ISSN:0570-0833    

DOI:10.1002/anie.199407951

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractCyclodextrins are frequently used as building blocks, because they can be linked both covalently and noncovalently with specificity. Thus one, two, three, seven, fourteen, eighteen, or twenty substituents have been linked to one β‐cyclodextrin molecule in a regioselective manner. Furthermore, Cyclodextrins may serve as organic host molecules. Their internal cavity is able to accommodate one or two guest molecules. Conversely, suitable guest molecules can be used to thread one, two, or many (one hundred or more) cyclodextrin rings. The resulting supramolecular structures are often formed in solution, which allows characterization by high‐resolution spectroscopic methods. Chemical conversion of these structures provides molecular architectures such as catenanes, rotaxanes, polyrotaxanes, and tubes, which are not readily prepared by other methods. The particular properties of Cyclodextrins can also be employed, for example, for the chromatographic separation of complex mixtures of substances, even racemates, by molecular recognition. Cyclodextrins and their derivatives have been found to be remarkably active catalysts as well. Finally, since Cyclodextrins can favorably influence the release of drugs, many new applications will certainly be developed in the near fu

ISSN:0570-0833    

DOI:10.1002/anie.199408031

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractCrystal structures potentially deliver far more information than is present in the average structural communication—if sufficient structural data on closely related molecules or molecular fragments are available, it may be possible to infer details of geometric changes occurring along certain reaction pathways for the species of interest. This geometric information is extrapolated from an analysis of the similarities between the structures of the fragment in the various crystalline environments, by a method that is now known as structure correlation analysis. Since it was first proposed twenty years ago, the method has been applied to a large variety of chemical systems, but none have received as much attention as the class of five‐coordinate compounds. Comparative analyses of the structures of pentacoordinate complexes have yielded information about the intimate mechanisms of substitution and addition/elimination reactions at tetrahedral and square‐planar complexes, and about intramolecular isomerizations of five‐coordinate compounds. Since its inception, the structure correlation method has gradually adapted techniques from other branches of science, in particular group‐theoretical and multivariate statistical techniques, which have been shown to be enormously powerful tools for probing geometrically complex systems. This review traces the development of the method of structure correlation and the evolution of these co‐opted techniques, with a specific emphasis on studies of five‐coordinate me

ISSN:0570-0833    

DOI:10.1002/anie.199408231

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408411

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408431

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408471

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408491

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408511

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408531

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199408551

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY