Elimination Of Acetone Research Articles

Lanthanide Complexes Containing a Terminal LnIII−O Bond: Hydrolysis as a Tool to Assess f‐Element Bond Covalency

AbstractWe report the preparation, isolation, and reactivity of gas‐phase lanthanide nitrate and acetate complexes featuring the elusive trivalent LnIII=O bond. Complexes [LnIII(O)(X)2]− (X=NO3− or CH3CO2−; Ln=La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Tm, Lu) are prepared from [LnIII(CH3CO2)(X)3]− precursors through decarboxylation followed by nitromethane or acetone elimination. The oxo complexes hydrolyze at rates indicating LnIII=O bond stability. The rates for [LnIII(O)(NO3)2]− are essentially invariant, whereas those for [LnIII(O)(CH3CO2)2]− exhibit a moderate decrease across the lanthanide series. The kinetics of lanthanide‐oxo bond hydrolysis are assessed in the context of participation of 5d2 electrons in bonding, changes in covalency via variations in 5d orbital energies and radial extensions, and steric crowding around the lanthanide center. The observed fast hydrolysis rates and lack of correlation to electronic and qualitative covalent considerations confirm the expected strong polarization in LnIII=O bonding, with variations in covalency minimally impacting reactivity. The LnIII=O bond reactivity is compared with previous results for LnIII−O⋅ and LnIV=O, and actinide AnIII=O and AnIV=O; implications for lanthanide/actinide and lanthanide/lanthanide partitioning are discussed. Additionally, nitromethane and acetone elimination are demonstrated as useful for inducing a 2e− O‐atom transfer resulting in non‐oxidative formation of lanthanide‐oxos.

Promoted Catalytic Properties of Acetone over Cerium-Modified Mullite Catalyst YMn2O5

Mullite catalysts have become one of the most widely studied catalysts due to their highly stable structure and unique coordination with oxygen. In this work, Ce-modified mullite-type oxides Y1-xCexMn2O5 have been prepared by sol-gel method to explore their Ce doping amount-dependent catalytic performance for acetone elimination. Experimental results confirm that Y0.9Ce0.1Mn2O5 had optimum acetone oxidation activity, completely achieving 100% acetone conversion at 120℃ under the reaction conditions of acetone concentration = 1000 ppm, 20 vol% O2/N2 and WHSV = 36000 ml·g-1·h-1. This excellent catalytic activity comes from its larger specific surface area and higher Mn4+/Mn3+ molar ratio. XRD and TEM results show that YMn2O5 and CeO2 phases form a multiphase oxide and interfacial structure. XPS results show that the content of doped CeO2 mainly affects the surface adsorbed oxygen (Oads) and Mn4+ content of the catalyst. Manganese species with higher chemical states are indeed more favorable for oxidation reactions on manganese-based catalysts. In addition, the reduction temperature of mixed oxides shifts to the lower temperature region, indicating that manganese and cerium oxides are more reducible, where the mobility of oxygen species is greatly enhanced. Y0.9Ce0.1Mn2O5 also exhibits strong long-term stability and has good resistance to acetone elimination, showing excellent potential in eliminating acetone.

Metals incorporated into OMS-2 lattice create flexible catalysts with highly efficient activity in VOCs combustion

Catalytic combustion of different types of VOCs with various functional groups generally requires certain catalysts with high efficiency. Here, a novel manganese oxide catalyst was tuned via incorporation of small amounts of different metals, including Ce, Ir, Ag, Pd, Cu and Fe respectively, exhibiting flexible activity in the abatement of different VOC species. Pd and Ag doping was beneficial for toluene oxidation, while the addition of Cu significantly enhanced the acetone elimination performance, and Ir incorporation boosted the removal of dichloromethane. XRD, Raman, and TEM results revealed that the different metal ions were well-dispersed into the lattice of OMS-2. Elemental mapping images and ICP-OES combined with DFT calculations demonstrated that Ce, Ir, Pd, Cu and Fe were incorporated into OMS-2 by substituting for Mn on octahedral sites, and Ag could be stabilized in the tunnel of OMS-2 via replacing K ions. EXAFS results suggested that the local tunnel structures of OMS-2 were almost intact after incorporation of the different metals. Pd-OMS-2 and Ag-OMS-2 exhibited excellent activity in catalytic oxidation of toluene due to the improved reducibility and mobility of oxygen. Cu ions improved the scission of CC bonds in acetone and Ir ions facilitated the cleavage of the CCl bond in dichloromethane, all of which contributed to their highly specific activity in removal of the corresponding VOCs. This work provides information on the production of highly efficient metal sites for catalytic oxidation of specific VOC species, and may assist with the design of flexible catalysts for control of miscellaneous VOCs.

