Showing papers in "Acta Chimica Sinica in 2014"

催化不对称[8+2]环加成反应构建环庚三烯并吡咯烷-3,3’-吲哚酮

Abstract: 设计了azaheptafulvenes作为偶极子与N-Boc-3-烯基吲哚酮反应,用来构建螺环[吡咯烷-3,3’-吲哚酮]衍生物.在1mol%手性氮氧-Ni(II)配合物催化剂条件下,该不对称[8+2]环加成反应以高的收率(90%~99%收率),好的非对映选择性(高达97∶3 dr)和优异的对映选择性(92%~99%ee)得到手性环庚三烯并螺环[吡咯烷-3,3’-吲哚酮]衍生物.

高对映选择性的有机催化的硝基烷烃对N-Boc靛红亚胺的不对称aza-Henry反应

Abstract: 研究实现了高对映选择性的硝基烷烃对N-Boc靛红亚胺1的不对称aza-Henry反应,来构建胺基季碳氧化吲哚.发现在金鸡纳碱衍生的叔胺-酚羟基双功能催化剂C5的作用下,10种不同取代的N-Boc靛红亚胺与硝基甲烷的反应均能顺利进行,以66%~91%的对映选择性得到目标产物,产物的绝对构型通过X-ray单晶衍射加以确定.硝基乙烷和硝基丙烷也能高对映选择性地参与反应,但非对映选择性不佳.

Recent Developments in Palladium-Catalyzed Asymmetric Intermolecular Heck Reaction

Abstract: Some important progress has been made in palladium-catalyzed asymmetric intermolecular Heck reaction in re- cent years. The breakthrough was achieved in the use of acyclic olefins, the aryl halide and benzylic electrophiles in asym- metric intermolecular Heck reaction with some newly developed chiral ligands by Jung, Sigman and Zhou groups. Asymmet- ric intermolecular oxidative Heck-type reaction of acyclic α,β-unsaturated carbonyls and boronic acids was realized by Jung group in high enantioselectivity in the presence of chiral NHC-amidate-alkoxide Pd(II) complexes as catalyst. The Heck re- action of acyclic hydroxyl alkenes and allyl alcohol aryldiazonium salts was achieved by Sigman group with a catalyst de- rived from Pd2dba3 and chiral pyridine oxazoline by using a redox-relay strategy, affording β-, γ-, and δ-aryl carbonyl prod- ucts in excellent enantioselectivity. Sigman group also reports a catalytic and enantioselective intermolecular Heck-type reac- tion of trisubstituted-alkenyl alcohols with aryl boronic acids, providing direct access to diverse molecular building blocks containing an enantiomerically enriched quaternary carbon center. The first examples of asymmetric Mizoroki-Heck reaction using benzyl electrophiles was reported by Zhou group with their newly developed phosphoramidite as the optimal chiral ligand. With this strategy, a key intermediate in asymmetric synthesis of (+)-anisomycin was quickly afforded when p-methoxybenzyl trifluoroacetate was adopted as starting material. Zhou group also realized the first Heck reaction of aryl bromides and chlorides with various cyclic olefins in high enantioselectivities with (R)-Xyl-SDP(O) as the ligand. The use of alcoholic solvents and alkylammonium salts were essential to creating cationic aryl-Pd species for enantioselective olefin insertion. Zhou group has also realized desymmetrization of substituted cyclic olefins successfully via asymmetric Heck reac- tion and found that the use of bisphosphine mono oxide as ligand was important. The Heck reaction of substituted cyclopen- tenes gives almost exclusively trans isomers and establishes two stereocenters in high ee. Under the effect of some newly developed chiral ligands, fused carbo- and heterocycles are synthesized in high ee via asymmetric domino cyclizations. The method is applied to a short synthesis of chiral diamine en route to (-)-martinellic acid. Keywords palladium-catalysis; asymmetric catalysis; Heck reaction; intermolecular reaction

Cl-20/hmx共晶及其为基pbx界面作用和力学性能的md模拟研究

Abstract: 为提高共晶炸药的实际使用价值,改善其安全性和力学性能,以CL-20/HMX共晶炸药为基,分别添加2种高聚物粘结剂Estane 5703（聚氨基甲酸乙酯）和HTPB（端羟基聚丁二烯）,共构建两种共晶基高聚物粘结炸药（PBX）模型,进行细致的295 K NPT分子动力学（MD）模拟研究.通过两种PBX模型及其与该共晶炸药的MD模拟结果比较表明,与基炸药之间的结合能Estane 5703大于HTPB,预示含少量Estane 5703的PBX稳定性和相容性更佳;对相关函数g（r）揭示粘结剂与基炸药界面相互作用的方式,以基炸药中H分别与Estane 5703中羰基O和HTPB中端羟基O之间的氢键较强.与CL-20/HMX共晶炸药相比,少量粘结剂Estane 5703或HTPB的加入,使弹性系数Cij下降,拉伸模量（E）、体积模量（K）和剪切模量（G）均显著减小,而泊松比（ν）,柯西压（C12-C44）和K/G值明显增大,表明PBXs体系刚性减小,延展性增强,力学性能大为改善.少量粘结剂包覆使PBXs致钝,主要归因于其隔热、吸热并使体系变＂软＂的缓冲作用,而界面作用造成的分子结构引发键键长变化变为次要因素.

手性磷酸催化的c（3）-取代吲哚和甲基乙烯基酮不对称串联反应

Abstract: 3位含有季碳手性中心的吲哚啉并环化合物是一类非常重要的化合物,广泛存在于各种天然产物和具有生物活性的分子中.化学家们发展了多种有效的途径来合成这类化合物.其中以方便易得的吲哚衍生物为起始原料,利用不对称去芳构化／环化串联的方法最为简单高效,但多数工作都是从色胺或色醇衍生物出发,合成二氢吡咯并吲哚啉或二氢呋喃并吲哚啉化合物.因此,发展其他类型的吲哚衍生物的不对称去芳构化／环化反应显得非常有必要.作者课题组发展了手性磷酸催化的吲哚衍生物与甲基乙烯基酮的不对称Michael加成／环化串联反应.以5 mol%（R）-SPINOL为骨架的手性磷酸（R）-4c为催化剂,以中等到良好的收率和优秀的对映选择性构建了一系列手性吲哚[2,3-b]并氢化喹啉化合物,而且该催化体系对于克级规模反应同样能够获得很好的结果.

Sixty Years of the Chemistry of Rare-earth Organometallic Complexes

Abstract: Rare-earth elements include scandium, yttrium and fifteen lanthanides. Since Wilkinson and Birmingham re- ported the fist example of rare-earth organometallic complex, the chemistry of rare-earth organometallic complexes has had a great advance during the past sixty years. A variety of Cp containing rare-earth metal complexes, including mono-Cp, bis-Cp, and tri-Cp complexes, have been synthesized. Variation of the size of substituent on Cp ring, introducing the nitrogen or oxy- gen containing pendant arm to Cp ring or using ansa bis-Cp ligands make the synthesis and stabilization of these three types of rare-earth metal Cp complexes available. The Cp related ligands, such as indenyl and fluorenyl, also have been applied for the rare-earth organometallic complexes. From 1990's, there was a tendency to explore the rare-earth organometallic com- plexes with ancillary ligands beyond Cp and its derivatives in order to search for more efficient rare-earth metal catalysts. Non-Cp ligands, such as biphenolates, β-diketiminates, amidinates, guanidinates, etc. have been introduced into the chemistry of rare-earth organometallic complexes, and a larger number of non-Cp rare-earth organometallic complexes have been syn- thesized and characterized. The application of non-cyclopentadienyl ligands not only resulted in the rare-earth organometallic complexes with new structural features, but also the catalysts with high activity and high selectivity for the polymer synthesis and organic synthesis. The rare-earth organometallic complexes catalyze homo- and co-polymerization of olefins as well as specific polymerization of dienes and polar monomers. The discovery of the catalytic system composed of the neutral rare-earth metal dialkyls/borate enables to synthesize some interesting polymers which are difficult to be prepared by using other catalytic system. The rare-earth organometallic complexes are also able to catalyze some important organic reactions, such as hydroamination, hydrophosphinylation, and hydroalkoxylation, etc. Different from the late-translation metal cata- lyzed organic reactions, most of the rare-earth metal catalyzed ones do not involve oxidative addition and reductive elimina- tion steps. The review describes some important developments of the chemistry of rare-earth organometallic complexes in the past sixty years. Keywords rare-earth organometallic complex; lanthanocene; ligand design; synthesis; catalysis

Application of Chiral Anion Metathesis Strategy in Asymmetric Transfer Hydrogenation of Isoquinolines

Abstract: asymmetric hydrogenation of n-hetero aromatics offers a very straightforward and efficient method to obtain the corresponding chiral n-hetero cyclic saturated or partially saturated compounds. as one of the most challenging substrates, asymmetric hydrogenation of isoquinolines has met with limited success probably because of lower reactivity and the catalyst deactivation resulted from strong coordination. considering the prevalence of the chiral 1,2,3,4-tetrahydroisoquinoline motif in natural alkaloids and drug molecules, the development of new catalyst system for asymmetric hydrogenation of isoquinolines is highly desirable and significant. herein, a novel chiral anion metathesis strategy successfully applied for asymmetric transfer hydrogenation of isoquinolines is reported. n-protected 1-substituted 1,2-dihydroisoquinolines were obtained with high yield and up to 79% ee in the presence of hantzsch ester and chloroformate using chiral phosphoric acid as catalyst. the phosphate salt and the activated n-acyl isoquinolinium chloride undergo anion metathesis to form chiral contact ion pair, which leads to a highly enantioselective transfer hydrogenation of isoquinolines. after systematically investigating the effects of activating reagent, solvent, base, hydride donor and catalyst on this transfer hydrogenation reaction, the best result was achieved under the optimized condition as follows: 5 mol% h8-binol-derived chiral phosphoric acid as catalyst, 1.2 equivalent 2,2,2-trichloroethyl chloroformate as activator, 1.5 equivalent dimethyl 2,6-diethyl-1,4-dihydropyridine-3,5-dicarboxylate as hydride donor, 1.5 equivalent sodium carbonate as base and cyclohexane as solvent. the reaction is tolerant toward a broad range of aryl or alkyl 1-substituted isoquinoline substrates. this methodology represents one of the rare examples of asymmetric hydrogenation of this challenging substrate. the utilizing of chiral anion metathesis strategy could enable chiral phosphoric acid to catalyze more asymmetric transformation process and further researching is ongoing in our laboratory.

Progress in Polyoxometalates-Catalyzed Water Oxidation

Abstract: H-2 is considered to be a clean, efficiently and renewable energy because H2O is the only product when H-2 Combines with O-2. The splitting of water into H-2 and O-2 by sunlight is viewed as one of the most promising ways to produce clean and sustainable energy that is expected to meet the future need as environmentally friendly and renewable energy sources. Artificial photosynthesis water splitting is currently the most ideal energy conversion mode, and it has attracted many researchers' interest. Through this way, H-2 can be separated from reaction system or in-situ used when a solar cell designed together. Water oxidation is identified as the bottleneck of water splitting because it requires a multi-electron stepwise building up of very high redox potentials. So, development of efficient and stable water oxidation catalysts (WOCs) is the key step in overall water splitting. Polyoxometalates (POMs) are a versatile family of early transition-metal oxide nanoclusters. Owing to the unmatched physical and chemical properties of POMs, they have been widely applied in catalysis, medicine, nanotechnology and materials science. Development of POMs as WOCs has given rise to more and more interesting of researchers because the all-inorganic ligands of POMs can resist the strong oxidizing environment of water oxidation reaction, which is a shortcoming of many organometallic complex WOCs. POMs have the nature between metal oxides and molecular catalysts (the so-called molecular metal oxide), thus, this kind of WOC combines the stability benefit of heterogeneous WOCs and other molecular benefits of homogeneous WOCs, which give rise to the attention of researchers. Based on a considerable number of POMs have been designed as WOCs so far, it is necessary to carry on a review for previous POM-WOCs work. In this review, various different type transition metal substituted POMs as WOCs were described and commented in detail.

SpinPHOX/Ir(I)催化的2-羟甲基-3-芳基丙烯酸的不对称氢化

Abstract: 光学活性的2-羟甲基-3-芳基丙酸类化合物是许多手性药物的关键合成中间体,但到目前为止其不对称合成方法大多存在对映选择性不高及/或底物范围有限等问题.报道了手性SpinPHOX/Ir(I)络合物在一系列2-羟甲基-3-芳基丙烯酸的不对称氢化中表现出优良的催化性能,取得完全的底物转化和良好到优秀的对映选择性(高达95%ee).对于同一2-羟甲基-3-芳基丙烯酸底物的不对称氢化,使用中心手性相同但螺环骨架上的轴手性相反的催化剂分别以优良的对映选择性获得构型相反的产物,从而为光学活性2-羟甲基-3-芳基丙酸及相关手性药物的不对称合成提供了一条简便高效的途径.

环状烯酮与环状1-氮杂二烯的非对映及对映选择性[4+2]环加成反应

Abstract: 有机胺能催化环状烯酮化合物在多个位点发生不对称合成反应.最近,我们发展了手性伯胺催化β-取代2-环戊烯酮与从糖精衍生的1-氮杂二烯的α’,γ-区域选择性的[5+3]形式环加成反应.这里我们将报道采用β-取代2-环己烯酮或β-未取代2-环戊烯酮时,在手性伯胺催化下却与相同1-氮杂二烯发生完全不同的α’,β-区域选择性的不对称[4+2]环加成反应,生成高度官能团化的手性[2.2.2]或[2.2.1]桥环骨架结构.重要的是利用不同类型的手性伯胺催化剂能够实现非对映选择性的反转,分别制备高立体选择性的endo-或exo-环加成产物.

Selenium-containing Coordinating Assemblies with Selective Anti-cancer Activity：the Control of Reactive Oxygen Species

Abstract: Reactive oxygen species (ROS) attract increasing interests due to the function of \"double-edged sword\" in physi- ological condition. In low concentration, ROS can benefit the growth of normal cells; however, in high concentration, they will induce cell apoptosis. Selenium is an essential trace element of human beings that can regulate the concentration of ROS. Previous work demonstrated the selective anti-cancer activity of coordinating assemblies consisting of selenium-containing amphiphile (EGSe) and cisplatin, but the structure and mechanism remain unclear. We synthesized another selenium-containing amphiphile—trimethyl-EGSe (EGSe-tMe) which has similar structure with EGSe but forms weaker interaction with platinum-containing compounds. Then, we prepared new coordinating assemblies composed of two types of selenium-containing amphiphiles and two types of platinum-containing compounds (cisplatin, platinum dichloride), in order to study the coordinating interaction between selenium and platinum. Additionally, we studied the mechanism of their selec- tive anti-cancer activity by testing the ability of regulating ROS concentration in cancer cells and normal cells. We found that EGSe could coordinate with both cisplatin and platinum dichloride, resulting in the formation of coordinating assemblies with selective anti-cancer activity. However, coordinating assemblies consisting of EGSe-tMe and platinum-containing com- pounds showed little selectivity. These results indicate the important role of tight interaction between selenium and platinum played in the selective anti-cancer activity. The anti-cancer activity comes from their function of regulating the concentration of ROS in cells. Selenium-containing coordinating assemblies can raise higher concentration of ROS in cancer cells than in normal cells, thus causing selective toxicity to cancer cells. In further study, we proposed the mechanism of ROS production by selenium-containing coordinating assemblies. The coordinating assemblies can induce ROS production with the proof of electron spin resonance (ESR) measurement. We hope that this work can not only broaden the applications of sele- nium-containing coordinating assemblies in the field of cancer treatment, but also provide a new route for developing selec- tive anti-cancer drugs. Keywords selenium; self-assembly; reactive oxygen species; coordination; anti-cancer

Molecular Simulation of Drug Adsorption and Diffusion in Bio-MOFs

Abstract: As the novel drug carriers, bio-metal-organic frameworks (bio-MOFs) have attracted much attention recently. As a branch of MOFs, bio-MOFs have features of low density, large specific area, and tunable structures. Bio-MOFs can be bio- logical compatible, thus they have great potential in drug delivery and other biomedical applications. Compared with experi- ment, it is generally believed that molecular simulation is an efficient way for investigating the fundamental mechanisms of drug delivery in MOFs. In this work, molecular simulation studies were carried out in three bio-MOFs (bio-MOF-1, bio-MOF-11, bio-MOF-100) and one MOF (UMCM-1) to investigate the adsorption and diffusion behaviors of ibuprofen in them. To develop a reliable force field for describing the interactions between bio-MOFs and drug molecules, Gaussian 03 software was used to study the influence of basic sets and algorithms on the calculation of atomic charges of bio-MOFs at- oms. Then a combined Monte Carlo and molecular dynamics (MD) simulations were carried out. Canonical Monte Carlo (NVT-MC) and Grand-canonical Monte Carlo (GCMC) simulations were employed to calculate the adsorption of ibuprofen in bio-MOFs studied. Equilibrium molecular dynamics (MD) simulations were carried out in the canonical (NVT) ensemble to investigate the diffusion behaviors of ibuprofen. The effects of the structures of bio-MOFs, the force field, and the electric charges on the adsorption and diffusion behaviors of ibuprofen in the MOFs adopted were studied systematically. In addition, the space configurations of ibuprofen in the selected bio-MOFs were analyzed. Our results show the influence of the struc- tures of bio-MOFs on the adsorption and diffusion properties of ibuprofen molecules is big. The entry and diffusion of guest molecules are influenced greatly by pore diameters of bio-MOFs and the loading and self-diffusion coefficients of ibuprofen are proportional to the porosity of materials. Electrostatic potential enhances the adsorption towards ibuprofen molecules. In addition, we found ibuprofen molecules were preferably adsorbed around the metal ions clusters of MOFs and different op- timal configurations of ibuprofen in different materials were found. The information obtained in this work is expected to ap- ply to other theoretical and experimental studies about bio-MOFs related systems in the future. Keywords bio-metal-organic frameworks; ibuprofen; molecular simulation; adsorption; diffusion

Synthesis and Self-Assembled Structure of A Cluster-Cluster Hybrid Molecule Composed of POM and POSS Clusters

Abstract: Polyhedral oligosilsesquioxane (POSS) and polyoxometalate (POM) are two kinds of clusters having totally dif- ferent physical and chemical properties. For instance, the POSS cluster dissolves in weakly polar solvents, such as toluene, while the POM cluster, encapsulated by tetrabutylammonium counterions, dissolves in strongly polar solvents, such as ace- tonitrile, meaning the strong incompatibility. Based on this reason and their fixed shape, a novel cluster-cluster hybrid mole- cule with a V-shaped molecular structure (POM-2POSS) was rationally designed by covalently linking the two POSS clusters on the one side of the POM cluster. In the experiment, a two-azido-containing organosilyl derivative of a Wells-Dawson-type POM cluster and a one-propargyl-containing derivative of a POSS cluster were prepared at first. Then, the cluster-cluster hybrid was successfully synthesized by Cu-catalyzed click reaction between the two azide groups in the one POM derivative and the two propargyl groups in the two POSS derivatives. The chemical structure of this hybrid molecule was carefully characterized by NMR, ESI-MS and IR. In view of their strong incompatibility and of the particular three-dimensional (3D) structure POM-2POSS was expected to be able to self-assemble into ordered supramolecular structures. In the sample prepa- ration POM-2POSS was dissolved in acetonitrile with a concentration of 5 mg/mL, and then the solution was dropped onto silicon substrates to prepare the thin film samples, finally the thin film samples were annealed in an acetonitrile vapor for 14 d. The film on the silicon substrate was characterized by XRD. The thin film samples for TEM characterization were made at first by floating onto the water surface and then transferred onto copper mesh. The structural analyses clearly demonstrated that the hybrid molecule self-assembled into a highly ordered lamellar morphology with a 5.1 nm periodicity, smaller than those found in block copolymers with a similar molecular weight. Formation of the highly ordered morphology reflects a self-assembly process due to absence of intermolecular entanglements, while the sub-5 nm periodicity is because of the 3D structures of the two building blocks. The findings provide a new platform for understanding of the self-assembly of nano-clusters and for development of novel hybrid materials. Keywords hybrids; polyoxometalates; polyhedral oligosilsesquioxanes; click reaction; self-assembly 1 引言

