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Molecular Oxygen (molecular + oxygen)
Kinds of Molecular Oxygen Selected AbstractsElectropolymerized Pyrrole-Substituted Manganese Phthalocyanine Films for the Electroassisted Biomimetic Catalytic Reduction of Molecular OxygenELECTROANALYSIS, Issue 2 2005Nazaré, Pereira Rodrigues Abstract We report for the first time on the electroassisted biomimetic activation of molecular oxygen by a newly prepared electropolymerized polypyrrole-manganese phthalocyanine film. The prepared films and their intervention in the electroassisted catalytic reduction of molecular oxygen were analyzed by cyclic voltammetry and UV-visible spectrophotometry on optically transparent electrodes. The obtained results demonstrate the probable existence of the key-steps responsible for the suggested formation of the highly reactive manganese oxo intermediate. [source] Gas-Phase Chemistry of Vanadium Oxide Cluster Cations VmOn+ (m = 1,4; n = 1,10) with Water and Molecular OxygenEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 31 2008Sandra Feyel Abstract Bare vanadium oxide cluster cations VmOn+ (m = 1,4; n =1,10) generated by electrospray ionization are investigated with respect to their reactivity toward water and molecular oxygen by using mass spectrometric techniques. Besides ion hydration, the ion/molecule reactions of VmOn+ with oxygen-labeled water (H218O) also lead to 16O/18O exchange reactions of the vanadium oxide clusters cations. Although the probability of degenerate 16O/18O exchange between VmOn+ and water is fairly high for the cluster cations with a medium valence state of vanadium, oxygen-atom exchange reactions between VmOn+ and 18O2 can only be accomplished by VO+, V3O6+, and V4O8+. Particularly interesting is the fact that not only oxygen atoms from vanadyl units are exchanged in the cluster cations, but bridging oxygen atoms are also most likely involved in the processes. Other reaction channels for the interaction of VmOn+ cluster cations with molecular oxygen are reported as well, such as oxidative degradation of the low-valent cluster cations upon collision with O2 and formation of association complexes for the high-valent cluster cations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Insertion of Molecular Oxygen in Transition-Metal Hydride Bonds, Oxygen-Bond Activation, and Unimolecular Dissociation of Metal Hydroperoxide Intermediates.HELVETICA CHIMICA ACTA, Issue 3 2008Short Communication Abstract Thermal activation of molecular oxygen is observed for the late-transition-metal cationic complexes [M(H)(OH)]+ with M=Fe, Co, and Ni. Most of the reactions proceed via insertion in a metalhydride bond followed by the dissociation of the resulting metal hydroperoxide intermediate(s) upon losses of O, OH, and H2O. As indicated by labeling studies, the processes for the Ni complex are very specific such that the O-atoms of the neutrals expelled originate almost exclusively from the substrate O2. In comparison to the [M(H)(OH)]+ cations, the ionmolecule reactions of the metal hydride systems [MH]+ (M=Fe, Co, Ni, Pd, and Pt) with dioxygen are rather inefficient, if they occur at all. However, for the solvated complexes [M(H)(H2O)]+ (M=Fe, Co, Ni), the reaction with O2 involving OO bond activation show higher reactivity depending on the transition metal: 60% for the Ni, 16% for the Co, and only 4% for the Fe complex relative to the [Ni(H)(OH)]+/O2 couple. [source] Palladium on Carbon-Catalyzed Synthesis of Benzil Derivatives from 1,2-Diarylalkynes with DMSO and Molecular Oxygen as Dual OxidantsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Shigeki Mori Abstract A palladium on carbon (Pd/C)-catalyzed synthetic method for the preparation of benzil derivatives from 1,2-diarylalkynes has been established using dimethyl sulfoxide (DMSO) and molecular oxygen as dual oxidants. Regardless of the electrical nature of the functional groups on the aromatic rings, 1,2-diarylalkynes were oxidized to the corresponding benzil derivatives in high to excellent yields. Furthermore, the oxidation could efficiently be catalyzed by both the dry and wet types of Pd/C under atmospheric conditions. [source] Palladium-Catalyzed Oxidation of Phenyl-Substituted Alkenes using Molecular Oxygen as the Sole OxidantADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Aline Abstract The palladium-catalyzed aerobic oxidation of styrene and 2-vinylnaphthalene in dimethylacetamide/water or dimethylformamide/water solutions under mild conditions has been developed, in which palladium(II) chloride is used in the absence of co-catalysts or special stabilizing ligands as the sole and recyclable catalyst. The corresponding methyl ketones have been obtained in good to excellent yields with low catalyst loadings (0.2,5,mol%) and high turnover numbers (up to ca. 1000 to palladium). This simple and efficient catalytic method represents an ecologically benign and economically attractive synthetic pathway to industrially important compounds used in the manufacture of various polymers and drugs. [source] Prevention of Manganese Precipitation during the Continuous Selective Partial Oxidation of Methyl Aromatics with Molecular Oxygen in Supercritical WaterADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Joan Fraga-Dubreuil Abstract Presented here is an investigation of the activity and recovery of the homogeneous manganese/bromide catalyst during the continuous flow oxidation of o -xylene, as model substrate, with molecular oxygen (O2) in supercritical water (scH2O). Two strategies are discussed for preventing catalyst precipitation, mainly in the form of oxides such as manganese(IV) oxide, The first strategy involves varying the manganese:bromide ratio using either manganese(II) acetate or manganese(II) bromide in the presence of hydrobromic and other acids. The results show that the effect of acidity and bromide concentration plays an important role in preventing the manganese/bromide catalyst from precipitating. The second strategy uses aromatic carboxylic acids in combination with the manganese/bromide catalyst, particularly benzoic acid, which improves the catalyst recovery dramatically over a certain range of acid concentrations. Our studies show how the presence of an organic acid and/or its precursors is important in stabilising the catalyst. Our results are rationalised on the basis of a tentative reaction mechanism. [source] Selective Oxidation of Acetophenones Bearing Various Functional Groups to Benzoic Acid Derivatives with Molecular OxygenADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Ryota Nakamura Abstract Acetophenones substituted by alkyl, alkoxy, acetoxy, and halogen groups were selectively oxidized with molecular oxygen to the corresponding benzoic acids by using the N,N,,N,, -trihydroxyisocyanuric acid (THICA)/cobalt(II) acetate [Co(OAc)2] and THICA/Co(OAc)2/manganese(II) acetate [Mn(OAc)2]. For example, 4-methylacetophenone was selectively oxidized with molecular oxygen to 4-acetylbenzoic acid (85%) by THICA/Co(OAc)2 and to 4-methylbenzoic acid (93%) by Mn(OAc)2, while terephthalic acid was obtained in 93% with the THICA/Co(OAc)2/Mn(OAc)2 catalytic system. It is interesting that the acetyl group on the aromatic ring is efficiently converted by a very small amount of Mn(OAc)2 to the corresponding carboxylic acid, and that the present method provides a versatile route to acetylbenzoic acids which are difficult to prepare by conventional methods. [source] Cobalt/Rhodium Heterobimetallic Nanoparticle-Catalyzed Oxidative Carbonylation of Amines in the Presence of Carbon Monoxide and Molecular Oxygen to UreasADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Ji Hoon Park Abstract An environmentally friendly oxidative carbonylation of aliphatic and aromatic primary amines to ureas has been successfully achieved in the presence of a catalytic amount of cobalt/rhodium heterobimetallic nanoparticles without any promoters. The catalyst system could be reused with only a slight loss of catalytic activity. [source] A Palladium-Catalyzed Oxidative Cycloaromatization of Biaryls with Alkynes Using Molecular Oxygen as the Oxidant,ANGEWANDTE CHEMIE, Issue 42 2009Zhuangzhi Shi Eine doppelte C-H-Aktivierung ermöglichte die Herstellung von polycyclischen Arenen aus Arylindolen und Arylbenzofuranen in Abwesenheit einer dirigierenden Gruppe unter Verwendung von O2 als Oxidationsmittel (siehe Schema). So lassen sich leicht polycyclische Arene von präparativem und medizinischem Interesse herstellen; darüber hinaus zeigen einige der polycyclischen Heteroarene eine intensive Fluoreszenz. [source] ChemInform Abstract: A Palladium-Catalyzed Oxidative Cycloaromatization of Biaryls with Alkynes Using Molecular Oxygen as the