摘要:

AbstractAn overview of the importance of and methods available for heat storage in the form of sensible and latent heat is followed by a discussion of the advantages and disadvantages of reversible thermochemical energy storage compared to conventional energy sources such as fuels, i.e. irreversible chemical energy carriers. Of the reversible metal‐hydride–metal systems, the MgH2Mg system is particularly attractive as a hydrogen and a high‐temperature heat storage material because of its high hydrogen content and the high energy content of the Mg–H bond. The advances made in this area over the past few years, namely in catalytic hydrogenation and the doping of magnesium powders, have led to the development of “active MgH2Mg systems” for energy storage. The first experimental results on high‐temperature heat storage (also with cooling) by coupling a MgH2Mg storage system with a low‐temperature metal hydride storage

ISSN:0570-0833    

DOI:10.1002/anie.199002233

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe efficiency and future development of the chemical industry are closely linked to catalysis. It has been estimated, for example, that 60 to 70% of all industrial chemicals have involved the use of a catalyst at some point during their manufacture. In the past two decades the share of the market credited to homogeneous transition metal catalysis increasead to 10–15%. Besides cobalt, which is used mainly in hydroformylation reactions, nickel is the most frequently used metal. Many carbon–carbon bond formation reactions can be carried out with high selectivity if catalyzed by organonickel complexes. Such reactions include, inter alia, carbonylation reactions, cyclic and linear oligomerization and polymerization reactions of monoenes and dienes, and hydrocyanation reactions. It wasReppeandWilkewho pioneered and shaped the field of homogeneous nickel catalysis. Great impetus was also given to the development of organonickel chemistry byWilkeand his students. Research in this area has contributed immensely towards an understanding of the reactions involved in catalysis.—This review is primarily concerned with nickel‐catalyzed reactions which are of interest both preparatively and industrially; some mechanistic aspects are also dea

ISSN:0570-0833    

DOI:10.1002/anie.199002351

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractHow structures fit together is the principal domain of molecular recognition, and current studies are evolving from the host–guest chemistry of ions to interactions between two molecules. Recent advances in the synthesis of sizable concave molecules, especially those featuring convergent functional groups, make it possible to bind smaller convex structures with considerable selectivity. One result is that hydrogen bonding can be addressed in model systems. The present review emphasizes the use of cleftlike structures as a means of probing the forces involved in nucleic acid recognition. The application of such molecules to the catalysis of chemical reactions, particularly those involved in self‐replicating systems, is also described. Some implications for future pharmaceutical agents are suggested as a result of access to synthetic receptors for biologically relevant targ

ISSN:0570-0833    

DOI:10.1002/anie.199002451

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractConformational preferences of two classes of organometal complexes have been surveyed by inspecting the Cambridge Structural Database (CSD). Lewis acid carbonyl complexes demonstrate a variety of coordination geometries, depending on the electronic and steric requirements of the carbonyl ligands and the nature of the Lewis acid. Similarly, the solid‐state conformation of various π‐bonding ligands in metal acyl, metal nitrosyl, metal acetylene, and metal imido complexes is revealed. These insights have stimulated the development of a conformational model that is based on considerations of π‐bond hybridization and frontier molecular orbital theory. The analyses are relevant to the mechanism and transition structures of many synthetically important transformations. A deeper understanding of the conformational properties of organometal complexes, based on accurate structural information, will likely expedite the design and improvement of metal‐mediated

ISSN:0570-0833    

DOI:10.1002/anie.199002561

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199002731

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199002751

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199002761

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199002791

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199002801

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199002821

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY