磁性Fe_3O_4@PS@PAMAM-Ag复合催化粒子的制备及其可再生催化性能(英文)

采用聚苯乙烯(PS)包裹Fe3O4磁性纳米粒子,制得Fe3O4@PS复合微球,以此作为磁性载体,通过微球表面的羧基将聚酰胺-胺类树形大分子(PAMAM)连接到磁性载体上,然后使Ag纳米粒子镶嵌在树形分子层中,制得可再生的金属复合催化粒子Fe3O4@PS@PAMAM-Ag.并采用红外光谱、扫描电镜、电感耦合等离子体质谱(ICP-MS)和X射线光电子能谱等方法对复合催化粒子进行了表征,结果表明,树形分子可以较好地分散和稳定金属Ag纳米粒子,所制复合催化粒子表面Ag含量为1.64%,具有较高的催化还原对硝基苯酚的活性.同时,利用外加磁场可以方便快捷地从反应体系中分离出来,继续用于下一次反应中,复合催化粒子循环使用6次后,仍保持完全的催化性能.     

双金属氰化物/稀土配合物催化二氧化碳和环氧丙烷的共聚合

使用双金属氰化物/稀土配合物复合催化剂催化二氧化碳和环氧丙烷共聚合,其催化效率比双金属氰化物催化剂有显著提高,得到了数均相对分子质量大于1.0×105的聚合物。研究了复合催化剂的组成(如稀土的种类、稀土与锌的比例(Ln/Zn)、稀土配合物中酸根离子的酸性等)对共聚反应的影响,同时研究了反应体系的压力及反应时间对催化活性的影响。采用Y(CCl3COO)3稀土金属配合物有利于共聚反应的进行。当n(Y)/n(Zn)=6、聚合4 h后,其催化活性比单纯的双金属氰化物提高了31.5%,聚合物的相对分子质量则没有太大变化,而副产物碳酸丙烯酯的质量分数低于2%,而在该温度下单独采用稀土三元催化剂时副产物碳酸丙烯酯的生成量通常在10%以上。聚合物中碳酸酯含量低于双金属氰化物的催化产物,说明稀土配合物只是起到活化金属与环氧丙烷配位的作用,没有提高共聚物的碳酸酯含量,整个共聚合反应依然遵循双金属氰化物催化的共聚反应机理。     

Trivalent copper chelate-luminol chemiluminescence system for highly sensitive CE detection of dopamine in biological sample after clean-up using SPE

A transition metal chelate unstable at a high oxidation state, diperiodatocuprate (III) (K?[Cu(HIO?)?], DPC), was synthesized and applied in the luminol-based chemiluminescence (CL) system for highly sensitive CE end-column detection of dopamine (DA). This method was based on the fact that DA enhanced the CL emission resulting from the reaction between luminol and DPC in alkaline medium. The DPC-luminol-DA CL system showed very intensive emission and very fast kinetic characteristics, thus resulting in a high sensitivity in flow-through detection mode for CE. Under optimal conditions, the linear range was 1.0 × 10??-5.0 × 10?? g/mL (R2 = 0.9984) with a limit of detection of 6.0 × 10?? g/mL (S/N = 3). The RSDs of the peak height and the migration time were about 4.2 and 2.4% for a standard sample at 3.0 × 10?? g/mL (n = 5), respectively. The presented method has been successfully used for the determination of DA in commercial preparation and human urine samples after clean-up using SPE.     

异羟肟酸类氧载体新模型化合物研究

异羟肟酸类氧载体新模型化合物研究阳华秦圣英＊吕志凤周先礼李建章卢晓霞（四川大学化学系，成都６１００６４）关键词异羟肟酸钴（Ⅱ）配合物氧载体氧合反应催化环氧化中图分类号Ｏ６１３．６１仿生氧载体研究，已成为当今生物有机和生物无机化学家最关注的课题之一。在...     

3-亚甲基苯并吡喃-2,4-二酮与烯醇硅醚的Diels-Alder反应合成3,4- 二氢-2H,5H-吡喃并[3,2-c][1]苯并吡喃-5-酮衍生物

通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应, 以较高产率合成了一系列含有硅氧基的3,4-二氢-2H,5H-吡喃并[3,2-c][1]苯并吡喃-5-酮衍生物. 用X射线单晶衍射确定了其中5个化合物的空间构型. 利用密度泛函(DFT)方法计算反应物之间的前线分子轨道相互作用, 对反应的区域选择性进行了研究, 计算结果与实验值相符.     

