Angewandte Chemie International Edition in English

Cover image for Vol. 16 Issue 2

February 1977

Volume 16, Issue 2

Pages 65–124

Currently known as: Angewandte Chemie International Edition

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews
    1. Chiral Derivatives of Achiral Molecules: Standard Classes and the Problem of a Right-Left Classification (pages 65–72)

      Prof. Dr. Ernst Ruch

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197700653

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      Right- and left-hand threaded screws can readily be classified. A corresponding classification is impossible with potatoes, although they are also chiral. How does this apply to molecules?

    2. Cyclometalation Reactions (pages 73–86)

      Prof. Dr. Michael I. Bruce

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197700731

      Internal metalation recation in transition metal complexes containing organic ligands frequently proceed according to the scheme (1) [RIGHTWARDS ARROW] (2) + HX (E=donor atom, X=leaving group). Formation of a metal-carbon σ bond is a typical consequence. These cyclometalation are of utility in organic syntheses: thus azobenzene can be transformed into indazole and quinazoline derivatives.

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    3. Early History of the Quantum Mechanical Treatment of the Chemical Bond (pages 87–91)

      Prof. Dr. Friedrich Hund

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197700871

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      The Schrödinger equation formulated some 50 years ago(1926) provided the basis for a theory of the electronic structure of molecules. A qualitative understanding of the homopolar bond in diatomic molecules was reached in 1927 to 1929, and of stereochemistry by 1931. Emeritus Professor Hund, actively involved in this epoch of physical history, recounts developments.

    4. The Surface Chemical Bond (pages 92–99)

      Prof. Dr. Gabor A. Somorjai

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197700921

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      The making and breaking of chemical bonds between adsorbates and the surface of solid are controlling processes in heterogeneous catalysis, and also play an important role in adhesion and lubrication. Only in the past decade have experimental methods become available for studying the surface bond.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews
    1. Substituted Phenylcyclohexanes—A New Class of Liquid-Crystalline Compounds (page 100)

      Dr. Rudolf Eidenschink, Dr. Dietrich Erdmann, Dr. Joachim Krause and Dr. Ludwig Pohl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701001

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      4-(trans-4-Alkylcyclohexyl)benzonitriles(1) form nematic phases with higher clearing points and wider temperature intervals than those of the industrially important 4′-alkylbiphenyl-4-carbonitriles

    2. Assignment of Configuration of Olefins, Diols, and Epoxides. Quantitative Analysis of Their Stereoisomeric Mixtures (pages 100–102)

      Prof. Dr. Alain Krief, Prof. Dr. László Hevesi, Dr. János B. Nagy and Prof. Dr. Eric G. Derouane

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701002

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      The 1H-NMR spectra of olefins permit assignment of configuration only in favorable cases. Better suited are the spectra of the cyclic thionocarbonates (2) readily obtained from (alkyl-)substituted olefins (1).

    3. p-Tolylketenyl as Novel dihapto 3-Electron Ligand (pages 102–103)

      Dr. Fritz R. Kreissl, Dipl.-Chem. Peter Friedrich and Doz. Dr. Gottfried Huttner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701021

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      The novel stable ketenyl complex(1) arises via elimination of PMe3 on dissolution of η-C5H5(CO)(PMe3)2 W[BOND]C([DOUBLE BOND]C[DOUBLE BOND]O)C6H4Me (2) in CH2Cl2 at room temperature. The ketenyl group is σ-bonded as a monohapto1-electron ligand in (2). In (1) two more electrons from the C[DOUBLE BOND]C bond become available for bonding to the metal; this π interaction leads to considerable changes in the bond lengths.

    4. Geometrical Dependence of [2π+2σ]Photocycloaddition (pages 103–104)

      Prof. Dr. Horst Prinzbach, Dipl.-Chem. Gottfried Sedelmeier and Prof. Dr. Hans-Dieter Martin

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701031

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      The correlation between photochemical behavior and the orientation of bonding orbitals has been examined for several examples. Thus (1) reacts to give (2) and (3), whereas (4) fails to give a cycloadduct but forms only the hydrogenated compound along with polymeric products.

    5. Unstable Intermediates in the Gaseous Phase: The Thermal Decomposition of Alkyl Sulfides RSnR (pages 104–105)

      Prof. Dr. Hans Bock and Dipl.-Chem. Shamsher Mohmand

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701041

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      An unusual application of PE spectroscopy is the optimization of gas-phase reactions. Photoelectron spectrometers provide “fingerprints” of molecules in the form of ionization band patterns. Gas-phase formation of ketene by elimination of HCl from acetyl chloride serves as an example. Information about the reaction mechanism can be obtained, e.g. from the PE spectrum of the residual gas(CO,CH4) which does not condense at −190°C.

    6. Unstable Intermediates in the Gaseous Phase: The Thermal Decomposition of Acyl Chlorides RCOCI (pages 105–107)

      Prof. Dr. Hans Bock, Dr. Takakuni Hirabayashi, Dipl.-Chem. Shamsher Mohmand and Dr. Bahman Solouki

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701051

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      An unusual application of PE spectroscopy is the optimization of gas-phase reactions. Photoelectron spectrometers provide “fingerprints” of molecules in the form of ionization band patterns. Gas-phase formation of ketene by elimination of HCl from acetyl chloride serves as an example. Information about the reaction mechanism can be obtained, e.g. from the PE spectrum of the residual gas(CO,CH4) which does not condense at −190°C.

    7. Alkylation of Diethyl Phosphoramidates – A Simple Route from Primary to Secondary Amines (page 107)

      Prof. Dr. Andrzej Zwierzak and Dipl.-Chem. Janina Brylikowska-Piotrowicz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701071

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      Transformation of primary into secondary amines can be accomplished by the reaction sequence (1)[RIGHTWARDS ARROW] (2)[RIGHTWARDS ARROW] (3)[RIGHTWARDS ARROW] (4). The yields are good and no tertiary amines are formed.

    8. Isolation and Vibrational Spectra of Bond-Isomeric Hexakis(thiocyanato-isothiocyanato) Complexes of Ruthenium(III) and Osmium(III) (pages 108–109)

      Dipl.-Chem. Hans-Joachim Schwerdtfeger and Prof. Dr. Wilhelm Preetz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701081

      The ambidenate ligand SCN can bond via S (thiocyanato) or N (isothiocyanato). High voltage electrophoresis resolved the RuIII complex (1) in to four bond isomers, and the OsIII complex (2) into three such isomers, which were identified by their vibrational spectra.

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    9. Cycloaddition of Phenyl Isocyanate to a Diaziridinimine (pages 109–110)

      Prof. Dr. Helmut Quast and Dipl.-Chem. Erwin Spiegel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701091

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      Compounds having a 1,2,4-triazolidine skeleton(2) are formed on [3+2] cycloaddition of phenyl isocyanate to diaziridinimines (1). Reactions with deuterium-labeled (1) revealed which N atoms participate in cycloaddition. Symmetrization does not occur.

    10. Resolution of a Chiral Olefin by Complexation Chromatography on an Optically Active Rhodium(I) Complex (page 110)

      Univ.-Doz. Dr. Volker Schurig

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701101

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      Differences in π-complexation strength of chiral olefins with the rhodium(I) complex 1R-(2) have now been exploited for resolving enantiomers by gas chromatography. Racemic 3-methylcyclopentene could be resolved quantitatively into the antipodes R-(1) and S-(1).

    11. Through-Bond Interaction between Two Mutually Perpendicular π Systems—A New Possibility of Conjugation (pages 110–112)

      Dr. Peter Bischof, Prof. Dr. Rolf Gleiter and Dipl.-Ing. Rudolf Haider

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701102

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      The interaction between orthogonal π systems becomes considerably stronger if the spiro center joining them (1a) is replaced by a four-membered ring (1b). The Walsh orbitals of the four-membered ring act as a “relay”.

