Efficient epoxidation of olefins with >/=99% selectivity and use of hydrogen peroxide

Epoxides are an important class of industrial chemicals that have been used as chemical intermediates. Catalytic epoxidation of olefins affords an interesting production technology. We found a widely usable green route to the production of epoxides: A silicotungstate compound, [gamma-SiW10O34(H2O)2]4-, is synthesized by protonation of a divacant, lacunary, Keggin-type polyoxometalate of [gamma-SiW10O36]8- and exhibits high catalytic performance for the epoxidation of various olefins, including propylene, with a hydrogen peroxide (H2O2) oxidant at 305 kelvin. The effectiveness of this catalyst is evidenced by >/=99% selectivity to epoxide, >/=99% efficiency of H2O2 utilization, high stereospecificity, and easy recovery of the catalyst from the homogeneous reaction mixture.     

4-氨基-3,5二-（4-吡啶基）-1,2,4三-氮唑-Cu（Ⅰ）配合物的溶剂热合成及结构表征

采用CuBr与4-氨基-3,5-二（4-吡啶基）-1,2,4-三氮唑配体（4-abpt）在溶剂热条件下合成了配合物[CuBr（4-abpt）],并用红外光谱、元素分析及X-射线单晶衍射对其进行了结构表征.结果表明,该配合物中Cu（Ⅰ）呈现四面体配位几何,4-abpt采取μ3-桥连模式与μ3-Cu（Ⅰ）在ab平面形成了具有（4.82）拓扑结构的[Cu-（4-abpt）]层,相邻层间通过N-H…Br氢键作用和π-π堆积构筑成三维超分子网络.配合物结晶于单斜晶系,P2（1）/n空间群,a=0.768 97（6）nm,b=1.332 70（10）nm,c=1.263 38（9）nm,β=91.388（2）,V=1.294 34（17）nm3,Z=4,S=1.050,R1=0.023 1,wR2=0.056 7[I〉2σ（I）].     

4-氨基-3,5二-（4-吡啶基）-1,2,4三-氮唑-Cu（Ⅰ）配合物的溶剂热合成及结构表征

采用CuBr与4-氨基-3,5-二（4-吡啶基）-1,2,4-三氮唑配体（4-abpt）在溶剂热条件下合成了配合物[CuBr（4-abpt）],并用红外光谱、元素分析及X-射线单晶衍射对其进行了结构表征.结果表明,该配合物中Cu（Ⅰ）呈现四面体配位几何,4-abpt采取μ3-桥连模式与μ3-Cu（Ⅰ）在ab平面形成了具有（4.82）拓扑结构的[Cu-（4-abpt）]层,相邻层间通过N-H…Br氢键作用和π-π堆积构筑成三维超分子网络.配合物结晶于单斜晶系,P2（1）/n空间群,a=0.768 97（6）nm,b=1.332 70（10）nm,c=1.263 38（9）nm,β=91.388（2）,V=1.294 34（17）nm3,Z=4,S=1.050,R1=0.023 1,wR2=0.056 7[I〉2σ（I）].     

The DNA binding arm of lambda repressor: critical contacts from a flexible region.

Segments of protein that do not adopt a well-ordered conformation in the absence of DNA can still contribute to site-specific recognition of DNA. The first six residues (NH2-Ser1-Thr2-Lys3-Lys4-Lys5-Pro6-) of phage lambda repressor are flexible but are important for site-specific binding. Low-temperature x-ray crystallography and codondirected saturation mutagenesis were used to study the role of this segment. All of the functional sequences have the form [X]1-[X]2-[Lys or Arg]3-[Lys]4-[Lys or Arg]5-[X]6. A high-resolution (1.8 angstrom) crystal structure shows that Lys3 and Lys4 each make multiple hydrogen bonds with guanines and that Lys5 interacts with the phosphate backbone. The symmetry of the complex breaks down near the center of the site, and these results suggest a revision in the traditional alignment of the six lambda operator sites.     

甘蔗与斑茅割手密复合体的回交后代真实性鉴定及染色体遗传分析

【目的】掌握斑茅割手密复合体(简称斑割复合体)在杂交利用过程中的染色体遗传规律,为斑割复合体适宜回交利用代数提供参考依据。【方法】选用4对引物对甘蔗与斑茅割手密复合体的回交后代进行SSR标记鉴定,并利用甘蔗根尖细胞酶解去壁低渗法对真实杂种进行染色体数目观察。【结果】供试的28个杂交后代材料(15个GT05-164与GXASF108-2-28杂交BC1代,13个GT42与GXASBC112-A6-25杂交BC2代)均为真实杂种。选择在2对SSR引物中均扩增出父本特征带的后代(5个BC1代和7个BC2代)进行染色体观察,结果发现,5个BC1代的染色体数目介于95~98条,其染色体按“n+n”方式传递;7个BC2代的染色体数目介于94~101条,其染色体也按“n+n”方式传递。【结论】甘蔗与斑割复合体杂交BC1和BC2代中染色体传递方式均为“n+n”,母本甘蔗的染色体未加倍,高贵化育种进程减慢,可能需要更高的杂交代数才能获得聚集斑茅和割手密血缘的优良品种(系)。     

由乙二胺、α-萘乙酸构筑的镍(Ⅱ)配合物的合成、结构和抑菌性质研究

[目的]α-萘乙酸是一种植物生长调节剂,乙二胺是一类很好的有机配体,二者与金属离子共同反应合成金属配合物,并研究配合物的抑菌活性。[方法]通过水热合成法合成新的配合物,利用牛津杯法研究配合物的抑菌活性。[结果]成功合成了配合物[Ni(C12H9O2)2(C2H8N2)3]2,采用单晶X-射线、元素分析和FT-IR对合成配合物[Ni(C12H9O2)2(C2H8N2)3]2进行结构表征。同时,研究了该配合物的抑菌活性。[结论]该晶体属于三斜晶系,P-1空间群:a=9.145(6),b=13.146(8),c=14.385(9);α=70.120(7)°,β=74.272(7)°,γ=69.819(7)°,Z=2。Ni(II)与来自3个乙二胺分子的六个氮原子配位,形成扭曲的八面体配位构型。配合物有一定的抑菌活性。     

一维链状镍配合物[Ni（C_（14）H_（10）N_2O_2）（Mf）]_n的合成和晶体结构

合成了含水杨醛缩苯甲酰腙的一维链状镍配合物[Ni（C14H10N2O2）（Mf）]n（Mf=C4H9NO,即吗啡啉）,通过元素分析,红外、电子光谱和X-射线单晶衍射进行了表征.晶体属单斜晶系,空间群为P21/c,a=0.9708（4）nm,b=1.4783（7）nm,c=1.2275（4）nm,β=95.728（14）°,V=1.7528（12）nm3,Z=4,Mr=384.07,Dc=1.455 g.cm-3,μ=1.129 mm-1,F（000）=800,R=0.0759,wR=0.2155.中心镍离子与水杨醛缩苯甲酰腙配体提供的2个氧原子与1个氮原子以及1个配位吗啡啉的氮原子配位,形成了N2O2的平面四边形的配位构型.晶体内每个配合物分子通过分子间氢键与相邻另一个配合物分子缔合成一个沿c轴方向的一维链状结构,N…N氢键键长为0.3239（10）nm,N-H…N氢键键角为173.56°.     

一种新型二茂铁丁酸混配合物的合成及晶体结构

以二茂铁基丁酸(Fb)、4,4′-联吡啶(bpy)以及Zn(AC)2.2H2O为原料合成了一个新的混配合物Zn(Fb)2(bpy)2。X-射线单晶衍射分析表明,该化合物是一个四配体六配位单核配合物,并以氢键另连接两个二茂铁分子。     

Enhancing hydrogen evolution activity in water splitting by tailoring Li⁺-Ni(OH)₂-Pt interfaces

