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Phosphine
Kinds of Phosphine Terms modified by Phosphine Selected AbstractsSELECTED ALTERNATIVES TO METHYL BROMIDE IN THE POSTHARVEST AND QUARANTINE TREATMENT OF ALMONDS AND WALNUTS: AN ECONOMIC PERSPECTIVEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2001ANTHONI F. AEGERTER Methyl bromide is a highly effective fumigant used in the postharvest and quarantine treatment of tree nuts. There will be a complete phase out in the United States of America (U.S.) of methyl bromide by 2005 according to The Montreal Protocol of 1991 with the exception of preshipment and quarantine uses as stated in the 1998 Clean Air Act. This study analyzed alternative treatment scenarios. The alternatives considered were phosphine, irradiation, and controlled atmosphere storage. Costs for each scenario were developed. Cost increases with irradiation ranged from two to fourteen times the benchmark costs for methyl bromide. Controlled atmosphere storage for both commodities had cost increases ranging from 174% to 256% over methyl bromide costs. Phosphine was used only to treat almonds. Phosphine application costs were 108% and 117% above the benchmark costs for methyl bromide. [source] Innentitelbild: Reaction of Singlet Dioxygen with Phosphine,Borane Derivatives: From Transient Phosphine Peroxides to Crystalline Peroxoboronates (Angew. Chem.ANGEWANDTE CHEMIE, Issue 35 201035/2010) Ambiphile Phosphan-Boronate spalten Singulett-Disauerstoff unter milden Bedingungen. Wie D. Bourissou et,al. in ihrer Zuschrift auf S.,6322,ff. erläutern, lagern sich dabei die zunächst gebildeten Phosphanperoxide spontan in stabile kristalline Peroxoboronate um. Bildgestaltung Christian Pradel. [source] Reaction of Singlet Dioxygen with Phosphine,Borane Derivatives: From Transient Phosphine Peroxides to Crystalline Peroxoboronates,ANGEWANDTE CHEMIE, Issue 35 2010Susana Porcel Dr. Singulett-Disauerstoff wird durch Phosphan-Boronate unter milden Bedingungen einfach gespalten. Die zunächst gebildeten Phosphanperoxide lagern sich spontan unter B,O-Wanderung zu Peroxoboronaten um. Diese wurden strukturell charakterisiert, und ihre Eignung für Sauerstofftransferreaktionen wurde nachgewiesen. [source] ChemInform Abstract: Remarkable Effect of Phosphine on the Reactivity of O,P-Acetal,Efficient Substitution Reaction of O,P-Acetal.CHEMINFORM, Issue 42 2010Hiromichi Fujioka Abstract Tri(o-tolyl)phosphine is identified as a good nucleophile for the formation of intermediate O,P-acetals from O,O-acetals (I) and a good leaving group for the successive nucleophilic substitution. [source] ChemInform Abstract: Chiral 1-Phenylethylamine-Derived Phosphine,Phosphoramidite Ligands for Highly Enantioselective Rh-Catalyzed Hydrogenation of ,-(Acylamino)acrylates: Significant Effect of Substituents on 3,3,-Positions of Binaphthyl Moiety.CHEMINFORM, Issue 36 2010Xiao-Mao Zhou Abstract Introduction of phenyl substituents at the phosphoramidite backbone of PEAPhos ligand (PEAPP) significantly increases its catalytic activity in the Rh-catalyzed asymmetric hydrogenation of ,-(acylamino)acrylates. [source] ChemInform Abstract: Water-Soluble Palladium and Gold Nanoparticles Functionalized by a New Phosphine with Zwitterionic Liquid Based on Imidazolium Sulfonate Linked Ethylene Glycol Moiety.CHEMINFORM, Issue 34 2010Taichi Akiyama Abstract The new phosphine (PHOS) is used to prepare stable metal nanoparticles in aqueous electrolyte. [source] ChemInform Abstract: Hydrogenation of Hindered Ketones Catalyzed by a Silica-Supported Compact Phosphine,Rh System.CHEMINFORM, Issue 10 2009Soichiro Kawamorita 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: Preparation of Polymer-Supported Phosphine from Ferrocene for Palladium-Catalyzed Suzuki,Miyaura Cross-Coupling Reactions.CHEMINFORM, Issue 17 2008Hong Wei Yu 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: Aerobic Oxidation under Visible Light Irradiation of a Fluorescent Lamp with a Combination of Carbon Tetrabromide and Triphenyl Phosphine.CHEMINFORM, Issue 15 2008Taichi Sugai 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] Chiral Phosphine,Olefin Ligands in the Rhodium-Catalyzed Asymmetric 1,4-Addition Reactions.CHEMINFORM, Issue 24 2007Wei-Liang Duan 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] Ruthenium Complexes of Phosphine,Aminophosphine Ligands.CHEMINFORM, Issue 39 2006Neil W. Boaz 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] Reductive Mannich-Type Reaction Using the Composite Reagents of Phosphine and Lewis Acid.CHEMINFORM, Issue 26 2006Satoshi Kikuchi 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] Palladium-Catalyzed Desulfitative Mizoroki,Heck Couplings of Sulfonyl Chlorides with Mono- and Disubstituted Olefins: Rhodium-Catalyzed Desulfitative Heck-Type Reactions under Phosphine- and Base-Free Conditions.CHEMINFORM, Issue 14 2006Srinivas Reddy Dubbaka 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] Chiral Phosphine,Olefin Bidentate Ligands in Asymmetric Catalysis: Rhodium-Catalyzed Asymmetric 1,4-Addition of Aryl Boronic Acids to Maleimides.CHEMINFORM, Issue 48 2005Ryo Shintani Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Versatile Synthesis of Phosphine,Aminophosphine Ligands for Asymmetric Catalysis.CHEMINFORM, Issue 45 2005Neil W. Boaz Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Efficient Method for the Synthesis of Enantiopure Phosphine,Imidazoline Ligands: Application to the Ir-Catalyzed Hydrogenation of Imines.CHEMINFORM, Issue 11 2005Ester Guiu Abstract For Abstract see ChemInform Abstract in Full Text. [source] Recyclable Sonogashira Coupling Reactions in an Ionic Liquid, Effected in the Absence of Both a Copper Salt and a Phosphine.CHEMINFORM, Issue 42 2004Soon Bong Park Abstract For Abstract see ChemInform Abstract in Full Text. [source] Formation of P-Ylide under Neutral and Metal-Free Conditions: Transformation of Aziridines and Epoxides to Conjugated Dienes in the Presence of Phosphine.CHEMINFORM, Issue 25 2004Ren-Hua Fan Abstract For Abstract see ChemInform Abstract in Full Text. [source] Asymmetric Hydrogenation of Aromatic Olefins Catalyzed by Iridium Complexes of Proline-Derived Phosphine,Oxazoline Ligands.CHEMINFORM, Issue 18 2003Guopin Xu Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Novel Chiral Phosphine,Oxazinane Ligands in Palladium-Catalyzed Asymmetric Allylic Alkylation.CHEMINFORM, Issue 41 2001Takashi Mino 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] Quinaphos and Dihydro-Quinaphos Phosphine,Phosphoramidite Ligands for Asymmetric HydrogenationCHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2010Thomas Pullmann Dr. Abstract New derivatives of the Quinaphos ligands and the related Dihydro-Quinaphos ligands based on the more flexible 1,2,3,4-tetrahydroquinoline backbone have been prepared and fully characterised. A general and straightforward separation protocol was devised, which allowed for the gram-scale isolation of the Ra,Sc and Sa,Rc diastereomers. These new phosphine,phosphoramidite ligands have been applied in the Rh-catalysed asymmetric hydrogenation of functionalised olefins with the achievement of excellent enantioselectivities (,99,%) in most cases and turnover frequency (TOF) values of up to ,20,000,h,1. These results substantiate the practical utility of readily accessible Quinaphos-type ligands, which belong to the most active and selective category of ligands for Rh-catalysed hydrogenation known to date. [source] The Ever-Surprising Chemistry of Boron: Enhanced Acidity of Phosphine,BoranesCHEMISTRY - A EUROPEAN JOURNAL, Issue 18 2009Marcela Hurtado Dr. Abstract The acidity-enhancing effect of BH3 in gas-phase phosphine,boranes compared to the corresponding free phosphines is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. Thus, the enhancement of the acidity of protic acids by Lewis acids usually observed in solution is also observed in the gas phase. For example, the gas-phase acidities (GA) of MePH2 and MePH2,BH3 differ by about 118,kJ,mol,1 (see picture). The gas-phase acidity of a series of phosphines and their corresponding phosphine,borane derivatives was measured by FT-ICR techniques. BH3 attachment leads to a substantial increase of the intrinsic acidity of the system (from 80 to 110,kJ,mol,1). This acidity-enhancing effect of BH3 is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. This indicates that the