Angewandte Chemie International Edition in English

Cover image for Vol. 35 Issue 10

June 3, 1996

Volume 35, Issue 10

Pages 1035–1135

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 10/1996)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610331

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      The cover picture shows the ball-and-stick model viewed down the crystallographic S4 axis of a tetrahedral cluster formed by the self-assembly of four gallium(III) ions (green) and six ligands (gold). The cavity of the supramolecular assembly is penetrated by four dimethylformamide molecules (red; space-filling representation). The cluster formation is driven by symmetry number incommensurate lock-and-key interactions. More about this concept and its application is reported by Raymond et al. on pages 1084ff. The picture was generated from crystal coordinates with CAChe software.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Free-Radical Carbonylations: Then and Now (pages 1050–1066)

      Prof. Ilhyong Ryu and Prof. Noboru Sonoda

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610501

      Rejuvenation of an almost forgotten reaction! The application of modern free-radical techniques has revealed the significant synthetic potential of free-radical carbonylation, which was long neglected after its discovery in the 1950s. A variety of carbonyl compounds including aldehydes, unsymmetrical ketones, macrolides, and δ-lactones can be prepared efficiently often in a single step.

    2. Si[BOND]H and C[BOND]H Activation by Transition Metal Complexes: A Step Towards Isolable Alkane Complexes? (pages 1068–1075)

      Priv.-Doz. Dr. Jörg J. Schneider

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610681

      The activation of molecules containing σ bonds in homogeneous and heterogeneous phases is of fundamental importance in particular with regard to conversions of hydrocarbons such CH4. However, structurally characterized model compounds with σ-coordinated alkanes are unknown to date. The development and the current level of understanding in the field of transition metal coordinated σ bonds is presented here using selected examples. Whether the recently synthesized organometallic silane complexes exhibit model character for isolable σ-alkane complexes is also discussed.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Nucleophilic Aromatic Substitution—A Possible Key Step in Total Syntheses of Vancomycin (pages 1077–1078)

      Prof. Kevin Burgess, Dongyeol Lim and Carlos I. Martinez

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610771

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      How one of the major obstacles to a total synthesis of vancomycin 1, R = sugar, might be overcome has been demonstrated by Zhu et al. and others. They have used nucleophilic aromatic substitution reactions for biaryl ring formation and concomitant ring closure. Conditions for this transformation are sufficiently mild that it can be applied to form complex macrocycles like the 16-membered rings of vancomycin.

    2. Self-Organized Superlattices of Nanoparticles (pages 1079–1081)

      Prof. Dr. Horst Weller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610791

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      Completely new materials arise when semiconductor nanoparticles are periodically ordered in superlattices. First pioneering preparations of such superlattices were achieved by self-organization of ligand-stabilized CdSe and CdS nanoparticles. The block polymerization to give micelles in the presence of gold salts and their reduction by the electron beam of a transmission electron microscope (TEM) led to ordered gold clusters. The picture on the right shows a TEM image of a material of this type.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Symmetry-Based Metal Complex Cluster Formation (pages 1084–1086)

      Dr. Thomas Beissel, Ryan E. Powers and Prof. Kenneth N. Raymond

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610841

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      As deduced from Nature, the principle of symmetry-driven self-assembly, based on incommensurate coordination numbers, is employed to design clusters using metal coordination as the driving force. The ten-component cluster on the right demonstrates the predicted cooperativity in cluster formation.

    2. Allylruthenium(IV) Complexes as Highly Efficient ROMP Catalysts (pages 1087–1088)

      Prof. Dr. Wolfgang A. Herrmann, Wolfgang C. Schattenmann, Prof. Dr. Oskar Nuyken and Stephan C. Glander

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610871

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      First activate, then polymerize. This is the way that ruthenium complexes such as 1 can be used to catalyze the ring-opening metathesis polymerization efficiently. Diazoalkanes serve as activating agents and depending on their substitution pattern subequivalent or excess amounts are required. When ethyl diazoacetate is used, turnover frequency values above 105 h−1 have been achieved in the ring-opening metathesis polymerization of norbornene.

    3. Polymeric Networks of Silver(I) and Copper(I) Ions Linked by an Anionic Acetonyl Derivative of Tetracyanoethylene (pages 1088–1090)

      Dr. Lucia Carlucci, Prof. Gianfranco Ciani, Dr. Davide M. Proserpio and Prof. Angelo Sironi

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610881

      Thumbnail image of graphical abstract

      Unexpectedly, the reaction of tetracyanoethylene (TCNE) with acetone yields a tetracyanopentanonide that forms interesting coordination polymers with AgI and CuI ions. [Ag(AcTCNE)] is a layer structure consisting of twofold interpenetrated 2D nets of hexagonal meshes, while [Cu(AcTCNE)]·Me2CO consists of a zeolite-like 3D network, whose large channels contain guest acetone molecules (shown on the right).

    4. Solubilization of NaX Salts in Chloroform by Bifunctional Receptors (pages 1090–1093)

      Dr. ir. Jurgen Scheerder, Dr. John P. M. van Duynhoven, Dr. Johan F. J. Engbersen and Prof. dr. ir. David N. Reinhoudt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610901

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      First the cation, then the anion. This describes the complexation of alkali metal halides with bifunctional receptors like that on the right (R = n-octyl) based on calix[4]arenes. The uncomplexed ligand has a strong intramolecular hydrogen bond between the urea moieties, which is disrupted by the conformational change induced by complexation of a Na+ ion. Only then is an anion like Cl bound in the upper portion of the calixarene.

    5. The First Model of the Neocarzinostatin Chromophore with an Epoxide Ring and a Carbonate Moiety (pages 1093–1096)

      Dipl.-Chem. Matthias Eckhardt and Prof. Dr. Reinhard Brückner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610931

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      A seven-step synthesis starting from 1 furnished the dienediyne analog 2 of the pharmacophore 3 of the antitumor agent neocarzinostatin. The eleven-membered ring of 2 was formed by the McMurry cyclization of a ketoaldehyde precursor. The resulting C = C bond was epoxidized selectively by taking advantage of a combination of substrate and reagent control. Tf = CF3SO2, Ar = aryl.

    6. Synthesis, Structure, and Thermolysis of N-Apical 1,2λ5-Azaphosphetidines with a Pentacoordinate P Center and the First Observation of Their N-Equatorial Pseudorotamers (pages 1096–1098)

      Prof. Dr. Takayuki Kawashima, Tomokazu Soda and Prof. Dr. Renji Okazaki

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610961

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      C-apical intermediates are implicated for the first time in the synthesis of olefins by the thermolysis of azaphosphetidines 1. Compound 1 and its pseudorotamer 2 are the first reported azaphosphetidines containing pentacoordinate phosphorus. R = H, CO2Me.

    7. Towards the Definition of the Maximum Allowable Tightness of an Electron Transfer Transition State in the Reactions of Radical Anions and Alkyl Halides (pages 1098–1100)

      Dr. G. Narahari Sastry, Dr. David Danovich and Prof. Dr. Sason Shaik

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199610981

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      A mechanistic continuum with a sharp changeover zone from electron transfer (ET) to substitution (SUB) reactions has been found in the analysis of the reactions of formyl radical anions with methyl halides (see below). The minimum C – C distance at which the transition state for ET collapses to that of SUB could be defined.

    8. Synthesis, Structure, Photophysics, and Excited-State Redox Properties of the Novel Luminescent Tetranuclear Acetylidocopper(I) Complex [Cu4(μ-dppm)4412-C[TRIPLE BOND]C-)](BF4)2 (pages 1100–1102)

      Dr. Vivian Wing-Wah Yam, Wendy Kit-Mai Fung and Dr. Kung-Kai Cheung

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611001

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      A strong reducing power in the excited state is just one of the features of the tetranuclear copper(I) complex 1. It contains an acetylide dianion bridging four copper atoms in both η1 and η2 bonding modes and exhibits long-lived luminescence. The central framework of the structure is shown on the right.

    9. Mesoporous Alumina Molecular Sieves (pages 1102–1105)

      Dr. Stephen A. Bagshaw and Prof. Thomas J. Pinnavaia

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611021

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      The hydrolysis of tri-sec-butoxyaluminum in the presence of nonionic surfactants leads to mesoporous alumina molecular sieves with wormlike arrays of channels with uniform diameters in the range 2.4 – 4.7 nm, depending on the nature of the surfactant. Molecular sieves of this type are of interest as possible catalysts and catalyst supports. The transmission electron micrograph of an alumina of this type is shown on the right.

