在CTAB胶束中羟乙基-双胺类Zn(Ⅱ),Ni(Ⅱ)配合物催化PNPP水解反应

本文将合成的三种配体与二价金属离子Zn(Ⅱ)，Ni(Ⅱ)形成配合物，在25℃不同pH值时，研究了它们在CTAB胶束溶液中催化水解PNPP的反应。利用金属胶束催化的三元复合物模型，处理获得了相关的PNPP催化水解反应的动力学参数及热力学参数。结果表明：在PNPP催化水解中，活性物种为配体与金属离子形成l：2的双核金属配合物。不同金属配合物的催化活性与配合物的桥联基团及反应的微环境相关。     

NH_2-Ga-MIL-53催化剂对Strecker反应的底物选择性（英文）

研究了金属有机骨架化合物NH_2-Ga-MIL-53对多种N-苯基亚胺底物的Strecker反应的催化性能,研究结果表明:(1) NH_2-Ga-MIL-53具有高度催化活性和良好的底物普适性;(2)亚胺底物上取代基的电子效应是影响催化反应速率的关键因素,在亚胺底物上引入给电子取代基团(如甲氧基和苯基)可以加快反应速率,引入吸电子取代基团(如三氟甲基和硝基)可降低反应速率;(3)亚胺底物上取代基的位置对于催化反应速率同样具有重要影响,在亚胺底物的邻位引入甲氧基取代基团时,反应速率加快得最明显;(4)作为非均相催化剂,NH_2-Ga-MIL-53可循环使用9次而不失活且保持骨架结构不变;(5) NH_2-Ga-MIL-53和GaMIL-53催化性能的对比结果表明,NH_2-Ga-MIL-53结构中的氨基可以作为路易斯碱活性中心协同路易斯酸催化中心(Ga~(3+))有效促进strecker反应的进行。此外,由NH_2-Ga-MIL-53、六水合硝酸镓和2-氨基对苯二甲酸对Strecker反应的催化效果的对比可知,NH_2-Ga-MIL-53的孔结构是提高反应产物专一性的重要因素。     

NH2-Ga-MIL-53催化剂对Strecker反应的底物选择性（英文）

研究了金属有机骨架化合物NH2-Ga-MIL-53对多种N-苯基亚胺底物的Strecker反应的催化性能,研究结果表明:(1)NH2-Ga-MIL-53具有高度催化活性和良好的底物普适性;(2)亚胺底物上取代基的电子效应是影响催化反应速率的关键因素,在亚胺底物上引入给电子取代基团(如甲氧基和苯基)可以加快反应速率,引入吸电子取代基团(如三氟甲基和硝基)可降低反应速率;(3)亚胺底物上取代基的位置对于催化反应速率同样具有重要影响,在亚胺底物的邻位引入甲氧基取代基团时,反应速率加快得最明显;(4)作为非均相催化剂,NH2-Ga-MIL-53可循环使用9次而不失活且保持骨架结构不变;(5)NH2-Ga-MIL-53和Ga-MIL-53催化性能的对比结果表明,NH2-Ga-MIL-53结构中的氨基可以作为路易斯碱活性中心协同路易斯酸催化中心(Ga3+)有效促进strecker反应的进行。此外,由NH2-Ga-MIL-53、六水合硝酸镓和2-氨基对苯二甲酸对Strecker反应的催化效果的对比可知,NH2-Ga-MIL-53的孔结构是提高反应产物专一性的重要因素。     

