- The Structure of Metallomicelles
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The morphology of micelles formed by two novel metallosurfactants has been studied by small-angle neutron scattering (SANS) and small-angle-X-ray scattering (SAXS). The two surfactants both contain a dodecyl chain as the hydrophobic moiety, but differ in the structure of the head group. The surfactants are CuII complexes of monopendant alcohol derivatives of a) the face-capping macrocycle 1,4,7-triazacyclanonane (tacn), and b) an analogue based upon the tetraazamacrocycle 1,4,7,10-tetraazacyclododecane. Here, neutron scattering has been used to study the overall size and shape of the surfactant micelles, in conjunction with X-ray scattering to locate the metal ions. For the 1,4,7,10-tetraazacyclododecane-based surfactant, oblate micelles are observed, which are smaller to the prolate micelles formed by the 1,4,7-triazacyclononane analogue. The X-ray scattering analysis shows that the metal ions are distributed throughout the polar head-group region, rather than at a well-defined radius; this is in good agreement with the SANS-derived dimensions of the micelle. Indeed, the same model for micelle morphology can be used to fit both the SANS and SAXS data.
- Griffiths,Fallis,Willock,Paul,Barrie,Griffiths,Williams,King,Heenan,Goergl, Richard
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Read Online
- A capillary electrophoretic determination of the kinetics of tetradecanedisulfate hydrolysis
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Capillary electrophoresis was used to follow the decrease in concentration of tetradecanedisulfate as a function of time during its hydrolysis in 0.5 M sulfuric acid solution at 60, 75, and 90°C. The hydrolyses were mostly carried out at premicellar concentrations of surfactant, from 1 to 7.5 mM. Large increases of rate occurred at higher concentrations (at least 15 mM). The reaction was found to be first order in tetradecanedisulfate. The activation energy and entropy of activation were calculated to be 97 kJ mol-1 and -55 J K-1 mol-1, respectively.
- Walker, Richard A.,Marangoni, D. Gerrard,Smith-Palmer, Truis
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- Well-defined Cp*Co(III)-catalyzed Hydrogenation of Carbonates and Polycarbonates
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We herein report the catalytic hydrogenation of carbonates and polycarbonates into their corresponding diols/alcohols using well-defined, air-stable, high-valent cobalt complexes. Several novel Cp*Co(III) complexes bearing N,O-chelation were isolated for the first time and structurally characterized by various spectroscopic techniques including single crystal X-ray crystallography. These novel Co(III) complexes have shown excellent catalytic activity to produce value added diols/alcohols from carbonate and polycarbonates through hydrogenation using molecular hydrogen as sole reductant or iPrOH as transfer hydrogenation source. To demonstrate the developed methodology's practical applicability, we have recycled the bisphenol A monomer from compact disc (CD) through hydrogenation under the established reaction conditions using phosphine-free, earth-abundant, air- and moisture-stable high-valent cobalt catalysts.
- Dahiya, Pardeep,Gangwar, Manoj Kumar,Sundararaju, Basker
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p. 934 - 939
(2020/12/15)
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- 1. 2 - O-alcohol synthetic method of the compound (by machine translation)
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The invention relates to a 1, 2 - O-alcohol synthetic method of the compound. The synthetic method comprises the following steps: (1) in order to at the end of the olefin as raw materials, potassium persulfate compound salt as the oxidizing agent, inorganic salt as catalyst, water and ketone organic solvent as a reaction solvent, for 30 - 100 °C reaction; (2) reaction after the end of the, 0 - 40 °C adding inorganic alkali, the pH for the reaction system 10 - 14; (3) for 30 - 100 °C continue to reaction, after the end of the reaction, separation and purification, be 1, 2 - O-alcohol compound. The method for synthesis of mild reaction system, the raw material is cheap, the oxidizing agent is environment-friendly, good reaction selectivity, high conversion rate. (by machine translation)
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Paragraph 0034; 0035
(2019/03/17)
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- Site-Selective Mono-Oxidation of 1,2-Bis(boronates)
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Site-selective oxidation of vicinal bis(boronates) is accomplished through the use of trimethylamine N-oxide in 1-butanol solvent. The reaction occurs with good efficiency and selectivity across a range of substrates, providing 2-hydro-1-boronic esters which are shown to be versatile intermediates in the synthesis of chiral building blocks.
- Yan, Lu,Morken, James P.
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supporting information
p. 3760 - 3763
(2019/05/24)
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- Straightforward synthesis of MTW-type magnesium silicalite for CO2 fixation with epoxides under mild conditions
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Aluminum-free magnesium silicalite with MTW topology (Mg-Si-ZSM-12) was fabricated via a straightforward hydrothermal synthesis route involving an initial acid co-hydrolysis step. Mg incorporation endowed superior basic properties to the MTW framework, as illustrated by CO2 sorption and temperature programmed desorption plus the activity in a typical basic reaction, Knoevenagel condensation. Mg-Si-ZSM-12 catalyzed the coupling of atmospheric CO2 with epoxides and led to the efficient production of cyclic carbonates with high yield and selectivity at relatively low temperature (down to 60 °C). The present strategy afforded a zeolitic solid base with regular 12-membered ring microporous channels that has potential application in CO2 fixation.