    10. Design, Synthesis, and Ion-Transport Properties of a Novel Family of Cyclic, Adamantane-Containing Cystine Peptides (pages 1105–1107)

      Dr. Darshan Ranganathan, V. Haridas, Dr. K. P. Madhusudanan, Dr. Raja Roy, Dr. R. Nagaraj, G. B. John and Dr. M. B. Sukhaswami

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611051

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      A one-step synthesis provided the cyclopeptides 1 – 4 (n = 2 – 5) composed of repeating adamantane and L-cystine units. These macrocycles assume a cavitand-like conformation, in which the interior is hydrophilic and the periphery hydrophobic. Consequently, they can transport Na+ and K+ ions selectively in model membranes.

    11. Directed Synthesis of Stable Hydrogen Polyphosphides: Preparation and Structural Characterization of HPmath image in (NBnMe3)2HP11 and (PBnPh3)2HP11 as Well as Its Comparison with the First “Naked” Pmath image Ion in (NEtMe3)3P11 (pages 1107–1110)

      Dr. Nikolaus Korber, Dipl.-Chem. Jörg Daniels and Prof. Dr. Hans Georg von Schnering

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611071

      Thumbnail image of graphical abstract

      Rapid decomposition in solution is characteristic for hydrogen polyphosphides. Nevertheless, two simple new syntheses—each with a little trick—have made it possible to prepare two stable salts of the novel anion HPmath image (shown on the right) for the first time, starting from cesium undecaphosphide.

    12. Enediyne Generation by a Retro-Diels–Alder Reaction (pages 1110–1112)

      Dr. Mark E. Bunnage and Prof. Dr. K. C. Nicolaou

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611101

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      Under remarkably mild conditions (25°C) the oxide anion accelerated retro-Diels – Alder reaction of 1 leads to cyclodecenediyne (3) via intermediate 2. This is a conceptually new strategy for the generation of reactive enediynes from stable 1,5-diyne progenitors, which should prove of wide applicability.

    13. Nickel(0) Complexes of Five-Membered Titana- and Zirconacyclocumulenes as Intermediates in the Cleavage of C[BOND]C Bonds of Disubstituted Butadiynes (pages 1112–1115)

      Dr. Siegmar Pulst, Dr. Perdita Arndt, Dr. Barbara Heller, Dr. Wolfgang Baumann, Dr. Rhett Kempe and Prof. Dr. Uwe Rosenthal

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611121

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      Ni(0) complexed metallacyclocumulenes such as 1 are intermediates in the heterobimetallic C – C cleavage reaction of disubstituted butadiynes. Furthermore, it was proven that the oxidative addition as well as the reductive elimination of butadiynes may proceed via metallacyclocumulenes.

    14. Formation of FeIV and NiIV by Electrochemical and Chemical Oxidation of an Iron-Substituted Nickel(II) Hydroxide: The Direct Two-Electron Step NiII [RIGHTWARDS ARROW] NiIV + 2e (pages 1115–1118)

      Dr. Peter Axmann, Dr. Christina Freire Erdbrügger, Dr. Dieter H. Buss and Prof. Dr. Ing. Oskar Glemser

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611151

      Six NiIV ions make up the coordination environment of each FeIV ion in the γ-NiOOH-like layer of the (electrochemically) oxidized form of the iron-substituted nickel(II) hydroxide 1, as can be deduced from Mössbauer spectroscopic and electrochemical investigations. No NiIII ions are present in the redox-active material. The direct two-electron step NiII [RIGHTWARDS ARROW] NiIV + 2e must be assumed.

      • equation image
    15. Knotted Heterodinuclear Complexes (pages 1119–1121)

      Dr. Christiane O. Dietrich-Buchecker, Dr. Jean-Pierre Sauvage, Nicola Armaroli, Paola Ceroni and Prof. Vincenzo Balzani

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611191

      Thumbnail image of graphical abstract

      Surprisingly stable is the dinuclear complex cation [1CuCu]2+ with entwined ligand 1 (shown on the right; •, ○ = Cu+) that can be demetalated in a stepwise manner. The singly demetalated complex [1Cu]+ can be converted to give dissymmetrical heterodi-nuclear complexes [1CuAg]2+ and [1CuZn]3+ (○ = Ag+ and Zn2+, respectively). The electrochemical and spectroscopic properties of these molecular knots, in which the coordinating phenanthroline groups are linked through a “conducting” phenylene spacer, differ considerably from the corresponding compounds with “nonconducting” bridges.

