检索结果-南通市图书馆

A novel ligand-free palladium catalytic system with SO_3H-functional ionic liquids as cocatalyst for amidocarbonylation reaction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2008年第10期19卷 1175-1178页

作者： Qing Lu Zhao lai lai wang State Key Laboratory for Oxo Synthesis ＆ Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China Graduate University of Chinese Academy of Sciences Beijing 100039 China

Effects of Lewis acid BF3·OEt2, and BrCnsted acids TsOH, CF3COOH, H3PO4, and HCIO4 as cocatalyst respectively on the ligand-free palladium-catalyzed amidocarbonylation were investigated. SO3H-functional ionic liquids 1-methyl-3-（4-sulfonic acid）butylimidazolium hydrosulfate [MIm（CH2）4803H][HSO4] and 1-methyl-3-（4-sulfonic acid）butylimidazolium triflate [MIm（CH2）4SO3H][OTf] were firstly employed as cocatalysts instead of these Lewis acid and Brφnsted acids. By using a ligand-free and weak corrosive catalyst in situ prepared form PdBr2, LiBr.H2O, and [MIm（CH2）4SO3H][OTf], the arnidocarbo- nylation of benzaldehyde, acetamide, and CO could proceed smoothly and afford N-acetyl-α-phenylglycine with yield of 58% in [C6mim]PF6 medium.

关键词： Amidocarbonylation Palladium Ionic liquids Benzaldehyde N-Acyl-α-amino acid

Synthesis of novel cyclohexanediol-derived chiral phosphite ligands and their application in the Cu-catalyzed conjugate addition of organozinc to cyclic enones

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2016年第2期27卷 271-276页

作者： Zeng-Bo Pang Hai-Feng Li lai-lai wang State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China University of Chinese Academy of Sciences Beijing 100039 China

A series of novel chiral diphosphite ligands have been synthesized from（1R,2R）-trans-1,2-cyclohexanediol,（1S,2S）-trans-1,2-cyclohexanediol, racemic trans-1,2-cyclohexanediol and chlorophosphoric acid diary ester, and were successfully employed in the Cu-catalyzed asymmetric 1,4-conjugate addition of diethylzinc to cyclohexenone with up to 99% ee. It was found that ligand 1,2-bis[（R）-1,10-binaphthyl-2,2＇-diyl]phosphitecyclohexanediol 6a derived from racemic diol skeleton can show similar catalytic performance compared with ligand（1R,2R）-bis[（R）-1,1＇-binaphthyl-2,2＇-diyl]phosphitecyclohexanediol 6a＇ derived from enantiopure starting material. A significant dependence of stereoselectivity on the type of enone and the ring size of the cyclic enone was observed. Moreover, the configuration of the products was mainly determined by the configuration of the binaphthyl moieties of diphosphite ligands in the 1,4-addition of cyclic enones.

关键词： Racemic and chiral cyclohexanedio Phosphite ligands Organozinc Cyclic enones Cu-catalyzed conjugate addition

Effect of a Trace of Bi and Ni on the Microstructure and Wetting Properties of Sn-Zn-Cu Lead-Free Solder

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2007年第1期23卷 81-84页

作者： Haitao MA Haiping XIE lai wang State Key Laboratory of Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Dalian 116024 China School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China

The microstructure and melting behavior of Sn-9Zn-2Cu （SZC） lead-free solder with 3 wt pct Bi and various amount of Ni additions were studied. The wetting properties and the interracial reaction of Sn-Zn-Cu with Cu substrate were also examined. The results indicated that the addition of 3 wt pct Bi could decrease the melting point of the solder and Ni would refine the microstructure and the rod-shape Cu5Zn8 phase changed into square-shape （Cu, Ni）5Zn8 phase. The addition of Bi, Ni greatly improved the wettability of SZC solder. In addition, the interracial phase of the solders/Cu joint was typical planar Cu5Zn8 in SZC-3Bi-INi alloy.

关键词： Lead-free solder Microstructure Wetting property Interfacial reaction Intermetallic compounds

Gravity-induced geometric spin Hall effect of freely falling quantum particle

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2022年第10期74卷 76-82页

作者： Zhen-lai wang Xiang-Song Chen School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China School of Physics and MOE Key Laboratory of Fundamental Quantities Measurement Huazhong University of Science and TechnologyWuhan 430074China

We discuss a new gravitational effect that the wave packet of a free-fall quantum particle undergoes a spin-dependent transverse shift in Earth’s gravitational *** effect is similar to the geometric spin Hall effect(GSHE)(Aiello 2009 et al ***.103100401),and can be called gravity-induced *** effect suggests that the free-fall wave packets of opposite spin-polarized quantum particles can be split in the direction perpendicular to spin and gravity.

关键词： gravity-induced geometric spin Hall effect quantum particle universality of free fall

Functionalization of covalent organic frameworks via multicomponent reactions

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第12期67卷 3906-3914页

作者： Xue-Hui Liu Peng-lai wang Wei wang San-Yuan Ding State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringMOE Frontiers Science Center for Rare IsotopesLanzhou UniversityLanzhou 730000China

Functionalized covalent organic frameworks(COFs)represent a fascinating class of porous materials that have attracted widespread interest due to their modifiable structures and impressive potential ***,the construction of functionalized COFs remains difficult as it requires simultaneous consideration of robust linkages,diversified structures,and tailorable ***,the introduction of multicomponent reactions(MCRs)into COF synthesis opens new avenues for creating highly stable and function-oriented COF materials,marking a significant advance in the development of *** minireview summarizes the types of MCRs used in COF synthesis,highlights the functionalization strategies of COFs via MCRs,and provides insights on the key challenges and future frontiers in this field.

关键词： covalent organic frameworks multicomponent reactions functionalization strategies

Wetting Behavior and Interfacial Reactions in (Sn-9Zn)-2Cu/Ni Joints during Soldering and Isothermal Aging

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第3期25卷 410-414页

作者： Ning Zhao Haitao Ma Haiping Xie lai wang School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China

The wetting property of （Sn-9Zn）-2Cu （wt pct） on Ni substrate and the evolution of interracial microstructure in （Sn-9Zn）-2Cu/Ni joints during soldering as well as isothermal aging were studied. The wetting ability of eutectic Sn-gZn solder on Ni substrate was markedly improved by adding 2 wt pct Cu into this solder alloy. Plate-like Cu5Zn8 intermetallic compounds （IMCs） were detected in （Sn-9Zn）-2Cu solder matrix. A continuous NisZn21 IMC layer was formed at （Sn-9Zn）-2Cu/Ni interface after soldering. This IMC layer kept its type and integrality even after aging at 170℃ for up to 1000 h. At the early aging stage （before 500 h）, the IMC layer grew fast and its thickness followed a linear relationship with the square root of aging time. Thereafter, however, the thickness increased very slowly with longer aging time. When the joints were aged for 1000 h, a new IMC phase, （Cu,Ni）5Zn8, was found in the matrix near the interface. The formation of （Cu,Ni）5Zns phase can be attributed to the diffusion of Ni atoms into the solder matrix from the substrate.

关键词： Lead-free solder Interfacial reaction Intermetallic compounds Aging

DFT Studies on Non-IPR C_(68) and Endohedral Fullerene Sc_3N@C_(68)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2007年第3期26卷 321-327页

作者： wang Dong-lai SUN Xiao-Ping ZHAI Yu-Chun College of Materials and Metallurgy Northeastern University Shenyang 110004 China Department of Chemistry Anshan Teachers College Anshan 114005 China

Density functional theory （DFT） calculations on two isomers of C68 with the minimal number of fused pentagon pairs, its anions and Sc3N as well as Sc3N@C68 （6140） metallofullerene were carded out at the B3LYP/6-31G^＊ level. The optimized configurations and electrostatic potential distributions have been obtained. The calculated results show that the electrostatic potentials of C68 （6140） inside the sphere have three minima in the middle of the double bonds at fusion of two hexagonal rings. In contrast, potential minimum Vmin（r） of C68 （6275） inside the sphere occurs at the center of the sphere. Concerning the two isomers of C68, the largest regions with the most negative MEP outside the sphere are both localized in the neighborhood of pentagon-pentagon vertex fusions. They constitute the most probable active sites in chemical reactions. Our results present a reasonable explanation for the bonding between scandium atoms and fullerene cage.

关键词： C68 fullerene metallofullerene electrostatic potential bonding

Asymmetric hydrogenation of aromatic ketones using new chiral-bridged diphosphine/diamine-Ru(Ⅱ) complexes

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2010年第12期21卷 1403-1406页

作者： Yu Ming Cui lai lai wang Fuk Yee Kwong Wei Sun State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis and Department of Applied Biology and Chemical technology The Hong Kong Polytechnic University Hong Kong China Graduate University of Chinese Academy of Sciences Beijing 100039 China

A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst *** hydrogenation of 2-methylacetophenone in n-butanol （t-BuOK/Ru =45.6/1,S/C = 500,20 *** H2,20℃,48 h） afforded（S）-1-（2＇-methylphenyl）ethanol in 92%ee and〉99% conversion.

关键词： Asymmetric hydrogenation Chiral alcohols Diphosphine ligand Ruthenium complexes Diamine

Tensile behavior of Sn-0.7Cu with Zn addition at various deformation temperatures

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2011年第2期24卷 155-160页

作者： Zhongbing L UO Jie ZHAO Junshan ZHANG lai wang School of Materials Science and Engineering Dalian University of Technology Dalian 116085 China

The tensile behavior of Sn-0.7Cu and Sn-0.7Cu-1Zn was compared at various deformation temperatures. Refined microstructure and γ-CuZn particles were discovered with Zn addition. The strengths of Zn-containing solder were higher than that of Sn-0.7Cu at room and subzero temperatures. With the elevation of deformation temperature, they both decreased and they were nearly the same at 80 ？ C. The works of fracture exhibited the similar evolution law. For Sn-0.7Cu solder, the elongation after fracture was smaller and the reduction of area was bigger than those of Sn-0.7Cu-1Zn. This shows that Zn addition improved the deformation stability, which is attributed to the modification of the microstructure. Dimples in fracture surface became smaller and shallower with the decreasing temperature. Ductile fracture was discovered in all the samples.

关键词： Sn-0.7Cu Zn Tensile Temperature Strength Ductility Fracture