Synthesis of Annulated Carbazoles via FeCl3/SnCl4‑Mediated Domino Reaction of Vinyl Ketone Tethered Bromomethylindoles with Arenes and Heteroarenes

AbstractOne-pot synthesis of aryl- as well as heteroaryl-annulated carbazoles was achieved from 2/3-bromomethylindoles involving Lewis acid mediated domino reaction with arenes as well as heteroarenes via successive Friedel–Crafts intermolecular as well as intramolecular alkylations followed by elimination of acetone. Further, the bis-domino reaction of 2,5-bis(bromomethyl)pyrrole was also carried out with selected heteroarenes. Additionally, the synthesized thienocarbazoles and thieno­dibenzofurans were successfully utilized for a second-generation domino reaction.

Identification of the carboxylic acid functionality in protonated drug metabolite model compounds by using tandem mass spectrometry based on ion-molecule reactions coupled with high performance liquid chromatography

The carboxylic acid functionality is among the many functionalities that drug metabolites, degradation products and impurities may contain. Therefore, analytical techniques that can be used to rapidly identify the carboxylic acid functionality are important for pharmaceutical industry. In this study, a tandem mass spectrometric approach based on diagnostic gas-phase ion-molecule reactions with (isopropenoxy)trimethylsilane (ITS) was developed for the identification of protonated compounds containing the carboxylic acid functionality in a modified linear quadrupole ion trap mass spectrometer. All protonated carboxylic acid, N-oxide, sulfoxide, carboxamide, ketone, amine, hydroxylamine, sulfone, sulfonamide, amide, ether, ester and aldehyde model compounds studied react with ITS to form protonated ITS and an adduct that has lost an acetone molecule, [adduct – acetone]+. Protonated compounds containing the carboxylic acid functionality can be differentiated from most other types of protonated compounds based on the formation of a secondary product, 2° [adduct – acetone]+, upon reactions of the [adduct – acetone]+ primary product with a second ITS molecule via addition and elimination of an acetone molecule. Quantum chemical calculations suggest that both addition/acetone elimination reactions are initiated by proton transfer to ITS. Nucleophilic substitution of acetone at the silicon atom by the carbonyl oxygen atom of the carboxylic acid or the primary reaction product leads to elimination of acetone. An equimolar mixture of 4-aminobenzoic acid, clozapine N-oxide, oxcarbamazepine, diphenylsulfoxide, naproxen and celecoxib was subjected to analogous HPLC/tandem mass spectrometry experiments to demonstrate the utility of this method for high-throughput drug metabolite characterization. A limitation of this method is that compounds that contain a phenol group and an additional basic functionality can show a false positive result.

Enhanced Acetone Oxidation over the CeO2/Co3O4 Catalyst Derived from Metal-Organic Frameworks.

A novel CeO2/Co3O4 catalyst with a high catalytic activity has been designed and prepared by pyrolysis of metal-organic frameworks, and its catalytic performance was evaluated by the acetone catalytic oxidation reaction. The Co3O4-M catalyst with T90 at 194 °C was prepared by pyrolysis of the MOF-71 precursor, which was 56 °C lower than that of commercial Co3O4 (250 °C). By the addition of cerium to the MOF-71 precursor, an enhanced CeO2/Co3O4 catalyst with T90 at 180 °C was prepared. Importantly, the CeO2/Co3O4 catalyst exhibited superior stability for acetone oxidation. After 10 cycle tests, the conversion could also be maintained at 97% for at least 100 h with slight activity loss. Characterization studies were used to investigate the influence of cerium doping on the property of the catalyst. The results showed that addition of cerium could facilitate the expansion of the surface area and enhance the porous structure and reducibility at low temperature. Furthermore, the surface ratio of Co3+/Co2+ and mobile oxygen obviously improved with the addition of cerium. Therefore, the metal oxides prepared by this method have potential for the elimination of acetone.

Intensified Biobutanol Recovery by using Zeolites with Complementary Selectivity.