- Wen, Haimeng,Xie, Jingyan,Zhou, Yang,Zhou, Yu,Wang, Jun
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p. 5725 - 5735
(2019/10/23)
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- Novel chromium (III) complexes with N4-donor ligands as catalysts for the coupling of CO2 and epoxides in supercritical CO2
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New neutral and cationic chromium(III) complexes with N4 Schiff base ligands have been prepared and characterized. These complexes are active catalysts for the cycloaddition of CO2 and styrene oxide in CH 2Cl2 solutions, affording epoxide conversions in a 39-92% range, with encouraging cyclic carbonate yields (up to 63%). It is to notice that the cationic species were significantly more active than their neutral analogs. Addition of tetrabutylammonium halides improved the selectivity toward styrene carbonate (87% yield). Dichloromethane could be avoided using solvent free or supercritical carbon dioxide as a solvent (scCO2) and, moreover, this improved the catalytic activity of the cationic complexes (TOF up to 652 h-1). Using scCO2, these chromium catalysts afforded the rapid and selective formation of cyclic carbonates from the coupling of CO2 to various linear terminal epoxides, such as epichlorydrin, propylene oxide and long chain terminal oxiranes. Coupling of cyclohexene oxide and carbon dioxide led to mixtures of poly(cyclohexene) carbonate and cyclic carbonate depending on the conditions (pressure and co-catalyst/catalyst ratio). Poly(cyclohexene) carbonate was isolated with a productivity 388 g/g Cr. Selective formation of the cyclic cyclohexene carbonate was obtained working under scCO2 conditions.
- Cuesta-Aluja, Laia,Djoufak, Mary,Aghmiz, Ali,Rivas, Raquel,Christ, Lorraine,Masdeu-Bultó, Anna M.
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p. 161 - 170
(2013/12/04)
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- Scope and mechanism of the Pt-catalyzed enantioselective diboration of monosubstituted alkenes
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The Pt-catalyzed enantioselective diboration of terminal alkenes can be accomplished in an enantioselective fashion in the presence of chiral phosphonite ligands. Optimal procedures and the substrate scope of this transformation are fully investigated. Reaction progress kinetic analysis and kinetic isotope effects suggest that the stereodefining step in the catalytic cycle is olefin migratory insertion into a Pt-B bond. Density functional theory analysis, combined with other experimental data, suggests that the insertion reaction positions platinum at the internal carbon of the substrate. A stereochemical model for this reaction is advanced that is in line both with these features and with the crystal structure of a Pt-ligand complex.
- Coombs, John R.,Haeffner, Fredrik,Kliman, Laura T.,Morken, James P.
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supporting information
p. 11222 - 11231
(2013/08/23)
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- Extracts of Isochrysis sp.
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The present invention relates to extracts of Isochrysis sp., preferably Tahitian Isochrysis, its cosmetic, dermatological and/or therapeutic uses and compositions and cosmetic, dermatological or therapeutic products comprising such an extract of Isochrysis sp., preferably Tahitian Isochrysis.
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- Extracts of isochrysis sp.
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The present invention relates to extracts of Isochrysis sp., preferably Tahitian Isochrysis, its cosmetic, dermatological and/or therapeutic uses and compositions and cosmetic, dermatological or therapeutic products comprising such an extract of Isochrysis sp., preferably Tahitian Isochrysis.
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- EXTRACTS OF TETRASELMIS SP.
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The present invention relates to extracts of Tetraselmis sp., preferably Tetraselmis suecica, its cosmetic, dermatological and/or therapeutic uses and compositions and cosmetic, dermatological or therapeutic products comprising such an extract of Tetraselmis sp., preferably Tetraselmis suecica.
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- Extracts of Tetraselmis sp. for cosmetic and therapeutic purposes
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The present invention relates to extracts of Tetraselmis sp., preferably Tetraselmis suecica, its cosmetic, dermatological and/or therapeutic uses and compositions and cosmetic, dermatological or therapeutic products comprising such an extract of Tetraselmis sp., preferably Tetraselmis suecica.
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- Osmium tetroxide in poly(ethylene glycol) (PEG): A recyclable reaction medium for rapid asymmetric dihydroxylation under Sharpless conditions
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PEG (400) has been used as a recyclable and rapid reaction medium for the asymmetric dihydroxylation of olefins; Sharpless ligand is efficiently recovered and recycled with good enantioselectivity.
- Chandrasekhar,Narsihmulu,Sultana, S. Shameem,Reddy, N. Ramakrishna
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p. 1716 - 1717
(2007/10/03)
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- DERMATOLOGICAL COMPOSITIONS AND METHODS
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Disclosed are methods and compositions for regulating the melanin content of mammalian melanocytes; regulating pigmentation in mammalian skin, hair, wool or fur; treating or preventing various skin and proliferative disorders; by administration of various compounds, including alcohols, diols and/or triols and their analogues.
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- Treatment of neurodegenerative diseases
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Disclosed are methods for increasing the differentiation of mammalian neuronal cells for purposes of treating neurodegenerative diseases or nerve damage by administration of various compounds including alcohols, diols and/or triols and their analogues.
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- Treatment of diseases mediated by the nitric oxide/cGMP/protein kinase G pathway
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Disclosed are methods and compositions for stimulating cellular nitric oxide (NO) synthesis, cyclic guanosine monophosphate levels (cGMP), and protein kinase G (PKG) activity for purposes of treating diseases mediated by deficiencies in the NO/cGMP/PKG signal transduction pathway, by administration of various compounds including alcohols, diols and/or triols and their analogues.
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- Process for the preparation of vicinal diols and/or epoxides
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The present invention provides a process for the preparation of vicinal diols and/or epoxides by the oxidation of olefinically-unsaturated compounds with the use of an inorganic heptavalent rhenium compound as catalyst and of hydrogen peroxide as oxidation agent, wherein the reaction is carried out in a solvent selected from the group consisting of organic phosphoric acid esters and ethers with a boiling point above 50° C. under atmospheric conditions.
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