Electrochemical response of ascorbic acid at conducting and electrogenerated polymer modified electrodes for electroanalytical applications: a review

The present short review deals with electroanalytical aspects of electrochemical response of ascorbic acid (Vitamin C) at conducting and electrogenerated polymer modified electrodes. Two main topics are considered: (i) electrocatalytic oxidation of ascorbate at conducting polymer modified electrodes, leading to electroanalytical techniques for ascorbate assay, and (ii) retardation of ascorbate penetration through a layer of electrogenerated polymers, leading to permselective coatings and their diverse uses, especially for biosensing devices.     

PPY催化合成乙酸沉香酯

利用吡啶与二氯亚砜反应 ,制成双吡啶盐 ,进而与四氢吡咯反应 ,一步法合成 4 ( 1 四氢吡咯 )吡啶(PPY)。利用PPY为催化剂进行沉香醇的酰化反应 ,并对影响反应的诸因素进行了讨论 ,醇的转化率为 99% ,酯的收率为 88.2 %。     

镧掺杂锶铁氧体-聚吡咯复合物的制备及磁性研究

用溶胶-凝胶法和溶液原位合成法分别制备镧掺杂锶铁氧体(Sr1－xLaxFe11.5Ni0.5O19, x＝0.0, 0.1, 0.2, 0.3, 0.4)粉末及其吡咯相对质量分数为60%和80%的聚吡咯-铁氧体复合物微粒PPY (Polypyrrole)/Sr0.8La0.2Fe11.5Ni0.5O19. 借助X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、红外光谱(FTIR)和振动样品磁强计(VSM)等分析手段表征了铁氧体粉末和复合物微粒的结构、形貌和磁性能. 结果表明, 包覆的聚吡咯外层对复合物微粒的形貌和磁性有一定的影响. 在外加磁场作用下, 复合物的饱和磁化强度MS随吡咯含量的增加而减小, 当吡咯含量等于0%, 60%和80%时, 对应的MS分别为59.4, 18.7和10.3 emu/g.     

Simple and Effective Synthetic Approach to Chiral 2-Amino-4-piperidinyl Pyridine Derivatives

A facile way has been developed to provide a series of novel chiral N-(4-(piperidin-1-yl)pyridin-2-yl)amide derivatives as potential stereoselective catalysts. The key intermediate, 2-amino-4-piperidinyl pyridine, was obtained by nucleophilic substitution of 2-amino-4-chloropyridine with piperidine in good yields (up to 96%). The total control of enantioselectivity was obtained for the synthesis of L-proline and (R)-1,1′-bi(2-naphthol) derivatives.     

Ir(PPY)3掺杂PVK的电致发光机理

近几年来发展起来的电致磷光(electrophosphorescence)是有机发光二极管(OLED)研究的新生长点。对电致磷光发光机理的研究随即得到了人们普遍的关注。比较了不同正向偏压条件下Ir(PPY)₃掺杂聚乙烯基咔唑(PVK)的光致发光(PL)和电致发光(EL)光谱。研究结果显示在电场和注入电流的共同作用下,PL光谱中基质PVK发光的相对强度并没有发生显著的变化。电场或注入载流子不会影响PVK向Ir(PPY)₃的能量传递。磷光掺杂聚合物EL主要是由于载流子在掺杂磷光分子上的直接复合,而不是由基质向磷光掺杂分子的能量传递。     

Fluorous analogues of DMAP (F-DMAP): Reusable organocatalysts for acylation reaction

A short and facile preparation of analogues of DMAP (F-DMAPs) labelled with fluorous chains is reported. These catalysts efficiently promote the acylation of alcohols with anhydrides (Ac₂O, (i-PrCO)₂O) and can be partially recovered and reused. The effectiveness of F-DMAP is similar to that of DMAP.     

Conducting polymers in chemical sensors and arrays

The review covers main applications of conducting polymers in chemical sensors and biosensors. The first part is focused on intrinsic and induced receptor properties of conducting polymers, such as pH sensitivity, sensitivity to inorganic ions and organic molecules as well as sensitivity to gases. Induced receptor properties can be also formed by molecularly imprinted polymerization or by immobilization of biological receptors. Immobilization strategies are reviewed in the second part. The third part is focused on applications of conducting polymers as transducers and includes usual optical (fluorescence, SPR, etc.) and electrical (conductometric, amperometric, potentiometric, etc.) transducing techniques as well as organic chemosensitive semiconductor devices. An assembly of stable sensing structures requires strong binding of conducting polymers to solid supports. These aspects are discussed in the next part. Finally, an application of combinatorial synthesis and high-throughput analysis to the development and optimization of sensing materials is described.     

聚并苯和聚并吡啶类化合物非线性光学性质及其分子材料设计

选取聚并苯、聚并吡啶和聚并吡嗪的 3种共振结构为基体 ,计算不同共轭单体齐聚物的结构及被取代后的聚合物二阶和三阶非线性光学系数 .结果表明 ,聚合物的二阶非线性光学系数与其单体相比有显著增大 ,被—NH2 和 NO2 取代后的聚并苯、聚并吡啶和聚并吡嗪的非线性光学系数又在聚合物的基础上进一步大幅度增加 ,有的增加 2～ 3个数量级 .在非取代的聚合物中 ,聚吡啶各种结构的二阶非线性光学系数均较大 ;取代聚合物中 ,单—NH2 和—NO2 取代的聚并苯 ,尤其是反式共振结构聚并苯的二位— NH2 和五位—NO2 取代结构的聚合物二阶非线性光学系数高达 3 .2 7× 1 0 - 2 7esu,说明这种— NH2 和 -NO2 取代后的聚并苯是一种很好的非线性光学材料 .