ISSN:0570-0833    

DOI:10.1002/anie.199509451

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractCombinatorial chemistry is a laboratory emulation of natural recombination and selection processes. Strategies in this developing discipline involve the generation of diverse, molecular libraries through combinatorial synthesis and the selection of compounds that possess a desired property. Such approaches can facilitate the identification of ligands that bind to biological receptors, promoting our chemical understanding of cellular processes. This article illustrates that the coupling of combinatorial synthesis, multidimensional NMR spectroscopy, and biochemical methods has enhanced our understanding of a protein receptor used commonly in signal transduction, the Src Homology 3 (SH3) domain. This novel approach to studying molecular recognition has revealed a set of rules that govern SH3–ligand interactions, allowing models of receptor–ligand complexes to be constructed with only a knowledge of the polypeptide sequences. Combining combinatorial synthesis with structural methods provides a powerful new approach to understanding how proteins bind their ligands in gene

ISSN:0570-0833    

DOI:10.1002/anie.199509531

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractOne of the great challenges in the field of heterogeneous catalysis is the conversion of methane to more useful chemicals and fuels. A chemical of particular importance is ethene, which can be obtained by the oxidative coupling of methane. In this reaction CH4is first oxidatively converted into C2H6, and then into C2H4. The fundamental aspects of the problem involve both a heterogeneous component, which includes the activation of CH4on a metal oxide surface, and a homogeneous gas‐phase component, which includes free‐radical chemistry. Ethane is produced mainly by the coupling of the surface‐generated CH 3•radicals in the gas phase. The yield of C2H4and C2H6is limited by secondary reactions of CH 3•radicals with the surface and by the further oxidation of C2H4, both on the catalyst surface and in the gas phase. Currently, the best catalysts provide 20% CH4conversion with 80% combined C2H4and C2H6selectivity in a single pass through the reactor. Less is known about the nature of the active centers than about the reaction mechanism; however, reactive oxygen ions are apparently required for the activation of CH4on certain catalysts. There is spectroscopic evidence for surface O−or O 22−ions. In addition to the oxidative coupling of CH4, cross‐coupling reactions, such as between methane and toluene to produce styrene, have been investigated. Many of the same catalysts are effective, and the cross‐coupling reaction also appears to involve surface‐generated radicals. Although a technological process has not been developed, extensive research has resulted in a reasonable understanding of the elementary reactions that occur during the oxid

ISSN:0570-0833    

DOI:10.1002/anie.199509701

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509811

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509862

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509891

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509901

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509931

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509961

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199509981

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY