Angewandte Chemie International Edition in English

Cover image for Vol. 31 Issue 2

February 1992

Volume 31, Issue 2

Pages 111–246

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 2/1992)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201111

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      The cover picture shows a section of a high-frequency oven used in a novel synthesis of fullerenes. The reaction zone (at approximately 2800°C, the light is dimmed by the soot beginning to deposit) is depicted at the start of the fullerene production. The inductor, boron nitride insulation tube, quartz tube, and initial formation of smoke can be seen. More about the novel efficient synthetic method is reported by M. Jansen and G. Peters on page 223. The boom in fullerene chemistry continues. The third in a series of highlights on the important recent results (previous updates were published last year in the January and June issues) will appear in the next issue. An overview of the preparations, properties, and reactions of C60 is planned. This issue includes two highlights on silicon clusters including Si60 (p. 173). a communication on He@C60 (p. 183), and, last but not least, an exciting account by H. Kroto on the start of the fullerene story (p. 111).

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. C60: Buckminsterfullerene, The Celestial Sphere that Fell to Earth (pages 111–129)

      Prof. Dr. Harold W. Kroto

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201113

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      A “round organic chemistry” has burgeoned this last year following the development of an efficient means of producing fullerenes in 1989/1990. One of the protoganists in the fullerene story describes in a lively personal style how this fascinating new chemistry came about. In this thriller he points out that the discovery of C60 in 1985 did not result from an applications-oriented search but rather from basic research and scientific curiosity.

    2. Two-Dimensional Crystallography of Amphiphilic Molecules at the Air–Water Interface (pages 130–152)

      Didier Jacquemain, Dr. Sharon Grayer Wolf, Franck Leveiller, Dr. Moshe Deutsch, Dr. Kristian Kjaer, Dr. Jens Als-Nielsen, Dr. Meir Lahav and Dr. Leslie Leiserowitz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201301

      Almost atomic resolution is achieved today in techniques for studying monomolecular Langmuir films of amphiphilic molecules. Synchrotron X-ray sources providing well-collimated, high-intensity radiation make this possible. In this review the principles and methods used to study thin films are discussed. In these investigations, for instance, a strong influence from solute molecules or ions in the subphase on the crystallinity of the monomolecular layer was revealed: whereas α-glycine increases the crystallinity of a fluorocarbon monolayer, β-alanine decreases it. Possible explanations for the phenomena are also presented.

    3. Control and Design Principles in Biological Mineralization (pages 153–169)

      Prof. Lia Addadi and Prof. Stephen Weiner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201531

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      Millions of years of evolution are reflected in the phenomenon of biomineralization. The large organized regions of macromolecules and crystals produced by organisms are the subjects of intense research. SiO2 is one of the amorphic minerals which is deposited, for example, by diatoms, in fantastic structures as shown right. The polymeric structure of SiO2 results in high viscosity and low solubility; the linkage of the coordination polyhedrons through their edges allows the formation of open structures. Both are important factors in the deposition of SiO2.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Phosphorus Nitrides—the Cinderella of Phosphorus Chemistry? (pages 170–171)

      Prof. Dr. Otto J. Scherer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201701

      Stamped as long since discovered and therefore completely characterized, simple inorganic molecules like the phosphorus nitrides are often neglected. Yet although P3N5 was synthesized in 1903, its structure is still a mystery. W. Schnick et al. resurrected the chemistry of these compounds in the synthesis of P-N analogues of known structural types. In this way they succeeded in synthesizing and characterizing the lithium salt of the complex anion P4Nmath image (Angew. Chem.1991, 103, 857; Angew. Chem. Int. Ed. Engl.1991, 30, 830) and Zn7[P12N24]Cl2, whose [P12N24] framework is analogous to that of the [Al6Si6O24]Cl2 unit of sodalite (communication on p. 213).

