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Showing 1 to 20 of 28 for “"hydrogen transfer"”.
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Hydrogen transfer in hydrogen bonded solid state materials
The investigation of strongly hydrogen bonded solid state materials and the hydrogen transfer processes therein are the subject of the present work. Strong hydrogen bonds are found whenever the hydrogen bonded species compete for the hydrogen atom, and are thereby on the verge of showing hydrogen …
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DEVELOPMENT OF BASE METAL-CATALYZED HYDROGEN TRANSFER AND CROSS-COUPLING REACTIONS
… use of iron catalysts for reactions involving hydrogen transfer and (ii) the development of nickel-catalysed C-heteroatom coupling reactions following the ‘metallaphotoredox’ approach exploiting readily available organic photocatalysts. Thanks to their attractive features, …
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Metabolic and molecular responses to interspecies hydrogen transfer between Ruminococcus albus and Wolinella succinogenes
The mutually beneficial interdependence of hydrogen-producing and hydrogen-utilizing bacteria was discovered by M. P. Bryant, M. J. Wolin and R. S. Wolfe at the University of Illinois in 1967. Based on thermodynamic principles, interspecies hydrogen transfer is a central process in anaerobic …
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Transition path sampling in organometallic catalysis: Overcoming the rare event problem in ab initio molecular dynamics
… study investigated the Ru---hydride catalyzed H2hydrogenation of olefins We identified non-RRKM behaviour of the elimination step of a critical reaction intermediate of the hydrogenation catalytic cycle. Through a spectral decomposition of the vibrational energy, we determined the non-RRKM …
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Transition Metal Complexes With Hydrosulfido and Thiophene Ligands
… coordination to the metal surface and subsequent hydrogen transfer from a surface hydrosulfido group to the bound substate. Transitional metal complexes with SH or thiophene ligands may be thought of as molecular analogs of these proposed surface species.
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PHOTOCHEMICAL HYDROXYLATION OF 1-METHYLANTHRAQUINONES: SYNTHESIS OF 9`-HYDROXYALOESAPONARIN II
… H from alkyl groups ortho to the carbonyl. The hydrogen transfer results in a 1,x biradical which then undergoes a variety of reactions. One of these, oxidation of an alkyl substituent ortho to one of the carbonyls, was believed to go through formation of an endoperoxide. Photolysis of …
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A study of benzazole derivatives showing large stokes shifts
… has been shown to be due to intramolecular hydrogen transfer. Substituent effects on the various steps in the proposed scheme have been studied. In an attempt to quantify these effects on the emission process, values for the radiative and non-radiative rate constants have been calculated and …
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Ruthenium catalysts for the synthesis of quinolines and enol esters
… quinolines. The key step in this method is a hydrogen transfer reaction, which can be performed by either a ruthenium catalyst or merely a strong base. In the second part, ruthenium catalysts are used for the activation of the alkyne triple bond, making it more susceptible to a nucleophilic …
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Spectroscopy and Photo-induced Chemistry of Atmospherically Significant Criegee Intermediates and Hydroxyl Radicals
… the atmosphere. The underlying mechanism for 1,4-hydrogen transfer from alkyl-substituted Criegee intermediates to vinyl hydroperoxide, and subsequent dissociation to OH radicals has been examined in detail. Infrared excitation was used to activate CH3CHOO and (CH3)2COO Criegee intermediates and …
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Supramolecular effects on the reactivity and structure of radical ions derived from aromatic carbaldehydes and crownophanes
… ketyl-ketyl coupling undergoes an electron transfer and two hydrogen transfer to yield the semidione. (2) The study of the radical anions and cations of crownophanes has revealed that the radical anions are not bound to the counterions (Li+, Na+, K+, Cs+) preferentially at the crown-ether …
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1. The Endocyclic Restriction Test: Oxygen Transfer From N-Sulfonyl Oxaziridines to Alkenes and Fluorine From N-Fluorosultams to Carbanions. 2. Intra- and Intermolecular Kinetic Isotope Effects in Directed Lithiations
