] complex (1) is much more active than the other analogous complexes in the transfer hydrogenation. Moreover, organic-inorganic rectifying contacts were fabricated forming rhodium(I) and iridium(III) complex thin films on n-Si semiconductors and evaporating Au metal on the structures. Electrical properties of the contacts including ideality factor, barrier height and series resistance were determined using their current-voltage (I-V) data. The photoelectrical characteristics of the devices were examined under the light with 40-100 mW/cm2 illumination conditions. It was seen that light had strong effects on I-V characteristics of the devices and the ones fabricated using 3 and 4 complexes had unusually forward and reverse bias photoconducting behavior.
- Rafikova, Khadichakhan,Kystaubayeva, Nurzhamal,Aydemir, Murat,Kayan, Cezmi,Ocak, Yusuf Selim,Temel, Hamdi,Zazybin, Alexey,Gürbüz, Nevin,?zdemir, Ismail
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- Synthesis and catalytic alcohol oxidation and ketone transfer hydrogenation activity of donor-functionalized mesoionic triazolylidene ruthenium(ii) complexes
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We report on the synthesis of a variety of C,E-bidentate triazolylidene ruthenium complexes that comprise different donor substituents E (E = C: phenyl anion; E = O: carboxylate, alkoxide; E = N: pyridine at heterocyclic carbon or nitrogen). Introduction of these donor functionalities is greatly facilitated by the synthetic versatility of triazoles, and their facile preparation routes. Five different complexes featuring a C,E-coordinated ruthenium center with chloride/cymene spectator ligands and three analogous solvento complexes with MeCN spectator ligands were prepared and evaluated as catalyst precursors for direct base- and oxidant-free alcohol dehydrogenation, and for transfer hydrogenation using basic iPrOH as a source of dihydrogen. In both catalytic reactions, the neutral/mono-cationic complexes with chloride/cymene spectator ligands performed better than the solvento ruthenium complexes. The donor functionality had a further profound impact on catalytic activity. For alcohol dehydrogenation, the C,C-bidentate phenyl-triazolylidene ligand induced highest conversions, while carboxylate or pyridine donor sites gave only moderate activity or none at all. In contrast, transfer hydrogenation is most efficient when a pyridyl donor group is linked to the triazolylidene via the heterocyclic carbon atom, providing turnover frequencies as high as 1400 h-1 for cyclohexanone transfer hydrogenation. The role of the donor group is discussed in mechanistic terms.
- Delgado-Rebollo, Manuela,Canseco-Gonzalez, Daniel,Hollering, Manuela,Mueller-Bunz, Helge,Albrecht, Martin
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p. 4462 - 4473
(2014/03/21)
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- Ionic liquid based Ru(II)-phosphinite compounds and their catalytic use in transfer hydrogenation: X-ray structure of an ionic compound 1-chloro-3-(3-methylimidazolidin-1-yl)propan-2-ol
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The compound 1-chloro-3-(3-methylimidazolidin-1-yl)propan-2-ol chloride (1) was prepared from the reaction of 1-methylimidazole with epichlorohydrine. The corresponding phosphinite ligands were synthesized by the reaction 1-chloro-3-(3-methylimidazolidin-1-yl)propan-2-ol chloride, [C7H 15N2OCl]Cl with one equivalent of chlorodiphenylphosphine or chlorodicyclohexylphosphine, in anhydrous CH2Cl2 and under an inert argon atmosphere. [Ru(η6-arene)(μ-Cl)Cl] 2 dimers readily react with the phosphinite ligands [(Ph 2PO)-C7H14N2Cl]Cl (2) or [(Cy 2PO)-C7H14N2Cl]Cl (3) at room temperature to afford the cationic derivatives [Ru((Ph2PO)-C 7H14N2Cl)(η6-arene)Cl 2]Cl and [Ru((Cy2PO)-C7H14N 2Cl)(η6-arene)Cl2]Cl {arene: benzene (4), (5); p-cymene (6), (7)}. The structures of these ligands and their corresponding complexes have been elucidated by a combination of multinuclear NMR and IR spectroscopy, TGA/DTA and elemental analysis. The molecular structure of the ionic compound 1 was also determined by an X-ray single crystal diffraction study. Furthermore, the catalytic activity of complexes 4-7 for the transfer hydrogenation of various ketones was investigated and these complexes were found to be efficient catalysts in the transfer hydrogenation of various ketones, with excellent conversions up to 99%. Specifically, [Ru((Cy2PO)- C7H14N2Cl)(η6-benzene)Cl 2]Cl (5) and [Ru((Cy2PO)-C7H14N 2Cl)(η6-p-cymene)Cl2]Cl (7) act as excellent catalysts, giving the corresponding alcohols in 98-99% conversions in 5 min (TOF ≤ 1188 h-1).
