摘要:

AbstractUntil now the study of organic compounds in which the π‐electron system is excited by absorbed light has been mainly concentrated on the ultraviolet and visible regions of the electromagnetic spectrum. Various new applications, such as the use of conjugated organic compounds as dye lasers or as materitals for storing information with the help of diode lasers, led to the synthesis of new compounds which absorb light in the near in infrared (NIR). It is possible to use structure‐color relationships to predict the properties of such new compounds when they belong to dyestuff classes which have already been studied in detail; in this case the approach involves decreasing the energy difference between the ground state and the first excited state. A less conventional starting point is provided by molecular structures in which from the outset there is only a very small energy difference between the lowest‐energy electronic states; such diradicaloid molecules occupy a special position among the various types of organic compounds. It is possible by means of suitable structural modification to stabilize such molecules in a singlet from which absorbs light at very long wavelengths (i.e. at small wave nu

ISSN:0570-0833    

DOI:10.1002/anie.198906773

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractEnantioselective biocatalysis in nonaqueous media is becoming increasingly important in preparative synthetic chemistry. This article discusses (1) the general catalytic properties of enzymes in nonaqueous environments, (2) the basic principles that govern lipase‐catalyzed enantioselective esterification and transesterification reactions in organic media for the preparation of optically active acids and alcohols, (3) the determination of kinetic and thermodynamic parameters, and (4) the quantitative analysis of published dat

ISSN:0570-0833    

DOI:10.1002/anie.198906951

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe electrochemical measurement of oxygen activity using ion‐conducting solid electrolytes (λ‐sensors) has become widely known, at least since the application of three‐way catalysts in the postcombustion of exhaust gases from spark‐ignition engines. However, the use of solid ion conductors is not limited to control devices. There are various other potential applications and numerous problems which can be studied: the formation of oxides in the course of catalytic reactions on metal surfaces, the improvement of selectivity and yield of catalytic reactions, such as the epoxidation of ethylene on silver catalysts and, finally, the cogeneration of electrical energy during oxidation reactions, such as the partial oxidation of methanol to form

ISSN:0570-0833    

DOI:10.1002/anie.198907081

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractOligonucleotide synthesis, until a few years ago the rather exotic preserve of a few experts, has become an integral part of the arsenal of molecular‐biological techniques. The last decade, in particular, has seen unbelievably rapid development in this area. DNA synthesis has been automated and can now produce genes greater than 1000 base pairs in length. Tailor‐made synthetic genes also permit the synthesis of altered or even novel proteins (de novo protein design) by gene‐technological methods. Together with modern methods of gene isolation, sequencing, and expression, gene synthesis has played a major part in the enormous advances achieved in gene techn

ISSN:0570-0833    

DOI:10.1002/anie.198907161

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198907351

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198907361

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198907371

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198907381

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198907401

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198907411

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY