Synthesis of novel BINOL-derived chiral bisphosphorus ligands and their application in catalytic asymmetric hydrogenation

Some novel ortho-substituted BINOL-derived bisphosphorous ligands (o-BINAPO and o-NAPHOS) were synthesis from readily available (S)-BINOL; these ligands showed excellent enantioselectivities (up to 99% ee) in Rh(I)-catalyzed asymmetric hydrogenation of functionalized olefins.     

A new electronically deficient atropisomeric diphosphine ligand (S)-CF3O-BiPhep and its application in asymmetric hydrogenation

A new electronically deficient atropisomeric diphosphine ligand (S)-CF₃O-BiPhep was synthesized from 1-bromo-3-(trifluoromethoxy)benzene in high yield. The key steps included oxidative coupling with anhydrous ferric chloride and optical resolution by (+)-DMTA. The ligand afforded high performance for Ir-catalyzed asymmetric hydrogenation of quinolines with ee up to 92% and TON up to 25,000. It was also successfully applied to the Pd-catalyzed asymmetric hydrogenation of simple indoles with ee up to 87% and Rh-catalyzed asymmetric 1,4-addition of phenylboronic acid to 2-cyclohexenone with 97% ee.     

Adsorptive removal of Eu(III) from simulated groundwater by GMZ bentonite on the repository conditions

Journal of Radioanalytical and Nuclear Chemistry - This study investigated the adsorption of Eu(III) from simulated Beishan groundwater onto Gaomiaozi bentontie. The effects of shaking time,...     

Inhibiting deactivation of iridium catalysts with bulky substituents on coordination atoms

Introducing bulky groups on the coordination phosphorus atoms can effectively block the formation of inactive dimer species and improve the activity of the iridium catalysts. Results of ESI-MS analysis gave strong evidence. This strategy was successfully applied to the asymmetric hydrogenation of quinolines with up to 93% ee on S/C ratio of 25,000.     

Highly enantioselective iridium-catalyzed hydrogenation of heteroaromatic compounds,quinolines

The highly enantioselective hydrogenation of quinoline derivatives is developed using [Ir(COD)Cl]2/(R)-MeO-Biphep/I2 system, and this methodology has been applied to the asymmetric synthesis of three naturally occurring alkaloids angustureine, galipinine, and cuspareine. This method provided an efficient access to a variety of optically active tetrahydroquinolines with up to 96% ee.     

用于短波长FEL的光阴极微波电子枪设计研究

高增益、短波长自由电子激光器需要发射度低、峰值电流高的短脉冲电子束流.采用发射度补偿技术,设计了一台S波段、一个半腔体的光阴极微波电子枪以用于建议中的SDUV-FEL装置.POISSON,SUPERFISH和PARMELA程序的计算表明:当微脉冲电量为2nC时,这种设计能产生ε_n,rms=2.3π·mm·mrad、E_k=4.8MeV的电子束流.报道了该枪的设计考虑和模拟结果.     

Thermal properties and liquid crystallinity of side-chain azobenzene copolymer containing pendant polyhedral oligomeric silsequioxanes

Vinylated polyhedral oligomeric silsesquioxane (POSS-M) was prepared by the reaction of POSS containing amine groups with acrylic acid. Azobenzene liquid crystalline copolymer (LCP-POSS) was then synthesized with 6.0 mol% POSS-M and 94.0 mol% acrylate monomer containing azobenzene liquid crystalline moiety (Azo-M) by free-radical copolymerization. Homopolymer of Azo-M (LCP) was also synthesized under the same conditions. Their thermal properties and liquid crystallinity were characterized by Thermal gravimetric analysis (TG), differential scanning calorimetry (DSC), Wide-angle X-ray diffraction experiments (XRD) and polarized optical micrographs (POM). The results showed that LCP-POSS has higher thermal stability and glass transition temperature than pure LCP due to the incorporation of the rigid cage-like POSS. Especially, LCP-POSS exhibits enantiotropic smectic and nematic liquid crystalline behaviors, its smectic-nematic transition temperature (T _SN) and nematic-isotropic transition temperature (T _NI) are higher than those of pure LCP, which may promote and extend its applications on stimuli-responsive materials and devices.     

Enantioselective Pd-catalyzed hydrogenation of fluorinated imines: facile access to chiral fluorinated amines

An enantioselective hydrogenation of simple fluorinated imines has been developed using Pd(OCOCF(3))(2)/(R)-Cl-MeO-BIPHEP as a catalyst, and up to 94% ee was achieved. This method provides an efficient route to enantioenriched fluorinated amines.     

An efficient route to 2,3-disubstituted indoles via reductive alkylation using H2 as reductant

An efficient route to 2,3-disubstituted indoles was developed via reductive alkylation of 2-substituted indoles using hydrogen as a clean and atom economic reductant under ambient pressure.