Improving the sluggish kinetics for the electrochemical reduction of water to molecular hydrogen in alkaline environments is one key to reducing the high overpotentials and associated energy losses in water-alkali and chlor-alkali electrolyzers. We found that a controlled arrangement of nanometer-scale Ni(OH)(2) clusters on platinum electrode surfaces manifests a factor of 8 activity increase in catalyzing the hydrogen evolution reaction relative to state-of-the-art metal and metal-oxide catalysts. In a bifunctional effect, the edges of the Ni(OH)(2) clusters promoted the dissociation of water and the production of hydrogen intermediates that then adsorbed on the nearby Pt surfaces and recombined into molecular hydrogen. The generation of these hydrogen intermediates could be further enhanced via Li(+)-induced destabilization of the HO-H bond, resulting in a factor of 10 total increase in activity.     

AlH2P3O10·2H2 O（Ⅰ）对水中Ni^2＋的吸附动力学和热力学研究

采用静态吸附法研究Al2O3-P2O5-H2O反应体系产物三聚磷酸二氢铝Ⅰ型二水物[AlH2P3O10.2H2O（Ⅰ）]吸附水中Ni2＋的动力学和热力学。考察了温度、浓度、粒径、pH和搅拌速度对吸附过程的影响,通过不同温度下的吸附等温热力学性能的变化,计算了吸附焓、吸附熵和自由能。结果表明,在试验范围内,AlH2P3O10.2H2O（Ⅰ）对Ni2＋的吸附符合Langmuir吸附等温方程式,过程受颗粒扩散控制,反应级数为1.88,298.15 K时的热力学数据为：Ea=11.561 kJ/mol,ΔH=35.75 kJ/mol,ΔS=190.58 J/（mol.K）,ΔG=-21.07 kJ/mol,吸附为自发的吸热过程,其吸附动力学总方程为：1-2/3x-（1-x）2/3=0.36r02C01.88exp（-11 561/RT）。     

Lipocalin核糖体展示文库的构建及雌二醇特异性模拟抗体的筛选

[目的]构建Lipocalin核糖体展示文库,并筛选雌二醇特异性模拟抗体。[方法]以Lipocalin蛋白家族中的BBP(胆汁三烯结合蛋白)为模板,设计包含16个随机突变位点的引物,合成BBP基因文库;引入核糖体展示所必需的全部组件,采用重叠PCR技术将BBP库与核糖体展示组件进行拼接,构建核糖体展示Anticalin模拟抗体库;再将构建的Anticalin文库进行体外转录与翻译,产生模拟抗体-核糖体-mRNA三联复合体文库。以小分子抗原雌二醇为靶标,采用固相亲和方法筛选抗雌二醇抗体,通过改变Mg2+浓度将模拟抗体-核糖体-mRNA三联复合体解离,得到与模拟抗体对应的mRNA,经过RT-PCR得到筛选后的DNA文库并重新引入核糖体展示元件进行下一轮淘筛。[结果]通过5轮生物淘筛,模拟抗体得到富集,获得高特异性抗雌二醇抗体。其中有一株克隆的亲和力为54 mmol/L(Kon=4.975 6×104个/M·S;Koff=0.002 7个/S)。IC50与LOD值分别为50和0.071 ng/ml。[结论]获得的雌二醇模拟抗体可以作为抗体并用于检测动物体内雌二醇的残留。     

Internal olefins to linear amines

The selective synthesis of linear amines from internal olefins or olefin mixtures was achieved through a catalytic one-pot reaction consisting of an initial olefin isomerization followed by hydroformylation and reductive amination. Key to the success is the use of specially designed phosphine ligands in the presence of rhodium catalysts. This reaction constitutes an economically attractive and environmentally favorable synthesis of linear aliphatic amines.     

陶粒负载生物滴滤塔净化恶臭气体研究(英文)

[目的]探讨净化单一恶臭气体H2S和NH_3工艺条件及影响因素。[方法]以陶粒作为生物滴滤塔的填料负载微生物,考察了生物滴滤塔于挂膜启动及稳定运行阶段对H_2S和NH_3的降解性能。[结果](1)净化H_2S废气的生物滴滤塔系统在9 d内即完成挂膜,在进口浓度100-1 000 mg/m~3,空床停留时间(EBRT)142-290 s的条件下,H_2S的去除率均可达到99%以上;(2)净化NH_3废气的生物滴滤塔在10 d内即完成挂膜,对NH_3去除率均达到94.61%。[结论]适宜条件下,生物滴滤塔对于H_2S和NH_3的去除率均较高。     

Primary alcohols from terminal olefins: formal anti-Markovnikov hydration via triple relay catalysis

Alcohol synthesis is critical to the chemical and pharmaceutical industries. The addition of water across olefins to form primary alcohols (anti-Markovnikov olefin hydration) would be a broadly useful reaction but has largely proven elusive; an indirect hydroboration/oxidation sequence requiring stoichiometric borane and oxidant is currently the most practical methodology. Here, we report a more direct approach with the use of a triple relay catalysis system that couples palladium-catalyzed oxidation, acid-catalyzed hydrolysis, and ruthenium-catalyzed reduction cycles. Aryl-substituted terminal olefins are converted to primary alcohols by net reaction with water in good yield and excellent regioselectivity.     

Low-temperature synthesis of zintl compounds with a single-source molecular precursor

Thermolysis of the heterobimetallic phosphinidene complex [Sb(PCy)3]2- Li6.6HNMe2 (Cy = C6H11) at 303 to 313 kelvin gives Zintl compounds containing (Sb7)3- anions. The complex thus constitutes a stable molecular single-source precursor to Zintl compounds and provides a potential low-temperature route to photoactive alkali metal antimonates. The new chemical reaction involved, which is driven thermodynamically by the formation of P-P bonds, has implications in the low-temperature synthesis of other technologically important materials (such as gallium arsenide).     

响应曲面优化丹参多糖提取工艺及抗氧化活性分析

【目的】优化丹参多糖提取的柔化工艺参数,并分析其抗氧化活性,为丹参多糖产品的研发提供参考依据。【方法】以液料比(A)、浸提温度(B)、浸提时间(C)为自变量,以丹参多糖提取率(Y)为响应值,采用3因素3水平的响应曲面分析法优化丹参多糖提取工艺,同时测定丹参多糖对羟基自由基的清除能力。【结果】建立的丹参多糖提取二次多项回归方程为:Y=1.94-0.041A-0.056B+0.022C-0.046AB+0.13AC-0.03BC-0.24A2-0.75B2-0.44C2,其中浸提温度与浸提时间的交互作用对丹参多糖提取率影响显著(P<0.05)。丹参多糖提取的最佳柔化工艺条件为:液料比25∶1(mL/g)、浸提温度75℃、浸提时间90 min,在此条件下多糖提取率为1.94%,与预测值1.97%接近。丹参多糖对羟基自由基有明显的清除能力,且随多糖质量浓度的增加而逐渐增强;丹参多糖质量浓度为4.5 mg/mL的清除率最高,为42%。【结论】采用响应曲面法优化的提取柔化工艺参数准确可靠,可用于丹参多糖提取;丹参多糖具有一定的体外抗氧化能力,可作为食品及医药行业的天然抗氧化剂资源进行开发利用。     

SCoT标记技术鉴定湖南甜橙变异类型

[目的]根据SCoT多态性对湖南甜橙变异类型进行鉴定和分析。[方法]首先对SCoT反应体系进行优化,并筛选合适的引物,然后对24份试材进行SCoT标记,获得的目的片段克隆测序,通过测序结果探讨其遗传变异。[结果]甜橙SCoT标记的20μl优化反应体系为：DNA模板80ng,Mg2＋1.6mmol/L,dNTPs0.3mmol/L,引物0.2μmol/L,TaqDNA聚合酶用量1.6U,扩增产物在100～2000bp,扩增条带明亮清晰,反应体系具有良好的稳定性和可重复性。24份试材的测序片段的大小为1090-1091bp,一致性达到99.84%,存在单碱基缺失与替换;利用单碱基变异可以区分其中的12个甜橙变异株系和‘安江香柚’。[结论]本研究将为甜橙的育种工作提供科学的理论依据。     

