化学

化学

磁共振对比剂标记的聚合物传输siRNA抑制基因表达

王卫娟，肖洪，程度，等

二乙烯三胺（DETA）修饰生物可降解的聚乙二醇（PEG）-聚天冬氨酸（PAsp）两嵌段聚合物PEG-PAsp，并通过配体交换将PEG-PAsp（DETA）修饰到磁共振（MR）对比剂SPIO表面，阳离子嵌段PAsp（DETA）可负载核酸分子siRNA，从而获得兼具MR显像和核酸传输功能的生物可降解载体.细胞毒性研究证实该载体聚合物具有较好的生物安全性，可被肿瘤细胞高效吸收，且使转基因细胞株A549-Luc（恒定表达萤火虫荧光素酶）中荧光素酶的活性下调60%.MR成像也证实，SPIO经载体负载后，其横场弛豫率比游离的水溶性SPIO（WSPIO）提高了3倍以上，达到147 Fe（mmol/L）-1s-1，显著提高了磁共振的显像效果.

核酸传输载体；联合输送；siRNA；磁共振对比剂

来源出版物：高分子学报，2015，（4）: 484-492联系邮箱：程度，chengdu@mail.sysu.edu.cn

Non-aqueous Suspension Polycondensation in NMP-CaCl2/Paraffin System —A New Approach for the Preparation of Poly（p-phenylene terephthalamide）

Pei-jian Wang，Kai Wang，Ji-song Zhang，et al.

来源出版物：Chinese Journal of Polymer Science，2015，33（4）: 564-575联系邮箱：Guang-sheng Luo，gsluo@tsinghua.edu.cn

有机催化蒽酮与β-硝基烯烃的不对称Michael加成反应

张天一，年文霞，金瑛

将金鸡纳生物碱衍生物用于催化蒽酮和 β-硝基芳基乙烯的不对称 Michael加成反应.考察了溶剂、温度及催化剂用量对反应催化性能的影响.结果表明，最佳条件为 5%（摩尔分数）催化剂1 b、甲苯为溶剂、0℃反应，得到了91%～99%的化学产率和最高达95%ee的对映体选择性.

金鸡纳生物碱衍生物；有机催化；不对称Michael加成反应；蒽酮；β-硝基烯烃

来源出版物：应用化学，2015，32（4）: 422-427

联系邮箱：金瑛，jinying1021@sina.com

来源出版物：SCIENCE CHINA Chemistry，2015，58（4）: 553-564联系邮箱：Xiaoming Cao，xmcao@ecust.edu

A non-aqueous suspension polycondensation method was proposed to proceed the reaction of p-phenylenediamine and terephthaloyl chloride for the preparation of poly（pphenylene terephthalamide）（PPTA）. The system was operated with NMP-CaCl2solution as the dispersed phase and inert liquid paraffin as the continuous phase. Each of NMP-CaCl2solution microdroplet suspended in paraffin served as a microreactor where the polycondensation took place. According to the results of TGA，XRD，IR，SEM and EA，PPTA with good quality was obtained through this novel method，and a number of main factors influencing this process were investigated to determine the optimum condition for the preparation of PPTA. Besides，this twophase polycondensation system brings many unique advantages compared to the conventional solution polycondensation method，including a sealed reaction environment keeping the reactants away from oxygen and water，easy removal of HCl to promote the reaction，well-controlled temperature and low viscosity which means less energy cost.

Poly（p-phenylene terephthalamide）； Non-aqueous suspension polycondensation； Weight-average molecular weight； Microreactor； Microdroplets

封面介绍：The chemical reduction of carbon dioxide CO2which is the primary greenhouse gas in the atmosphere is thought to be responsible for increasingly global warming leading to numerous ecological problems. Industrial synthesis of methanol utilizing copper-based catalysts is a commonly used process for CO2hydrogenation. The selectivities of CO2electroreduction at copper electrode could mainly be towards carbon monoxide（CO），formic acid（HCOOH），methane（CH4）or ethylene（C2H4），which depends on the chemical potentials of hydrogen controlled by the applied potential. Interestingly，methanol could hardly be produced electrochemically despite utilizing metallic copper as catalysts in both processes. Hence，in this work，a critical review is provided concentrated on the present proposals of reaction mechanisms of copper catalyzing CO2reduction in industrial methanol synthesis and electrochemical environment in terms of density functional theory（DFT）calculations，respectively. Furthermore，the influence from the simulation method of solvation and electrochemical model at liquid-solid interface on the reaction mechanism to explore the possible roles of different operation environments involving water and potential in the different selectivities of these two processesare investigated，to achieve a better understanding of the possible reaction mechanisms（see the review by Xitong Sun，Xiaoming Cao & P. Hu on page 553-564）.

Theoretical insight into the selectivities of copper-catalyzing heterogeneous reduction of carbon dioxide

Xitong Sun，Xiaoming Cao，P. Hu

The chemical reduction of carbon dioxide（CO2）has always drawn intensive attentions as it can not only remove CO2which is the primary greenhouse gas but also produce useful fuels. Industrial synthesis of methanol utilizing copper-based catalysts is a commonly used process for CO2hydrogenation. Despite extensive efforts on improving its reaction mechanism by identifying the active sites and optimizing the operating temperature and pressure，it is still remains completely unveiled. The selectivities of CO2electroreduction at copper electrode could mainly be towards carbon monoxide（CO），formic acid（HCOOH），methane（CH4）or ethylene（C2H4），which depends on the chemical potentials of hydrogen controlled by the applied potential. Interestingly，methanol could hardly be produced electrochemically despite utilizing metallic copper as catalysts in both processes. Moreover，the mechanistic researches have also been performed aiming to achieve the higher selectivity towards more desirable higher hydrocarbons. In this work，we review the present proposals of reaction mechanisms of copper catalyzing CO2reduction in industrial methanol synthesis and electrochemical environment in terms of density functional theory（DFT）calculations，respectively. In addition，the influences of the simulation methods of solvation and electrochemical model at liquid-solid interface on the selectivity are discussed and compared.

methanol synthesis； electrocatalytic reduction of CO2； CO2hydrogenation； selectivity