【期】：12 【起页】：50 【止页】：55 【总页数】：6 【分类号】：O647 【关键词】：catalysts Pd/C;nanostructural features;X-ray analysis;催化剂;纳米结构;X射线分析; 【语种】：英语 【文摘】：This study used XRPD techniques to investigate thenanocrystalline features of a series of four Pd/C catalysts, whichhad the same load of 0.53 wt.% of palladium, with differentdispersions, obtained by applying different temperature ageings upto 873K . By means of a rietveld refinement, performed using aspecial fitting procedure which takes into account the variouscontributions to the background scattering, the palladium
fractionresponsible for the \fraction which gives rise to diffuse scattering(due to nanocrystallites or nanoclusters smaller than about 2?m).The amount of carbon was also determined. A systematic increasein the \observed to be a function of the thermaltreatment temperature. A comparison of this Rietveld absolutequantitative analysis was made using a single peak standardrelative analysis, which needs a suitable reference sample. 【馆藏单位】：冶金工业信息标准研究院
4.J.&J. Dyson acquires Saffil from ICI 【刊名】：World Ceramics & Refractories 【ISSN】：0959-6127 【出版年】：1999 【卷】：10 【期】：5 【起页】：5 【止页】：0 【总页数】：1 【分类号】TQ17 【关键词】：catalyst;temperature;alumina;fibres;quality;催化剂;温度;氧化铝;纤维;质量; 【语种】：英语 【馆藏单位】：冶金工业信息标准研究院
5. Structure of a bacterial ribonuclease P holoenzyme in complex with tRNA Nicholas J. Reiter;Amy Osterman;Alfredo Torres-Larios;Kerren K. Swinger;Tao Pan;Alfonso Mondragon; 【作者单位】：Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA;Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA;Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA Departamento de Bioquimica y Biologia Estructural, Institute de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria,
Apartado Postal;Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA;Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA;Department of Molecular Biosciences, Northwestern University,
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Evanston, Illinois 60208, USA 【刊名】：Nature 【ISSN】：0028-0836 【出版年】：2010 【卷】：468 【期】：Dec.9 TN.7325 【起页】：784 【止页】：789,iii 【总页数】：7 【分类号】：N 【语种】：英语 【文摘】：Ribonuclease (RNase) P is the universal ribozyme responsible for 5'-end tRNA processing. We report the crystal structure of the Thermotoga maritima RNase P holoenzyme in complex with tRNA~(Phe). The 154 kDa complex consists of a large catalytic RNA (P RNA). a small protein cofactor and a mature tRNA. The structure shows that RNA-RNA recognition occurs through shape complementarity. specific intermolecular contacts and base-pairing interactions. Soaks with a pre-tRNA 5' leader sequence with and without met al help to identify the 5' substrate path and potential catalytic met al ions. The protein binds on top of a universally conserved structural module in P RNA and interacts with the leader. but not with the mature tRNA. The active site is composed of phosphate backbone moieties. a universally conserved uridine nucleobase. and at least two catalytically important met al ions. The active site structure and conserved RNase P-tRNA contacts suggest a universal mechanism of catalysis by RNase P. 【其他语种文摘】：转移RNA(tRNA)是作为前体合成的，这些前体要求在5’和3’端进修剪并对特定核苷酸进行些修饰。 Ribozyme Rnase P普遍对处理tRNA的5’端负责。 现在，与成熟苯基丙氨酸转移RNA结合在一起的fqNase P(来自Thermoto- ga maritima)的晶体结构已被确定。 该结构显示了在pre-tRNA识别中所涉及的相互作用、活性点位置及催化中金属的作用。 Rnase P/tRNA 核糖核蛋白结构也为一个基于RNA的古老世界是怎样演化为当今由蛋白一催化剂支配的世界的提供了线索。
【馆藏单位】：中国科学技术信息研究所
6.Catalytic functionalization of unactivated primary C-H bonds directed by an alcohol Eric M. Simmons;John F. Hartwig; 【作者单位】：Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. tPresent address: Department of Chemistry, University of California, Berkeley, California 91820, USA;Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. tPresent address: Department of Chemistry, University of California, Berkeley, California 91820, USA 【刊名】：Nature 【ISSN】：0028-0836 【出版年】：2012 【卷】：483 【期】：Mar.1 TN.7387 【起页】：70 【止页】：b1