- Aydemir, Murat,Rafikova, Khadichakhan,Kystaubayeva, Nurzhamal,Pa?a, Salih,Meri?, Nermin,Ocak, Yusuf Selim,Zazybin, Alexey,Temel, Hamdi,Gürbüz, Nevin,?zdemir, Ismail
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p. 245 - 255
(2014/07/21)
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- The application of tunable tridendate P-based ligands for the Ru(II)-catalysed transfer hydrogenation of various ketones
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Two novel versatile tridendate aminophosphine-phosphinite and phosphinite ligands were prepared and their trinuclear neutral ruthenium(II) dichloro complexes were found to be effective catalysts for the transfer hydrogenation of various ketones in excellent conversions up to 99% in the presence of 2-propanol/NaOH in 0.1M isopropanol solution. Particularly, [Ru3 (PPh2OC2H4)2 N-PPh2(η6-p-cymene)3Cl6] acts as an excellent catalyst giving the corresponding alcohols in excellent conversion up to 99% (turnover frequency ≤ 1176 h-1). A comparison of the catalytic properties of the complexes is also discussed briefly. Furthermore, the structures of these ligands and their corresponding complexes have also been clarified using a combination of multinuclear NMR spectroscopy, infrared spectroscopy and elemental analysis. 1H-13C HETCOR or 1H-1H COSY correlation experiments were used to confirm the spectral assignments.
- Meric, Nermin,Durap, Feyyaz,Aydemir, Murat,Baysal, Akin
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p. 803 - 808
(2015/02/19)
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- New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations
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Schiff base disulfide ligands (H2L1-6) were synthesized from the condensation of cystamine with salicylaldehyde(H 2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H 2L4), 3-methyl-2-hydroxyacetophenone(H2L 5), 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.
- Prakash, Govindan,Viswanathamurthi, Periasamy
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p. 352 - 358
(2014/05/06)
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- Dramatic promotion of copper-alumina catalysts by sodium for acetone trimerisation
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Na-promoted Cu-Al materials are efficient multifunctional catalysts for the direct conversion of gas phase acetone to diisobutyl ketone (DIBK) with unprecedented yields (up to 31%). The Na content is a major parameter determining the stability and the catalytic performance of these materials.
- Ligner, Emanuelle,Meunier, Frederic,Travert, Arnaud,Maury, Sylvie,Cadran, Nicolas
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p. 2480 - 2483
(2014/07/22)
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- Ruthenium(II) carbonyl complexes containing pyridine carboxamide ligands and PPh3/AsPh3/Py coligands: Synthesis, spectral characterization, catalytic and antioxidant studies
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New ruthenium(II) carbonyl complexes bearing pyridine carboxamide and triphenylphosphine/triphenylarsine/pyridine have been prepared by direct reaction of ruthenium(II) precursors with some pyridine carboxamide ligands, N,N-bis(2-pyridinecarboxamide)-1,2-ethane (H2L1), N,N-bis(2-pyridinecarboxamide)-1,2-benzene (H2L2) and N,N-bis(2-pyridinecarboxamide)-trans-1,2-cyclohexane (H2L 3). The organic ligands offering two Namide and two N pyridine donor sites to the metal centre. They have been characterized by elemental analyses, FT-IR, UV-Visible, NMR (1H, 13C and 31P) and ESI-MS techniques. Based on the above data, an octahedral structure has been assigned for all the complexes. The catalytic efficiency of the complexes in transfer hydrogenation of ketones in the presence of iPrOH/KOH and N-alkylation of amine in the presence of tBuOK was examined. Furthermore, the antioxidant activity of the ligands and its ruthenium(II) complexes were determined by DPPH radical, nitric oxide radical, hydroxyl radical and hydrogen peroxide scavenging methods, which indicates that the ruthenium(II) complexes exhibit more effective antioxidant activity than the ligands alone.
- Ramachandran, Rangasamy,Viswanathamurthi, Periasamy
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