小菜蛾性信息素与性信息素结合蛋白、受体蛋白结合机理研究

【目的】研究小菜蛾性信息素与性信息素结合蛋白、受体蛋白之间作用的关键氨基酸残基和作用力类型,揭示小菜蛾识别性信息素的分子机制,为开发新型性诱剂和小菜蛾的无害化防治提供新思路。【方法】运用Discovery Studio 2.5对小菜蛾性信息素结合蛋白PxylPBP2和受体蛋白PxylOR4进行同源建模,运用程序包中LibDock模块进行分子对接,运用Calculate Energy模块计算复合物结合自由能,分析性信息素Z9-14∶AC与PxylPBP2和PxylOR4的结合模式及相互作用力。【结果】Thr9是PxylPBP2与Z9-14∶AC形成氢键的关键氨基酸残基,Z9-14∶AC易与PxylOR4中的Leu残基产生疏水作用力;PxylPBP2与Z9-14∶AC结合的主要驱动力是静电力,PxylOR4与Z9-14∶AC结合的主要驱动力是范德华力,溶剂化能均抑制Z9-14∶AC与PxylPBP2和Z9-14∶AC与PxylOR4的结合。【结论】小菜蛾性信息素受体蛋白和性信息素结合蛋白在识别和结合性信息素分子方面存在明显差异,性信息素受体蛋白与性信息素反应更灵敏、形成的复合物更稳定。     

南方水稻黑条矮缩病毒安徽分离物S5片段的克隆及S5-2基因的原核表达

【目的】探讨南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)安徽分离物(SRBSDVAn Hui-HN2)的遗传特性,并获得原核表达的P5-2蛋白。【方法】RT-PCR扩增SRBSDV S5片段,克隆、测序并进行序列分析。将S5-2基因插入原核表达载体,重组载体转化大肠埃希菌并用IPTG诱导,Ni2+-NTA亲和柱纯化融合蛋白,SDS-PAGE分析P5-2蛋白的表达情况。【结果】SRBSDV-An Hui-HN2 S5片段全长3 167 bp,包含S5-2基因全长612 bp,编码204个氨基酸。序列比对结果显示,SRBSDV-An Hui-HN2 S5片段与其他SRBSDV分离物S5片段的序列相似性极高,达99.0%~99.7%,而与斐济病毒属(Fijivirus)其他成员S5片段的序列相似性较低,仅为38.0%~71.3%;构建的S5片段系统发育树表明SRBSDV和RBSDV聚成1个分支,其中6个SRBSDV分离物聚成1个亚分支。原核表达获得相对分子质量约为47 000的重组蛋白,Western blot分析显示,GST单抗能够与重组融合蛋白发生特异性反应。【结论】SRBSDV各分离物之间亲缘关系非常近,而与Fijivirus其他成员亲缘关系较远,原核表达获得的融合蛋白为靶标蛋白。     

Interpenetrating As20 fullerene and Ni12 icosahedra in the onion-skin [As@Ni12@As20]3- ion

The [As@Ni12@As20]3- ion was prepared from As7(3-) and Ni(COD)2 in ethylenediamine solutions and isolated as the Bu4P+ salt (As, arsenic; Ni, nickel; COD, cyclooctadiene; Bu, butyl; P, phosphorus). The anion contains an icosahedral [Ni12(mu12-As)]3- fragment that resides at the center of an As20 dodecahedral (fullerene) cage to give an onion-skin-like [As@Ni12@As20]3- cluster with Ih point symmetry. The icosahedron and pentagonal dodecahedron are reciprocal platonic solids, and the 32 surface atoms form a dimpled geodesic sphere composed of 60 triangular faces. In the gas phase, the [As@Ni12@As20]3- ion sequentially loses all 21 As atoms to form a series of Ni12As(21-x) clusters where 0 相似文献