A vapor-phase adsorptive recovery process is proposed as an alternative way to isolate biobutanol from acetone-butanol-ethanol (ABE) fermentation media, offering several advantages compared to liquid phase separation. The effect of water, which is still present in large quantities in the vapor phase, on the adsorption of the organics could be minimized by using hydrophobic zeolites. Shape-selective all-silica zeolites CHA and LTA were prepared and evaluated with single-component isotherms and breakthrough experiments. These zeolites show opposite selectivities; adsorption of ethanol is favorable on all-silica CHA, whereas the LTA topology has a clear preference for butanol. The molecular sieving properties of both zeolites allow easy elimination of acetone from the mixture. The molecular interaction mechanisms are studied by density functional theory (DFT) simulations. The effects of mixture composition, humidity and total pressure of the vapor stream on the selectivity and separation behavior are investigated. Desorption profiles are studied to maximize butanol purity and recovery. The combination of LTA with CHA-type zeolites (Si-CHA or SAPO-34) in sequential adsorption columns with alternating adsorption and desorption steps allows butanol to be recovered in unpreceded purity and yield. A butanol purity of 99.7 mol % could be obtained at nearly complete butanol recovery, demonstrating the effectiveness of this technique for biobutanol separation processes.

Comprehensive investigations of biobutanol production by a non-acetone and 1,3-propanediol generating Clostridium strain from glycerol and polysaccharides.

BackgroundLow-cost feedstocks, a single product (butanol), and a high butanol titer are three key points for establishing a sustainable and economically viable process for biological butanol production. Here, we comprehensively investigated the butanol production from mono-substrates, mainly glycerol and polysaccharides, mainly starch and xylan by a newly identified wild-type Clostridium pasteurianum GL11.ResultsStrain GL11 produced 14.7 g/L of butanol with a yield of 0.41 g/g from glycerol in the batch mode without formation of by-products of acetone and 1,3-propanediol (1,3-PDO). With in situ extraction with biodiesel, the amount of butanol was finally improved to 28.8 g/L in the fed-batch mode. Genomic and enzymatic analysis showed that the deficiency of key enzymes involved in acetone and 1,3-PDO pathway within strain GL11 led to the elimination of these by-products, which may also greatly simplify downstream separation. The elimination of acetone and 1,3-PDO and high butanol tolerance contributed to its high butanol production yield from glycerol. More importantly, strain GL11 could directly convert polysaccharides, such as xylan and starch to butanol with secretion of xylanase and amylase via consolidated bioprocessing.ConclusionsThe wild-type strain GL11 was found to be particularly advantageous due to its capability of efficient butanol production from glycerol and polysaccharides with elimination of acetone and 1,3-PDO formation. And the high butanol production with in situ extraction by using biodiesel would significantly enhance the economic feasibility of fermentative production of butanol from glycerol. These unique features of C. pasteurianum GL11 open the door to the possibility of cost-effective biofuels production in large scale.

Sequential multicomponent synthesis of highly functionalized pyridin-2(1H)-one derivatives

Highly functionalized pyridin-2(1H)-one derivatives were synthesized in high yields by a sequential multicomponent reaction. The mechanism involves the Michael addition of Meldrum's acid to 3-formylchromone, followed by the addition of an amine, intramolecular amidation and elimination of acetone. Depending on the temperature used, decarboxylation can occur. The mechanism of this reaction has been proposed based on the by-products obtained when the reaction was performed using poorly reactive amines. The versatility of this approach has been exemplified using various 3-formylchromones and amines. Analogues of Meldrum's acid were also tested, allowing the synthesis of pyridin-2(1H)-one derivatives with various substituents on the aromatic ring.

Stereoselective synthesis of β-d-GlcNAc-(1 → 4)-d-Glc disaccharide starting from lactose

The stereoselective preparation of the β-d-GlcNAc-(1→4)-d-Glc disaccharide starting from known 4-O-[6-O-(1-methoxy-1-methylethyl)-3,4-O-isopropylidene-β-d-talopyranosyl]-2,3:5,6-di-O-isopropylidene-aldehydo-d-glucose dimethyl acetal (2), in turn easily obtained from lactose, is reported. Key steps of this new procedure, that avoids the glycosylation reaction, are (a) a first epimerization at C-4′ through an unusual procedure involving a completely stereospecific hydroboration–oxidation of the enol ether group of the hex-4-enopyranoside 4, obtained from 3 by base promoted acetone elimination, (b) an amination with inversion by SN2 reaction on an imidazylate intermediate, and, finally, (c) N-acetylation followed by complete deprotection.

Synthesis of phenanthridine and its analogues via aerobic ligand-free domino Suzuki coupling–Michael addition reaction catalyzed by in situ generated palladium-nanoparticles in water

Abstract A convenient methodology has been developed towards the synthesis of substituted phenanthridines and analogous benzo[ k ] and benzo[ i ] derivatives via aerobic ligand-free domino Suzuki coupling–Michael addition reaction in the presence of Pd(OAc) 2 and K 3 PO 4 as a catalytic system in H 2 O at 90 °C in good yields. Reaction was believed to be catalyzed by in situ generated palladium nanoparticles in water with the elimination of acetone.

CO Activation by (Diphosphane)platinum(0): Carbonate and Acetone Formation – Experimental and Mechanistic Study

AbstractThe platinum(II) complex [(dcpp)Pt(C7H7)H] (1) [dcpp = 1,3‐bis(dicyclohexylphosphanyl)propane] reacts under 1 atm of CO to form the bis(carbonyl) complex of Pt0, [(dcpp)Pt(CO)2] (2). Complex2slowly crystallizes in toluene solution to form crystals of the Pt0dimer [(dcpp)(η1‐CO)Pt{μ‐C(O)}Pt(dcpp)] (3) in which one Pt atom is only three‐coordinated with the diphosphane dcpp and one μ‐C(O), while the other is coordinated in a tetrahedral arrangement with one μ‐C(O) and one η1‐CO. Complexes2and3were characterized in solution by31P NMR spectroscopy, and complex3readily reacts with O2to form the carbonate complex, [(dcpp)Pt(CO3)] (4). The reaction of the dimeric complex3with MeI allows the insertion of a methyl group into the carbonyl group to form the PtIIcomplex [(dcpp)Pt(C(O)Me)I] (5). Reaction of another equivalent of MeI with complex5leads to the formation and elimination of acetone and the bis(iodide) complex [(dcpp)PtI2] (6). X‐ray crystal structures of complexes3and4are reported along with DFT calculations and mechanistic studies of the formation of3,4,5, and6.

Investigation of the Rearrangement in Alkyl-Bridged Bis(carbamoyldiaziridine) Derivatives

The thermal treatment of alkyl-bridged bis(carbamoyldiaziridine) derivatives in toluene at 100 °C led to the formation of new saturated five- and six-membered 1,3-diaza-heterocyclic compounds from ethylene- or propylene-bridged bis(carbamoyldiaziridine) derviatives, respectively. Detailed experimental investigations of this reaction revealed an unprecedented intramolecular eliminative rearrangement, involving the two adjacent diaziridine moieties. The loss of a three-carbon fragment by elimination of acetone during the reaction was confirmed by GC–MS measurements. The products of the rearrangement were fully characterized, and their structures were confirmed by X-ray crystal structure analysis. Furthermore, a reaction mechanism of the eliminative rearrangement was proposed, and the reaction pathway was corroborated by DFT calculations of gas-phase model structures at the B3LYP/6-31G** level.

Effect of air-drying on the solvent evaporation, degree of conversion and water sorption/solubility of dental adhesive models

This study evaluated protocols to eliminate acetone from dental adhesives and their effect on the kinetic of water sorption and percent of conversion of these adhesives. Experimental methacrylate-based adhesives with increasing hydrophilicity (R2, R3, R5) were used as reference materials. Primer-like solutions were prepared by addition of 50 wt% acetone. Acetone elimination was measured gravimetrically before and after: a spontaneous evaporation, an application of air-drying at room temperature or application of 40°C air-drying. Protocols were performed from 15 to 60 s. Specimens of adhesive/acetone mixtures were photo-activated and tested for degree of conversion, water sorption and solubility. Data were analyzed by ANOVA and Bonferroni's tests (α = 0.05). Complete acetone elimination was never achieved, but it was significantly greater after the 40°C air-drying application. Higher acetone elimination was observed for the least hydrophilic adhesive. Longer periods for acetone evaporation and heated air-stream can optimize polymerization and reduce the water sorption/solubility of adhesive system models.

Crystal Structure and Catalytic Properties of (C6H8N)3[PMo12O40

The 4-picolinium salt (C6H8N)3[PMo12O40] was synthesized hydrothermally and characterized by IR spectroscopy, TG-DTA data and single-crystal X-ray diffraction. The results indicate that the compound consists of a [PMo12O40]3− heteropolyoxoanion and 4-picolinium cations [C6H8N]+. A supramolecular structure is formed via intermolecular hydrogen-bonding between the different structural units. Crystal data: monoclinic, space group P21/c, a = 19.7004(3), b = 14.0785(2), c = 33.0209(5) Å, β = 91.3590(10)°, V = 9155.8(2) Å3, Z = 8, wR2 = 0.0730. (C6H8N)3[PMo12O40] has a high catalytic activity for the oxidative elimination of acetone from gases as tested in a continuousflow fixed-bed micro-reactor. When the initial concentration is 5.2 gm−3 in air, and the flow rate is 3.3 mLmin−1, 93% of the acetone is eliminated at 70 °C.

Mechanism of autoreduction of 2,2,6,6-tetramethyl-1,4-dioxopiperidinium cation in alkaline medium

Autoreduction of 2,2,6,6-tetramethyl-1,4-dioxopiperidinium ion to nitroxyl radical in alkaline medium involves a number of parallel and consecutive reactions. The primary products of the reaction of 2,2,6,6-tetramethyl-1,4-dioxopiperidinium with hydroxide ion are three nitroso compounds and N-hydroxy-2,2,6,6-tetramethylpiperidine N-oxide. Isomerization of the nitroso compounds and elimination of acetone from the N-oxide give cyclic hydroxylamines which reduce the initial cation to nitroxyl radical, being oxidized to nitrones.

Crystallization of amorphous poly(lactic acid) induced by organic solvents

AbstractCrystallization of amorphous poly(lactic acid) (PLA) was investigated in various organic solvents, such as acetone, ethylacetate, diethylether, tetrahydrofurane, methanol, hexane, toluene, xylene, and o‐dichlorobenene. Most of the solvents, except hexane, induced crystallization of amorphous PLA. Acetone was the most effective solvent to accelerate the crystallization among the solvents used. The crystallization was induced by permeation of acetone into the amorphous phase of PLA, and the permeation obeyed Fick type diffusion. The crystallization rate increased with increasing of conducting temperature. Crystallized PLA formed α crystalline structure. The permeated acetone in the crystallized PLA gradually evaporated as time passes, and the elimination of acetone affected thermal and mechanical properties of the crystallized PLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synthesis and Reactivity of an Iridium(I) Acetonyl PNP Complex. Experimental and Computational Study of Metal−Ligand Cooperation in H−H and C−H Bond Activation via Reversible Ligand Dearomatization

The complex (PNP)IrI(CH2COCH3) 2 (PNP = 2,6-bis((di-tert-butylphosphino)methyl)pyridine) was prepared by reaction of the dearomatized, electron-rich complex (PNP*)IrI(COE) (1; PNP* = deprotonated PNP, COE = cyclooctene) with acetone. Upon treatment with CO, complex 2 undergoes a surprising elimination of acetone to form the dearomatized species (PNP*)IrI(CO) (4), involving proton migration from the ligand “arm” to the acetonyl moiety. DFT studies reveal that this process occurs via the square-pyramidal intermediate 2+CO, formed upon CO coordination to 2, in which the acetonyl moiety is located at the apical position prior to proton migration. Reaction of 2 with H2 (D2) indicates an equilibrium between complex 2 and the nonaromatic (PNP*)IrIII(H)(CH2COCH3) complex 2b, which is the species that actually activates H2 to exclusively form the trans-dihydride (PNP)IrIII(H)2(CH2COCH3) (5a) and activates D2 to form the trans-hydride−deuteride 5b with benzylic-D incorporation, as also corroborated by DFT studies. Interestingly, benzene C−H activation by complex 2 results in formation of the complex (PNP)IrI(C6H5) (6a) and elimination of acetone. DFT studies show that the benzene C−H bond is actually activated by the dearomatized “bare” (PNP*)IrI intermediate 2c, formed upon acetone elimination from 2.