The transition state geometry for the transfer of oxygen from N-sulfonyl oxaziridines to alkenes and fluorine transfer from N-fluoro sultams to carbanions was investigated. In the former application of the endocyclic restriction test, a transition state model was developed, however, a model has not …
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Application of Density Functional Theory to Study the Mechanism of Alkali Metal Enolate Oxidation by N-sulfonyloxaziridines, Umpolung Amide Synthesis from Halo-Amino-Nitro Alkanes, Alkali-Metal Catalyzed Transfer Hydrogenation of Ketones, and Asymmetric Catalyzed Aza-Henry Reactions
… (3) alkali (Li+, Na+, and K+) metal-catalyzed transfer hydrogenation of acetophenone, the mechanism of which was found to proceed via a six-membered transition state affording direct hydrogen transfer to acetophenone generating the product phenylethanol. The TMEDA ligand had a profound effect …
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A novel membrane process for autotrophic denitrification
… gas delivery in biological dentrification using hydrogen-oxidizing bacteria. Autotrophic denitrification is a biological process that reduces nitrate to nitrogen gas using an inorganic carbon source. Hydrogen gas is an electron donor and nitrate is the electron acceptor in the reaction. The …
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Potential Energy Surfaces for Intermolecular Proton Transfers in Crystalline Aspirin: A Computational Study
… energy surface of intermolecular proton transfers in crystalline aspirin. Using these surfaces the importance of intermolecular interactions and excited states to the proton transfer were also explored. In addition, the ability of ab initio molecular orbital methods and density functional …
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Mechanistic Investigations Into The Thermal C-C Bond Forming Cyclization Of Metal Pyridine-Enamide Complexes And The Synthesis And Reactivity Of Cationic And Neutral Iron(Iv) Alkylidene Complexes
… supported a mechanism consisting of reversible hydrogen transfer followed by rate-determining CC bond formation, in accord with computational results. Iron(II) complexes bearing cyclometalated benzyldialkylphosphine ligands were synthesized via a salt metathesis approach by treating FeCl2(PMe3)2 …
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Contribution à l'étude de la production d'hydrogène par voie microbiologique
Hydrogen is currently considered as to become an important energy carrier and energy resource in the next century. Research and developments are now focusing on a green way to produce the hydrogen. One of these way is the microbial way, which uses microorganisms in anaerobic condition to produce …
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Spectroscopic and functional models for Hmd hydrogenase
The hydrogenases are metalloenzymes that catalyze transformations of dihydrogen. Two hydrogenase classes, [FeFe] and [NiFe] catalyze the interconversion of dihydrogen to protons and electrons. In order to facilitate electron transfer, these enzymes contain iron-sulfur clusters. Synthetic models for …
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Ab Initio Studies of Intramolecular Proton Transfer and Electronic Relaxation
"Excited state intramolecular proton transfer (ESIPT) and electronic relaxation were explored in a variety of small molecules, using a combination of quantum chemistry and ab initio molecular dynamics. The standard level of electronic structure treatment was provided by complete active space …
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Quantum Mechanical Study of Spin-Forbidden Reactions in Organometallic Catalysis and Astrochemistry
… species followed by an intramolecular hydrogen transfer. Moreover, we proposed a new formation mechanism for acetimidic acid, a molecule that is challenging to observe in the interstellar medium because of its small dipole moment. In the last part, we show that the Morse potential can …
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Homogeneous and heterogeneous rhenium catalysts for sustainable transformations of polyols, alcohols, and amines
… complexes show excellent oxophilicity to transfer oxygen and deoxygenate alcohols. Oxorhenium(VII) complexes can efficiently catalyze the transformation of glycerol to allyl alcohol, acrolein, and propanal. The volatile SUO products were easily separated from the nonvolatile residues via …
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