格尔德霉素C(11)～C(21)片段的合成

以D-三乙酰葡萄糖烯为最初原料,经三步反应合成了已知内酯化合物5.以羰基α位亚甲基化、底物诱导的不对称催化氢化反应为关键步骤,构建了关键的C(14)位手性中心.最终,经10步反应、以24%的总产率合成了苯醌安莎霉素类天然产物格尔德霉素(Geldanamycin)的C(11)~C(21)片段.     

The Adsorption and Simulated Separation of Light Hydrocarbons in Isoreticular Metal–Organic Frameworks Based on Dendritic Ligands with Different Aliphatic Side Chains

Three isoreticular metal–organic frameworks, JUC‐100, JUC‐103 and JUC‐106, were synthesized by connecting six‐node dendritic ligands to a [Zn₄O(CO₂)₆] cluster. JUC‐103 and JUC‐106 have additional methyl and ethyl groups, respectively, in the pores with respect to JUC‐100. The uptake measurements of the three MOFs for CH₄, C₂H₄, C₂H₆ and C₃H₈ were carried out. At 298 K, 1 atm, JUC‐103 has relatively high CH₄ uptake, but JUC‐100 is the best at 273 K, 1 atm. JUC‐100 and JUC‐103 have similar C₂H₄ absorption ability. In addition, JUC‐100 has the best absorption capacity for C₂H₆ and C₃H₈. These results suggest that high surface area and appropriate pore size are important factors for gas uptake. Furthermore, ideal adsorbed solution theory (IAST) analyses show that all three MOFs have good C₃H₈/CH₄ and C₂H₆/CH₄ selectivities for an equimolar quaternary CH₄/C₂H₄/C₂H₆/C₃H₈ gas mixture maintained at isothermal conditions at 298 K, and JUC‐106 has the best C₂H₆/CH₄ selectivity. The breakthrough simulations indicate that all three MOFs have good capability for separating C2 hydrocarbons from C3 hydrocarbons. The pulse chromatographic simulations also indicate that all three MOFs are able to separate CH₄/C₂H₄/C₂H₆/C₃H₈ mixture into three different fractions of C1, C2 and C3 hydrocarbons.     

Solvent‐Free Syntheses of Hierarchically Porous Aluminophosphate‐Based Zeolites with AEL and AFI Structures

Development of sustainable routes for synthesizing aluminophosphate‐based zeolites are very important because of their wide applications. As a typical sustainable route, solvent‐free synthesis of zeolites not only decreases polluted wastes but also increases product yields. Systematic solvent‐free syntheses of hierarchically porous aluminophosphate‐based zeolites with AEL and AFI structures is presented. XRD patterns and SEM images show that these samples have high crystallinity. N₂ sorption isotherm tests show that these samples are hierarchically porous, and their surface areas are comparable with those of corresponding zeolites from hydrothermal route. Chosen as an example, catalytic oxidation of ethylbenzene with O₂ shows that cobalt substituted APO‐11 from the solvent‐free route (S‐CoAPO‐11) is more active than conventional CoAPO‐11 from hydrothermal route owing to the sample hierarchical porosity.     

Mechanical,aging, optical and rheological properties of toughening polylactide by melt blending with poly(ethylene glycol) based copolymers

Two novel biodegradable copolymers, including poly(ethylene glycol)-succinate copolymer (PES) and poly(ethylene glycol)-succinate-l-lactide copolymer (PESL), have been successfully synthesized via melt polycondensation using SnCl₂ as a catalyst. The copolymers were used to toughen PLA by melt blending. The DSC and SEM results indicated that the two copolymers were compatible well with PLA, and the compatibility of PESL was superior to that of PES. The results of tensile testing showed that the extensibility of PLA was largely improved by blending with PES or PESL. At same blending ratios, the elongation at break of PLA/PESL blends was far higher than that of PLA/PES ones. The elongation maintained stable through aging for 3 months. The moisture absorption of the blends enhanced due to the strong moisture absorption of PEG segments in PES or PESL molecules, which did not directly lead to enhance the hydrolytic degradation rate of the PLA. The PLA blends containing 20–30 wt% PES or PESL were high transparent materials with high light scattering. The toughening PLA materials could potentially be used as a soft biodegradable packaging material or a special optical material.     