SÍNTESE E CARACTERIZAÇÃO DO NÚCLEO PIRIDO[2,3-g]QUINOLÍNICO SUBSTITUÍDO E AVALIAÇÃO DE SUAS PROPRIEDADES CITOTÓXICAS

Segundo a Organização Mundial da Saúde, a leishmaniose e a tripanossomíase são problemas crescentes de saúde pública, sendo endêmicos particularmente na América Latina. Os fármacos utilizados no tratamento destas doenças foram desenvolvidos há muitas décadas, e apresentam pouca eficácia e fortes efeitos colaterais. As piridoquinolinas são compostos heterocíclicos diazaantracênicos que apresentam propriedades citotóxicas. A importância biológica das piridoquinolinas e o interesse em descobrir novos agentes leishmanicidas e tripanocidas estimularam a síntese de pirido[2,3–g]quinolinas substituídas, e a avaliação do seu potencial leishmanicida e tripanocida. Assim, este trabalho descreve a síntese de piridoquinolinas empregando a reação de termociclização do bis-aduto fenilenodiamínico do ácido de Meldrum. O 2,5-dimetil-1,4-bis[(2,2-dimetil-4,6-dioxo-1,3-dioxano-5-ilidenometil)amino]-benzeno foi obtido em bom rendimento pela condensação do ácido de Meldrum com a 2,5-dimetil-1,4-fenilenodiamina em ortoformato de trimetila. A termociclização em éter difenílico foi acompanhada pela eliminação espontânea de acetona e dióxido de carbono gerando o diazatriciclo, que foi clorado sem prévia purificação com oxicloreto de fósforo originando a 4,9-dicloro-5,10-dimetil-pirido[2,3-g]quinolina, em rendimentos baixos. A reação de substituição nucleofílica com o 2-amino-5-dietilaminopentano foi repetida várias vezes em diferentes condições reacionais, mas não se obteve o produto esperado, necessitando da busca de novos procedimentos e otimização das condições de reação. Os compostos obtidos foram caracterizados por técnicas espectroscópicas de IV e RMN 1H. A avaliação das propriedades leishmanicida e tripanocida foi feita para o composto 4,9-dicloro-5,10-dimetil-pirido[2,3-g]quinolina, porém o mesmo não apresentou qualquer atividade.

New Benzo[h]quinoline‐Based Ligands and their Pincer Ru and Os Complexes for Efficient Catalytic Transfer Hydrogenation of Carbonyl Compounds

New benzo[h]quinoline ligands (HCN'N) containing a CHRNH2 (R=H (a), Me (b), tBu (c)) function in the 2-position were prepared starting from benzo[h]quinoline N-oxide (in the case of ligand a) and 2-chlorobenzo[h]quinoline (for ligands b and c). These compounds were used to prepare ruthenium and osmium complexes, which are excellent catalysts for the transfer hydrogenation (TH) of ketones. The reaction of a with [RuCl2(PPh3)3] in 2-propanol at reflux afforded the terdentate CN'N complex [RuCl(CN'N)(PPh3)2] (1), whereas the complexes [RuCl(CN'N)(dppb)] (2-4; dppb=Ph2P(CH2)4PPh2) were obtained from [RuCl2(PPh3)(dppb)] with a-c, respectively. Employment of (R,S)-Josiphos, (S,R)-Josiphos*, (S,S)-Skewphos, and (S)-MeO-Biphep in combination with [RuCl2(PPh3)3] and ligand a gave the chiral derivatives [RuCl(CN'N)(PP)] (5-8). The osmium complex [OsCl(CN'N)(dppb)] (12) was prepared by treatment of [OsCl2(PPh3)3] with dppb and ligand a. Reaction of the chloride 2 and 12 with NaOiPr in 2-propanol/toluene afforded the hydride complexes [MH(CN'N)(dppb)] (M=Ru 10, Os 14), through elimination of acetone from [M(OiPr)(CN'N)(dppb)] (M=Ru 9, Os 13). The species 9 and 13 easily reacted with 4,4'-difluorobenzophenone, via 10 and 14, respectively, affording the corresponding isolable alkoxides [M(OR)(CN'N)(dppb)] (M=Ru 11, Os 15). The complexes [MX(CN'N)(P2)] (1-15) (M=Ru, Os; X=Cl, H, OR; P=PPh3 and P2=diphosphane) are efficient catalysts for the TH of carbonyl compounds with 2-propanol in the presence of NaOiPr (2 mol %). Turnover frequency (TOF) values up to 1.8x10(6) h(-1) have been achieved using 0.02-0.001 mol % of catalyst. Much the same activity has been observed for the Ru--Cl, --H, --OR, and the Os--Cl derivatives, whereas the Os--H and Os--OR derivatives display significantly lower activity on account of their high oxygen sensitivity. The chiral Ru complexes 5-8 catalyze the asymmetric TH of methyl-aryl ketones with TOF approximately 10(5) h(-1) at 60 degrees C, up to 97 % enatiomeric excess (ee) and remarkably high productivity (0.005 mol % catalyst loading). High catalytic activity (TOF up to 2.2x10(5) h(-1)) and enantioselectivity (up to 98 % ee) have also been achieved with the in-situ-generated catalysts prepared from [MCl2(PPh3)3], (S,R)-Josiphos or (S,R)-Josiphos*, and the benzo[h]quinoline ligands a-c.