Oxidant.CHEMINFORM, Issue 6 2010Zhuangzhi Shi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Air-Tolerant C,C Bond Formation via Organometallic Ruthenium Catalysis: Diverse Catalytic Pathways Involving (C5Me5)Ru or (C5H5)Ru Are Robust to Molecular Oxygen.CHEMINFORM, Issue 45 2009Lukas Severa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Air-Tolerant C,C Bond Formation via Organometallic Ruthenium Catalysis: Diverse Catalytic Pathways Involving (C5Me5)Ru or (C5H5)Ru Are Robust to Molecular Oxygen.CHEMINFORM, Issue 45 2009Lukas Severa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Oxidation of 5-Hydroxy-6-methyluracil to 5,5,6-Trihydroxy-6-methylpyrimidine-2,4-dione with Molecular Oxygen.CHEMINFORM, Issue 3 2009Timur R. Nugumanov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Ruthenium-Catalyzed Oxidative Cyanation of Tertiary Amines with Molecular Oxygen or Hydrogen Peroxide and Sodium Cyanide: sp3 C,H Bond Activation and Carbon,Carbon Bond Formation.CHEMINFORM, Issue 51 2008Shun-Ichi Murahashi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Immobilization of Ruthenium in Organic,Inorganic Hybrid Copolymers: A Reusable Heterogeneous Catalyst for Oxidation of Alcohols with Molecular Oxygen.CHEMINFORM, Issue 23 2008Tsutomu Matsumoto Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Photooxidation of Aldehydes with Molecular Oxygen in the Presence of Catalytic Bromine or Hydrobromic Acid.CHEMINFORM, Issue 26 2007Shin-ichi Hirashima Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Efficient Oxidation of Adamantanes by Sodium Nitrite with Molecular Oxygen in Trifluoroacetic Acid.CHEMINFORM, Issue 3 2007Osamu Onomura Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Copper-Catalyzed Oxidative Cleavage of Carbon,Carbon Double Bond of Enol Ethers with Molecular Oxygen.CHEMINFORM, Issue 11 2006Makoto Tokunaga Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Efficient Oxidation of Cycloalkanols by Sodium Nitrite with Molecular Oxygen in Trifluoroacetic Acid.CHEMINFORM, Issue 5 2005Yoshihiro Matsumura Abstract For Abstract see ChemInform Abstract in Full Text. [source] Oxidation of the Methyl Group at the Aromatic Nucleus with Molecular Oxygen in the Presence of N-Bromosuccinimide under Photoirradiation.CHEMINFORM, Issue 11 2004Akichika Itoh Abstract For Abstract see ChemInform Abstract in Full Text. [source] Oxidative Degradation of Small Cationic Vanadium Clusters by Molecular Oxygen: On the Way from V+n (n = 2,5) to VO+m (m = 1, 2).CHEMINFORM, Issue 28 2003Marianne Engeser Abstract For Abstract see ChemInform Abstract in Full Text. [source] Preparation of Acyloins by Cerium-Catalyzed, Direct Hydroxylation of ,-Dicarbonyl Compounds with Molecular Oxygen.CHEMINFORM, Issue 22 2003Jens Christoffers Abstract For Abstract see ChemInform Abstract in Full Text. [source] The Heck Reaction in the Presence of Molecular Oxygen.CHEMINFORM, Issue 11 2003Takahiro Hosokawa Abstract For Abstract see ChemInform Abstract in Full Text. [source] Participation of Molecular Oxygen in Cyclization of 5-Arylmethyleneamino-4-(3,4-dimethoxyphenyl)pyrazoles.CHEMINFORM, Issue 48 2002S. L. Bogza No abstract is available for this article. [source] Periodic Density Functional Theory Study of the Dissociative Adsorption of Molecular Oxygen over La2O3.CHEMINFORM, Issue 39 2002Michael S. Palmer No abstract is available for this article. [source] ChemInform Abstract: Ruthenium Catalyzed Oxidation of Tertiary Nitrogen Compounds with Molecular Oxygen: An Easy Access to N-Oxides under Mild Conditions.CHEMINFORM, Issue 37 2002Suman L. Jain Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Oxidative Double Bond Cleavage of ,-Substituted Styrenes with Molecular Oxygen.CHEMINFORM, Issue 33 2002Yujiro Hayashi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Photooxygenation of Some Alkaloids by Singlet Molecular Oxygen.CHEMINFORM, Issue 16 2002Shubha Jain Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Visible Light-Induced Photoepoxidation of Propene by Molecular Oxygen over Chromia,Silica Catalysts.CHEMINFORM, Issue 9 2002Chizu Murata Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Catalytic Oxyalkylation of Alkenes with Alkanes and Molecular Oxygen via a Radical Process Using N-Hydroxyphthalimide.CHEMINFORM, Issue 6 2002Takafumi Hara Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] | ||||||||||||||||||||||||||||||||||||||||