    12. Detection of S6 and S7 in Molten Cyclooctasulfur (pages 112–113)

      Prof. Dr. Ralf Steudel and Hans-Joachim Mäusle

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701121

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      The composition of sulfur melts has still not been completely elucidated. The vibrational spectrum of a hexane extract of a quenched melt reveals the presence of S6 and S7 rings, in addition to S8 rings.

    13. Photochromism of Rhodamine Derivatives (page 113)

      Dr. Karl-Heinz Knauer and Prof. Dr. Rolf Gleiter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701131

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      When used as photo-switches, in data processing technology, etc., photochromic compounds should exhibit a reversible photochromic effect that is as large as possible. The photoreaction (1)⇌(2) of rhodamine derivatives is strictly reversible.

    14. Synthesis of Cyclodepsipeptides by Cyclooligomerization (pages 113–114)

      Prof. Dr. Manfred Rothe and Dr. Wolfgang Kreiss

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701132

      The antibiotic valinomycin is a cyclic depsipeptide of formula (2), n=3. All cyclodepsipeptides (2) can be prepared by cyclooligomerization of the linear subunits of type (1) in toulene or diethyl phosphite.

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    15. Determination of Reaction Enthalpy in the Ion-Exchange of Chlorine Isotopes (pages 114–115)

      Prof. Dr. Klaus G. Heumann and Dr. Rainer Hoffmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701141

      Isotope exchange equilibrium of chloride ions according to eq. (1) has now been characterized thermodynamically. A knowledge of thermodynamic data is an important requirement for developing chromatographic processes intended for chemical pre-enrichment of chlorine isotopes.

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    16. Serious Detonation during the Preparation of tert-Butyl-oxycarbonyl Azide (Boc-Azide) (page 115)

      Dr. Peter Feyen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701151

      Caution with Boc azide! A serious explosion recently occurred during the preparation of tBu[BOND]O[BOND]CO[BOND]N3 (Boc azide) from the hydrazide (1) and HNO2 in ether. The reason is not known. It is urgently recommended that other reagents be employed for introducing the Boc protecting group.

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    17. Synthesis and Absolute Configuration of Enantiomerically Pure D3-Trishomocubanes(Pentacyclo [6.3.0.02,6.03,10.05,9] undecane) and Trishomocubanones (pages 116–117)

      Dr. Günter Helmchen and Gerhard Staiger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701161

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      Rigid chiral hydrocarbons such as (1) and (2) are of interest as test cases for chiroptical theories. (−)-Trishomocubane (1) and (+)-trishomocubane (2), which have now been obtained enantiomerically pure, are apparently the smallest stable organic molecules of point symmetry D3.

    18. Synthetic Hemopolymers for Reversible Binding of Molecular Oxygen (pages 117–118)

      Prof. Dr. Ernst Bayer and Dipl.-Biochem. Gunter Holzbach

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701171

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      Protein-free model compounds for hemoglobin, e.g. (1), have now been prepared. The synthetic polymers have properties closely resembling those of natural oxygen carriers and can serve as a basis for novel catalyst systems.

    19. Extension of the Scope of Anionic Cycloadditions by Activating Organoelement Groups (page 119)

      Prof. Dr. Thomas Kauffmann, Holger Ahlers, Angelika Hamsen, Herbert Schulz, Dipl.-Chem. Hans-Joachim Tilhard and Annemarie Vahrenhorst

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701191

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      Activation of olefins in the anionic cycloaddition of 2-azaallyl compounds such as (1) can be accomplished by the organoelement groups SPh, SePh, PPh2 and AsPh2. They can be removed from the cycloadducts (2) with relative ease.

    20. Collision Activation Mass Spectrometry with Novel Analysis Technique (pages 120–121)

      Dr. Richard Robbiani, Dr. Thomas Kuster and Prof. Dr. Joseph Seibl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701201

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      The “observational window” for studies on collision induced reactions in the mass spectrometer is shifted to shorter times by the linked scan technique. This approach permits distinction between molecular ions such as (1) and (2), which both isomerize to the same ion on recording the DADI mass spectra.

  3. Abstracts

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews
    1. ABSTRACTS (pages 121–123)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197701211

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews

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