Combinatorial synthesis of functionalized chiral and doubly chiral ionic liquids and their applications as asymmetric covalent/non-covalent bifunctional organocatalysts

A facile combinatorial strategy was developed for the construction of libraries of functionalized chiral ionic liquids (FCILs) including doubly chiral ionic liquids and bis-functional chiral ionic liquids. These FCIL libraries have the potential to be used as asymmetric catalysts or chiral ligands. As an example, novel asymmetric bifunctional catalysts were developed by simultaneously incorporating functional groups onto the cation and anion. The resultant bis-functionalized CILs showed significantly improved stereoselectivity over the mono-functionalized parent CILs.     

聚苯胺在离子液体/水体系中的微乳液法合成

通过乳化剂OP-10的乳化作用,将油相为溶有苯胺单体的1-丁基-3-甲基咪唑六氟磷酸盐([bmim]PF6)离子液体与水形成了水包油型微乳液.利用该微乳液制备了纳米粒径的导电聚苯胺颗粒.红外光谱和能量散射谱分析结果表明,离子液体负离子已掺杂进入聚苯胺分子链,所得聚苯胺颗粒热稳定性和电化学稳定性好,且具有良好的充放电性能.     

Syntheses,crystal structures and properties of two novel imino-π-extended TTF derivatives

Two novel conjugated imino-π-extended tetrathiafulvalenes with p-iminobenzene, N,N′-bis(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)benzene-1,4-diamine (1) and N,N′-bis(4,5-bis(ethylenedithio)-1,3-dithiolo-2-ylidene)benzene-1,4-diamine (2), have been synthesized and characterized by NMR, IR, MS and X-ray single-crystal diffraction. Both the two targets adopt chair-like conformation, and the central rings of p-iminobenzene moieties of the two molecules are severely twisted from the planarity of two dithiole rings, respectively. The UV–vis spectra of 1 and 2 show the lowest-energy absorption bands caused by the HOMO–LUMO one-electron promotion. Cyclic voltammetry (CV) measurements show only one, two-electron irreversible oxidation picks. These experimentally estimated energy levels of the frontier orbital of 1 and 2 (E_HOMO 1: = ?5.45, 2: ?5.47 eV) are in good agreement with those obtained from DFT calculations (E_HOMO 1: = ?5.5, 2: = ?5.3 eV). The high HOMO–LUMO gaps of 1 (4.05 eV) and 2 (4.00 eV) indicate high kinetic stability of the title compounds.     

Non-centrosymmetric sodium borate: Crystal growth,characterization and properties on Na2B4O12H10

In this study, both solvent evaporation and hydrothermal methods were employed to grow hydrated sodium borate crystals using NaOH and H₃BO₃ as reagents, and transparent and colorless single-crystals were successfully obtained with sizes up to 12 × 6 × 6 mm³ and 6 × 5 × 4 mm³, respectively. The structure is determined by single-crystal X-ray diffraction techniques. The title compound crystallizes in the trigonal space group R32, with a = 11.1042(16) Å, b = 11.1042(16) Å, c = 21.131(4) Å, Z = 9 and R₁ = 0.0322, wR₂ = 0.0840. Infrared and transmission spectra are presented for the reported material. The powder second-harmonic generation (SHG) intensity measured by the Kurtz-Perry method indicates that the SHG effect of Na₂B₄O₁₂H₁₀ is about one-third times that of KH₂PO₄ (KDP).     

Investigation on periodic cracking of elastic film/substrate system by the extended finite element method

Multiple cracking behavior in a thin elastic film bonded to a thick elastic substrate is investigated by the extended finite element method. Stress and stress intensity factor are obtained using a periodic finite element model for the cracked film/substrate system. The influences of various parameters including crack length, film thickness, periodic crack spacing, and relative stiffness of the substrate on the stress and stress intensity factor are discussed in detail. It is demonstrated that the effects of geometric parameters are more sensitive than that of material property. In particular, the crack spacing has a saturation value due to interactions of neighboring cracks and relief of tensile stress in the film. The film/substrate couple with multiple periodic cracks can exhibit a positive potential in improving the durability of the film/substrate system.     

大孔树脂吸附分离速溶茶副产品中茶多酚的研究

通过静态试验比较了不同树脂对速溶茶副产品中茶多酚的吸附和解析特性,筛选出对茶多酚有较好的吸附率和解析率的NKA-9型树脂。动态试验确定了最佳的吸附和解析参数:上样流速为0.8mL/min、上样液温度为60℃、pH为5,洗脱流速为0.9mL/min、乙醇浓度为80%、洗脱剂用量为3BV。经过NKA-9纯化后速溶茶副产品中茶多酚含量达到58.7%,得率为14%。     

Copper‐Catalyzed Enantioselective Sonogashira Type Coupling of Alkynes with α‐Bromoamides

An asymmetric copper‐catalyzed Sonogashira type coupling between alkynes and α‐bromoamides has been developed. This method represents a facile approach to synthetically useful β, γ‐alkynyl amides from two readily available starting materials in a highly enantioselective manner. A Bisoxazoline diphenylanaline (BOPA) serves as the effective chiral ligand. Preliminary mechanistic studies support the formation of alkyl radical species .