含有非对称型双吡啶甲基吡唑甲基胺配体的高活性双核铜配合物催化叠氮与炔烃环加成反应

Cu(Ⅰ)催化的炔烃与叠氮的Huisgen 1,3-偶极环加成反应(CuAAC)可用于构建三唑环,该反应条件温和,产物专一,被认为是“点击化学”的精髓,并广泛应用于医药、生物有机及材料化学等多个领域.CuSO4/抗坏血酸钠体系是该反应最常用的催化方法,但近年来,大量更高效的催化体系被成功开发以解决当前催化体系中存在的问题,例如,外加配体的使用可以明显加快反应速率,从而降低催化剂用量和缩短反应时间,这归因于配体参与配位可以更好地稳定Cu(Ⅰ)催化中心.目前应用于该反应体系的配体大多为对称型多齿氮配体,例如三三唑甲胺衍生物(TBTA)等.我们开发了两类含有吡唑、苯并咪唑等基团的非对称型多齿氮配体及其应用,发现这类配体除了具有稳定金属中心的作用外,还因有吡唑或苯并咪唑等基团的存在,所形成的配合物往往比那些包含对称型配体的配合物表现出更高的催化活性.本文合成了一类含有非对称型配体的铜配合物.将铜前体Cu(CH3CN)4PF6与非对称型多齿氮配体二吡啶甲基吡唑甲基胺(HNpy2pz)在甲醇中反应,由于配体结构中吡唑NH基团的存在,反应在最终脱除一分子H2O后,意外获得了一种双核结构的铜配合物,其分子结构通过X射线单晶衍射成功表征.受到两个金属中心协同效应的影响,双核配合物催化剂往往能表现出比单核配合物更优异的催化性能,因此,我们进一步考察了该双核配合物催化CuAAC反应的活性.结果表明,在催化剂用量低至0.1-0.3 mol％的情况下,22种炔烃和叠氮在25℃反应16h均能得到单一的1,4-二取代三唑产物,分离收率在95％以上,且抗坏血酸钠还原剂用量仅需1-3 mol％,说明受到配体的影响,催化剂的稳定性非常好.这是目前该反应成功开发出的几个高效双核催化剂之一.     

含有非对称型双吡啶甲基吡唑甲基胺配体的高活性双核铜配合物催化叠氮与炔烃环加成反应（英文）

Cu(I)催化的炔烃与叠氮的Huisgen 1,3-偶极环加成反应(CuAAC)可用于构建三唑环,该反应条件温和,产物专一,被认为是"点击化学"的精髓,并广泛应用于医药、生物有机及材料化学等多个领域.CuSO_4/抗坏血酸钠体系是该反应最常用的催化方法,但近年来,大量更高效的催化体系被成功开发以解决当前催化体系中存在的问题,例如,外加配体的使用可以明显加快反应速率,从而降低催化剂用量和缩短反应时间,这归因于配体参与配位可以更好地稳定Cu(I)催化中心.目前应用于该反应体系的配体大多为对称型多齿氮配体,例如三三唑甲胺衍生物(TBTA)等.我们开发了两类含有吡唑、苯并咪唑等基团的非对称型多齿氮配体及其应用,发现这类配体除了具有稳定金属中心的作用外,还因有吡唑或苯并咪唑等基团的存在,所形成的配合物往往比那些包含对称型配体的配合物表现出更高的催化活性.本文合成了一类含有非对称型配体的铜配合物.将铜前体Cu(CH_3CN)_4PF_6与非对称型多齿氮配体二吡啶甲基吡唑甲基胺(HNpy2pz)在甲醇中反应,由于配体结构中吡唑NH基团的存在,反应在最终脱除一分子H_2O后,意外获得了一种双核结构的铜配合物,其分子结构通过X射线单晶衍射成功表征.受到两个金属中心协同效应的影响,双核配合物催化剂往往能表现出比单核配合物更优异的催化性能,因此,我们进一步考察了该双核配合物催化CuAAC反应的活性.结果表明,在催化剂用量低至0.1 0.3 mol%的情况下,22种炔烃和叠氮在25 oC反应16 h均能得到单一的1,4-二取代三唑产物,分离收率在95%以上,且抗坏血酸钠还原剂用量仅需1 3 mol%,说明受到配体的影响,催化剂的稳定性非常好.这是目前该反应成功开发出的几个高效双核催化剂之一.     

手性方酰胺基醇钛合物诱导的芳醛的不对称呐醇偶联反应

合成了两个手性方酰胺基醇, 与TiC1₄(THF)₂-Zn形成了手性配合物, 并用来催化芳醛的不对称呐醇偶联反应, 反应取得很高的化学产率和较高的光学收率, 同时考察了芳醛结构和共还原剂对反应的化学产率和光学收率影响.     

零价铜催化含氮杂环的N-芳基化合物的合成

由于氮的负性基团的亲核性低,使得在芳香卤代物的环上引入含氮基团的反应(或者说在含氮杂环化合物的亚氨基上进行 N-芳基化)不易进行,因而需要强烈的反应条件或加入催化剂促使反应的发生。曾有人用一价铜盐作为催化剂研究了芳香卤代物的亲核取代反应。本文用零价铜催化的方法,合成了 N-芳基含氮杂环化合物(3 a～h)。反应机理可能是芳香肉代物与铜首     

“中国化学会第一届酞菁化学及其应用学术会议”征文通知

由中国化学会应用化学委员会与福建省化学会联合主办、福州大学化学系功能材料研究所承办的“中国化学会第一届酞菁化学及其应用学术会议”于 2 0 0 0年 1 0月在福州举行。主　席 :黄金陵　　副主席 :宋心琦　李俊　张新惠　陈耐生 (常务 )会议主题 :( 1 )酞菁及其配合物的合成新方法与新技术 ;( 2 )酞菁化合物的结构化学 ;( 3)酞菁及其配合物的波谱学、光化学、电化学和催化 ;( 4)酞菁及其配合物的应用 (包括在电、光、磁、催化和生物医学等领域中的应用 )。征文要求 :应征论文内容应符合上述范围 ,且未在国内外正式刊物上与其它会议上发…     

甲烷单加氧酶的手性模型配合物及其催化反应研究

合成和表征了4种酚氧桥联双L-苯丙氨酸双西佛碱的(VO)_2,Cr_2,Mn_2,Fe_2手性配合物,并以PhIO为单氧原子源,研究了它们作为甲烷单加氧酶(MMO)的模型化合物催化苯乙烯不对称环氧化反应的活性,结果表明,Mn_2配合物模型体系催化苯乙烯环氧化反应得到R-(+)-环氧苯乙烷 (ee42.8%),而同一配体的(VO)_2配合物却得到相反的结果:S-(-)-环氧苯乙烷(ee19.2%).EPR研究表明Mn_2,Cr_2,Fe_2配合物在催化过程中以M=O为活性中间体,而(VO)_2配合物以O=V-OIPh为活性中间体.催化活性大小顺序为Mn_2>Cr_2>(VO)_2>Fe_2.     

席夫碱-铝化合物催化己内酯的开环聚合

设计合成了一系列不对称席夫碱-铝化合物1a~3a,考察了化合物在己内酯(CL)开环聚合反应中的催化性能,研究发现,配合物对CL聚合具有较高的反应活性,并具有活性聚合的特点,聚合反应均符合一级动力学反应特征.在其它条件相同时,吸电子取代的配合物的催化速率约为无吸电子的配合物的4倍,表明席夫碱配体上吸电子基团的存在可以提高配合物催化聚合的活性.     

Disulfide symmetric dimers as stable pre-hapten forms for bioconjugation: a strategy to prepare immunoreagents for the detection of sulfophenyl carboxylate residues in environmental samples

A convenient, generic synthesis of bioconjugates from haptens with a thiol group has been established. The corresponding haptens are synthesized as stable symmetric dimmers through a disulfide bond that is reduced immediately before conjugation with the aid of a di(n-butyl)phenylphosphine polystyrene (DBPP) resin. This strategy was used to prepare haptenized biomolecules and to raise antibodies against short-alkyl-chain sulfophenyl carboxylates (X-C(z)-SPCs; X is the position of the benzylic group and z is the alkyl-chain length) formed after degradation of the widely used domestic and industrial linear alkylbenzene sulfonates (LASs) surfactants. Because of the complexity of the LASs technical mixture, homologous and pseudo-heterologous immunization strategies have been studied with the aim of broadening antibody recognition of the SPC family. With this purpose, two types of immunizing haptens have been synthesized and used to prepare bioconjugates and raise antibodies. Type-A bioconjugates (SPC(A)-protein) were prepared by synthesizing type-A haptens as stable symmetric dimers, generically 2,2'-dithiobis[5-{4-(N-ethylsulfamoyl)}phenylalkanoic acids] (X-C(z)-S-SPC). On the other hand, type-B bioconjugates (SPC(B)-protein) were prepared by treating the carboxylic groups of the corresponding 4-sulfophenylalkanoic acids (X-C(z)-SPC) with the amino groups of the lysine residues by using classical carbodiimide procedures. Type-A haptens produced antibodies with a much higher avidity for the target analyte. Under competitive immunochemical configurations (As112/2-C(5)-ovalbumin), these antibodies can reach a limit of detection (LOD) of 40 ng L(-1) with an IC(50) value of 200 ng L(-1) for 3-C(6)-SPC, which opens up the possibility of trace contamination of edible waters by surfactants with 3-C(6)-SPC as a marker of LAS pollution. A comparative study of the properties of the three families of polyclonal antibodies produced revealed that antibodies raised through pseudo-heterologous immunization strategies produced antibodies with a broader specificity versus the SPC family. These results indicate that this approach could be useful in avoiding synthetic difficulties associated with preparing haptens that preserve all the most important chemical functionalities of the molecule.     

