Enantiomeric separations of four basic drugs containing N-alkyl groups by a RP-HPLC system using SBE-β-CD as chiral mobile phase additive

The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive(CMPA)in a RP-HPLC system(the resolution is 2.701 for ondansetron hydrochloride,1.996 for sulpiride,1.293 for clenbuterol hydrochloride and 0.816 for omeprazole).In addition,the effects of different parameters such as CD type and CD concentration were investigated.The separation mechanism arises through the combination of several potential interactions,including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions,which allow for the SBE-β-CD–drug complexation with strong stereoselectivity and stability.The resolution also relates to the number and location of N atoms in the enantiomers.This method will be applicable to the isolation of various types of biologically important enantiomers containing N-alkyl groups.     

Two new cyclic diarylheptanoids from the stems of Ostryopsis nobilis

Two new cyclic diarylheptanoids named ostryopsitrienol(1) and ostryopsitriol(2),together with six known compounds,were isolated from the stems of endemic medicinal plant of Ostryopsis nobilis (Betulaceae).The structures of the new compounds were elucidated by means of HRMS,~1D NMR,~2D NMR and X-ray crystallography analysis.     

Preparation and study of photoswitchable fluorescence nanoparticles based on spirobenzopyran

The preparation and performance characterization of〈50 nm spirobenzopyran-based photochromic nanocomposites with photoswitchable fluorescence are presented.The nanocomposites were fabricated by means of a modifed miniemulsion polymerization process,in which the hydrophobic spirobenzopyran was covalently attached to the polymer chains and the matched fluorescent dyes were noncovalently embedded in the nanoscale cross-linked polymeric matrix,respectively.The obtained nanocomposites with a high relative fluorescence quantum yield（Q）exhibited superior fluorescent photoswitchable performance due to the effective photo-induced intermolecular energy transfer.The stability of photomerocyanine was also improved.     

Effective synthesis of benzyl halides triggered by in situ prepared hypervalent halides

An effective approach for the direct benzylhalogenation with in situ generation of hypervalent halides has been developed.A variety of benzyl halides are produced in moderate to excellent yields(up to 99%) with high regioselectivities.UV absorption spectrum is employed to detect the formation of ferr-butyl hypoiodite.     

PO43-掺杂和AlF3包覆协同增强Li1.2Ni0.13Co0.13Mn0.54O2正极材料电化学性能

本研究采用PO₄^3-掺杂和AlF₃包覆的协同改性策略制备了P-LNCM@AlF₃正极材料(P=PO₄^3- ,LNCM=Li_1.2Ni_0.13Co_0.13Mn_0.54O₂),提高了LNCM的结构稳定性以及抑制了界面副反应。其中,大四面体的PO₄^3-聚阴离子掺杂在晶格中抑制了过渡金属离子的迁移,降低体积变化,从而稳定了晶体结构,而且PO₄^3-掺杂能够扩大锂层间距,促进Li⁺的扩散,从而提升材料的倍率性能。此外,AlF₃包覆层能抑制材料与电解液的副反应从而提升界面稳定性。基于以上优势,P-LNCM@AlF₃正极表现出了优异的电化学性能。在1C电流密度下表现出了179.2 mAh·g^-1的放电比容量,循环200圈后仍有161.5 mAh·g^-1的放电比容量,容量保持率可达90.12%。即使在5C的高电流密度下仍可提供128.8 mAh·g^-1的放电比容量。     

EDTA辅助水热法制备性能优异的棒状LiFePO4/C材料

以乙二胺四乙酸为配位剂采用水热法制备了棒状LiFePO₄/C材料。采用X射线衍射、扫描电镜、透射电镜、循环伏安、交流阻抗和恒电流充放电测试等对材料进行表征。结果表明:乙二胺四乙酸对材料的形貌和电性能均有很大影响。通过加入乙二胺四乙酸, 材料的形貌由不规则的颗粒变为棒状的颗粒且颗粒的厚度由140~200 nm减少至40~90 nm, 材料的表面包覆约3.5 nm的均匀碳层, 且该材料极化较小且界面阻抗较低。0.1C放电比容量为167 mAh·g^-1(接近理论容量170 mAh·g^-1)。     

四溴代对苯二甲酸及2，2′-联吡啶构筑的铜配位聚合物的合成、晶体结构及热稳定性

以四溴代对苯二甲酸(H2TBTA)与2,2′-联吡啶(2,2′-bipy)为配体,与硝酸铜在水和甲醇混合溶剂中合成了1个一维铜配合物{[Cu(2,2′-bipy)(TBTA)(H2O)].H2O}n,并通过元素分析、红外分析、热重分析、X-射线粉末衍射和X-射线单晶衍射对其进行了表征。该配合物属于正交晶系,空间群为Pna21,a=1.399 9(11)nm,b=0.929 3(7)nm,c=1.557 9(11)nm,V=2.027(3)nm3,Z=4,R1=0.053 5。中心Cu(Ⅱ)离子处于一个五配位环境中,且在配合物中存在着π-π相互作用和氢键作用。热重分析表明该配合物在203℃开始发生分解。     

基于5-(4-(2,6-二(2-吡嗪基)-4-吡啶基)苯氧基)间苯二甲酸的Mn(Ⅱ)和Ca(Ⅱ)配位聚合物的合成与晶体结构

采用对苯二甲酸为模板剂, 溶剂热法合成了2个以5-(4-(2, 6-二(2-吡嗪基)-4-吡啶基)苯氧基)间苯二甲酸(H₂L)为配体的金属-有机配位聚合物:{[MnL] ·0.5H₂O}_n (1), {[CaL(H₂O)₂]·H₂O}_n (2)。通过X-射线单晶衍射, 元素分析和红外光谱进行了结构表征。结构分析表明, 1具有(3, 3)-连接的不同手性型二维层面结构, 这些交替出现的单手性左旋型和右旋型二维平面通过配体的吡啶环与吡嗪环间π…π堆积作用构成了三维超分子结构;2是通过L^2-配体羧基桥连接相邻的Ca(Ⅱ)金属中心, 形成一条平行于b轴方向的一维链结构。研究了配位聚合物的热稳定性和2的荧光性质。     

茚三酮衍生高效毛细管电泳法测定纯奶中的甘氨酸含量

建立了茚三酮衍生高效毛细管电泳法测定纯奶中甘氨酸含量的方法,该法可选择性测定甘氨酸含量。使用氯化镁为蛋白沉淀剂,沉淀效果较好,研究了甘氨酸–茚三酮聚合物衍生条件,确定最佳实验条件为:未涂层弹性石英毛细管柱(60 cm×75μm,有效长度49 cm),分离缓冲溶液为3.5 mmol磷酸二氢钾–8.2 mmol磷酸氢二钠(pH 6.8),检测波长为570 nm,电泳电压为25 kV,进样压力为25 kPa,进样时间为3 s,电泳温度为室温。甘氨酸的线性范围为2.00~200.00μg/mL,检出限为0.14μg/mL,线性相关系数不小于0.999。甘氨酸的加标回收率为88.7%~107.2%,测定结果的相对标准偏差为2.9%~4.2%(n=6)。该法简便、快速、准确,可用于测定纯奶中甘氨酸含量。     

离子色谱法测定面制品和面包改良剂中的溴酸盐

用离子色谱法测定面制品和面粉改良剂中的溴酸盐。用30 mL水超声提取样品15 min(脂肪含量高的样品先用正己烷除脂),过HLB柱和银氢柱净化,以AS9–HC色谱柱分离,NaHCO3作为淋洗液,电导检测器检测,实现了复杂基质面制品中溴酸盐的检测。方法线性相关系数大于0.999,最低检测浓度为0.5 mg/kg,加标回收率为78.4%~106.3%。利用建立的方法对面制品和面包改良剂中的溴酸盐进行检测,共检测各类面制品144份,总体合格率为97.2%;检测面包改良剂类产品10份,合格率为40.0%。