    16. Bis(diisopropylamino)carbene (pages 1121–1123)

      Dr. Roger W. Alder, Dr. Paul R. Allen, Dr. Martin Murray and Prof. A. Guy Orpen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611211

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      The first acyclic diaminocarbene 1 can be isolated by deprotonation of the corresponding formamidinium ion 2. In solution both compounds show dynamic behavior (interchange of iPr groups) with activation barriers of 53 and 55 kJmol−1, respectively.

    17. Structures of XeFmath image and Xe2Fmath image (pages 1123–1125)

      Dr. Arkady Ellern, Dr. Ali-Reza Mahjoub and Prof. Dr. Konrad Seppelt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611231

      The lattice symmetry chiefly determines the structure of the XeFmath image ion in CsXeF7. The influence of the lone pair of electrons is here very weak, and the anion has a capped octahedral structure (C3v symmetry). The dinuclear anion Xe2Fmath image in NO2Xe2F13 can be structurally divided into an XeF6 molecule and an XeFmath image ion. In this case the anion XeFmath image is a capped trigonal prism (C2v symmetry).

    18. Structural Diversity in Alkali Metal Phospholides: A Kalocene-Type Structure (pages 1125–1127)

      Dr. Frédéric Paul, Dr. Duncan Carmichael, Dr. Louis Ricard and Prof. Dr. François Mathey

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611251

      Thumbnail image of graphical abstract

      Phospholide anions can stabilize unusual structures, for example the first crystallographically characterized derivative of “kalocene” (structural formula on the right). Counterion: [K([18]crown-6)(THF)2]+.

    19. Lithium 2,2′-Biphenyldiyltrimethylsilicate; First Observation of Pentaorganosilicates (pages 1127–1128)

      Drs. Ing. Adrianus H. J. F. de Keijzer, Dr. Franciscus J. J. de Kanter, Dr. Marius Schakel, Robert F. Schmitz and Prof. Dr. Gerhard W. Klumpp

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611271

      Thumbnail image of graphical abstract

      Postulated previously only as intermediates, lithium pentaorganosilicates of type 2-L4 (L = THF, hexamethylphosphoric triamide), which are in equilibrium with silafluorene 1 and the corresponding organolithium, have now been detected at low temperatures by NMR spectroscopy.

    20. Metallopinacolate Intermediates in the Reductive Coupling of Acetone Promoted by Uranium Reagents (pages 1129–1130)

      Olivier Maury, Dr. Claude Villiers and Dr. Michel Ephritikhine

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611291

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      New aspects of the mechanism of the McMurry reaction were revealed by studying the coupling of acetone with uranium tetrachloride and lithium or sodium amalgam. The two metallopinacolate intermediates 1 and 2 were isolated. Only the cyclic complex 2, formed by reaction of 1 with the reducing agent, was transformed, under more forcing conditions, into tetramethylethylene. Counterion: Li+.

    21. Molecular Tweezers as Synthetic Receptors in Host—Guest Chemistry: Inclusion of Cyclohexane and Self-Assembly of Aliphatic Side Chains (pages 1130–1133)

      Prof. Dr. Frank-Gerrit Klärner, Dr. Johannes Benkhoff, Prof. Dr. Roland Boese, Dipl.-Chem. Ulrich Burkert, Dipl.-Chem. Markus Kamieth and Dipl.-Chem. Ulf Naatz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199611301

      Thumbnail image of graphical abstract

      Highly stereoselective, repetitive Diels–Alder reactions provide a route to novel molecular tweezers, which are excellently preorganized for the formation of complexes and for the self-assembly of side chains. Bond angle deformations, which require little energy, allow the tweezer arms to be expanded or compressed; thus, as receptors they can, to a certain extent, provide a geometrical fit to the structure of a potential substrate. The structure of a tweezer of this kind is shown schematically on the right.

  4. Book Reviews

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