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Phosphine Complexes (phosphine + complex)
Selected AbstractsSynthesis of Polybutadiene Nanocomposites: In situ Polymerization of 1,3-Butadiene Catalyzed by Phyllosilicate Interlayer Spacing-Confined Cobalt(II) Phosphine ComplexesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 3-4 2009Giuseppe Leone Abstract Heterogeneous phyllosilicate interlayer spacing-confined cobalt catalysts were prepared by reaction of cobalt phosphine complexes with methylaluminoxane-modified clay. The catalytic systems obtained were used for the in situ polymerization of 1,3-butadiene. The polymerization taking place within the silicate galleries separates the pristine layer aggregates, allowing for the design of polybutadiene-based nanocomposites through the intercalation of the active polymerization centers. Depending on the type of cobalt complex used (i.e., type of phosphine bond to the metal) it is possible to control the microstructure (1,2 content) and the tacticity (percentage of rr, mr and mm triads) of the polymer growing directly in between the inorganic silicate host lamellae. [source] Catalytic Hydrosilylation of Acetylenes Mediated by Phosphine Complexes of Cobalt(I), Rhodium(I), and Iridium(I).CHEMINFORM, Issue 2 2004Leslie D. Field Abstract For Abstract see ChemInform Abstract in Full Text. [source] High Asymmetric Induction with ,-Turn-Derived Palladium Phosphine Complexes.CHEMINFORM, Issue 51 2003Scott J. Greenfield Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Bis-Cyclopentadienyl Nickel (Nickelocene): A Convenient Starting Material for Reactions Catalyzed by Ni(0) Phosphine Complexes.CHEMINFORM, Issue 15 2002Nicholas E. Leadbeater 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] Highly Selective Cobalt-Catalyzed Hydrovinylation of StyreneADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009Michiel M. Abstract Phosphine complexes of cobalt halide salts activated by diethylaluminum chloride are shown to yield highly active catalysts in the hydrovinylation of styrene, with unprecedented high selectivity to the desired product 3-phenyl-1-butene (3P1B). Double-bond isomerization, a common problem in codimerization reactions, only occurs after full conversion with these catalyst systems, even at elevated temperature. The most active catalysts are based on cobalt halide species combined with either C1 - or C2 -bridged diphosphines, heterodonor P,N or P,O ligands, flexible bidentate phosphine ligands or monodentate phosphine ligands. Kinetic investigations show an order >1 in catalyst, which indicates either the involvement of dinuclear species in the catalytic cycle or partial catalyst decomposition via a bimolecular pathway. [source] Regio- and Stereoselective Intermolecular Hydroalkoxylation of Alkynes Catalysed by Cationic Gold(I) ComplexesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Avelino Corma Abstract Vinyl ethers and ketals are obtained from the reaction of phenylacetylene derivatives and dimethyl acetylenedicarboxylate (DMAD) with alcohols in good yields and levels of stereoselectivity by using cationic gold(I)-phosphine complexes as catalysts. By choosing the appropriate phosphine, the selective formation of the Z or the E isomer of the vinyl ether can be tuned, and the undesired formation of the ketal can be controlled. The isomerisation of fumarates (Z -isomer) to maleates (E -isomer) is a gold-catalysed process that can be conducted in one-pot. When using polyols, 5-membered cyclic ketals are easily isolated by extraction with hexane and the gold complex can be reused. [source] Reusable Gold(I) Catalysts with Unique Regioselectivity for Intermolecular Hydroamination of AlkynesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Antonio Leyva Abstract Two gold(I) phosphine complexes bearing the low-coordinating bis(trifluoromethanesulfonyl)imidate ligand, namely AuSPhosNTf2 and AuPPh3NTf2, are active catalysts for the regioselective intermolecular hydroamination of both internal and terminal alkynes under mild reaction conditions. The catalysts show a regioselectivity based on electronic rather than steric factors, which allow the preferential synthesis of regioisomers opposite to those described previously. This subtle chemo- and regioselectivity depends on the catalyst, substrates and reaction conditions employed, and allows one to perform new tandem reactions. These gold(I) complexes operate under free-solvent conditions, without exclusion of air, without addition of acidic promoters and can be quantitatively recovered and reused by simple precipitation in hexane. [source] Synthesis of Polybutadiene Nanocomposites: In situ Polymerization of 1,3-Butadiene Catalyzed by Phyllosilicate Interlayer Spacing-Confined Cobalt(II) Phosphine ComplexesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 3-4 2009Giuseppe Leone Abstract Heterogeneous phyllosilicate interlayer spacing-confined cobalt catalysts were prepared by reaction of cobalt phosphine complexes with methylaluminoxane-modified clay. The catalytic systems obtained were used for the in situ polymerization of 1,3-butadiene. The polymerization taking place within the silicate galleries separates the pristine layer aggregates, allowing for the design of polybutadiene-based nanocomposites through the intercalation of the active polymerization centers. Depending on the type of cobalt complex used (i.e., type of phosphine bond to the metal) it is possible to control the microstructure (1,2 content) and the tacticity (percentage of rr, mr and mm triads) of the polymer growing directly in between the inorganic silicate host lamellae. [source] Highly Active and Removable Ruthenium Catalysts for Transition-Metal-Catalyzed Living Radical Polymerization: Design of Ligands and CocatalystsCHEMISTRY - AN ASIAN JOURNAL, Issue 8-9 2008Makoto Ouchi Dr. Abstract The systematic search and design of phosphine ligands (PR3) and amine cocatalysts resulted in obtaining pentamethyl-cyclopentadienyl (Cp*) ruthenium(II) phosphine complexes [RuCp*Cl(PR3)2], which are highly active and removable catalysts, for transition-metal-catalyzed living radical polymerization of methyl methacrylate (MMA). The catalysts are conveniently prepared in situ from a tetrameric precursor [RuCp*(,3 -Cl)]4 and a selected phosphine (PR3). The combination of the meta -tolyl phosphine [P(m -Tol)3] ligand and a primary diamine cocatalyst [NH2(CH2)6NH2] provides a highly active catalytic system with precision control of the molecular weight of the polymer. The high activity enables a low catalyst dose and a high turn-over frequency without deteriorating the controllability. A hydrophilic amine cocatalyst (amino alcohol) in place of the diamine, further forms an active and removable catalyst; simple treatment with acidic water gave colorless polymers visually free from metal residues (>97,% removal; <64,ppm). [source] | ||||||||||