Thermodynamics of Halogen Bonding in Solution: Substituent, Structural, and Solvent Effects
作者:Mohammed G. Sarwar、Bojan Dragisic、Lee J. Salsberg、Christina Gouliaras、Mark S. Taylor
DOI:10.1021/ja9086352
日期:2010.2.10
demonstrating that both substituent constants (sigma) and calculated molecular electrostatic potential surfaces are useful for constructing such relationships. An electrostatic model is, however, limited in its ability to provide correlation with a more comprehensive data set in which both halogen bond donor and acceptor abilities are varied: the ability of computationally derived binding energies to accurately
Fluorinated biphenyls from aromatic arylations with pentafluorobenzenediazonium and related cations. Competition between arylation and azo coupling
作者:Dmitry Kosynkin、T. Michael Bockman、Jay K. Kochi
DOI:10.1039/a701745f
日期:——
High yields of the mixed perfluorinated biaryls (C6F5–Ar) are obtained by the catalytic dediazoniation of the pentafluorobenzenediazonium salt (C6F5N2+BF4–) in acetonitrile solutions containing various aromatic substrates (ArH) together with small amounts of iodide salts. Activated (electron-rich) as well as deactivated (electron-poor) arenes are successfully pentafluorophenylated by this method. The arylation is distinct from the azo coupling of the same substrates, which takes place in the absence of the iodide catalyst and yields the corresponding diazene (C6F5NN–Ar) as product. The catalytic role of iodide, and the isomeric product distributions obtained with this procedure indicate that the arylation proceeds via the pentafluorophenyl radical in a efficient homolytic chain process. Since azo coupling involves electrophilic aromatic substitution of electron-rich ArH by C6F5N2+, the two competing pathways are distinct and do not have reactive intermediates in common.
and emission wavelengths of the complexes are almost invariant to the change of 2‐R group, the phosphorescence quantum efficiency varies from highly emissive (ΦPL≈0.80 for R=H, alkyl) to poorly emissive (R=aryl) depending on the 2‐R group and the polarity of the medium. Theoretical studies suggest that 1) the almost nonemissive nature of the 2‐aryl‐substituted complexes is mainly attributable to the
一系列的[(C ^ N)2的Ir(acac)]的配合物[5-(2-R-CB)PPY} 2的Ir(acac)]的(3 - 3克; ACAC =乙酰,CB = Ö -碳硼烷-1-基,ppy = 2-苯基吡啶; R = H(3 a),Me(3 b),i Pr(3 c),i Bu(3 d),Ph(3 e),CF 3 C 6 H 4(3 f),C 6 F 5(3 g))和各种2-R-取代的o制备了ppy配体苯环中5位的碳酮。X射线衍射研究表明,碳硼烷CC键的长度随着2-R取代基的空间位阻和吸电子作用的增加而增加。尽管复合物的吸收和发射波长几乎不变的2-R基团的变化,磷光量子效率从高发射(可变Φ PL ≈0.80为R = H,烷基)不佳发射(R =芳基),这取决于在2‐R组和介质的极性上 理论研究表明:1)2-芳基取代的配合物几乎没有排斥性,这主要归因于O对S 1激发态的LUMO的巨大贡献。-ca
[EN] COMT INHIBITORS<br/>[FR] INHIBITEURS DE COMT
申请人:HOFFMANN LA ROCHE
公开号:WO2014102233A1
公开(公告)日:2014-07-03
The present invention relates to compounds of formula (I), wherein the substituents are described in claim 1 and to the pharmaceutically acceptable salts thereof. These compounds inhibit the enzyme catechol-O-methyltransferase (COMT). The compounds may be used for the treatment of Parkinson's disease, depression, cognitive impairment and motor symptoms, resistant depression, cognitive impairment, mood and negative symptoms of schizophrenia.
Pd-Tetrahydrosalan-Type Complexes as Catalysts for Sonogashira Couplings in Water: Efficient Greening of the Procedure
作者:Krisztina Voronova、Levente Homolya、Antal Udvardy、Attila C. Bényei、Ferenc Joó
DOI:10.1002/cssc.201402147
日期:2014.8
diphenylacetylenes can be isolated in 76–98 % yield. The aqueous catalyst solution can be recycled four times with decreasing activity; however, yields between 93 and 98 % can still be achieved with extended reaction times. Several water‐insoluble products can be isolated in excellent yield by simple filtration and purification by washing with water; this method is used, for the first time, for this type
合成了新的磺化四氢salen型配体及其水溶性钯(II)配合物。钯(II)配合物催化各种芳基卤化物(包括氯代芳烃)与末端炔烃的Sonogashira偶联(23个实例),在温和条件下(80°C,空气,无Cu I助催化剂)在有机水溶液中具有良好至优异的转化率混合物和周转频率高达2790 h -1。在优化的反应条件下,以最小化环境污染,可以分离出76.98%的二苯乙炔。催化剂水溶液可以降低活性地循环使用四次。但是,延长反应时间仍可实现93%至98%的收率。通过简单的过滤和水洗纯化,可以分离出几种不溶于水的产物,收率很高。这种方法首次用于这种CC耦合过程。