摘要:

AbstractAttempts to explain the surprising violet color of the new azobisphosphonic acid derivatives Y2OPNNPOY2have led to the preparation and spectroscopic characterization of more than 60 azo compounds. The long‐wavelength n → π*transitions on which the color depends exhibit regularities which justify the assumption of substitutent‐specific absorption increments. The complex relation between color and constitution of azo compounds can be qualitatively explained with the aid of orbital models. Infrared and ultraviolet spectral data show that conjugation is inhibited by tetra‐coordinated phosphorus (V). the π‐system of these compounds therfore comprises only for atoms, P·N·N·P. The unexpected violet color of the phosphorus azo compounds can be ascribed to a π*/d orbital interaction. The substituent effects described have general significance, and n→π*transitions of other chromophore

ISSN:0570-0833    

DOI:10.1002/anie.196504571

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractIn spite of the large number of reactions which involve the formation of isonitriles, the only preparative routes to these compounds, until recently, were the classical isonitrile syntheses discovered about one hundred years ago by Gautier and Hofmann. These methods are not generally applicable, and give satisfactory yields only in exceptional cases. Isonitriles have recently become readily available by the elimination of water from N‐substituted formamides, using acyl halides of Group IV–;VI elements in the presence of bases as dehydrating agents. A dehydrating system with a particularly wide range of application consists of phosgene with tertiary amines. This system generally provides the easiest and most productive route to isonitriles, particularly where large quantities (>1 mole) are to be prepa

ISSN:0570-0833    

DOI:10.1002/anie.196504721

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractA historical survey is followed by a discussion of a number of problems associated with concentrated solutions of electrolytes containing two ion constituents: general thermodynamic properties, dissociation equilibria, phase separation, analytical representation of the thermodynamic functions over the entire range of concentrations, and general relationships in electrical conductivity, diffusion, and sedimentation. A number of relationships valid at all concentrations is formulated, and known relationships pertaining to dilute solutions are derived from these as special cases. The discussion of concentrated solutions is illustrated by numerical examples, most of which are based on recent results.

ISSN:0570-0833    

DOI:10.1002/anie.196504851

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractFlurophosphoranes are a recently discovered new type of phosphorus compound derived from phosphorous pentafluoride by substitution of fluorine atoms with various groups. Synthesis, chemistry, and stereochemistry of this class of compounds containing phosphorus in the comparatively rare coordination number 5 will be discussed.

ISSN:0570-0833    

DOI:10.1002/anie.196504961

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractThe present paper is the first of two reports describing the principles which can be applied to the construction of automatic counter‐tube diffractometers for the X‐ray analysis of crystals. These instruments can reduce the time required for the analysis of an organic crystal (measurement of a few thousand intensities) from several months (by the photographic method) to a few d

ISSN:0570-0833    

DOI:10.1002/anie.196505081

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractThe ultraviolet spectra of all organic compounds can be classified according to the chemical constitution with the aid of a simple code based on a ten‐digit decimal system, each digit indicating the “spectroscopic weight” of the encoded information. The code discussed here will shortly be used in the Atlas of Ultraviolet Spectra which appears in the Documentation of Molecular Spectroscopy S

ISSN:0570-0833    

DOI:10.1002/anie.196505161

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196505181

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196505192

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196505202

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196505213

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY