- Mesoporous MgO and Ni-MgO prepared by using carboxylic acids
-
MgO and NiO-MgO with large mesopores were prepared by using the corresponding nitrates and carboxylic acids. Their pore structures were characterized by N2 adsorption, and reduced Ni-MgO samples were used in the liquid-phase hydrogenation of ketone. The mesopore size of MgO was controllable with the alkyl-chain length of the carboxylic acid in the range between 13 and 38 nm. The mesopores are located at the MgO interparticles. In the hydrogenation of 4-heptanone to 4-heptanol, the catalytic activity of the Ni-MgO, which had mesopores at 11 nm, prepared using dodecanoic acid was higher than that of a commercial Raney Ni with mesopores around 4 nm, while the Ni surface of the Ni-MgO was lower than that of a Raney Ni catalyst. At an optimum regulated size of mesopores, the Ni-MgO catalyst would show high catalytic activity satisfying both rapid mass transfer of the reactants and high dispersion of Ni metals on the catalyst surface.
- Takenaka, Shoichi,Sato, Satoshi,Takahashi, Ryoji,Sodesawa, Toshiaki
-
-
Read Online
- Robust Mn(iii): N -pyridylporphyrin-based biomimetic catalysts for hydrocarbon oxidations: heterogenization on non-functionalized silica gel versus chloropropyl-functionalized silica gel
-
Two classes of heterogenized biomimetic catalysts were prepared and characterized for hydrocarbon oxidations: (1) by covalent anchorage of the three Mn(iii) meso-tetrakis(2-, 3-, or 4-pyridyl)porphyrin isomers by in situ alkylation with chloropropyl-functionalized silica gel (Sil-Cl) to yield Sil-Cl/MnPY (Y = 1, 2, 3) materials, and (2) by electrostatic immobilization of the three Mn(iii) meso-tetrakis(N-methylpyridinium-2, 3, or 4-yl)porphyrin isomers (MnPY, Y = 4, 5, 6) on non-modified silica gel (SiO2) to yield SiO2/MnPY (Y = 4, 5, 6) materials. Silica gel used was of column chromatography grade and Mn porphyrin loadings were deliberately kept at a low level (0.3% w/w). These resulting materials were explored as catalysts for iodosylbenzene (PhIO) oxidation of cyclohexane, n-heptane, and adamantane to yield the corresponding alcohols and ketones; the oxidation of cyclohexanol to cyclohexanone was also investigated. The heterogenized catalysts exhibited higher efficiency and selectivity than the corresponding Mn porphyrins under homogeneous conditions. Recycling studies were consistent with low leaching/destruction of the supported Mn porphyrins. The Sil-Cl/MnPY catalysts were more efficient and more selective than SiO2/MnPY ones; alcohol selectivity may be associated with hydrophobic silica surface modification reminiscent of biological cytochrome P450 oxidations. The use of widespread, column chromatography, amorphous silica yielded Sil-Cl/MnPY or SiO2/MnPY catalysts considerably more efficient than the corresponding, previously reported materials with mesoporous Santa Barbara Amorphous No 15 (SBA-15) silica. Among the materials studied, in situ derivatization of Mn(iii) 2-N-pyridylporphyrin by covalent immobilization on Sil-Cl to yield Sil-Cl/MnP1 showed the best catalytic performance with high stability against oxidative destruction and reusability/recyclability.
- Pinto, Victor Hugo A.,Falc?o, Nathália K. S. M.,Mariz-Silva, Bárbara,Fonseca, Maria Gardennia,Rebou?as, Júlio S.
-
supporting information
p. 16404 - 16418
(2020/12/03)
-
- Single-phase catalysis for reductive etherification of diesel bioblendstocks
-
Reductive etherification is a promising catalytic chemistry for coupling biomass derived alcohols and ketones to produce branched ethers that can be used as high cetane, low sooting blendstocks for diesel fuel applications. Previous catalyst materials examined for reductive etherification have typically been limited to binary physical mixtures of metal hydrogenation and acidic acetalization catalysts with limited thermal stability and industrial applicability. To address this, we developed a single-phase catalyst comprising Pd supported on acidic metal oxides with high catalytic activity, product selectivity, and regeneration stability. Batch reactor screening identified niobium phosphate (NbOPO4) as the most active acidic metal oxide catalyst support, which was downselected to synthesize single-phase catalysts by Pd loading. Several branched ethers with favourable fuel properties were synthesized to demonstrate broad catalyst applicability. The fresh Pd/NbOPO4 catalyst displayed a surface area of 130 m2 g-1, high acidity of 324 μmol g-1 and Pd dispersion of 7.8percent. The use of acidic metal oxide support allowed for elevated reaction temperatures with a mass selectivity to 4-butoxyheptane of 81percent at 190 °C and an apparent activation energy of 40 kJ mol-1. Continuous flow reactor testing demonstrated steady catalyst deactivation due to coke formation of 10 wtpercent after 117 h of time-on-stream. Four simulated catalyst regeneration cycles led to small changes in surface area and total acidity; however, a decrease in Pd site density from 18 to 8 μmol g-1, in combination with an apparent Pd nanoparticle size effect, caused an increase in the production rate of 4-butoxyheptane from 138 to 190 μmol gcat-1 min-1 with the regenerated catalyst. Lastly, technoeconomic analysis showed that higher H2 equivalents and lower weight hourly space velocity values can reduce ether catalytic production costs.
- Conklin, Davis R.,Guo, Qianying,Hafenstine, Glenn R.,Huo, Xiangchen,Huq, Nabila A.,Unocic, Kinga A.,Vardon, Derek R.,Wiatrowski, Matthew R.
-
supporting information
p. 4463 - 4472
(2020/08/10)
-
- Regioselective C-H hydroxylation of: N -alkanes using Shilov-type Pt catalysis in perfluorinated micro-emulsions
-
Shilov-chemistry inspired catalysis has remained largely overlooked as a tool for establishing the remote hydroxylation of non-polar compounds, such as long linear alkanes, due to the need for an acidic aqueous solution. To circumvent the solubility issue, the concept of micellar catalysis is introduced, using PtII in perfluorinated micro-emulsions. Notably, the terminal C-H activation of n-heptane is demonstrated under an oxygen atmosphere using perfluorooctanoic acid (PFOA) as a surfactant, along with the intrinsic ability of PtII to convert the highly inert primary C-H bonds. Coordination of PtII to the carboxylate groups of PFOA proved to be particularly important for achieving maximum catalyst activity towards the hydrocarbon substrate solubilized inside the micelle interior. Based on these insights, optimization of the reaction parameters allowed a positional selectivity of 60% for 1-heptanol, among the C7 alcohols, to be achieved, using low catalyst and surfactant loadings under acid-free conditions.
- De Vos, Dirk E.,Janssen, Michiel
-
p. 1264 - 1272
(2020/03/23)
-
- Benzimidazole fragment containing Mn-complex catalyzed hydrosilylation of ketones and nitriles
-
The synthesis of a new bidentate (NN)–Mn(I) complex is reported and its catalytic activity towards the reduction of ketones and nitriles is studied. On comparing the reactivity of various other Mn(I) complexes supported by benzimidazole ligand, it was observed that the Mn(I) complexes bearing 6-methylpyridine and benzimidazole fragments exhibited the highest catalytic activity towards monohydrosilylation of ketones and dihydrosilylation of nitriles. Using this protocol, a wide range of ketones were selectively reduced to the corresponding silyl ethers. In case of unsaturated ketones, the chemoselective reduction of carbonyl group over olefinic bonds was observed. Additionally, selective dihydrosilylation of several nitriles were also achieved using this complex. Mechanistic investigations with radical scavengers suggested the involvement of radical species during the catalytic reaction. Stoichiometric reaction of the Mn(I) complex with phenylsilane revealed the formation of a new Mn(I) complex.
- Ganguli, Kasturi,Mandal, Adarsha,Sarkar, Bidisha,Kundu, Sabuj
-
-
- Metal-Ligand Cooperation Facilitates Bond Activation and Catalytic Hydrogenation with Zinc Pincer Complexes
-
A series of PNP zinc pincer complexes capable of bond activation via aromatization/dearomatization metal-ligand cooperation (MLC) were prepared and characterized. Reversible heterolytic N-H and H-H bond activation by MLC is shown, in which hemilability of the phosphorus linkers plays a key role. Utilizing this zinc pincer system, base-free catalytic hydrogenation of imines and ketones is demonstrated. A detailed mechanistic study supported by computation implicates the key role of MLC in facilitating effective catalysis. This approach offers a new strategy for (de)hydrogenation and other catalytic transformations mediated by zinc and other main group metals.
- Rauch, Michael,Kar, Sayan,Kumar, Amit,Avram, Liat,Shimon, Linda J. W.,Milstein, David
-
supporting information
p. 14513 - 14521
(2020/10/13)
-
- Metal-Organic Architectures Assembled from Multifunctional Polycarboxylates: Hydrothermal Self-Assembly, Structures, and Catalytic Activity in Alkane Oxidation
-
A three-component aqueous reaction system comprising copper(II) acetate (metal node), poly(carboxylic acid) with a phenylpyridine or biphenyl core (main building block), and 1,10-phenanthroline (crystallization mediator) was investigated under hydrothermal conditions. As a result, four new coordination compounds were self-assembled, namely, {[Cu(μ3-cpna)(phen)]·H2O}n (1), {[Cu(μ-Hbtc)(phen)]·H2O}n (2), {[Cu(μ3-Hcpic)(phen)]·2H2O}n (3), and [Cu6(μ-Hcptc)6(phen)6]·6H2O (4), where H2cpna = 5-(2′-carboxylphenyl)nicotinic acid, H3btc = biphenyl-2,4,4′-tricarboxylic acid, H3cpic = 4-(5-carboxypyridin-2-yl)isophthalic acid, H3cptc = 2-(4-carboxypyridin-3-yl)terephthalic acid, and phen = 1,10-phenanthroline. Crystal structures of compounds 1-3 reveal that they are 1D coordination polymers with a ladder, linear, or double-chain structure, while product 4 is a 0D hexanuclear complex. All of the structures are extended further [1D a?' 2D (1 and 2), 1D a?' 3D (3), and 0D a?' 3D (4)] into hydrogen-bonded networks. The type of a multicarboxylate building block has a considerable effect on the final structures of 1-4. The magnetic behavior and thermal stability of 1-4 were also investigated. Besides, these copper(II) derivatives efficiently catalyze the oxidation of cycloalkanes with hydrogen peroxide under mild conditions. The obtained products are the unique examples of copper derivatives that were assembled from H2cpna, H3btc, H3cpic, and H3cptc, thus opening up their use as multicarboxylate ligands toward the design of copper-organic architectures.
- Gu, Jinzhong,Wen, Min,Cai, Yan,Shi, Zifa,Arol, Aliaksandr S.,Kirillova, Marina V.,Kirillov, Alexander M.
-
p. 2403 - 2412
(2019/02/28)
-
- Silica-Supported MnII Sites as Efficient Catalysts for Carbonyl Hydroboration, Hydrosilylation, and Transesterification
-
Manganese, the third most abundant transition-metal element after iron and titanium, has recently been demonstrated to be an effective homogeneous catalyst in numerous reactions. Herein, the preparation of silica-supported MnII sites is reported using Surface Organometallic Chemistry (SOMC), combined with tailored thermolytic molecular precursors approach based on Mn2[OSi(OtBu)3]4 and Mn{N(SiMe3)2}2?THF. These supported MnII sites, free of organic ligands, efficiently catalyze numerous reactions: hydroboration and hydrosilylation of ketones and aldehydes as well as the transesterification of industrially relevant substrates.
- Ghaffari, Behnaz,Mendes-Burak, Jorge,Chan, Ka Wing,Copéret, Christophe
-
supporting information
p. 13869 - 13873
(2019/11/11)
-
- Cooperative Mn(i)-complex catalyzed transfer hydrogenation of ketones and imines
-
The synthesis and reactivity of Mn(i) complexes bearing bifunctional ligands comprising both the amine N-H and benzimidazole fragments are reported. Among the various ligands, the N-((1H-benzimidazol-2-yl)methyl)aniline ligand containing Mn(i) complex presented higher reactivity in the transfer hydrogenation (TH) of ketones in 2-propanol. Experimentally, it was established that both the benzimidazole and amine N-H proton played a vital role in the enhancement of the catalytic activity. Utilizing this system a wide range of aldehydes and ketones were reduced efficiently. Notably, the TH of several imines, as well as chemoselective reduction of unsaturated ketones, was achieved in the presence of this catalyst. DFT calculations were carried out to understand the plausible reaction mechanism which disclosed that the transfer hydrogenation reaction followed a concerted outer-sphere mechanism.
- Ganguli, Kasturi,Shee, Sujan,Panja, Dibyajyoti,Kundu, Sabuj
-
p. 7358 - 7366
(2019/06/06)
-
- Heptanuclear Fe5Cu2-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C-H Compounds
-
A new representative of an unusual family of metallagermaniumsesquioxanes, namely the heterometallic cagelike phenylgermsesquioxane (PhGeO2)12Cu2Fe5(O)OH(PhGe)2O5(bipy)2 (2), was synthesized and structurally characterized. Fe(III) ions of the complex are coordinated by oxa ligands: (i) cyclic (PhGeO2)12 and acyclic (Ph2Ge2O5) germoxanolates and (ii) O2- and (iii) HO- moieties. In turn, Cu(II) ions are coordinated by both oxa (germoxanolates) and aza ligands (2,2′-bipyridines). This "hetero-type" of ligation gives in sum an attractive pagoda-like molecular architecture of the complex 2. Product 2 showed a high catalytic activity in the oxidation of alkanes to the corresponding alkyl hydroperoxides (in yields up to 30%) and alcohols (in yields up to 100%) and in the oxidative formation of benzamides from alcohols (catalyst loading down to 0.4 mol % in Cu/Fe).
- Bilyachenko, Alexey N.,Khrustalev, Victor N.,Zubavichus, Yan V.,Shul'Pina, Lidia S.,Kulakova, Alena N.,Bantreil, Xavier,Lamaty, Frédéric,Levitsky, Mikhail M.,Gutsul, Evgeniy I.,Shubina, Elena S.,Shul'Pin, Georgiy B.
-
p. 528 - 534
(2018/01/11)
-
- New oxidovanadium(iv) complex with a BIAN ligand: synthesis, structure, redox properties and catalytic activity
-
Reaction of VCl3 with bis[N-(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) in air afforded [VOCl2(dpp-bian)] (1). The complex was characterized by IR and UV-vis spectroscopies and elemental analysis. The crystal structure of 1 was determined by X-ray diffraction (XRD) analysis. The vanadium atom is in a square-pyramidal OCl2N4 coordination environment. The cyclic voltammogram (CV) in dichloromethane reveals an irreversible oxidation process at +1.40 V (vs. Ag/AgCl) assigned to the V(iv)/V(v) couple, and two consecutive quasi-reversible one-electron reduction processes at ?0.32 V and ?1.05 V (vs. Ag/AgCl), respectively, assigned to the bian/bian?/ and bian?//bian2? couples, followed by irreversible reduction at ?1.6 V (vs. Ag/AgCl). The EPR spectrum of 1 in toluene shows a single 8-line signal typical for oxidovanadium(iv) complexes with d1 configuration. The magnetic behavior of 1 confirms the presence of one unpaired electron (μeff (330 K) = 1.67 μB), and the isolation of the paramagnetic centers. Application of 1 to oxidation of alkanes documented high catalytic activity under mild conditions. The kinetics and selectivity of alkane oxygenation by the 1/H2O2 and 1/PCA/H2O2 systems (PCA is pyrazine-2-carboxylic acid) were studied. The reaction is more efficient in the presence of PCA.
- Fomenko, Iakov S.,Gushchin, Artem L.,Shul'pina, Lidia S.,Ikonnikov, Nikolay S.,Abramov, Pavel A.,Romashev, Nikolay F.,Poryvaev, Artem S.,Sheveleva, Alena M.,Bogomyakov, Artem S.,Shmelev, Nikita Y.,Fedin, Matvey V.,Shul'pin, Georgiy B.,Sokolov, Maxim N.
-
supporting information
p. 16200 - 16210
(2018/10/04)
-
- OPEN-FLASK HYDROBORATION AND THE USE THEREOF
-
The present disclosure generally relates to a process for hydroboration of an alkene or alkyne using ammonia borane (AB). In particular, the present invention relates to hydroboration of an alkene or alkyne in the presence of air or moisture, and a clean process for facile preparation of an alcohol by oxidizing the organoborane so formed with hydrogen peroxide. The products, including aminodialkylboranes, ammonia trialkylborane complexes, as well as various alcohols so prepared, are within the scope of this disclosure.
- -
-
Paragraph 0046; 0049; 0059; 0060; 0061
(2018/03/25)
-
- Interplay between H-bonding and interpenetration in an aqueous copper(ii)-aminoalcohol-pyromellitic acid system: self-assembly synthesis, structural features and catalysis
-
Two new copper(ii) coordination compounds, [Cu(H1.5mdea)2]2(H2pma) (1a) and [{Cu2(μ-Hmdea)2}2(μ4-pma)]n·2nH2O (1b), were self-assembled at different temperatures from the same multicomponent reaction system, comprising copper(ii) nitrate, N-methyldiethanolamine (H2mdea), pyromellitic acid (H4pma), and potassium hydroxide. Products 1a and 1b were isolated as microcrystalline solids and fully characterized and their structures were established by single-crystal X-ray diffraction. Compound 1a features the bis-aminoalcohol(ate) monocopper(ii) units and H2pma2? anions that are multiply interconnected by strong H-bonds into a firm 2D H-bonded layer. Compound 1b reveals the bis-aminoalcoholate dicopper(ii) motifs that are interlinked by the μ4-pma4? spacers into a 3D + 3D interpenetrated metal-organic framework. From a topological perspective, both networks of 1a and 1b are uninodal and driven by similar 4-connected H2pma2? or pma4? nodes, but result in distinct sql and dia topologies, respectively. Compound 1a was applied as an efficient catalyst for two model cycloalkane functionalization reactions: (1) oxidation by H2O2 to form cyclic alcohols and ketones and (2) hydrocarboxylation by CO/H2O and S2O82? to form cycloalkanecarboxylic acids. The substrate scope, effects of various reaction parameters, selectivity and mechanistic features were also investigated.
- Fernandes, Tiago A.,Kirillova, Marina V.,André, Vania,Kirillov, Alexander M.
-
p. 16674 - 16683
(2018/12/05)
-
- Synthesis of Mono- and Dinuclear Vanadium Complexes and Their Reactivity toward Dehydroperoxidation of Alkyl Hydroperoxides
-
Several vanadium(V) complexes with either dipic-based or Schiff base ligands were synthesized. The complexes were fully characterized by elemental analysis, IR, 1H, 13C, and 51V NMR spectroscopy, as well as mass spectrometry and X-ray diffraction. Furthermore, they were tested toward their catalytic deperoxidation behavior and a significant difference between 4-heptyl hydroperoxide and cyclohexyl hydroperoxide was observed. In the case of 4-heptyl hydroperoxide, the selectivity toward the corresponding ketone was higher than with cyclohexyl hydroperoxide. DFT calculations performed on the vanadium complex showed that selective decomposition of secondary hydroperoxides with vanadium(V) to yield the corresponding ketone and water is indeed energetically feasible. The computed catalytic path, involving cleavage of the O-O bond, hydrogen transfer, release of ketone/water, and finally addition of hydroperoxide, can proceed without the generation of radical species.
- Schmidt, Anna-Corina,Hermsen, Marko,Rominger, Frank,Dehn, Richard,Teles, Joaquim Henrique,Sch?fer, Ansgar,Trapp, Oliver,Schaub, Thomas
-
supporting information
p. 1319 - 1332
(2017/02/15)
-
- Direct Au-Ni/Al2O3 catalysed cross-condensation of ethanol with isopropanol into pentanol-2
-
Ethanol and isopropanol cross-condensation 0.2Au-0.06Ni/γ-Al2O3 catalyst have been developed based on the synergetic effect of gold and nickel in many reactions. A cross-condensation reaction results in the formation of pentanol-2 and pentanon-2 in high yields in the absence of any alkali or sacrificial agents (e.g., hydrogen acceptors or hydrogen donors). In this study, heterogeneous Au-Ni/Al2O3 catalysts were used in this type of reaction for the first time. The catalyst developed in this study is also effective for the self-condensation of ethanol, providing 85% selectivity of linear α-alcohols at 63.5% ethanol conversion. Structural investigations show that the morphological peculiarities and charge state of gold may produce the different activities of mono- and bimetallic Au- and Ni-containing catalysts.
- Chistyakov,Zharova,Nikolaev,Tsodikov
-
-
- A Manganese Pre-Catalyst: Mild Reduction of Amides, Ketones, Aldehydes, and Esters
-
A new (N-phosphinoamidinate)manganese complex is shown to be a useful pre-catalyst for the hydrosilative reduction of carbonyl compounds, and in most cases at room temperature. The Mn-catalyzed reduction of tertiary amides to tertiary amines, with a useful scope, is demonstrated for the first time by use of this catalyst, and is competitive with the most effective transition-metal catalysts known for such transformations. Ketones, aldehydes, and esters were also successfully reduced under mild conditions by using this new Mn catalyst.
- Kelly, Colin M.,McDonald, Robert,Sydora, Orson L.,Stradiotto, Mark,Turculet, Laura
-
supporting information
p. 15901 - 15904
(2017/12/13)
-
- Synthesis, structures and catalytic activity of p-tolylimido rhenium(V) complexes incorporating quinoline-derived ligands
-
p-Tolylimido rhenium(V) complexes, trans-(Cl,Cl)-[Re(p-NC6H4CH3)Cl2(4-MeO-quin-2-COO)(PPh3)] (1), trans-(Br,Br)-[Re(p-NC6H4CH3)Br2(4-MeO-quin-2-COO)(PPh3)]·2MeCN (2), trans-(Cl,Cl)-[Re(p-NC6H4CH3)Cl2(isoquin-1-COO)(PPh3)] (3), trans-(Br,Br)-[Re(p-NC6H4CH3)Br2(isoquin-1-COO)(PPh3)] (4), cis-(Cl,Cl)-[Re(p-NC6H4CH3)Cl2(4-MeO-quin-2-COO)(PPh3)] (5), cis-(Br,Br)-[Re(p-NC6H4CH3)Br2(4-MeO-quin-2-COO)(PPh3)]·MeOH (6), cis-(Cl,Cl)-[Re(p-NC6H4CH3)Cl2(isoquin-1-COO)(PPh3)] (7) and cis-(Br,Br)-[Re(p-NC6H4CH3)Br2(isoquin-1-COO)(PPh3)] (8), have been synthesized and characterized using X-ray analysis and spectroscopic methods (IR,1H,13C and31P NMR, UV–Vis). To elucidate the structural, spectroscopic and bonding properties, the theoretical calculations at the DFT level were undertaken for 1, 3, 5 and 7. The synthesized complexes exhibited moderate activity in the oxidation of 1-phenylethanol and certain alkanes (n-heptane and methylcyclohexane) with tert-butyl hydroperoxide (TBHP) in acetonitrile. Chromatograms of products obtained from the alkanes indicated that a sufficient sterical hindrance exists around of the rhenium catalytic center.
- Gryca,Machura,Shul'pina, Lidia S.,Shul'pin, Georgiy B.
-
supporting information
p. 683 - 695
(2016/12/02)
-
- A non-dissociative open-flask hydroboration with ammonia borane: Ready synthesis of ammonia-trialkylboranes and aminodialkylboranes
-
Under open-flask conditions, ammonia borane hydroborates olefins in refluxing tetrahydrofuran. Unlike conventional hydroboration, the Lewis base (ammonia) is not dissociated from the boron center. Terminal alkenes selectively provide ammonia-trialkylborane complexes. On the other hand, internal alkenes afford aminodialkylboranes via a metal-free hydroboration-dehydrogenation sequence. Alkaline hydrogen peroxide oxidation of the products provides the corresponding alcohols in high yields.
- Ramachandran, P. Veeraraghavan,Drolet, Michael P.,Kulkarni, Ameya S.
-
supporting information
p. 11897 - 11900
(2016/10/09)
-
- Catalytic alkylation of acetone with ethanol over Pd/carbon catalysts in flow-through system via borrowing hydrogen route
-
Consecutive alkylation of acetone with ethanol as model reactants was studied in order to obtain biomass based fuels by continuous processing of acetone-butanol-ethanol (ABE) mixture. Butanol, which can inevitably form as Guerbet side product in a self-aldol reaction of ethanol was not applied in our study as an initial component, in order to follow the complexity of the reaction mechanism. A flow-through reactor was applied with inert He or reducing H2 stream in the temperature range of 150-350°C. Efficient catalysts containing Pd and base (K3PO4 or CsOH) crystallites were prepared applying commercial activated carbon (AC) support. The catalyst beds were pre-treated in H2 flow at 350°C. Mono- or dialkylated ketones were formed with high yields and these products could be reduced only to alcohols over palladium.
- Novodárszki, Gyula,Onyestyák, Gy?rgy,Wellisch, ágnes Farkas,Pilbáth, Aranka
-
p. 251 - 257
(2016/07/06)
-
- Oxidation of Alkanes by Periodate Using a MnV Nitrido Complex as Catalyst
-
The design of catalytic systems that can selectively oxidize unactivated C?H bonds under mild conditions is a challenge to chemists. We report here that the manganese(V) nitrido complex [MnV(N)(CN)4]2? is a highly efficient catalyst for the oxidation of alkanes by periodate (IO4 ?) at ambient conditions. Excellent yields of alcohols and ketones (>95 %) are obtained with a maximum turnover number (TON) of 3000.
- Ma, Li,Chen, Lingjing,Lau, Tai-Chu
-
p. 2846 - 2848
(2016/10/25)
-
- Highly efficient reduction of carbonyls, azides, and benzyl halides by NaBH4 in water catalyzed by PANF-immobilized quaternary ammonium salts
-
A series of polyacrylonitrile fiber-supported quaternary ammonium salts (PANF-QAS) were prepared and applied to the catalytic reduction of aldehydes, ketones, azides, and benzyl halides in water using NaBH4 as the reducing reagent in a highly efficient, economic, and environmentally benign way. The structure-activity relationships were investigated, which showed that the catalysts made up of quaternary ammonium salts with longer alkyl chains, larger cationic radii and better lipophilicity speed up the reduction reaction to afford the products in excellent yield. Moreover, the optimized catalyst can be applied to the reduction of 1-naphthaldehyde in a continuous flow process with outstanding reactivity and recyclability.
- Du, Jianguo,Xu, Gang,Lin, Huikun,Wang, Guangwei,Tao, Minli,Zhang, Wenqin
-
supporting information
p. 2726 - 2735
(2016/05/24)
-
- Ketone hydrogenation catalyzed by a new iron(II)-PNN complex
-
The formal FeII-hydride complex [Fe(H)(CO)(MeCN)LPNN](BF4) (1) (LPNN = 2-[(di-tert-butylphosphino)methyl]-6-[1-(mesitylimino)ethyl]pyridine) catalyzes the hydrogenation of ketones under mild conditions (room temperature, p(H2) = 4 bar) and short reaction times (1-3 h) in the presence of catalytic amounts of KHMDS as a base. The reaction presumably proceeds via a dearomatization/rearomatization mechanism. However, in comparison with the reaction of related iron-PNP complexes, the reaction mechanism seems to be different, and an enolate formation step appears to precede catalysis. Moreover, the catalytic performance of the PNN system is inferior under similar conditions, and this observation is probably a consequence of an intramolecular deactivation pathway, which involves reductive proton migration within a dearomatized FeII-hydride complex to form a catalytically inactive Fe0 species. The weaker electron-donating properties of the PNN ligand system, when compared with analogous PNP-based ligands, cause the dearomatized PNN iron(ii)-hydride intermediate to be less electron-rich and consequently more prone to the intramolecular reductive elimination pathway. This result is in line with the need for electron-rich metal hydrides for efficient hydrogenation catalysis to take place.
- Butschke,Feller,Diskin-Posner,Milstein
-
p. 4428 - 4437
(2016/07/06)
-
- 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
-
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 (2) 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 2 displayed significantly higher activity. Additionally, exploiting the metal-ligand cooperativity in complex 2, 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.
- Paul, Bhaskar,Chakrabarti, Kaushik,Kundu, Sabuj
-
supporting information
p. 11162 - 11171
(2016/07/16)
-
- Highly Active and Selective Manganese C=O Bond Hydrogenation Catalysts: The Importance of the Multidentate Ligand, the Ancillary Ligands, and the Oxidation State
-
The replacement of expensive noble metals by earth-abundant transition metals is a central topic in catalysis. Herein, we introduce a highly active and selective homogeneous manganese-based C=O bond hydrogenation catalyst. Our catalyst has a broad substrate scope, it is able to hydrogenate aryl–alkyl, diaryl, dialkyl, and cycloalkyl ketones as well as aldehydes. A very good functional group tolerance including the quantitative and selective hydrogenation of a ketone in the presence of a non-shielded olefin is observed. In Mn hydrogenation catalysis, the combination of the multidentate ligand, the oxidation state of the metal, and the choice of the right ancillary ligand is crucial for high activity. This observation emphasizes an advantage and the importance of homogeneous catalysts in 3d-metal catalysis. For coordination compounds, fine-tuning of a complex coordination environment is easily accomplished in comparison to enzyme and/or heterogeneous catalysts.
- Kallmeier, Fabian,Irrgang, Torsten,Dietel, Thomas,Kempe, Rhett
-
supporting information
p. 11806 - 11809
(2016/11/16)
-
- Synthesis and kinetic regularities of the thermal decomposition of new hydrotrioxides of cyclic alcohols
-
Cyclic hydrotrioxides were synthesized by low-temperature (?78 °C) ozonolysis of a series of cyclic alcohols and identified using 1H NMR spectra. The kinetic regularities of the thermal decomposition of the synthesized hydrotrioxides were studied. The experimental proof of the induced decomposition of alcohol hydrotrioxides was obtained for the first time using cyclohexanol hydrotrioxide as an example. The influence of cyclic substituents on the thermal stability of the hydrotrioxides is shown.
- Grabovskiy,Khalitova,Fedorova,Lobov,Rol’nik,Kabal’nova
-
p. 464 - 468
(2017/03/08)
-
- ALKANE OXIDATION BY MODIFIED HYDROXYLASES
-
This invention relates to modified hydroxylases. The invention further relates to cells expressing such modified hydroxylases and methods of producing hydroxylated alkanes by contacting a suitable substrate with such cells.
- -
-
Paragraph 0323; 0324
(2016/02/16)
-
- Acetone alkylation with ethanol over multifunctional catalysts by a borrowing hydrogen strategy
-
Step by step alkylation of acetone (A) with ethanol (E) in a ratio of 1: 2 was investigated. A fixed bed flow-through reactor system was used at a total pressure of 21 bar and in the temperature range of 150-350 °C in inert He or a reducing H2 medium. Following the hydrogen borrowing methodology, two types of catalysts were prepared; using neutral activated carbon (AC) and alkaline hydrotalcite (HT) supports, namely 5 wt% Pd/AC in the presence of alkaline additives (10, 20 and 30 wt% KOH or 20% K3PO4); 9 wt% Cu/HT and 5 wt% Pd/HT. The catalysts were activated in a H2 flow at 350 °C. Different yields of mono- or dialkylated ketones were observed. In a hydrogen medium over the same catalyst systems the ketone products could be reduced to alcohols. In this study the Pd/HT catalyst seems to be the most promising for fuel production based on biomass fermentation.
- Onyestyák, Gy.,Novodárszki, Gy.,Barthos,Klébert, Sz.,Wellisch, á. Farkas,Pilbáth
-
p. 99502 - 99509
(2015/12/04)
-
- Synthesis of new metalloporphyrin derivatives from [5,10,15,20-tetrakis (pentafluorophenyl)porphyrin] and 4-mercaptobenzoic acid for homogeneous and heterogeneous catalysis
-
Synthetic metalloporphyrins are catalysts that can efficiently insert oxygen and other atoms such as nitrogen and sulfur in hydrocarbons and in a wide variety of other organic compounds. This work reports on a synthetic strategy to prepare new metalloporphyrins via structural modification of [5,10,15,20-tetrakis (pentafluorophenyl)porphyrin], or [H2(TPFPP)], with 4-mercaptobenzoic acid; it also describes their characterization and catalytic activity. The substituent groups present in the structure of the resulting porphyrins furnished structured solids, which could potentially serve as catalysts in heterogeneous medium. Investigation of the catalytic activity of the new derivatives in the oxidation of (Z)-cyclooctene, cyclohexane, and heptane, under homogeneous conditions, and in the oxidation of (Z)-cyclooctene, in heterogeneous medium, proved that the new metalloporphyrins constituted excellent catalysts for (Z)-cyclooctene epoxidation. As for alkane oxidation, they selectively gave the corresponding alcohol in good yields.
- de F. Castro, Kelly A.D.,Sim?es, Mário M.Q.,da Gra?a P.M.S. Neves, Maria,Cavaleiro, José A.S.,Ribeiro, Ronny R.,Wypych, Fernando,Nakagaki, Shirley
-
-
- Catalytic oxidation of alkanes by a (salen)osmium(VI) nitrido complex using H2O2 as the terminal oxidant
-
The osmium(vi) nitrido complex, [OsVI(N)(L)(CH3OH)]+ (1, L = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion) is an efficient catalyst for the oxidation of alkanes under ambient conditions using H2O2 as the oxidant. Alkanes are oxidized to the corresponding alcohols and ketones, with yields up to 75% and turnover numbers up to 2230. Experimental and computational studies are consistent with a mechanism that involves O-atom transfer from H2O2 to [OsVI(N)(L)]+ to generate an [OsVIII(N)(O)(L)]+ active intermediate.
- Chen, Man,Pan, Yi,Kwong, Hoi-Ki,Zeng, Raymond J.,Lau, Kai-Chung,Lau, Tai-Chu
-
supporting information
p. 13686 - 13689
(2015/09/02)
-
- Oxidation of alkanes and benzene with hydrogen peroxide catalyzed by ferrocene in the presence of acids This article is dedicated to the memory of Aleksandr Evgenievich Shilov (1930-2014).
-
The efficient (turnover numbers attained 1200) oxidation of alkanes to the corresponding alkyl hydroperoxides by H2O2 in the presence of catalytic amounts of ferrocene proceeds in MeCN at 40-50 °C. Benzene is oxidized in the same system to phenol. An obligatory component of the catalytic system for both reactions is pyrazine-2-carboxylic acid (PCA) or trifluoroacetic acid (TFA). Kinetic study as well as selectivity parameters testified that the oxidation proceeds with the participation of hydroxyl radicals. In the case of PCA as a co-catalyst the initial rate W0 of the reaction with both cyclohexane and benzene depends quadratically on [Cp2Fe]0 whereas the two reactions in the presence of TFA are of half order in ferrocene. The ferrocene-catalyzed reaction of cyclohexane with H2O216 in an atmosphere of labeled 18O2 gave after 2 h a mixture of labeled and unlabeled cyclohexyl hydroperoxide (total yield 20% based on starting cyclohexane) containing up to 69% of 18O (the analysis was after reduction of cyclohexyl hydroperoxide into cyclohexanol with PPh3).
- Shul'pina, Lidia S.,Kudinov, Aleksandr R.,Mandelli, Dalmo,Carvalho, Wagner A.,Kozlov, Yuriy N.,Vinogradov, Mikhail M.,Ikonnikov, Nikolay S.,Shul'pin, Georgiy B.
-
p. 217 - 231
(2015/09/01)
-
- 16-Electron pentadienyl- and cyclopentadienyl-ruthenium half-sandwich complexes with bis(imidazol-2-imine) ligands and their use in catalytic transfer hydrogenation
-
Bis(η5-2,4-dimethylpentadienyl)ruthenium(ii), [(η5-C7H11)2Ru] (1, "open ruthenocene"), which has become accessible in high yield and large quantities via an isoprene-derived diallyl ruthenium(iv) complex, can be converted into the protonated open ruthenocene 2 by treatment with HBF4 and subsequently into the protonated half-open ruthenocene 3 by reaction with cyclopentadiene. The electronic structure of 3 was studied by DFT methods, revealing that the CH-agostic complex [(η5-C5H5)Ru{(1-4η)-C7H12-η2-C5,H5}]BF4 (A) represents the global minimum, which is 3.7 kcal mol-1 lower in energy than the hydride complex [(η5-C5H5)RuH(η5-C7H11)]BF4 (B). 2 and 3 were treated with the ligands N,N′-bis(1,3,4,5-tetramethylimidazolin-2-ylidene)-1,2-ethanediamine (BLMe) and N,N′-bis(1,3-diisopropyl-4,5-dimethylimidazolin-2-ylidene)-1,2-ethanediamine (BLiPr) to afford the cationic 16-electron pentadienyl and cyclopentadienyl complexes [(η5-C7H11)Ru(BLR)]BF4 (4a, R = Me; 4b, R = iPr) and [(η5-C5H5)Ru(BLR)]BF4 (5a, R = Me; 5b, R = iPr). All complexes catalyse the transfer hydrogenation of acetophenone in isopropanol, and the most active complex 4a in this reaction was employed for the hydrogenation of a broader range of aliphatic and aromatic ketones.
- Gl?ge, Thomas,Jess, Kristof,Bannenberg, Thomas,Jones, Peter G.,Langenscheidt-Dabringhausen, Nadine,Salzer, Albrecht,Tamm, Matthias
-
p. 11717 - 11724
(2015/06/30)
-
- Facile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive Deoxygenation of Ketones and Aldehydes
-
A series of ketones and aldehydes are reduced in toluene under H2 in the presence of 5 mol % B(C6F5)3 and either cyclodextrin or molecular sieves affording a facile metal-free protocol for reduction to alcohols. Similar treatment of aryl ketones resulted in metal-free deoxygenation yielding aromatic hydrocarbons.
- Mahdi, Tayseer,Stephan, Douglas W.
-
supporting information
p. 8511 - 8514
(2015/11/27)
-
- Synthesis of pyrrole N-derivatives from oxazolidines
-
Transformations of oxazolidine derivatives synthesized from industrially produced amino alcohols, aldehydes, and ketones under basic or acidic catalysis lead to the formation of N-alkyl- and N-(hydroxyalkyl)-substituted pyrroles in 19-81% yields.
- Sadykov, E. Kh.,Stankevich,Lobanova,Klimenko
-
p. 219 - 224
(2014/04/17)
-
- Highly efficient alkane oxidation catalyzed by [MnV(N)(CN) 4]2-. Evidence for [MnVII(N)(O)(CN) 4]2- as an active intermediate
-
The oxidation of various alkanes catalyzed by [MnV(N)(CN) 4]2- using various terminal oxidants at room temperature has been investigated. Excellent yields of alcohols and ketones (>95%) are obtained using H2O2 as oxidant and CF3CH 2OH as solvent. Good yields (>80%) are also obtained using (NH4)2[Ce(NO3)6] in CF 3CH2OH/H2O. Kinetic isotope effects (KIEs) are determined by using an equimolar mixture of cyclohexane (c-C6H 12) and cyclohexane-d12 (c-C6D12) as substrate. The KIEs are 3.1 ± 0.3 and 3.6 ± 0.2 for oxidation by H2O2 and Ce(IV), respectively. On the other hand, the rate constants for the formation of products using c-C6H12 or c-C6D12 as single substrate are the same. These results are consistent with initial rate-limiting formation of an active intermediate between [Mn(N)(CN)4]2- and H2O2 or CeIV, followed by H-atom abstraction from cyclohexane by the active intermediate. When PhCH2C(CH3)2OOH (MPPH) is used as oxidant for the oxidation of c-C6H12, the major products are c-C6H11OH, c-C6H10O, and PhCH2C(CH3)2OH (MPPOH), suggesting heterolytic cleavage of MPPH to generate a Mn=O intermediate. In the reaction of H2O2 with [Mn(N)(CN)4]2- in CF 3CH2OH, a peak at m/z 628.1 was observed in the electrospray ionization mass spectrometry, which is assigned to the solvated manganese nitrido oxo species, (PPh4)[Mn(N)(O)(CN)4] -·CF3CH2OH. On the basis of the experimental results the proposed mechanism for catalytic alkane oxidation by [MnV(N)(CN)4]2-/ROOH involves initial rate-limiting O-atom transfer from ROOH to [Mn(N)(CN)4]2- to generate a manganese(VII) nitrido oxo active species, [MnVII(N)(O) (CN)4]2-, which then oxidizes alkanes (R'H) via a H-atom abstraction/O-rebound mechanism. The proposed mechanism is also supported by density functional theory calculations.
- Ma, Li,Pan, Yi,Man, Wai-Lun,Kwong, Hoi-Ki,Lam, William W.Y.,Chen, Gui,Lau, Kai-Chung,Lau, Tai-Chu
-
p. 7680 - 7687
(2014/06/10)
-
- Enabling catalytic ketone hydrogenation by frustrated lewis pairs
-
Hydrogenation of alkyl and aryl ketones using H2 is catalytically achieved in 18 examples using 5 mol % B(C6F5)3 in an ethereal solvent. In these cases the borane and ether behave as a frustrated Lewis pair to activate H2 and effect the reduction.
- Mahdi, Tayseer,Stephan, Douglas W.
-
supporting information
p. 15809 - 15812
(2015/02/19)
-
- Bioproduction of chiral epoxyalkanes using styrene monooxygenase from rhodococcus sp. ST-10 (RhSMO)
-
We describe the enantioselective epoxidation of straight-chain aliphatic alkenes using a biocatalytic system containing styrene monooxygenase from Rhodococcus sp. ST-10 and alcohol dehydrogenase from Leifsonia sp. S749. The biocatalyzed enantiomeric epoxidation of 1-hexene to (S)-1,2-epoxyhexane (44.6 mM) using 2-propanol as the hydrogen donor was achieved under optimized conditions. The biocatalyst had broad substrate specificity for various aliphatic alkenes, including terminal, internal, unfunctionalized, and di- and tri-substituted alkenes. Here, we demonstrate that this biocatalytic system is suitable for the efficient production of enantioenriched (S)-epoxyalkanes.
- Toda, Hiroshi,Imae, Ryouta,Itoh, Nobuya
-
supporting information
p. 3443 - 3450
(2015/02/05)
-
- A new binuclear oxovanadium(v) complex as a catalyst in combination with pyrazinecarboxylic acid (PCA) for efficient alkane oxygenation by H 2O2
-
A new binuclear oxovanadium(v) complex [{VO(OEt)(EtOH)}2L] (1) where H4L is bis(2-hydroxybenzylidene)terephthalohydrazide has been synthesized and fully characterized. The combination of 1 with pyrazine-2-carboxylic acid (PCA; a cocatalyst) affords a catalytic system for the efficient oxidation of saturated hydrocarbons, RH, with hydrogen peroxide and air in acetonitrile solution at 50°C to produce alkyl hydroperoxides, ROOH, as the main primary products. Very high turnover numbers (TONs) have been attained in this reaction: for example, after 2220 min, TON = 44 000 and initial TOF (turnover frequency) = 3300 h-1 per molecule of complex 1. The estimated activation energy of the cyclohexane oxygenation in the presence of 1/PCA is Ea = 16 ± 2 kcal mol-1. This value is identical to that obtained for the cyclohexane oxidation with H 2O2 catalyzed by the (n-Bu4N)[VO 3]/PCA combination (17 ± 2 kcal mol-1). The dependences of initial oxidation rates W0 on the initial concentrations of all components of the reaction mixture have been determined. Based on these kinetic data and on the regio- and bond-selectivity parameters measured in the oxidation of linear and branched alkanes a mechanism of the oxidation has been proposed which includes the generation of hydroxyl radicals in the crucial stage. The Royal Society of Chemistry.
- Sutradhar, Manas,Shvydkiy, Nikita V.,Guedes Da Silva, M. Fátima C.,Kirillova, Marina V.,Kozlov, Yuriy N.,Pombeiro, Armando J. L.,Shul'Pin, Georgiy B.
-
p. 11791 - 11803
(2013/09/02)
-
- SYNTHESIS OF HIGH CALORIC FUELS AND CHEMICALS
-
In one embodiment, the present application discloses methods to selectively synthesize higher alcohols and hydrocarbons useful as fuels and industrial chemicals from syngas and biomass. Ketene and ketonization chemistry along with hydrogenation reactions are used to synthesize fuels and chemicals. In another embodiment, ketene used to form fuels and chemicals may be manufactured from acetic acid which in turn can be synthesized from synthesis gas which is produced from coal, biomass, natural gas, etc.
- -
-
Paragraph 0091
(2013/05/23)
-
- Highly efficient divanadium(V) pre-catalyst for mild oxidation of liquid and gaseous alkanes
-
A new binuclear oxovanadium(V) complex bearing an NO2-donor Schiff base ligand, [{VO(EtO)(EtOH)}2(1κ2O,κN: 2κ2O,κN-L)]·2H2O (H4L = bis(2-hydroxybenzylidene)oxalohydrazonic acid) was prepared and fully characterized by IR, 1H NMR and electronic spectroscopies, elemental analysis and single crystal X-ray diffraction. In the presence of 2-pyrazinecarboxylic acid (PCA) or another acid promoter, this compound acts as a highly efficient pre-catalyst towards the oxidation of gaseous and liquid alkanes by aqueous H2O2 under mild conditions, in aqueous MeCN. Total yields of oxygenates up to 45% and overall turnover numbers up to 7.8 × 103 are achieved.
- Gupta, Samik,Kirillova, Marina V.,Guedes Da Silva, M. Fátima,Pombeiro, Armando J.L.
-
-
- General and highly efficient iron-catalyzed hydrogenation of aldehydes, ketones, and α,β-unsaturated aldehydes
-
EnvIRONmentally friendly: The title hydrogenation of aldehydes, ketones, and α,β-unsaturated aldehydes is reported. In the presence of the catalyst 1, primary, secondary, and allylic alcohols were obtained in good to excellent yields under mild reaction conditions. The catalyst is easily and inexpensively prepared, and is also stable to air, water, and column chromatography. Copyright
- Fleischer, Steffen,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
-
p. 5120 - 5124
(2013/06/27)
-
- Heterogeneous transfer hydrogenation over mesoporous SBA-15 co-modified by anionic sulfonate and cationic Ru(III) complex
-
Via ion-pair electrostatic interactions with sulfonate anions, the phosphine-ligated Ru(III) complex cations of [RuIIICl 4(L)2]+ (L = 1-butyl-2-(diphenylphosphino)-3- methylimidazolium) were successfully immobilized into a sulfonated SBA-15 framework, leading to the formation of the cationic Ru(III) complex and anionic sulfonate co-modified SBA-15 material (referred to as Ru-SO3-SBA-15). This material was characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), N2 adsorption-desorption isotherms, FT-IR, and elemental analysis techniques. As a heterogeneous catalyst, Ru-SO3-SBA-15 exhibited comparable activity and selectivity to the parent homogeneous catalyst [RuIIICl4(L) 2]PF6 in transfer hydrogenation of ketones. However, as a result of the limited durability of Ru-SO3-SBA-15 in strongly alkaline environments at high temperature, the activity of Ru-SO 3-SBA-15 could not be maintained during subsequent recycled uses.
- Chen, Sheng-Jie,You, Hong-Xing,Vo-Thanh, Giang,Liu, Ye
-
p. 851 - 858
(2013/07/19)
-
- (N -Phosphinoamidinate)Iron pre-catalysts for the room temperature hydrosilylation of carbonyl compounds with broad substrate scope at low loadings
-
The synthesis and structural characterization of three-coordinate iron(II) and cobalt(II) complexes supported by new N-phosphinoamidinate ligands is reported, along with the successful application of these complexes as precatalysts for the challenging room-temperature hydrosilylation of carbonyl compounds to afford alcohols upon workup. Under the rigorous screening conditions employed (0.015 mol % Fe) for the reduction of acetophenone, the well-defined iron(II) amido precatalyst 2b, featuring bulky N-2,6- diisopropylphenyl and di-tert-butylphosphino moieties within the N-phosphinoamidinate ligand, exhibited exceptional catalytic performance. Further experimentation revealed that the yield achieved in the hydrosilylation of acetophenone employing 2b was unaltered when conducting reactions in the absence of light, in the presence of excess mercury, or under solvent-free conditions. Notably, precatalyst 2b was found to exhibit the broadest substrate scope reported to date for such room-temperature iron-catalyzed carbonyl hydrosilylations en route to alcohols, enabling the chemoselective reduction of structurally diverse aldehydes and ketones, as well as for the first time esters, at remarkably low loadings (0.01-1.0 mol % Fe) and using only 1 equiv of phenylsilane reductant.
- Ruddy, Adam J.,Kelly, Colin M.,Crawford, Sarah M.,Wheaton, Craig A.,Sydora, Orson L.,Small, Brooke L.,Stradiotto, Mark,Turculet, Laura
-
supporting information
p. 5581 - 5588
(2013/11/06)
-
- In vitro double oxidation of n-heptane with direct cofactor regeneration
-
A novel concept for the direct oxidation of cycloalkanes to the corresponding cyclic ketones in a one-pot synthesis in water with molecular oxygen as sole oxidizing agent was reported recently. Based on this concept we have developed a new strategy for the double oxidation of n-heptane to enable a biocatalytic resolution for the direct synthesis of heptanone and (R)-heptanols in a one-pot reaction. The bicatalytic cascade employs an NADH driven P450 BM3 monooxygenase variant (WTNADH, 19A12NADH or CM1 NADH) and an (S)-enantioselective alcohol dehydrogenase (RE-ADH). In the initial step n-heptane is hydroxylated under consumption of NADH to produce (R/S)-heptanol. In the second oxidation step the (S)-heptanol enantiomers are transformed to the corresponding ketones, reducing and thereby regenerating the cofactor. Characterization of initial hydroxylation step revealed high turnover frequencies (TOF) of up to 600 min-1, as well as high coupling efficiencies using NADH as cofactor (up to 44%). In the cascade reaction a nearly 2-fold improved product formation was achieved, compared to the single hydroxylation reaction. The total product concentration reached 1.1 mM, corresponding to a total turnover number (TTN) of 2500. Implementation of an additional cofactor regeneration system (D-glucose/glucose dehydrogenase) enabled a further enhancement in product formation with a total product concentration of 1.8 mM and a TTN of 3500. Copyright
- Mueller, Christina A.,Akkapurathu, Beneeta,Winkler, Till,Staudt, Svenja,Hummel, Werner,Groeger, Harald,Schwaneberg, Ulrich
-
supporting information
p. 1787 - 1798
(2013/07/19)
-
- Alkali metal directed assembly of heterometallic Vv/M (M = Na, K, Cs) coordination polymers: Structures, topological analysis, and oxidation catalytic properties
-
The reactions of [VO(acac)2] with bis(salicylaldehyde)- oxaloyldihydrazone (H4L) and an alkali metal carbonate M 2CO3 (M = K, Na, Cs), in EtOH/H2O medium upon reflux, resulted in the generation of three new heterometallic VV/M materials, namely the 1D [(VO2)2(μ4-L) {Na2(μ-H2O)2(H2O) 2}]n (1), 2D [{V(μ-O)2}2(μ 4-L){K2(μ-H2O)2(H 2O)2}]n (2), and 3D [{V(μ-O) (μ3-O)}2(μ8-L){Cs2(μ-H 2O)2(H2O)2}]n (3) coordination polymers. They were isolated as air-stable solids and fully characterized by IR, UV-vis, 1H, and 51V NMR spectroscopy, ESI-MS(±), elemental, thermal, and single-crystal X-ray diffraction analyses, the latter showing that 1-3 are constructed from the resembling [(VO2)2(μ4/8-L)]2- blocks assembled by the differently bound aqua-metal [M2(μ-H 2O)2(H2O)2]2+ moieties (M = Na, K, Cs). The main distinctive features of 1-3 arise from the different coordination numbers of Na (5), K (7), and Cs (9) atoms, thus increasing the complexity of the resulting networks from the ladder-like 1D chains in 1 to double 2D layers in 2, and layer-pillared 3D framework in 3. The topological analysis of 2 disclosed a uninodal 4-connected underlying net with a rare kgm [Shubnikov plane net (3.6.3.6)/kagome pattern] topology, while 3 features a trinodal 4,7,8-connected underlying net with an unprecedented topology. Compounds 1-3 also show solubility in water (S25 C ≈ 4-7 mg mL-1) and were applied as efficient precatalysts for the homogeneous oxidation of cyclohexane by aqueous H2O2, under mild conditions (50 C) in MeCN/H2O medium and in the presence of an acid promoter. Total yields (based on substrate) of cyclohexanol and cyclohexanone up to 36% and turnover numbers (TONs) up to 5700 were achieved.
- Gupta, Samik,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Pombeiro, Armando J. L.,Kirillov, Alexander M.
-
p. 8601 - 8611
(2013/09/02)
-
- A heterogenized vanadium oxo-aroylhydrazone catalyst for efficient and selective oxidation of hydrocarbons with hydrogen peroxide
-
A hydrazone Schiff base ligand derived from salicylaldehyde and benzhydrazide has been synthesized and reacted with vanadium(IV) leading to the corresponding vanadium(V) complex. The complex has been anchored on the surface of functionalized silica gel by N,O-coordination to the covalently Si-O bound modified salicylaldiminato ligand. The supported complex has been evaluated as a catalyst for hydrocarbon oxidation with hydrogen peroxide in acetonitrile. The heterogeneous system proved to be an efficient catalyst and was able to activate hydrogen peroxide toward the oxidation of alkenes, alkanes, benzene, and alkylaromatic compounds with more than 2,500 h-1 activity. Springer Science+Business Media B.V. 2011.
- Monfared, Hassan Hosseini,Abbasi, Vahideh,Rezaei, Adineh,Ghorbanloo, Massomeh,Aghaei, Alireza
-
experimental part
p. 85 - 92
(2012/08/28)
-
- PHOSPHO-AMINO PINCER-TYPE LIGANDS AND CATALYTIC METAL COMPLEXES THEREOF
-
The present invention provides phospho-amino pincer-type ligands, metal complexes thereof, and catalytic methods comprising such metal complexes.
- -
-
Page/Page column 10-11
(2013/02/27)
-
- Synthesis of an ionic paramagnetic ruthenium(III) complex and its application as an efficient and recyclable catalyst for the transfer hydrogenation of ketones
-
A novel ionic complex, bis[1-butyl-2-(diphenylphosphanyl)-3- methylimidazolium]tetrachloridoruthenium(III) hexafluorophosphate (2), has been synthesized and fully characterized. The single-crystal X-ray diffraction analysis showed that 2 is composed of an Ru complex cation and PF 6- anion. The cation has a highly symmetrical Ru-centered octahedron geometry with four Cl atoms in the equatorial plane and two imidazolium-substituted phosphane ligands in the axial positions. It exhibits paramagnetism due to the presence of one unpaired electron in the phosphane-ligated low-spin RuIII complex. Complex 2 exhibited good catalytic performance in the transfer hydrogenation of a wide range of ketones by using alcohols as hydrogen donors. Owing to its high polarity, good thermal stability, and insensitivity to moisture and oxygen, complex 2 could be used in six catalytic cycles in the transfer hydrogenation of acetophenone without any obvious loss of activity. A novel ionic complex 2 containing an RuIII cation and PF6- anion has been synthesized. The Ru III cation possesses ideal octahedral geometry and exhibits paramagnetism due to the presence of one unpaired electron in the phosphane-ligated low-spin RuIII complex. Complex 2 proves to be an efficient and recyclable catalyst for the transfer hydrogenation of ketones with alcohols as hydrogen donors. Copyright
- Zhou, Chengliang,Zhang, Jing,Dakovic, Marijana,Popovic, Zora,Zhao, Xiaoli,Liu, Ye
-
experimental part
p. 3435 - 3440
(2012/09/08)
-
- Ruthenium(II) pincer complexes with oxazoline arms for efficient transfer hydrogenation reactions
-
Well-defined PNNCN 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 PN3P analogs. These reactions proceed under mild and base-free conditions via protonation- deprotonation of the 'NH' group in the aromatization-dearomatization process.
- Chen, Tao,He, Li-Peng,Gong, Dirong,Yang, Limin,Miao, Xiaohe,Eppinger, J?rg,Huang, Kuo-Wei
-
supporting information; experimental part
p. 4409 - 4412
(2012/09/25)
-
- Purification and characterization of an NADH-dependent alcohol dehydrogenase from Candida maris for the synthesis of optically active 1-(pyridyl)ethanol derivatives
-
A novel (R)-specific alcohol dehydrogenase (AFPDH) produced by Candida maris IFO10003 was purified to homogeneity by ammonium sulfate fractionation, DEAE-Toyopearl, and Phenyl-Toyopearl, and characterized. The relative molecular mass of the native enzyme was found to be 59,900 by gel filtration, and that of the subunit was estimated to be 28,900 on SDS-polyacrylamide gel electrophoresis. These results suggest that the enzyme is a homodimer. It required NADH as a cofactor and reduced various kinds of carbonyl compounds, including ketones and aldehydes. AFPDH reduced acetylpyridine derivatives, β-keto esters, and some ketone compounds with high enantioselectivity. This is the first report of an NADH-dependent, highly enantioselective (R)-specific alcohol dehydrogenase isolated from a yeast. AFPDH is a very useful enzyme for the preparation of various kinds of chiral alcohols.
- Kawano, Shigeru,Yano, Miho,Hasegawa, Junzo,Yasohara, Yoshihiko
-
experimental part
p. 1055 - 1060
(2012/02/03)
-
- Mild homogeneous oxidation of alkanes and alcohols including glycerol with tert-butyl hydroperoxide catalyzed by a tetracopper(II) complex
-
The homogeneous catalytic system composed of the aqua-soluble tetracopper(II) triethanolaminate complex [O?Cu4{N(CH2CH2O)3}4(BOH)4][BF4]2 (1), t-BuOOH (TBHP), water and acetonitrile solvent (optional) has been applied for the mild oxidation of (i) linear and cyclic alkanes to the corresponding alkyl peroxides, alcohols and ketones, (ii) secondary or primary alcohols to ketones or aldehydes, respectively and (iii) glycerol (GLY) to dihydroxyacetone (DHA). Unusual regio-, bond and stereoselectivity parameters have been determined for the alkane oxygenations and discussed in terms of possible steric, hydrophobic and electronic effects. In alcohol oxidations, secondary alcohols are the most reactive substrates. Yields and TONs up to 82% and 1200, respectively, have been obtained in the oxidation of isopropanol to acetone. The selective oxidation of GLY to DHA by the 1/TBHP system has been also achieved, although providing lower conversions. The 1/H2O2 system for the GLY oxidation is particularly advantageous in terms of selectivity and oxidant efficiency. These systems constitute one of the first examples of a metal-catalyzed oxidation of glycerol under homogeneous conditions.
- Kirillova, Marina V.,Kirillov, Alexander M.,Mandelli, Dalmo,Carvalho, Wagner A.,Pombeiro, Armando J.L.,Shul'Pin, Georgiy B.
-
scheme or table
p. 9 - 17
(2010/09/09)
-
- Formamidines - Versatile ligands for zinc-catalyzed hydrosilylation and iron-catalyzed epoxidation reactions
-
In the present study the abilities of catalysts modified by formamidine ligands have been examined in the zinc-catalyzed hydrosilylation of ketones and the iron-catalyzed epoxidation of stilbene, In case of hydrosilylation diethylzinc combined with easily accessible formamidine ligands allow for the efficient reduction of various aryl and alkyl ketones. By using a convenient in situ catalyst system high turnover frequencies up to more than 1.000 h -1 and a broad functional group tolerance were achieved. Moreover, the formamidine ligands were successfully applied, in the iron-catalyzed epoxidation of stilbene with hydrogen peroxide in good yield and chemoselectivity.
- Enthaler, Stephan,Schroeder, Kristin,Inoue, Shigeyoshi,Eckhardt, Bjoern,Junge, Kathrin,Beller, Matthias,Driess, Matthias
-
experimental part
p. 4893 - 4901
(2010/10/03)
-