Review of Electrolyte for Lithium Sulfur Battery

Abstract: Of the high energy density chemical power systems currently being considered, lithium/sulfur (Li/S) batteries which use elemental sulfur as the cathode and lithium metal as the anode, are attracting increased attention in recent decades. Li/S batteries have a high energy density (2600 Wh/kg in theoretical, about 400 Wh/kg in practice nowadays), consist of abundant raw materials, are low cost and environmentally friendly. Although the rechargeable Li/S batteries possess more advantages over the conventional lithium ion batteries, the practical use faces with a variety of problems such as low utiliza- tion of sulfur and bad cycle life. Central to the operation of Li/S batteries are polysulfide anions ( 2 Sn - , 4≤n≤8)), which are intermediate products generated during the electrochemical reduction process. These anions have high solubility in organic electrolytes. On the one hand, these anions typically diffuse to the lithium anode according to a concentration gradient and directly react with the anode. This diffusion causes an internal shuttle phenomenon and significantly corrodes the anode, which decreases active material utilization during the discharge process and reduces its cycle life. On the other hand, there are residual Li2S2 and/or Li2S on the surface of sulfur cathode and Li anode even at 100% depth of charge. The formation of Li2S2 and Li2S increasing with cycling results in active material loss. These drawbacks have seriously retarded industrial production of Li/S batteries. In this paper, combining with the works of our research team, the main research directions and the latest development of the electrolyte to enhance the cycle performance of Li-S batteries are reviewed from the aspects of the composition of the liquid electrolyte, the additives in liquid electrolyte, the polymer electrolyte and the inorganic electro- lyte. At the meanwhile, the principle, the preparation of electrolyte, the influence on the performance of Li-S batteries, and problem in each research are analyzed. Finally, the further development of the electrolyte in Li-S battery is discussed. Keywords lithium sulfur battery; liquid electrolyte; ionic liquid electrolyte; additive in electrolyte; polymer electrolyte; inorganic electrolyte

Research Progress of Non-Fullerene Small-Molecule Acceptor Materials for Organic Solar Cells

Abstract: Bulk heterojunction organic photovoltaics have been the subject of intensive academic interest over the past two decades. Numerous recent efforts have been directed towards this area with the vision of developing next-generation low-cost solar cells. In the field of bulk heterojunction organic photovoltaics, fullerene and its derivatives are an important class of n-type electron acceptor materials. However, their disadvantages such as narrow wavelength absorption, high affinity, poor solubility, have severely limited their wide application as electron acceptors for organic solar cells and have largely hampered further improvement of the device performance. Recently, a number of research efforts have been focused on the develop- ment of novel non-fullerene n-type small-molecule acceptors. Various design rules and interesting new materials have been explored. The non-fullerene n-type small-molecule acceptors usually appear to possess lots of attractive advantages, such as adjustable energy levels, facile synthesis, good solubility, low processing cost. More important, when compared to the fullerene and its derivatives, this kind of small-molecule acceptors has wider spectral absorption that allows to absorb more sunlight to generate electricity. Recent breakthroughs rely mostly on the development of novel high-performance acceptor materials and optimization of the device structures. The up-to-date power conversion efficiencies exceeding 4% with using non-fullerene small-molecule acceptor materials in bulk heterojunction organic solar cells have been achieved. In this review, recent advances of non-fullerene small-molecule n-type acceptor materials for organic solar cells are reviewed, including rylene diimide-based acceptors, pentacene-based acceptors, benzothiadiazole-based acceptors, 1,4-diketopyrrolo-(3,4-c)- pyrrole (DPP)-based acceptors, fluorene-based acceptors, fluoranthene-fused imide-based acceptors and so on. Meanwhile, the future trends on material design and development have also been discussed. This review on illustrating the influence of the molecular structures and corresponding photovoltaic properties would thus be helpful to further unravel the role of elec- tron acceptors and shed light on exploring efficient n-type electron acceptor materials for high performance organic photo- voltaic devices. Keywords n-type small-molecular acceptors; wide spectral absorption; solution processing; organic photovoltaics

Facile Preparation of Graphene Dots Functionalized Au Nanoparticles and Their Application as Peroxidase Mimetics in Glucose Detection

Abstract: Based on the reducing property of graphene dots, we developed a facile strategy to synthesize well-stable gra- phene dots functionalized Au nanoparticles (denoted as GQD@AuNP) by one-step process at low temperature without added protecting agent. The prepared GQD@AuNP were characterized by transmission electron microscopy (TEM), X-ray photo- electron spectroscopy (XPS) and UV-vis absorption spectra. It was found that the as-prepared GQD@AuNP are spherical and monodisperse with an average diameter of ca. 10 nm. Graphene dots not only act as a mild reductant to reduce HAuCl4, but also as a capping agent to endow the GQD@AuNP with good stability in aqueous solvent and monodispersity and restrains the Au crystal growth, making the particles have narrow size distribution. Furthermore, the as-prepared GQD@AuNP showed an excellent intrinsic peroxidese-like activity, which could catalyze oxidization of 3,3',5,5'-tetramethylbiphenyl (TMB) by H2O2 to produce a colour variation. Using TMB as substrate, we systematically studied the effect of a series of conditions, such as temperature and pH, on the catalytic activity of the as-prepared GQD@AuNP. Results of electron para- magnetic resonance (ESR) suggest that the catalyse-mimic activity of the GQD@AuNP like HRP and effectively catalyzed the decomposition of H2O2 intoOH radicals. On this basis, a highly sensitive and rapid colorimetric and visualization method was developed for glucose in blood samples, when combined with glucose oxidase (GOx). Under optimum condi- tions, the proposed method allowed the detection of glucose in the range of 2.0×l0

不对称双酸催化吲哚的Friedel-Crafts烷基化反应：抗衡阴离子调控对映选择性

Abstract: 研究了双酸催化剂对吲哚和β,γ-不饱和α-酮酸酯的不对称Friedel-Crafts烷基化反应.金属铟(III)盐和手性磷酸组成的双酸催化体系可以高效、高选择性地催化吲哚与β,γ-不饱和α-酮酸酯的Friedel-Crafts烷基化反应.简单改变铟(III)盐的抗衡阴离子从F-到Br-,就能使产物的构型发生反转,并同时获得相应的高产率(最高达98%)和高对映选择性(最高大于99%)的1,4-加成产物.

手性膦烯配体在铑催化的芳基硼酸对 β -芳基- α , β -不饱和磺酸酯不对称共轭加成反应中的应用

Abstract: 报道了手性膦烯配体在金属铑催化的芳基硼酸对β-芳基-α,β-不饱和磺酸酯不对称共轭加成中的应用.经过系统的反应条件筛选和配体结构优化,发现含手性1,1’-联-2-萘酚骨架的膦烯配体L7与Rh(I)形成的催化剂可以高对映选择性地实现β-芳基-α,β-不饱和磺酸酯化合物的不对称1,4-加成反应.此反应体系条件温和,底物普适性广,并取得了较高的收率(up to 95%)和优秀的对映选择性(up to 99%ee),为合成手性偕二芳基取代的磺酸酯类化合物提供了一种新方法.