Determination of ultra-low glass transition temperature via differential scanning calorimetry

A novel method was developed to determine the ultra-low glass transition temperature (T_g) of materials through physical blending via differential scanning calorimetry. According to the Fox equation for polymer blends, a blend of two fully compatible polymers has only one T_g. The single T_g is a function of the T_gs of the two simple polymers. Thus, the ultra-low T_g of one material can be obtained from the T_gs of another polymer and their blends. The error of T_g measurements depends on the measurement error of the T_gs for the blends and another polymer. The method was successfully applied to determine the T_gs of acetyl tributyl citrate (ATBC), tributyl citrate (TBC) and poly(ethylene glycol)s (PEG)s with different molecular weights. The T_gs for ATBC, TBC, PEG-4000 and PEG-800 were ?57.0 °C, ?62.7 °C, ?76.6 °C and ?83.1 °C, respectively. For all the samples, the standard deviation of measurements was less than 3.3 °C, and the absolute error of measurements was theoretically not more than 5.3 °C. These results indicate that this method has acceptable precision and accuracy.     

Novel N-heteroaromatic dyes for textile substrates

This study reports the synthesis and characterization of quinoline derivatives. The synthesized quinoline compounds were applied to the dyeing treatment of acrylic fabrics. The color fastness to washing and light of quinoline compound-dyed fabrics was examined. Human skin HaCaT cell line was also used for the skin cytotoxicity evaluation of the quinoline compound-dyed acrylic fabrics.     

多组态含时自旋非限制HartreeFock理论

基于自旋非限制HartreeFock理论,发展了自旋非限制多组态含时HartreeFock理论方法来研究激光场中的多电子相关动力学．自旋向上和自旋向下的自旋轨道分别在他们各自的子空间内传播;并通过约化密度矩阵和平均场算符相互作用．分别利用了自旋限制和非限制的多组态含时HartreeFock方法虚时和实时传播计算氦原子基态能量和电离几率．自旋非限制的计算结果与其他报道相吻合．     

Green synthesis of benzimidazole derivatives catalyzed by ionic liquid under microwave irradiation

An efficient synthesis of benzimidazole derivatives from o-phenylene diamine and substituted aromatic aldehyde catalyzed by ionic liquid under microwave irradiation was reported. The synthesis conditions were first optimized by single factor experiments. Then, a central composite design combined with response surface methodology was used to study the most effective factors. Optimal conditions were synthesis time 1 h, the reactant/catalyst molar ratio 1:1:0.200, the temperature 50 °C and the microwave power 500 W. Under optimized conditions, the yields of benzimidazole derivatives were 78.55–97.66 %. This method offered the outstanding advantages, such as faster reaction rate, higher yields, recyclable catalyst, environmental friendliness, and simple workup procedure.     

Spectrofluorimetric method for the determination of uric acid in human serum

A new spectrofluorimetric method is described for the determination of uric acid (UA), that can remarkably reduce the fluorescence intensity of the enoxacin (ENX)-terbium ion (Tb³⁺) complex at 545 nm. The reduced fluorescence intensity of Tb³⁺ ion at pH 5.7 is proportional to the concentration of UA. Optimum conditions for the determination of UA have been investigated. The linear range and detection limit for the determination of UA are 6.0 × 10^?7–3.0 × 10^?5 M and 1 × 10^?7 M, respectively. The relative standard deviation (RSD) was 0.4% for 6 × 10^?6 M UA (n = 11). The method is simple, practical and relatively free of interferences. It has been successfully applied to assess UA in serum at the level of 3 × 10^?4 M with an RSD of 5–7% (n = 3). The results were evaluated by comparison with a common clinical spectrophotometric method using phosphotungstic acid as developer.     

Synthesis and formation mechanism of pinnoite in sulfated-type boron concentrated brine by dilution method

The synthesis of pinnoite (MgB₂O(OH)₆) in boron-containing brine was established with a novel dilution method. Effects of temperature, precipitation time, boron concentration and mass dilution ratio on the formation of pinnoite were investigated. The products obtained were characterized by X-ray diffraction (XRD), Raman, thermogravimetric and differential scanning calorimeter (TG-DSC), and scanning electron microscopy. The transformation mechanism of pinnoite with different dilution ratios was assumed by studying the crystal growth of pinnoite. The results showed that pinnoite was synthesized above 60 °C in the diluted brine. There were two reaction steps – precipitation of amorphous solid and the formation of pinnoite crystals – during the whole reaction process of pinnoite when the dilution ratio is more than 1.0 at 80 °C. While in the 0.5 diluted brine, only one reaction step of pinnoite crystal formation was observed and its transformation mechanism was discussed based on dissociation of polyborates in brine. Besides, the origin of pinnoite mineral deposited on salt lake bottom was proposed.