    2. Structure and Reactivity of Silicon Clusters in the Gas Phase (pages 172–173)

      Dipl.-Chem. Thomas Lange and Dr. T. Patrick Martin

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201721

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      Bearing in mind the further miniaturization in microelectronics and the possibility of discovering new materials, as was the case with the fullerenes, many research groups are at present studying clusters of semiconductor elements like silicon. Reactions of mass-selected Sin clusters with reactive gases such as ethylene and subsequent analysis of the products provide information on the structures of these complexes. Thus for instance, Si10 does not have the adamantane structure expected from the structure of elemental silicon, but a compact structure (two calculated structures of almost the same energy are depicted for Si10) with fewer free valencies at the Si atoms. There is no evidence for a “round Si60 chemistry” analogous to that of C60, although Si60 represents a stability maximum (calculated structure depicted to the right). A direct structure determination will probably remain elusive for some time, because the absolute stability of Si60 is orders of magnitude smaller than that of C60.

    3. Si60, an Analogue of C60? (pages 173–175)

      Dr. Christian Zybill

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201731

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      Bearing in mind the further miniaturization in microelectronics and the possibility of discovering new materials, as was the case with the fullerenes, many research groups are at present studying clusters of semiconductor elements like silicon. Reactions of mass-selected Sin clusters with reactive gases such as ethylene and subsequent analysis of the products provide information on the structures of these complexes. Thus for instance, Si10 does not have the adamantane structure expected from the structure of elemental silicon, but a compact structure (two calculated structures of almost the same energy are depicted for Si10) with fewer free valencies at the Si atoms. There is no evidence for a “round Si60 chemistry” analogous to that of C60, although Si60 represents a stability maximum (calculated structure depicted to the right). A direct structure determination will probably remain elusive for some time, because the absolute stability of Si60 is orders of magnitude smaller than that of C60.

    4. Inhibition of Fruit Ripening by Antisense-RNA Technology (pages 175–177)

      Dr. Peter Eckes

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201751

      Controlled ripening of tomatoes—the application of antisense-RNA technology by an American research group made this possible. The biosynthesis of ethylene, the signal compound which induces ripening, can be suppressed by these molecular biological methods. The storage and transportation of the green fruits is much easier. Their subsequent exposure to ethylene then triggers ripening. Antisense-RNA technology can be applied in other areas, for example in medical research.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Microcalorimetry of the Spin-Transition Systems [Fe(bts)2(NCS)2] and [Fe(2-pic)3]Cl2· EtOH in the Range 15K < T < 300K (pages 178–180)

      Ralf Jakobi, Harald Romstedt, Hartmut Spiering and Prof. Dr. Philipp Gütlich

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201781

      For compounds with poor thermal conductivity and samples of only a few milligrams the heat capacity may be determined as a function of temperature with great accuracy with the microcalorimeter presented here. This was demonstrated on two FeII spin-transition systems. Comparison with the results of measurements conducted with a Nernst calorimeter on a sample almost 1000 times larger was possible in one case; the agreement of the two data sets was quite good. Simultaneously the change in the thermal conductivity at the spin transition was determined for the first time.

    2. Stable N, N′-Di-tert-butyl-meta-phenylene-bisnitroxides—Unexpected Ground-State Singlets (pages 180–181)

      Dr. Maya Dvolaitzky, Dr. Robert Chiarelli and Prof. Dr. André Rassat

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201801

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      In contrast to m-xylylene and related diradicals, bisnitroxide 1 has a singlet ground state according to ESR spectroscopic investigations. Diradical 1 can be isolated as two stable atropoisomers. In both, the free electron is possibly localized on the oxygen atom, because conjugation is prevented by the steric hindrance of the methyl groups. The parent compound with an unsubstituted benzene ring has a triplet ground state.

    3. Activation Parameters and Stereochemistry of an Antibody-Catalyzed Claisen Rearrangement (pages 182–183)

      Dr. David Y. Jackson, Michael N. Liang, Prof. Paul A. Bartlett and Prof. Peter G. Schultz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201821

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      The catalysis of the same reaction through different mechanisms was attributed to the diversity of the immune response. The chorismate–prephenate conversion 1 [RIGHTWARDS ARROW] 3 can be catalyzed by antibodies raised against an analogue of the transition state 2. These antibodies give rise to a variety of activation parameters for the catalysis. An extremely low activation entropy was found for the antibody 11F1-2E11, which supports the notion that conformational restriction may play an important role in antibody catalysis.

    4. The Neutralization of HeCmath image in the Gas Phase: Compelling Evidence for the Existence of an Endohedral Structure for He@C60 (pages 183–185)

      Dr. Thomas Weiske, Thomas Wong, Dr. Wolfgang Krätschmer, Prof. Dr. Johan K. Terlouw and Prof. Dr. Helmut Schwarz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201831

      Neutralization-reionization mass spectrometry was used to show that for both neutral He@C60 and He@Cmath image, the noble gas atom is incorporated within the fullerene cavity. The C60H˙+ ions were generated by high-energy collisions of Cmath image with quasi-stationary 4He target atoms and cleaved in the mass spectrometer by loss of C2 or multiples thereof, as is usual for endohedral MC60 complexes.

    5. On the Bonding in Carbosilanes (pages 185–187)

      Priv.-Doz. Dr. Andreas Savin, Dipl.-Chem. Heinz-Jürgen Flad, Dr. Jürgen Flad, Prof. Dr. Heinzwerner Preuss and Prof. Dr. Hans Georg von Schnering

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201851

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      No direct Si[BOND]Si bond is present in 1 in spite of the short interatomic distance; however, the long C[BOND]C distance does not prevent weak bond formation in 2. These results are predicted by an analysis of the compounds with the electron localization function. The explanation for the short Si[BOND]Si bond in 1 lies in the different sizes of C and Si.

    6. Electron Localization in Solid-State Structures of the Elements: the Diamond Structure (pages 187–188)

      Priv.-Doz. Dr. Andreas Savin, Dr. Ove Jepsen, Dr. Jürgen Flad, Prof. Dr. Ole Krogh Andersen, Prof. Dr. Heinzwerner Preuss and Prof. Dr. Hans Georg von Schnering

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201871

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      To determine solid-state structures, the electron localization function (ELF) must be interpreted somewhat differently than for molecules. The example of the diamond structures of C (right, top), Si, Ge, and α- and β-Sn (right, bottom) show clearly that ELF depicts the electronic changes in regional space as the covalent bond gives way to metallic bonding.

    7. Molecular Imaging of Alkanol Monolayers on Graphite (pages 189–191)

      Dr. Stefan Buchholz and Dr. Jürgen P. Rabe

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201891

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      The structure and dynamics of monomolecular adsorbed layers of long-chain 1-alkanols can be made visible by electron scanning tunneling microscopy. The packing in single domains and the pattern at the domain boundaries (shown here for 1-octadecanol) confirm the crucial role of the hydroxy groups in the packing of molecules; the common structures at the domain boundaries suggest that all potential hydrogen bonds are indeed formed. The reorganization of regions containing many defects and the incorporation into the domain structure of impurities are also observed.

    8. The Trapping of Iron Hydroxide Units by the Ligand “heidi”: Two New Hydroxo(oxo)iron Clusters Containing 19 and 17 Iron Atoms (pages 191–193)

      Sarah L. Heath and Dr. Anne K. Powell

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201911

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      A shell of iron atoms and tetradentate amino ligands surrounds the close-packed cluster core [Fe73-OH)62-OH)4{(μ3-O)Fe}2]13+ common to 1 and 2. These types of compounds could help in understanding naturally occurring hydroxo-(oxo)iron clusters.

    9. New Chiral α-Benzyloxyacryliron(II) Complex for Asymmetric Synthesis of α, α-Dialkyl-α-hydroxycarbonyl Compounds (pages 193–195)

      Felix Stolz, Dr. Peter Strazewski, Prof. Dr. Christoph Tamm, Markus Neuburger and Priv.-Doz. Dr. Margareta Zehnder

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201931

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      From simple achiral starting materials the chiral organoiron(II) complex 1 can be prepared as either the R or S enantiomer. A Michael addition and subsequent stereospecific alkylation followed by oxidative cleavage of the Fe complex fragment and hydrogenolysis of the O-benzyl function yields the α,α-dialkyl-α-hydroxycarbonyl compounds with the desired chirality.

    10. Enzymatic Preparation of Enantiomerically Pure N-alkyl Amino Acids (pages 195–197)

      Dr. Ulrich Groeger, Dr. Karlheinz Drauz and Dr. Herbert Klenk

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201951

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      The isolation of enantiomerically pure L-amino acids is now possible with a bacterial acylase from N-acylated racemic precursors 1 (R1 [DOUBLE BOND] Me, Et, nPr; R2 [DOUBLE BOND] Me, Et); chemical preparation of these enantiomerically pure compounds is difficult. The viability of the reaction depends on the substitution pattern at the α carbon atom, but similar aminoacylases with a still wider substrate spectrum are expected to be discovered by microbiological screening.

    11. Threading Cyclodextrin Rings on Polymer Chains (pages 197–199)

      Dr. Gerhard Wenz and Dipl.-Chem. Bruno Keller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201971

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      Another form of molecular self-assembly—the threading and unthreading of ring-shaped molecules on a polymer chain (represented schematically here) was studied by NMR spectroscopy and followed qualitatively for the formation of polymeric inclusion compounds made up of cyclodextrins and poly-(iminooligomethylene)s. The structures of the polymeric inclusion compounds are proven by their conversion to polyrotaxanes.

    12. Selectivity Control By Temperature Variation in the Formation of Isotactic vs. Syndiotactic Polypropylene with a Titanocene/Alumoxane Catalyst (pages 199–202)

      Prof. Dr. Gerhard Erker and Dipl.-Chem. Cornelia Fritze

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199201991

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      The opposing effects of activation enthalpy and entropy most likely cause the transition from isotactic via atactic to syndiotactic polypropylene in polymerizations with the soluble metallocene catalyst 1 (X [DOUBLE BOND] Ph) and methylalumoxane when the reaction temperature is increased from −50 to +10°C. This proves how important temperature considerations are for structure–reactivity discussions.

    13. Observation and Properties of a Hydrogen Bond to Carbon in a Short-Lived, Gas-Phase Complex of Methyl Isocyanide and Hydrogen Fluoride (pages 202–203)

      Prof. A. C. Legon, Prof. D. G. Lister and Dr. H. E. Warner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202021

      Through coaxial mixing of a pulsed jet of CH3NC/Ar with a continuous stream of HF/Ar, the complex CH3NCċHF is formed. Since the two components are separate until their expansion in the Fourier-transform microwave spectrometer, their high reactivity can be suppressed. The rotation spectrum of the complex is characteristic of that of a symmetric top, that is, the C3v symmetric complex contains a linear CNCċHF arrangement.

    14. New Thermo-Response Dyes: Coloration by the Claisen Rearrangement and Intramolecular Acid–Base Reaction (pages 204–205)

      Dr. Masahiko Inouye, Kikuo Tsuchiya and Prof. Dr. Teijiro Kitao

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202041

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      Applications in information storage and in thermally activated recording systems are anticipated for the novel allyl aryl ether 1. At 180°C 1 rearranges to phenol lactone 2, which in turn undergoes intramolecular proton migration to provide colored 3.

    15. Molecular Mechanisms of the Reduction of NO to NH2OH at Mo[BOND]S Centers (pages 205–207)

      Prof. Dr. Dieter Sellmann and Dr. Bernd Seubert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202051

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      The coordinatively flexible and redox-active complex fragment [Mo(NO)(′S4′)] in 1 makes the stepwise, and in principle catalytic, reduction of NO to NH2OH possible. The two single steps can be clearly distinguished as 2e/2H+ and 1e/1H+ reductions. This reaction may be considered a model for the molecular processes in the reduction of NO to NH2OH within the conversion of NOmath image to NH3 in the nitrogen cycle in nature.

    16. En Route to Synthetic Phosphodiesterases: Supramolecular Phosphoryl-Transfer Mediated by Amidinium–Phosphate Contact Ion-Pairs (pages 207–209)

      Dr. Michael W. Göbel, Dr. Jan W. Bats and Dr. Gerd Dürner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202071

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      Proximity effects and electrophilic activation combined account for the accelerated ring-opening in the transesterification of 1 with amidinium alcohol 2. The spatial proximity effects arise in a contact ion-pair of 1 and 2. Electrophilic activation causes the 9000-fold rate enhancement of the reaction of 1 with 2 relative to the reaction with phenylalcohol; the addition of 2 to the transesterification of 1 with phenyl alcohol to form 3 caused a 25-fold rate increase.

    17. A New Synthesis for Imidazolo- and Pyrrolophanes by [3+2]Cycloaddition with Azaallenyl Radical Cations (pages 209–210)

      Dipl.-Chem. Felix Müller and Prof. Dr. Jochen Mattay

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202091

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      Imidazolophanes 3 bridged by short chains (n [DOUBLE BOND] 5, 6) are readily accessible by [3 + 2] cycloadditions of imines with 2, formed from the bicyclic azirines 1 under electron-transfer conditions. Other heterocyclophanes can also be prepared by this method. DCN [DOUBLE BOND] naphthalene dicarbonitrile.

    18. Calculation of Molecular Dynamics for Peptides in Dimethyl Sulfoxide: Elimination of Vacuum Effects (pages 210–212)

      Dipl.-Chem. Michael Kurz, Dr. Dale F. Mierke and Prof. Dr. Horst Kessler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202101

      The γ turns not found experimentally in cyclic hexapeptides are also not found in molecular dynamics (MD) simulations if the calculations take the surrounding solvent into consideration. In this report the structures obtained from simulations conducted for the peptide in vacuum were used in subsequent simulations with dimethyl sulfoxide as the solvent. The two γ turns originally obtained disappeared, and only the experimentally proven β turns remained. These results show that the solvent must be explicitly included in MD simulations of peptide conformations in solutions.

    19. BaNb7O9, a New Oxoniobate with Double Layers of Corner-Sharing Nb6 Octahedra (pages 212–213)

      Dr. Gunnar Svensson, Dr. Jürgen Köhler and Prof. Dr. Arndt Simon

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202121

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      The first step in the transition from two- to three-dimensional systems in reduced oxoniobates was achieved in the title compound, which was prepared from NbO2, Ba5Nb4O15, and Nb at temperatures above 1800 K. The structure (shown right) can be considered as “intergrowths” of BaO and NbO or as the perovskite BaNbO3 and NbO.

    20. Zn7[P12N24]Cl2—A Sodalite with a Phosphorus–Nitrogen Framework (pages 213–215)

      Dr. Wolfgang Schnick and Dipl.-Chem. Jan Lücke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202131

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      A three-dimensional network of corner-sharing PN4 tetrahedrons is found in the sodalite-like [P12N24] framework of the title compound, synthesized simply from NH4C1, (PNC12)3, and ZnCl2. A Cl ion surrounded tetrahedrally by Zn2+ ions occupies the center of the β cages, as is shown on the right. The modification of the sodalite framework by exchanging O atoms for N atoms opens new horizons in zeolite research. • [DOUBLE BOND] P; o [DOUBLE BOND] N.

    21. Radical Intermediates in the Coenzyme B12 Dependent Methylmalonyl-CoA Mutase Reaction Shown by ESR Spectroscopy (pages 215–216)

      Dipl.-Chem. Ymin Zhao, Dr. Peter Such and Prof. Dr. János Rétey

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202151

      Only after the addition of the substrate, methylmalonyl-CoA, to the binary complex of highly purified methylmalonyl-CoA mutase and coenzyme B12 is a clear ESR signal observed. This proves that radical intermediates that have only been postulated in the past are indeed involved in the enzymatic rearrangement of the carbon skeleton.

    22. Electrostatic Activation of Nucleofuges: Cationic Leaving Groups (pages 216–217)

      Prof. Dr. Robert Weiss and Dr. Stefan Engel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202161

      The substitution of two chlorine atoms by dimethylaminopyridino groups in PCl3 (1), MeOPCl2 (2), and MeOP(O)Cl2 (3) yields phosphorus derivatives that are dicationic (1 and 2) or monocationic (3). These molecules are highly activated toward nucleophilic attack. For the first time, in nucleophilic reactions a cationic group is the leaving group. In fact, the nucleofuge derived from 3 is a better leaving group than the trifluoromethane sulfonate ion.

    23. TaNi2Te2, A Novel Layered Telluride, and TaCo2Te2, a Structural Variant with Peierls Distortion (pages 217–220)

      Prof. Dr. Wolfgang Tremel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202171

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      Interpenetrating diamond-shaped Ta2Ni2 clusters in two-dimensional layers are found in the novel metal-rich layer compound TaNi2Te2, which is synthesized at 950 °C from the elements (structure right: large dotted spheres Te, medium-sized partially shaded spheres Ta, small spheres Ni). Band-structure calculations predict that TaNi2Te2 should have metallic properties.

    24. A Dramatic Difference in the Reactivities of Alkoxido- and Aryloxidorhenium Complexes in Insertion Reactions (pages 220–223)

      Robert D. Simpson and Prof. Robert G. Bergman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202201

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      Extremely fast and at low temperatures, alkoxido complex 1 reacts with CS2 to the corresponding Re–O insertion product by direct attack of the electrophile on the O atom of the alkoxido ligand. In contrast, the reaction of aryloxido complex 2 with CS2 requires higher temperatures (100 °C) and seven days' reaction time; here the loss of a phosphine ligand probably constitutes the first step. The importance of such studies in the design of catalyst systems is obvious.

    25. A New Fullerene Synthesis (pages 223–224)

      Dipl.-Chem. Gregor Peters and Prof. Dr. Martin Jansen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202231

      Larger amounts of fullerenes at the remarkably low temperature of formation of 2700 °C (helium pressure 150 kPa) are provided by a new synthetic method. Cylindrical carbon bodies are inductively heated and evaporated, the resulting fullerenes are extracted from the soot formed, and the product distribution is determined by mass spectrometry.

    26. New Route to α-[(1E, 3E)-dienyl]allenes via Butadiene-tricarbonyliron Complexes (pages 224–226)

      Kurt Nunn, Dr. Paul Mosset, Dr. René Grée, Prof. Dr. Rolf W. Saalfrank, Dr. Karl Peters and Prof. Dr. Hans Georg von Schnering

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202241

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      Complexes of propargyl carbonates 1 react with organocopper(I) compounds stereo selectively to yield the α-(allenylbutadiene)tricarbonyliron complexes 2. Decomplexation with eerie ammonium nitrate furnishes the α-[(lE,3E)-dienyl]allenes 3 rapidly and in high yields. R1 [DOUBLE BOND] Ph, tBu, SiMe3; R2 [DOUBLE BOND] Et; E [DOUBLE BOND] Co2Me.

    27. Ion-Spray Mass Spectrometry of Lipopeptide Vaccines (pages 226–228)

      Dr. Jörg W. Metzger, Dipl.-Chem. Werner Beck and Prof. Dr. Günther Jung

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202261

      Its speed and accuracy and the extremely simple sample preparation required recommends ion-spray mass spectrometry as a technique for studying highly lipophilic and amphiphilic molecules of high molecular mass and, in particular, for biomolecules (which have not previously been able to be characterized by mass spectrometry). Routine analyses detect molecular masses up to 6000 u with an accuracy of ± 1 u.

    28. Asymmetric Ligands for Transition-Metal-Catalyzed Reactions: 2-Diphenylphosphinobenzoyl Derivatives of C2-Symmetric Diols and Diamines (pages 228–230)

      Prof. Barry M. Trost and David L. Van Vranken

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202281

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      For Pd-catalyzed allylic alkylations a series of novel C2-symmetric bis-(diphenylphosphino) ligands have proved to be extremely efficient. For example, the model reaction 1 [RIGHTWARDS ARROW] 2 with diamide 3 as ligand proceeds in 94% yield and 88% ee. Ts [DOUBLE BOND] para-toluolsulfonyl, dba [DOUBLE BOND] dibenzylidenacetoacetonate.

    29. Spontaneous Self-Assembly of a Dinickel(II) Double Helicate Containing a 1, 3-Benzenediyl Spacer Group (pages 230–232)

      Dr. Edwin C. Constable, Michael J. Hannon and Dr. Derek A. Tocher

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202301

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      A new type of potentially helical ligand is represented by 1. The twist of the molecule's chain required to form double helical complexes by self-organization occurs at the C[BOND]C bonds between the arene rings. Ligand 1 forms double helical complexes with Cu+, Ag+, and Ni2+ salts. A crystal structure analysis of the complex [Ni2(OAc)2(lb)2](PF6)2 revealed neither intermetallic interactions nor stacking interactions between almost coplanar rings.

    30. The Hydroxyl-Directed Hydrogenation of Vinylstannanes and Silanes: A Highly Diastereoselective Route to β-Stannyl and β-Silyl Alcohols (pages 232–234)

      Professor Mark Lautens, Dr. ChunHao Zhang and Cathleen M. Crudden

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202321

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      Under mild reaction conditions and catalyzed by Rh+, the (E)/(Z)-γ-hydroxyvinylstannanes 1 and 3 and -silanes 2 and 4 were successfully hydrogenated in an autoclave at about 107 Pa. Till now, hydrogenations were possible only for olefins with alkyl, aryl, and acyl substituents. The diastereoselectivity of the new reaction depends on the size of the substituents R and R′ (R [DOUBLE BOND] C6H11, Me, H; R′ [DOUBLE BOND] H, alkyl, SnBu3; X [DOUBLE BOND] SnBu3, SiPhMe2).

    31. Nucleophilic Attack at the Central Carbon Atom of (π-Allyl)palladium Complexes: Formation of α-Cyclopropyl Esters (pages 234–236)

      Prof. H. Martin R. Hoffmann, Andreas R. Otte and Andreas Wilde

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202341

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      Distinctly higher yields of functionalized cyclopropanes such as 1 can be achieved when 1,2-bis(dimethylamino)ethane, followed by CO, are added to the reaction of π-allylpalladium complexes with lithium enolates of esters. The usual, energetically favored allylic alkylation is efficiently suppressed in this way. The role of the amine ligands is crucial: addition of 1,2-bis(dimethylamino)methane produces no cyclopropanation product; with sparteine only low yields are obtained.

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Book Review: Atomic Spectroscopy. By J. W. Robinson (pages 236–237)

      Günther Tölg

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202361

    2. Book Review: Chemical Kinetics. By K. A. Connors (pages 239–240)

      Franz L. Dickert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202391

    3. Book Review: Polymer Solutions. By H. Fujita (pages 240–241)

      Manfred Schmidt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199202402

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