基于环糊精的农药吸附剂的研究进展

农药的研发与使用极大地提高了农作物的产量,为解决人类温饱、改善人类生活品质做出了贡献。但是,农药广泛残留于农副产品以及土壤和水体中,造成的污染日趋严重。残留的农药通常具有微量致毒、难生物降解、生物累积等特性,对生物健康与生态系统造成了巨大威胁。高效检测微量农药、减小污染危害是亟待解决的问题。吸附法具有成本低、操作简单、稳定性强、可重复性强的特点,在农药分离预富集领域得到了广泛关注。作为一种常用的农药吸附剂材料,环糊精是一类具有空腔的超分子化合物,能够作为主体通过主客体作用形成包合物;另外,可以通过醚化、酯化、氧化等化学反应对环糊精进行后修饰以提高其吸附性能。疏水作用、静电作用、范德华力、氢键作用、立体效应协同促进对农药的吸附。环糊精在农药吸附领域已经取得了一定进展,但是目前还没有基于环糊精的农药吸附剂的综述。该文针对杀菌剂、杀虫剂、除草剂、植物生长调节剂这4类农药,系统性地评述了基于环糊精的农药吸附剂的制备、吸附机理及应用,目前存在个别吸附剂吸附容量不高、降解机理不明确、降解产物对环境不友好、容易造成二次污染的问题,研发高吸附容量、易回收、易分离、易再生的基于环糊精的农药吸附剂是未来的主要研究方向。     

具有好的溶解性和高的热稳定性的富勒烯-苝化合物的合成

在氩气保护下,利用N-(正丁基)-N’(4-甲酰基苯氧戊基)-1．6,7,12-四-(4-叔丁基苯氧基)-3,4,9,10-苝酰亚胺和N-甲基甘氨酸产生的亚胺叶立德与富勒烯反应,合成了含富勒烯的苝化合物,用NMR、FT—IR、UV-Vis及TGA等方法对其结构和性能进行了表征和测试。研究结果表明此类化合物具有好的溶解性和高的热稳定性。     

基于网络的有机化学试题库的建设

使用ASP.net和SQL server数据库建立有机化学网络试题库,实现了学生开放性学习和教师客观命题的功能,并将试题库按专业课时分层次管理,实现有机化学课程的标准化考试。     

青蒿素的生物素标记衍生物的合成

青蒿素1及其衍生物具有特征的过氧桥结构, 并呈现优秀的抗疟生物活性. 为了研究详细的作用机制和确定生物学作用靶标, 本研究从易得的青蒿素衍生物出发, 通过酰胺键相连, 合成了生物素标记的青蒿素衍生物.     

基于钯催化的Catellani反应的Rhazinal的高效全合成

Rhazinal是Rhazinilam家族中的一员,其家族都含有一个因环张力而形成的吡咯-苯胺手性轴,一个高张力的九元内酰胺,一个全碳季碳手性中心以及[3.4]并环结构.Rhazinilam被发现是一个很好的多种癌细胞的抑制剂,具有诱导和促进微管蛋白的聚合、防止解聚、稳定微管的作用.自其被分离之后得到了有机和生物有机化学家的广泛重视,至今已有多个其家族成员的全合成的报道.中国科学技术大学化学系顾振华小组将Pd催化的Catellani反应首次成     

紫精的负离子对耐水的紫精－聚合物膜的光致变色性能的影响

将合不同负离子的苄基紫精分散在混合有ＰＶＰ的ＭＭＡ－ＨＥＭＡ共聚物基质中可制成耐水的光致变色膜。它们的光致变色速度的大小随紫精负离子的不同而有如下序列：这与这些紫精在ＤＭＦ中的溶解度以及在共聚物基质中的溶解性大小的序列相一致．负离子对这些光致变色膜在空气中的氧化退色速度没有很大影响，对这些膜的光疲劳性能的影响也不大。将Ｖ３～Ｖ６分散在不很有ＰＶＰ的ＭＭＡ－ＨＥＭＡ共聚物基质中制成的膜也表现出光致变色的特性，表明它们的多原子负离子本身在聚合物膜中也能充当电子给体的角色．     

气体的溶解度与温度的关系

用热力学原理导出气体在液体中的溶解度与温度之间的关系.当溶解过程减熵时,溶解度随着温度的升高而减小;当溶解过程增熵时,溶解度随着温度的升高而增大.     

基于压力的速率方程的应用

通过具体实例说明对于气相反应,使用基于压力的速率方程解题比使用基于浓度的速率方程更直接﹑更简便。总结了具有简单级数的反应的基于压力的速率方程及其特征。     

鲍林的经验教训与信息的关系

分析了鲍林（ＬｉｎｕｓＰａｕｌｉｎｇ，１９０１—１９９４）在事业上成败的经验教训与信息的关系，举例说明了信息给鲍林带来过成功的喜悦，但信息的误导或中断也给鲍林在事业成功的道路上留下了遗憾。     

无处不在的化学——颜色的故事

This is a popular science article introducing the chemical knowledge contained in the search and use of colors. From the different aspects of architectural, textile dyeing and paints, three examples are chosen to reveal the chemical principles behind. Humanistic story and science interpretations are combined to reflect the close connection between chemistry and human life.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.