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Palladium Acetate (palladium + acetate)
Selected AbstractsRedox Active Two-Component Films of Palladium and Covalently Linked Zinc Porphyrin,Fullerene DyadELECTROANALYSIS, Issue 9 2006Marta Plonska Abstract Redox active films have been generated electrochemically by the reduction of dyads consisting of fullerene C60 covalently linked to zinc meso -tetraphenyloporphyrin, ZnPC60, and palladium acetate. The films are believed to consist of a polymeric network formed via covalent bonds between the palladium atoms and the fullerene moieties. In these films, the zinc porphyrin moiety is covalently linked to the polymeric chains through the pyrrolidine ring of the fullerene. The ZnPC60/Pt films are electrochemically active in both positive and negative potential excursions. At positive potentials, two oxidation steps for the zinc porphyrin are observed. In the negative potential range, electron transfer processes involving the zinc porphyrin and the fullerene entities are observed. Film formation is also accompanied by palladium deposition on the electrode surface. The presence of a metallic phase in the film influences its morphology, structure and electrochemical properties. [source] Phosphonylation of 2-Amino- and 2-Amido-3-bromopyridines and 2-Amino-3-chloroquinoxalines with Triethyl PhosphiteEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2009M. Shaker S. Adam Abstract The Tavs reaction of 2-amino- and 2-acylamido-3-bromopyridines 1 and 2 with triethyl phosphite in the presence of palladium acetate or chloride allows the synthesis of 2-amino- and 2-acylamidopyridine-3-phosphonates 3 and 4. A second ring nitrogen atom causes strong activation and leads to excellent yields in the phosphonylation of 2-amino-3-chloroquinoxalines. 2,3-Dichloroquinoxaline does not need a catalyst and undergoes double phosphonylation with sodium diethyl phosphite under Michaelis,Becker conditions. The results show an activating influence of pyridine nitrogen (,M) and deactivating influence of the amino group (+M). The reactivity of 1 and 2 in the Tavs coupling is compared with that of the 3-NH-2-bromopyridine position isomers and 2-bromoanilines and discussed in terms of the opposite effects of pyridine and amino(amido) nitrogen and different position of the N atoms towards the reaction site. The advantage of the Tavs reaction is the easy optimization because neither auxiliary ligands are required nor a base to trap the halide or a solvent. Triethyl phosphite itself acts as ligand and forms Pd0{P(OEt)3}n in the initial phase of the reaction. The structures of the products and the expected intramolecular N,H···O=P hydrogen bridging bonds were proven by solution NMR and by X-ray crystal structure analysis of single crystalline 3c.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Palladium/Phosphite or Phosphate Catalyzed Oxidative Coupling of Arylboronic Acids with Alkynes to Produce 1,4-Diaryl-1,3-butadienesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2008Hakaru Horiguchi Abstract The intermolecular oxidative coupling of arylboronic acids with internal alkynes efficiently proceeds in a 2:2 manner in the presence of palladium acetate, a triaryl phosphite or phosphate, and silver carbonate as catalyst, ligand, and oxidant, respectively, to produce the corresponding 1,4-diaryl-1,3-butadiene derivatives. [source] Palladium-Catalyzed Intermolecular Three-Component Coupling of Organic Halides with Alkynes and Alkenes: Efficient Synthesis of Oligoene CompoundsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2007Kana Shibata Abstract The intermolecular three-component coupling of aryl or vinyl halides, diarylacetylenes, and monosubstituted alkenes effectively proceeds in the presence of palladium acetate, lithium chloride, and sodium bicarbonate as catalyst, promoter, and base, respectively, in aqueous DMF or DMSO to produce the corresponding 1,3-butadiene or 1,3,5-hexatriene derivatives. Use of dienyl bromides allows the coupling to afford 1,3,5,7-octatetraenes. Under the present catalytic conditions, fulvene derivatives are also formed efficiently by the 1:2 coupling of vinyl bromides and diarylacetylenes without adding the alkenes. [source] Long-chain silanes as reducing agents part 1: a facile, efficient and selective route to amine and