(3S,6S)-及(3S,6R)-3-苄氧甲基-6-甲基-吗啉-2,5-二酮的 制备及其晶体结构

以2-溴丙酸和N-叔丁氧羰基-O-苄基-L-丝氨酸为起始试剂首先制得N-(2-溴丙基)-O-苄基-L-丝氨酸(BPBS), 在N,N-二甲基甲酰胺(DMF)/三乙胺(Et3N)溶剂中80 ℃经9 h后BPBS发生分子内环化反应生成(3S,6S)-3-苄氧甲基-6-甲 基-吗啉-2,5-二酮[(3S,6S)-BMMD]及(3S,6R)-BMMD共存体, 产率70%. 将所制得的共存体以乙酸乙酯为重结晶溶剂, 采用微分重结晶法, 经4次“溶解-部分重结晶”操作循环制得两种纯光学构型的(3S,6S)-BMMD和(3S,6R)-BMMD. 将两种光学纯双手性中心的BMMD分别溶于乙酸乙酯, 室温下培养得(3S,6S)-BMMD和(3S,6R)-BMMD的单晶体, 以X射线衍射法测定上述两种BMMD的分子结构.     

A CIDEP study of photolysis of duroquinone/hydrogen-donor homogeneous and triton micelle solutions

The CIDEP spectra of transient radicals during photolysis of the duroquinone (DQ)/ethylene glycol (EG) system in acid, basic, and micellar environments were measured with a home-made highly time-resolved ESR spectrometer. In the DQ/EG homogeneous solution, the enhanced emissive CIDEP signal of the neutral durosemiquinone radical DQH^• was observed. When the DQ/EG solution at pH 9 or the DQ/EG/TX-100/H₂O micelle system was photolyzed, the CIDEP signal of the duroquinone anion radical (DQ^•−) was obtained. When the DQ/EG solution at pH 2.5 was irradiated, the CIDEP signal of DQH^• appeared. These experimental results indicate that the neutral radical DQH^• was formed by proton transfer from EG to ³DQ*, and that DQ^•− was formed by dissociation of DQH^• accompanying polarization transfer.     

液相色谱-串联质谱结合谱库检索测定猪组织中的9种β-兴奋剂残留量

建立了猪组织中9种β-兴奋剂(克伦特罗、莱克多巴胺、沙丁胺醇、利托君、特布他林、班布特罗、妥布特罗、西马特罗和异舒普林)多残留的液相色谱-四极杆/线性离子阱串联质谱(QTrap LC-MS/MS)检测方法。样品经β-葡萄糖醛苷酶/芳基硫酸酯酶酶解提取,液液萃取净化,以乙腈-甲酸水溶液为流动相,经C18柱分离后用QTrap LC-MS/MS进行多反应监测(MRM)、信息相关采集(IDA)、增强子离子扫描(EPI)和谱库检索分析。9种β-兴奋剂的线性范围为0.1～50.0 μg/L,线性关系良好(r＞0.99);样品中9种目标物在0.5、1.0和5.0 μg/kg添加水平下的回收率为72.0%～95.1%,相对标准偏差为3.1%～12.1%;方法检出限为0.1～0.2 μg/kg。实际样品检测结果表明,本方法可实现猪组织样本中β-兴奋剂残留量的灵敏、准确的定性和定量分析。     

Solid phase extraction of trace Hg(II) on silica gel modified with 2-(2-oxoethyl)hydrazine carbothioamide and determination by ICP-AES

In this work, a new 2-(2-oxoethyl)hydrazine carbothioamide modified silica gel (SG-OHC) sorbent was prepared and applied for preconcentration of trace mercury(II) prior to the measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES). The optimization of some analytical parameters affecting the adsorption of the analyte such as acidity, shaking time, sample flow rate and volume, eluent condition, and interfering substances were investigated. At pH 3, the maximum static adsorption capacity of Hg(II) onto the SG-OHC was 37.5 mg g⁻¹. The quantitative recovery (>95%) of Hg(II) could be obtained using 2 mL of 0.5 mol L⁻¹ HCl and 1% CS(NH₂)₂ solution as eluent. Common coexisting substances did not interfere with the separation of mercury(II) under optimal conditions. The detection limit of present method was 0.10 ng mL⁻¹, and the relative standard deviation (RSD) was lower than 4.0% (n = 8). The prepared sorbent was successfully applied for the preconcentration of trace Hg(II) in certified and water samples with satisfactory results.     

环境友好型Michael加成的研究进展

Michael加成反应是有机合成领域一类非常重要的反应.随着人们环保意识的增强和对绿色化学研究的深入,环境友好型Michael加成取得了诸多成功.综述了近5年来离子液体、酶催化、负载固相催化、聚乙二醇(PEG)等参与的Michael加成反应的研究进展.着重分析了反应体系的高效性、催化剂可能的催化反应机理以及催化剂的循环使用性,并以此对环境友好型Michael加成的发展做出了展望.