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【总页数】：5 【分类号】：N 【语种】：英语 【文摘】：New synthetic methods for the catalytic functionalization of C-H bonds have the potential to revolutionize the synthesis of complex molecules1\However, the realization of this synthetic potential requires the ability to functionalize selectively one C-H bond in a compound containing many such bonds and an array of functional groups. The
site-selective functionalization of aliphatic C-H bonds is one of the greatest challenges that must be met for C-H bond functionalization to be used widely in complex-molecule synthesis, and processes catalysed by transition-metals provide the opportunity to control selectivity. Current methods for catalytic, aliphatic C-H bond functionalization typically rely on the presence of one inherently reactive C-H bond or on installation and subsequent removal of directing groups that are not components of the desired molecule. To overcome these limitations, we sought catalysts and reagents that would facilitate aliphatic C-H bond functionalization at a single site, with chemoselectivity derived from the properties of the catalyst and site-selectivity directed by common functional groups contained in both the reactant and the desired product. Here we show that the combination of an
iridium-phenanthroline catalyst and a dihydridosilane reagent leads to the site-selective y-functionalization of primary C-H bonds controlled by a hydroxyl group, the most common functional group in natural products. The scope of the reaction encompasses alcohols and ketones bearing many substitution patterns and auxiliary functional groups; this broad scope suggests that this methodology will be suitable for the site-selective and diastereoselective functionalization of complex natural products. 【其他语种文摘】：用于C-H键选择性功能化的新合成方法的开发 极为重要，因为这种化学反应有可能使复杂分 子的合成发生革命性变化。 在这篇文章中，Eric Simmo rls和John Hartwig发现，一种“铱-邻 二氦杂菲”催化剂和一种“dihvdrdosi Jane”试 剂的组合，导致靠近一个羟基官能团的主C-H 键的地点选择性功能化。 该反应的范围包括醇 和酮，说明这种方法将适合于复杂天然产物中 C．H键的选择性功能化。 【馆藏单位】：中国科学技术信息研究所
7. High-valent organometallic copper and palladium in catalysis 【作者单位】：University of Michigan, Department of Chemistry, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.;University of Michigan, Department of Chemistry, 930 North University Avenue, Ann Arbor, Michigan 48109, USA. 【刊名】：Nature 【ISSN】：0028-0836 【出版年】：2012 【卷】：484 【期】：Apr.12 TN.7393 【起页】：177 【止页】：A3 【总页数】：10 【分类号】：N 【语种】：英语 【文摘】：Copper and palladium catalysts are critically important in numerous commercial
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chemical processes. Improvements in the activity, selectivity and scope of these catalysts could drastically reduce the environmental impact, and increase the sustainability, of chemical reactions. One rapidly developing strategy for achieving these goals is to use 'high-valent' organometallic copper and palladium intermediates in catalysis. Here we describe recent advances involving both the fundamental chemistry and the applications of these high-valent metal complexes in numerous synthetically useful catalytic transformations. 【其他语种文摘】：均相铜和铂催化剂被用来合成包括药物、商业化学品及聚合物在内的一系列有机分子。 在这些催化剂的活性、选择性和范围方面所实现的改进，有可能提高他们的用途，减少化学反应的环境影响。 在这篇Review文章中，Amanda Hickman和Melanie Sanford总结了对一个子类的催化剂进行研究的有机金属化学家所取得的最新进展。 这个子类的催化剂通过在+3或+4氧化态含有铂或在+3氧化态含有铜的一个中间体来发挥催化作用。 【馆藏单位】：中国科学技术信息研究所
8.Engineering the third wave of biocatalvsis
U. T. Bornscheuer;R. J. Kazlauskas;S. Lutz;J. C. Moore;G. W. Huisman;K. Robins; 【作者单位】：
Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, Greifswald University, Felix-Hausdorff-StraBe 4, D-l 7487 Greifswald, Germany;Department of
Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, 1479 Gortner Avenue, Saint Paul, Minnesota 55108, USA,Department of Chemical and Biological Engineering, Seoul National University, Seoul 151-7;Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA;Merck Research Laboratories, Merck & Co., Rahway, New Jersey 07065, USA;Codexis Inc., 200 Penobscot Drive, Redwood City, California 94063, USA;Lonza AG, Valais Works, CH-3930 Visp, Switzerland 【刊名】：Nature 【ISSN】：0028-0836 【出版年】：2012 【卷】：485 【期】：May 10 TN.7397 【起页】：185 【止页】：a1 【总页数】：11 【分类号】：N 【语种】英语 【文摘】：Over the past ten years, scientific and technological advances have established biocatalysis as a practical and environmentally friendly alternative to traditional metallo- and organocatalysis in chemical synthesis, both in the laboratory and on an industrial scale. Key advances in DNA sequencing and gene synthesis are at the base of tremendous progress in tailoring biocatalysts by protein engineering and design, and the ability to reorganize enzymes into new biosynthetic pathways. To highlight these achievements, here we discuss applications of protein-engineered biocatalysts ranging from commodity chemicals to advanced pharmaceutical intermediates that use enzyme catalysis as a key step.
【其他语种文摘】：2001年，Nature杂志上的一篇Review Article (go.nature.com/t38uzr)盘点
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了生物催化(用酶或微生物来进行合成化学反应)领域当时的最新进展，并预测了该技术的稳定发展。 在此后的十年问，生物催化已成为在化学反应中使用基于过渡金属的催化剂的方法的一种实用的、环保的替代方法。 在一篇新的Review文 章中，Bornscheuer等人对该领域进行了重新审视。 他们说，我们正在见证生物催化领域的第三轮发展，在这一轮发展中，我们可以通过工程方法使酶具有全新的活性。 本文作者们特别指出了生物催化剂在几种应用中所取得的成功，其中包括重要商业化学品及高级药物中间体的合成。 【馆藏单位】：中国科学技术信息研究所
八．美国《工程索引》
1. Scientific bases for the preparation of heterogeneous catalysts Feaviour, Mark R. ; Schofield, Emma R.
Source: Platinum Metals Review, v 51, n 1, p 42-44, January 2007; E-ISSN: 14710676; DOI: 10.1595/147106707X169786; Publisher: Johnson Matthey Public Limited Company Author affiliation:
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1
1
Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, United Kingdom Abstract:
The 9th International Symposium on the Scientific Bases for the Preparation of Heterogeneous Catalysts took place at the Universite′ Catholique de Louvainin
Louvain-la-Neuve, Belgium, on September 10-14, 2006. The symposium attended by the delegates from the industry and Europe covered the topics such as key aspects in catalyst preparation, saturated catalysts, supported metal catalysts, micro- and mesoporous supports, tailored Zeolites, catalysis by bases, and catalysts for fuel production. These categories of topics included precious metal catalysts such as platinum, palladium, ruthenium, and gold. The symposium also featured novel catalyst preparation techniques and the magnetron sputtering for preparation of precious metal catalysts. The symposium featured the role of pgms for Heterogeneous Catalysts, understanding of the base metals, precious metal species used in catalyst precursors, and the active metallic species involved in catalysis.(2 refs)
Main heading: Technical presentations
Controlled terms: Catalysis - Fuels - Magnetron sputtering - Platinum - Ruthenium - Zeolites
Uncontrolled terms: Catalyst preparation - Precious metal catalysts - Saturated catalysts Classification Code: 522 Gas Fuels - 547.1 Precious Metals - 802.2 Chemical
Reactions - 804.2 Inorganic Compounds - 901.2 Education - 932.1 High Energy Physics Treatment: General review (GEN)
Database: Compendex
2. Fundamentals in the preparation of heterogeneous catalysts
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