Home About us Contact
|
Home About us Contact | ||
|
|
||
Stille Coupling Reaction (stille + coupling_reaction)
Selected AbstractsAtom-Efficient, Palladium-Catalyzed Stille Coupling Reactions of Tetraphenylstannane with Aryl Iodides or Aryl Bromides in Polyethylene Glycol 400 (PEG-400)ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Wen-Jun Zhou Abstract The Stille coupling of tetraphenylstannane with aryl iodides or aryl bromides using the bis(triphenylphosphine)palladium dichloride/sodium acetate/polyethylene glycol 400 [PdCl2(PPh3)2/NaOAc/PEG-400] catalytic system at 100,°C has been developed. The reactions were carried out in an atom-efficient way, as 4 equivalents of aryl iodides or aryl bromides coupled effectively with 1 equivalent of tetraphenylstannane to furnish 4 equivalents of the corresponding functionalized biaryls in high yields. [source] A Practical Heterogeneous Catalyst for the Suzuki, Sonogashira, and Stille Coupling Reactions of Unreactive Aryl Chlorides,ANGEWANDTE CHEMIE, Issue 6 2010Myung-Jong Jin Prof. Praktischer Katalysator: Ein Palladiumkatalysator, der auf einem magnetischen Nanopartikel fixiert ist, wurde für hocheffiziente heterogene Suzuki-, Sonogashira- und Stille-Kupplungen einer Vielzahl von Arylchloriden entwickelt. Darüber hinaus ließ sich der Katalysator durch einfache magnetische Trennung ohne jeglichen Aktivitätsverlust zurückgewinnen. TBAB=Tetrabutylammoniumbromid. [source] Stille Coupling Reactions in the Synthesis of Hypoxia-Selective 3-Alkyl-1,2,4-benzotriazine 1,4-Dioxide Anticancer Agents.CHEMINFORM, Issue 52 2006Karin Pchalek 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] Regioselectivity in the Stille Coupling Reactions of 3,5-Dibromo-2-pyrone.CHEMINFORM, Issue 12 2004Won-Suk Kim Abstract For Abstract see ChemInform Abstract in Full Text. [source] Soluble dithienothiophene polymers: Effect of link patternJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2009Shiming Zhang Abstract Soluble conjugated polymers based on 3,5-didecanyldithieno[3,2- b:2,,3,- d]thiophene,single-bond (1), double-bond (2), and triple-bond linked (3),were synthesized by palladium(0)-catalyzed Stille coupling reaction and oxidation polymerization. The thermal, absorption, emission, and electrochemical properties of these polymers were examined; the effect of the link pattern was studied. All polymers exhibit decomposition temperatures over 295 °C and glass-transition temperatures in the range of 137,202 °C. The absorption spectra of 1, 2, and 3 in thin films exhibit absorption maxima at 381, 584, and 444 nm, respectively. Polymer 1 exhibits intense green emission located at 510 nm in film, whereas polymers 2 and 3 are nonemissive both in solution and in film due to H-aggregate. Cyclic voltammograms of polymers 1, 2, and 3 display irreversible oxidation waves with onset oxidation potentials at 1.73, 0.78, and 1.03 V versus Ag+/Ag, respectively. Theory calculation on model compounds suggests that the dihedral angle decreases in the order of 1 > 3 > 2. On reducing the dihedral angle, the polymer exhibits a longer absorption maximum, a smaller bandgap, a less oxidizing potential and fluorescence quench, due to more coplanar and more ,-electron delocalized backbone structure. Polymer solar cells were fabricated based on the blend of polymer 2 and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM). The power conversion efficiency of 0.45% was achieved under AM 1.5, 100 mW cm,2 using polymer 2:PCBM (1:2, w/w) as active layer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2843,2852, 2009 [source] Novel saturated red-emitting poly(p -phenylenevinylene) copolymers with narrow-band-gap units of 2,1,3-benzothiadiazole synthesized by a palladium-catalyzed Stille coupling reactionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2005Xianzhen Li Abstract Novel poly(p -phenylenevinylene) (PPV) copolymers derived from 1-methoxy-4-octyloxyphenylene (MOP), 2,1,3-benzothiadiazole (BT), and trans -1,2-bis(tributylstannyl)ethylene were first prepared by a palladium-catalyzed Stille coupling reaction. The feed ratios of MOP to BT were 99.5:0.5, 99:1, 95:5, 85:15, 70:30, and 50:50. An efficient energy transfer from the 2-methoxy-5-octyloxy- p -phenylenevinylene segment to the narrow-band-gap units was observed. The poly(2-methoxy-5-octyloxy- p -phenylenevinylene-2,1,3-benzothiadiazolevinylene) copolymers emitted deep red light. The maximum electroluminescence emission of these PPV copolymers occurred at 659,724 nm and was accompanied by gradual redshifting with an increasing BT concentration. The photophysical properties were examined in comparison with those of copolymers based on BT and fluorene or N -alkylcarbazole doped with the same BT concentration in the copolymer main chain. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2325-2336, 2005 [source] Linking Polythiophene Chains Through Conjugated Bridges: A Way to Improve Charge Transport in Polymer Solar CellsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 10 2006Erjun Zhou Abstract Summary: A series of cross-linked polythiophene derivatives (P1,4) are synthesized by adding different ratio (0, 2, 5, and 10%) of conjugated cross-linker via a Stille coupling reaction. From P1,4, with the increase of the content of the conjugated bridges, the UV-visible absorption peaks of the polymers were shifted towards blue and their electrochemical bandgap increased. The hole mobilities of P1,4 as determined from the SCLC model are 5.23,×,10,6, 1.28,×,10,4, 7.01,×,10,3, and 2.34,×,10,5 cm2,·,V,1,·,s,1, respectively. The PCEs of the polymer solar cells based on P1,4 are 0.37, 1.05, 1.26, and 0.78%, respectively. The improvement of PCE of the devices based on P2,4 compared with that of P1 may be due to the increase of hole mobility. Molecular structure of the polythiophene derivatives (P1,4). [source] A Self-Assembling Polythiophene Functionalised with a Cysteine MoietyMACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2003Adele Mucci Abstract A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal-ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N -(tert -butoxycarbonyl)- S -thien-3-ylcysteinate and distannylthiophene through a Stille coupling reaction. UV-vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self-assembling structures, through the formation of a hydrogen-bond network, not only in the solid state but also in solution. [source] MCM-41-supported mercapto palladium(0) complex: an efficient and recyclable catalyst for the heterogeneous Stille coupling reactionAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2010Hong Zhao Abstract The Stille cross-coupling reaction of organostannanes with aryl halides was achieved in the presence of a catalytic amount of MCM-41-supported mercapto palladium(0) complex (1 mol%) in DMFH2O (9:1) under air atmosphere in good to high yields. This MCM-41-supported palladium catalyst can be reused at least 10 times without any decrease in activity. Copyright © 2009 John Wiley & Sons, Ltd. [source] Air-Stable and Highly Active Dendritic Phosphine Oxide- Stabilized Palladium Nanoparticles: Preparation, Characterization and Applications in the Carbon-Carbon Bond Formation and Hydrogenation ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2008Lei Wu Abstract Dendrimer-stabilized palladium nanoparticles were formed in the reduction of palldium bis(acetylacetonate) [Pd(acac)2] in the presence of phosphine dendrimer ligands using hydrogen in tetrahydrofuran. The resulting Pd nanoparticles were characterized by TEM, 31P,NMR and 31P MAS NMR. The results indicated that the dendritic phosphine ligands were oxidized to phosphine oxides. These dendrimer-stabilized Pd nanoparticles were demonstrated to be efficient catalysts for Suzuki and Stille coupling reactions and hydrogenations. The dendritic wedges served as a stabilizer for keeping the nanoparticles from aggregating, and as a vehicle for facilitating the separation and/or the recycling of the Pd catalyst. In the case of the Suzuki coupling reaction, these Pd nanoparticles exhibited high catalytic efficiency (TON up to 65,000) and air stability as compared with the commonly used homogeneous catalyst tetrakis(triphenylphosphine)palladium [Pd(PPh3)4]. In addition, the results obtained from the bulky dendritic substrate suggest that the Pd nanoparticles might act as reservoir of catalytically active species, and that the reaction is actually catalyzed by the soluble Pd(0) and/or Pd(II) species leached from the nanoparticle surface. [source] Synthesis of Oligo(thienylfuran)s with Thiophene Rings at Both Ends and Their Structural, Electronic, and Field-Effect PropertiesCHEMISTRY - AN ASIAN JOURNAL, Issue 12 2007Yasuo Miyata Dr. Abstract Oligo(thienylfuran)s with thiophene rings at both ends (SOSOSOS, DE-SOSOS, DH-SOSOS, DE-SOSOSOS, and DH-SOSOSOS; S and O denote thiophene and furan rings, respectively, DE and DH denote diethyl- and dihexyl-substituted, respectively) were newly synthesized by repetitive Stille coupling reactions. The UV/Vis maximum absorptions of the oligomers, SO, SOSO, SOSOS, SOSOSO, and SOSOSOS, exhibited a clear bathochromic shift with increasing number of heterocycles. The value of the oxidation peak potential (Epa1) determined by cyclic voltammetry decreased with an increase in the number of heterocycles by 0.06,0.08,V per heterocycle. The crystal-packing structures of DE-SOSOS and DH-SOSOS determined by X-ray crystallography have a herringbone motif and are denser than the reported structures of pentacene and ,-sexithiophene. The morphologies of thin films prepared by vacuum deposition and spin coating were investigated by atomic force microscopy and X-ray diffraction. Among these films, those of DE-SOSOS and DH-SOSOS exhibited highly ordered arrangements. The devices based on vacuum-deposited and spin-coated films of DE-SOSOS and DH-SOSOS displayed the highest FET mobilities of 10,2,10,3,cm2,V,1,s,1 among the oligomers reported in this study. [source] | |||||||||||||||||||||||||