Development and characterization of new polyclonal antibodies specific for three polychlorinated biphenyls

Three polychlorinated biphenyls(PCBs)congeners and their corresponding haptens bearing four carbon length carboxylic groups that can be linked to a protein for raising antibodies were synthesized.The three resultant immunogens were fabricated and used to stimulate immune responses in rabbits to survey the characteristics of the haptens.Three of the resultant polyclonal antibodies(Pabs)were obtained.The antiserum exhibited relatively high antibody titres(1:32-64)in double agar diffusion.◎2008 Hui Sheng Zhuang.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All rights reserved.     

具有谷胱甘肽过氧化物酶活性的催化抗体的研究Ⅰ．谷胱甘肽特征全抗原的合成、表征及性质

用２，４－二硝基氯苯保护谷胱甘肽的巯基制出半抗原，再通过戊二醛共价反应使其与牛血清白蛋白表面的氨基结合，经超胶ＡｃＡ５４凝胶层析纯化，制备出有较强免疫原性的谷胱甘肽全抗原。用元素分析、红外光谱及核磁共振表征了半抗原的结构。电泳分析得全抗原分子量平均为８７０００道尔顿。光谱分析及圆二色谱研究表明其有较强的可见、紫外及荧光特征吸收，且抗原结构的紧密性增强。     

Direct hydroxide attack is a plausible mechanism for amidase antibody 43C9

Direct hydroxide attack on the scissile carbonyl of the substrate has been suggested as a likely mechanism for esterase antibodies elicited by phosphonate haptens, which mimic the transition states for the alkaline hydrolysis of esters.1 The unique amidase activity of esterase antibody 43C9 has been attributed to nucleophilic attack by an active-site histidine residue.2 Yet, the active site of 43C9 is strikingly similar to those of other esterase antibodies, particularly 17E8. We have carried out quantum mechanical calculations, molecular dynamics simulations, and free energy calculations to assess the mechanism involving direct hydroxide attack for 43C9. Results support this mechanism and suggest that the mechanism is plausible for other antiphosphonate antibodies that catalyze the hydrolysis of (p-nitro)phenyl esters.     

Development of an enzyme-linked immunosorbent assay for metolcarb residue analysis and investigation of matrix effects from different agricultural products

The development of a direct competitive enzyme-linked immunosorbent assay based on polyclonal antibodies for N-methylcarbamate insecticide metolcarb is described. Two new haptens for the metolcarb were designed and synthesized. Both haptens were conjugated with keyhole limpet hemocyanin to form the immunogens. Four rabbits were immunized with the immunogens for production of polyclonal antibodies against metolcarb. Antisera titers were tested on the homologous coating antigens using a noncompetitive indirect enzyme-linked immunosorbent assay. The high titer antisera were used to develop the direct competitive enzyme-linked immunosorbent assay for the detection of metolcarb. The antibody–antigen combination with the highest selectivity for metolcarb was further optimized and its tolerance to changes in chemical conditions (ionic strength, pH value, and organic solvent) was studied. Under optimum conditions, the sensitivity and the limit of detection were determined to be 22 μg L⁻¹ and 1.2 μg L⁻¹ respectively. Determination of metolcarb in fruit juices and vegetables was accomplished by simple, rapid, and efficient extraction methods. Recoveries of metolcarb from spiked samples ranged from 80.5% to 109.5%. Validation of the developed immunosorbent assay was conducted by comparison of results from high-performance liquid chromatography. The correlation between the data obtained using developed immunosorbent assay and high-performance liquid chromatography was high (R ² = 0.9884). Therefore, the developed immunosorbent assay in this study was suitable for the rapid quantitative determination of metolcarb in agricultural products.     

A catalytic antibody against a tocopherol cyclase inhibitor

The cyclic ammonium cation 5 and its guanidinium analogue 4 are inhibitors of tocopherol cyclase. Monoclonal antibodies were raised against protein conjugates of the haptens 1-3 and screened for catalytic reactions with alkene 8, a short chain analogue of the natural substrate phytyl-hydroquinone 6, and its enol ether analogues 10a,b. Antibody 16E7 raised against hapten 3 was found to catalyze the hydrolysis of Z enol ether 10a to form hemiacetal 12 with an apparent rate acceleration of k(cat)/k(uncat)=1400. Antibody 16E7 also catalyzed the elimination of Kemp's benzisoxazole 59. The absence of cyclization in the reaction of enol ether 10a was attributed to the competition of water molecules for the oxocarbonium cation intermediate within the antibody binding pocket. Hapten and reaction design features contributing to this outcome are discussed. Antibody 16E7 provides the first example of a carboxyl group acting both as an acid in an intrinsically acid-catalyzed process and as a base in an intrinsically base-catalyzed process, as expected from first principles. In contrast to the many examples of general-acid-catalyzed processes known to be catalyzed by catalytic antibodies, the specific-acid-catalyzed cyclization of phytyl-hydroquinone 6 or its analogue 8 still eludes antibody catalysis.     