phosphine-stabilized active Pd-nanoparticlesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010Bhanu P. S. Chauhan Abstract Recently, metal nanoparticles have found applications in various fields, which have necessitated exploration of new avenues to obtain such materials. In this publication, a hydrosilane-based reduction and characterization of resulting palladium nanoparticles is achieved using palladium acetate as nanoparticle precursor and octadecylsilane as a reducing agent. The influence of phosphine and amine ligands in the stabilization of nanoparticles is also investigated. In addition, a brief mechanistic proposal of the reduction process is also discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Three-step synthesis of arylpolyboronic acids from phenols via organotin compoundsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2007Pablo M. Fidelibus Abstract In this paper we describe a three-step synthesis of aryldi- and triboronic acids starting from phenols. Several substituted phenols (I) were converted into the corresponding aryldiethylphosphates (II) in good to excellent yields. The latter, on reaction with sodium trimethylstannide in liquid ammonia, under irradiation, afforded the aryl- and heteroarylpoly(trimethylstannyl) derivatives in 65,90% yield. The third step is the reaction of the organotin compounds with borane in THF, which leads to the corresponding arylpolyboronic acids in around 80% yield. In order to confirm their structure, some of the diboronic acids were converted into the corresponding pinacol esters. The results obtained in a study on the synthesis of various terphenyls through double and triple Suzuki couplings catalyzed by palladium acetate between the obtained arylpolyboronic acids and various aryl halides are also reported. These reactions proceeded with an average 65% yield, and also enabled us to confirm the structures of some of the diboronic acids. The structure of the new compounds was determined by 1H, 13C and 119Sn NMR spectroscopy, mass spectrometry and IR spectroscopy. Copyright © 2007 John Wiley & Sons, Ltd. [source] Palladium-Catalyzed Formation of Highly Substituted Naphthalenes from Arene and Alkyne HydrocarbonsCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2008Yao-Ting Wu Prof. Abstract Several highly substituted naphthalenes 3 have been synthesized in a one-pot reaction by treatment of arenes 1 with alkynes 2 in the presence of palladium acetate and silver acetate. In this Pd-catalyzed protocol, an arene provides a benzo source for the construction of a naphthalene core through twofold aryl CH bond activation. Reaction of triphenylphosphine with diphenylethyne (2,a) under the catalysis of PdIV complexes produced 1,2,3,4-tetraphenylnaphthalene (3,ba) in 62,% yield. Here, triphenylphosphine undergoes one aryl CP bond cleavage and one aryl CH bond activation to serve as a benzo moiety. Crystal structures of cycloadducts 3,ea, 3,ga, and 3,ac have been analyzed. The twisted naphthalenes arise not only from the overcrowded substituents but also from the contribution of the CH3,, interaction. [source] MCM-41 Supported Aminopropylsiloxane Palladium Acetate Complex: A Highly Active and Stereoselective Catalyst for Heck ReactionCHINESE JOURNAL OF CHEMISTRY, Issue 10 2001Jian-Min Zhou Abstract A new MCM-41 supported aminopropylsiloxane palladium acetate was prepared and characterized. This catalyst is highly active and stereoselective for Heck reaction at 70°C. [source] Simple Methodology for Heck Arylation at C-8 of Adenine NucleosidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2008Pallavi Lagisetty Abstract A simple method for the arylation of 8-vinyladenine nucleoside derivatives is reported. With a broad set of aryl iodides and bromides, the reaction is catalyzed by the simple combination palladium acetate/tris(o -tolyl)phosphine/triethylamine [Pd(OAc)2/(o -tol)3P/Et3N]. As expected, aryl chlorides are more difficult coupling partners but some undergo reactions with more exotic catalysts. Although trans -olefins are the major products, minor amounts of cis -isomers are detected in some cases, and a post -arylation mechanism for their formation is proposed. Finally, by subtle catalyst modulation chemoselective N -arylation of the nucleoside can be achieved in the presence of the vinyl moiety. [source] | ||||||||||||||||||||||