enhancement of the acidity of protic acids by Lewis acids usually observed in solution also occurs in the gas phase. High-level DFT calculations reveal that this acidity enhancement is essentially due to stronger stabilization of the anion with respect to the neutral species on BH3 association, due to a stronger electron donor ability of P in the anion and better dispersion of the negative charge in the system when the BH3 group is present. Our study also shows that deprotonation of ClCH2PH2 and ClCH2PH2,BH3 is followed by chloride departure. For the latter compound deprotonation at the BH3 group is found to be more favorable than PH2 deprotonation, and the subsequent loss of Cl, is kinetically favored with respect to loss of Cl, in a typical SN2 process. Hence, ClCH2PH2,BH3 is the only phosphine,borane adduct included in this study which behaves as a boron acid rather than as a phosphorus acid. [source] Palladium-Catalyzed Desulfitative Mizoroki,Heck Couplings of Sulfonyl Chlorides with Mono- and Disubstituted Olefins: Rhodium-Catalyzed Desulfitative Heck-Type Reactions under Phosphine- and Base-Free ConditionsCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2005Srinivas Reddy Dubbaka Abstract New conditions have been found for the desulfitative Mizoroki,Heck arylation and trifluoromethylation of mono- and disubustituted olefins with arenesulfonyl and trifluoromethanesulfonyl chlorides. Thus (E)-1,2-disubstituted alkenes with high stereoselectivity and 1,1,2-disubstituted alkenes with 12:1 to 21:1 E/Z steroselectivity can be obtained. Herrmann's palladacycle at 0.1 mol,% is sufficient to catalyze these reactions, for which electron-rich or electron-poor sulfonyl chlorides and alkenes are suitable. If phosphine- and base-free conditions are required, 1 mol,% [RhCl(C2H4)2] catalyzes the desulfitative cross-coupling reactions. Contrary to results reported for [RuCl2(PPh3)2]-catalyzed coupling reactions with sulfonyl chlorides, the palladium and rhodium desulfitative Mizoroki,Heck coupling reactions are not inhibited by radical scavenging agents. Possible sulfones arising from the sulfonylation of alkenes at 60,°C are not desulfitated at higher temperatures in the presence of the Pd or Rh catalysts. De nouvelles conditions sont rapporteés pour les couplages désulfitants du type Mizoroki,Heck des chlorures d'arènesulfonyles et trifluorométhanesulfonyle avec des oléfines mono- et disubstitueés. La méthode permet la synthèse de (E)-alcènes 1,2-disubstitués avec haute stéréosélectivité et d'alkènes 1,1,2-trisubstitués avec des stéréosélectivités E/Z variant de 12:1 à 21:1. La palladacycle de Herrmann à 0.1 mol% est suffisant pour catalyser ces reactions qui peuvent engager des chlorures de sulfonyles et des alcènes soit riches ou pauvres en électron. Si des conditions sans phosphine et sans base sont requises, 1 mol,% de [RhCl(C2H4)2] est un excellent catalyseur pour ces couplages désulfitants. Contrairement à ce qui est rapporté pour des réactions analogues catalysées par [RuCl2(PPh3)2] et qui impliquent des intermédiaires radicalaires, les couplages du type Mizoroki,Heck désulfitants catalysés par des complexes de palladium ou de rhodium ne sont pas inhibés par des pièges à radicaux. De plus, les sulfones qui peuvent se former par sulfonylation des alcènes (60,oC) ne sont pas désulfitées à plus haute température en présence des catalyseurs au Pd ou au Rh. [source] Synthesis of Chiral 2-Phospha[3]ferrocenophanes and their Behaviour as Organocatalysts in [3+2],Cyclization ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Arnaud Voituriez Abstract Planar chiral 2-phospha[3]ferrocenophanes have been prepared via a stereoselective three-step synthesis. The key step is the lithiation of the 1,1,-disubstituted ferrocene 11 bearing (S)-2-(methoxymethyl)pyrrolidines as the chiral ortho -directing groups. The diastereoselectivity of these reactions has been mastered by an appropriate choice of the metallating agent, so as to afford a suitable access to C2 -symmetrical, tetrasubstituted ferrocenes. These compounds have been converted into the enantiomerically pure 2-phospha[3]-ferrocenophanes 16, via the corresponding acetates and their reactions with primary phosphines. Phosphines 16 have been used as nucleophilic catalysts in model cyclization reactions. Unlike 2-phospha[3]-ferrocenophanes with stereogenic ,-carbons, the planar chiral derivatives 16 proved to be suitable catalysts for these processes. Thus, for instance, phosphine 16c successfully promotes the enantioselective [3+2],annulations of allenes and enones into functionalized cyclopentenes (ees up to 96%). Among others, spirocyclic derivatives have been obtained in good yields and ees in the range 77,85%. The robustness of this catalyst has been demonstrated by recycling experiments. [source] ,Click' Dendritic Phosphines: Design, Synthesis, Application in Suzuki Coupling, and Recycling by NanofiltrationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Michèle Janssen Abstract A new synthetic route towards stable molecular-weight enlarged monodentate phosphine ligands via ,click' chemistry was developed. These ligands were applied in the Pd-catalyzed Suzuki,Miyaura coupling of aryl halides and phenyl boronic acid. The supported systems show very similar activities compared to the unsupported analogues. Moreover, recycling experiments by means of nanofiltration using ceramic nanofiltration membranes demonstrate that these systems can be recovered and reused efficiently. [source] Synthesis, characterization and hydroformylation activity of 7-azaindolate-bridged dinuclear rhodium(I)phosphines with pendant polar-groupsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2009Chandra Sekhar Vasam Abstract New dinuclear Rh(I),Phosphines of the types [Rh(µ-azi)(CO)(L)]2 (1,3,7) and [Rh(µ-azi)(L)]2 (8) with pendant polar groups, and a chealated mononuclear compound [Rh(azi-H)(CO)(L)] (2) (where azi = 7-azaindolate, L = polar phosphine) were isolated from the reaction of [Rh(µ-Cl)(CO)2]2 with 7-azaindolate followed by some polar mono - and bis -phosphines (L1,L8). A relationship between ,,31P-NMR and ,(CO) values was considered to define the impact of polar-groups on ,-donor properties of the phosphines. These compounds were evaluated as catalyst precursors in the hydroformylation of 1-hexene and 1-dodecene both in mono- and biphasic aqueous organic systems. While the biphasic hydroformylations (water + toluene) gave exclusively the aldehydes, the monophasic one (aqueous ethanol) showed propensity to form both aldehydes and alcohols. The influence of bimetallic cooperative effects, and ,-donor and hydrophilic properties of the phosphines with pendant polar-groups in enhancing the yields and selectivity of hydroformylation products was emphasized. In addition, when strong ,-donor phosphine was used, the ,-acceptor nature of pyridine ring of 7-azaindolate spacer was found to be a considerable factor in facilitating the facile cleavage of CO group during hydroformylation and in supplementing the cooperative effects. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterization of Silver Trimethylacetate Complexes with Tertiary Phosphines as CVD Precursors of Thin Silver Films,CHEMICAL VAPOR DEPOSITION, Issue 1 2005P. Piszczek Abstract AgI complexes [Ag(O2CtBu)(PMe3)] (1) and [Ag(O2CtBu)(PEt3)] (2) were used as CVD precursors. Silver films between 30,nm and 100,nm were deposited from the above compounds using hot-wall and cold-wall CVD techniques on Si(111) and Si(100) substrates in the temperature range 180-220,°C, under the reactor pressure 1,3,mbar. Metallic films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and conductivity measurements. [source] ChemInform Abstract: Convenient Methods for the Synthesis of a Library of Hemilabile Phosphines.CHEMINFORM, Issue 43 2009M. Victoria Jimenez 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: Preparation of Diphenyl Phosphide and Substituted Phosphines Using Alkali Metal in Silica Gel (M,SG).CHEMINFORM, Issue 36 2009Partha Nandi 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: Solvent-Free Heterogeneous Organocatalysis: Stereoselective Isomerization of ,,,-Ynones to (E,E)-,,.beta±gamma.,,-Dienones Catalyzed by Polymer-Supported Tertiary Phosphines.CHEMINFORM, Issue 11 2008Hai-Ling Liu 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. 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