Enantioselective sequential-injection chemiluminescence immunoassays for 3,3′,5-triiodothyronine (T3) and thyroxine (T4)

This study deals with the development of enantioselective flow-through immunosensors for triiodothyronine (T₃) and tetraiodothyronine (thyroxine, T₄) on the basis of a competitive assay using enantioselective antibodies. The instrumental set-up is based on a simple sequential-injection system equipped with a chemiluminescence detector and an immunoreactor, which consists of a flow-cell packed with immobilized haptens. As haptens, 4-amino-l-phenylalanine (4-amino-l-Phe), 4-amino-d-Phe or l-T₃ were used. Antibodies directed against 4-amino-l- or d-Phe or l-T₃ were labeled with an acridinium ester. Three different approaches for immobilizing the haptens were investigated including simple adsorption on polystyrene, chemical binding to an activated methacrylate polymer and binding via the biotin-streptavidin binding (BSB) system. The latter approach showed the best results regarding repeatability and sensivity. Using biotinylated l-T₃ immobilized onto a streptavidin-derivatized trisacryl support and labeled anti-l-T₃ antibodies, a detection limit of 15.5 fmol/ml for l-T₃ was obtained. One assay cycle including regeneration takes only about 5 min. This approach was applied to detect l-T₃ in plasma samples without any sample pre-treatment. The average recovery from spiked plasma sample was about 93% with a R.S.D. below 5%.     

Optimization of an immunoassay of 2,6-dichlorobenzamide (BAM) and development of regenerative surfaces by immunosorbent modification with newly synthesised BAM hapten library

Dichlobenil is an extensively used herbicide worldwide which is transformed to the mobile 2,6-dichlorobenzamide (BAM) in soil. BAM has been found in many European groundwater resources that are exploited for drinking water. Currently, immunoassay based monitoring technique (plate based ELISA) is being employed to quantitatively detect BAM in water samples. In this work, as a starting step of developing immunoassay based on-site monitoring systems for pesticide analysis, the heterogeneous BAM immunoassay is optimised in terms of surface (polymer) regeneration. We have synthesised a small library of BAM haptens which are slightly different in chemical structures, immobilised them on surfaces and compared the affinity constants of the monoclonal antibody HYB 273 towards them. By using ELISA technology, we also have checked the regeneration potentials of the haptens, correlated these results to the affinity constants and found that BAM hapten with an intermediate affinity has better regeneration potential.     

不同载体负载的铂催化剂在丙酮酸乙酯不对称氢化反应中的活性及其铂流失率比较

以介孔树脂材料FDU-14和介孔碳材料CMK-3为载体制备了两种负载型铂催化剂, 用N₂气吸附、X射线衍射及CO化学吸附等手段对这两种催化剂进行了表征, 并将这两种不同的负载型铂催化剂在丙酮酸乙酯不对称氢化反应中的催化性能及其铂流失率与商品化Pt/Al₂O₃催化剂进行了比较. 研究结果表明, 尽管Pt/Al₂O₃催化剂的初始活性和光学选择性均较高, 然而相同反应条件下乙酸溶剂中Pt/FDU-14和Pt/CMK-3催化剂的铂流失率比Pt/Al₂O₃催化剂的低. 通过对催化剂进行CO吸附原位傅里叶变换红外漫反射光谱(DRIFTS)表征, 从载体的不同表面电子性质角度解释了不同载体负载的铂催化剂在丙酮酸乙酯不对称氢化反应中的活性和铂流失率的差异.     

Concise and modular synthesis of regioisomeric haptens for the production of high-affinity and stereoselective antibodies to the strobilurin azoxystrobin

The immune response to regioisomeric haptens of azoxystrobin with varied derivatization sites was studied. Based on the Sonogashira and Suzuki-Miyaura couplings and following a straightforward modular design, we have synthesized four haptens with the same linker anchored through C-C bonds and located at different sites of the molecule. The most stereoselective antibodies were produced from immunogens with the spacer arm at a distal position from the β-methoxyacrylate moiety characteristic of strobilurins. Moreover, we observed that assay cross-reactivity was reliant on the functionalization site of the competitor derivative. Finally, the antibody binding site was explored using synthetic chemical analogues.