Highly Regioselective Sequential 1,1‐Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes

A regioselective double 1,1‐hydrosilylation of terminal aliphatic alkynes with primary silanes catalyzed by one cobalt catalyst has been developed. gem‐Bis(dihydrosilyl)alkanes containing four silicon‐hydrogen bonds are efficiently constructed in an atom‐economical manner. Tolerated substrates include simplest alkyne‐ethyne, a complicated drug derivative and various functionalized terminal aliphatic alkynes. Asymmetric approach using two catalysts is achieved with excellent enantioselectivities to access corresponding chiral products. The transformations of Si—H bonds into Si—C, Si—O, and Si—F bonds and the synthesis of enantioriched α‐hydroxysilane show synthetic utility.     

超分子砌块间苯二酚杯芳烃的研究进展

间苯二酚杯芳烃是一类以间苯二酚为单元的杯芳烃, 作为新一代超分子砌块, 在分子催化、分子识别、超分子自组装、晶体工程和纳米材料等方面都获得了广泛的应用, 已成为当今化学研究的新热点. 综述了间苯二酚杯芳烃的功能化修饰及其应用新进展.     

Synthesis and Biological Activity of Some New Pyrazolo[3,4‐b]Pyrazines

New derivatives of pyrazolo[3,4‐b]pyrazine and related heterocycles were prepared starting from 6‐amino‐3‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyrazine‐5‐carbonitrile ( 2 ) and using the key intermediates 4 , 5 , 6 , 14 , 15 and 16 . Some of the prepared compounds were evaluated for their antifungal and antibacterial activities.     

Application of Liquid Crystalline NMR Solvents to a Mixture of Ketones

A series of dilute liquid crystalline solvents are used to study the effect of slight anisotropy caused by partial alignment on chemical shift and residual dipolar coupling (RDC) in small molecules. The residual dipolar couplings between protons in solutes are found to be almost independent of the local environment. It is also found that the chemical shift does not change over the concentration range observed. A linear relationship between residual dipolar coupling and liquid crystal concentration is observed at relatively low concentrations, but is severely violated at high concentrations.     

A Structural Study of the Solid Solution Eu2(Mo1‐xWx)3O12

A structural study by means of X‐ray and electron diffraction of intermediate oxides between Eu₂Mo₃O₁₂ and Eu₂W₃O₁₂ shows the existence of a new Eu₂(Mo_1?xW_x)₃O₁₂ solid solution with the scheelite structural type. The essential feature of the x = 1/3 and x = 2/3 compounds is the presence of isolated oxygen tetrahedra, in which, according to X‐ray and electron diffraction data, W and Mo are randomly distributed. Eu atoms occupy distorted square antiprisms sites.     

PLLA/β-TCP杂化微纳米纤维的制备及其性能

将湿法工艺合成的β-磷酸钙纳米粒子与左旋聚乳酸(PLLA)的混合溶液通过电纺丝法制成杂化纳米纤维膜,以期制备一种新型纳米纤维骨组织修复材料。采用FT-IR,XRD,TEM,DSC等手段研究了β-磷酸钙(β-TCP)的结构和形态,采用SEM和直径分布探讨了优化PLLA/β-TCP纤维的电纺丝工艺。结果表明:采用湿法合成β-TCP的纳米粒子具有良好的晶型结构,直径在219~328 nm之间;采用双溶剂体系在优化条件下制备的PLLA/β-TCP杂化纳米纤维直径在500~700 nm之间,PLLA/β-TCP界面结合良好,β-TCP起到了增强作用。在湿态条件下,PLLA纤维膜的力学性能有所提高,而PLLA/β-TCP纤维膜的力学性能则呈现下降趋势。