Angewandte Chemie International Edition in English

Cover image for Vol. 33 Issue 10

June 6, 1994

Volume 33, Issue 10

Pages 1017–1120

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 10/1994)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410151

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      The cover picture provides a view into the otherwise closed measurement cell of a luminometer used routinely for chemiluminescent immunoassays in clinical laboratories. The sample tube containing a chemiluminescent substance is situated in front of the highly sensitive detector of a photomultiplier. The substances that trigger the emission of light are injected immediately prior to measurement. The structural formula shows the proposed. light-emitting dioxetane intermediate of the N-methylacridinium-9-(N-sulfony1)carboxamide derivative which decays to N-methylacridone. More about luminescent labels can be found in the review by A. Mayer and S. Neuenhofer on p. 1044 ff.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Chemical Analysis of Inorganic and Organic Surfaces and Thin Films by Static Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) (pages 1023–1043)

      Prof. Dr. Alfred Benninghoven

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410231

      Recording high-resolution surface images of Al/Ti/W structures on silicon wafers, identifying polymer particles and determining their lateral distribution, quantitatively analyzing therapeutically significant peptides, and locating impurities in organic layers on metals are only four examples of applications of the powerful coupling of secondary ion generation and time-of-flight mass spectrometry. The high sensitivity, good spatial resolution, and applicability for almost all materials and sample types make TOF-SIMS a universally employable technique.

    2. Luminescent Labels—More than Just an Alternative to Radioisotopes? (pages 1044–1072)

      Dr. Andreas Mayer and Dr. Stephan Neuenhofer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410441

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      Better lower detection limits in the attomol range (10−18mol), higher stabilities, and no radioactivity—these advantages over the classical isotope-labeled compounds (125I, 32P) are shown by the modern luminescent markers, such as acridiniumacyl-sulfonamide (1). Therefore the question raised in the title can be answered emphatically with yes, even if the method does not become established overnight. Luminescent labels and gene probes are already an integral part in modern immune diagnostics.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Polyynes–Fascinating Monomers for the Construction of Carbon Networks?** (pages 1073–1076)

      Dr. Uwe H. F. Bunz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410731

      Carbon-rich compounds are accessible from topologically unusual polyynes. Impressive advances have been made in this area recently by the research groups led by Moore, Tour, Diederich, and de Meijere. The novel monomers not only display fascinating chemistry of their own, they may also be suited for the synthesis of new carbon allotropes.

    2. Homoleptic Noble Metal Carbonyl Cations** (pages 1077–1078)

      Prof. Dr. Lothar Weber

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410771

      Novelties and surprises from metal carbonyl chemistry: salts thermally stable up to 200 °C with [M(CO)2]+ (M = Ag, Au) and [M(CO)4]2+ ions (M = Pt, Pd), which show only negligible π-backbonding, indicate that we need to revise our understanding of transition metal carbonyl interactions. Further investigations should reveal whether these salts with their unusual bonding also react differently from classical metal carbonyls.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. The Pressure Effect in Pericyclic Rearrangements: the Cope Rearrangement, Electrocyclization, and the Intramolecular Diels–Alder Reaction (pages 1079–1081)

      Dipl.-Chem. Matthias K. Diedrich, Dr. Dirk Hochstrate, Prof. Dr. Frank-Gerrit Klärner and Dipl.-Chem. Bernd Zimny

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410791

      Important information about the geometry of the transition state is contained in the activation volume ΔV obtained from the pressure dependence of the reaction rate, which in the title reactions allows a correlation to be drawn between the size of the activation volume and the number of new interactions in the cyclic transition states. Every additional five- or six-membered ring formed in the transition state contributes about −10 to −12cm3mol−1 to ΔV.

    2. Polymorphism and C[DOUBLE BOND]N[BOND]N[DOUBLE BOND]C Conformational Isomers of Azines: X-ray Crystal and Ab Initio Structures of Two Rotational Isomers of Methyl (para-Tolyl) Ketone Azine (pages 1081–1084)

      Grace Shiahuy Chen, Mitchell Anthamatten, Dr. Charles L. Barnes and Prof. Dr. Rainer Glaser

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410811

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      Conjugative effects are not significant for the conformation of diaryl-substituted azines such as 1—whether within the azine unit or between the aryl substituents and the azine or imino units. This was the conclusion of studies of X-ray crystal structures and quantum chemical calculations.

    3. Isolation of RNA Aptamers for Biological Cofactors by In Vitro Selection (pages 1084–1087)

      Dipl.-Chem. Petra Burgstaller and Dr. Michael Famulok

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410841

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      Short RNA sequences with specific secondary structure (see below) are the binding motifs for the cofactors flavin adenine dinucleotide and flavin mononucleotide (FAD and FMN, respectively), according to selection experiments with randomized RNA pools and FAD- and FMN-modified agarose. It was also shown that only the flavin portion plays a role in binding. Analogous experiments were conducted with NAD+ and its mononucleotide.

    4. Functionalization of C60 Buckminsterfullerene by [8 + 2] Cycloaddition: Spectroscopic and Electron-Transfer Properties of a Tetrahydroazulenofullerene (pages 1087–1089)

      Dipl.-Chem. Ernst Beer, Michaela Feuerer, Dipl.-Chem. Andreas Knorr, Dr. Albert Mirlach and Prof. Dr. Jörg Daub

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410871

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      The novel C60 cycloadduct 1 is formed in the reaction of 8-methoxyheptafulvene with buckminster-fullerene C60. Compound 1 can be reduced to its tetraanion in four reversible steps; the spectral properties of the radical anion, dianion, and trianion were examined by UV/VIS/NIR spectroelectro-chemistry. Adduct 1 may lead to other functional-ized fullerenes having substructures with electron-transfer properties.

    5. Regio- and Enantioselective Silane-Terminated Intramolecular Heck Reactions (pages 1089–1091)

      Prof. Dr. Lutz F. Tietze and Dipl.-Chem. Ralph Schimpf

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410891

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      The selective formation of tertiary sp3 centers is possible when allylsilanes 1 are employed as the alkene component in the title reaction. Application of a chiral catalyst system makes the reaction enantioselective. Primarily hetero- and carbo-cycles 2 arise with the catalyst system [Pd2(dba)3/PPh3/Ag2O]; 3 is the main product with Pd(OAc2)/PPh3/NPr4Br/KOAc.

    6. Effects of Metal-Ion Dopants on the Photocatalytic Reactivity of Quantum-Sized TiO2 Particles (pages 1091–1092)

      Wonyong Choi, Andreas Termin and Michael R. Hoffmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410911

      Oxidation and reduction rates are increased when the photocatalyst TiO2 is doped with metal ions. The photochemical oxidation of CHCl3 and the photochemical reduction of CCl4 were examined in the presence of 21 different doped TiO2 catalysts. Dopant metal ions with closed shells were found to have little effect on reactivity. The authors present their results in the form of a periodic chart.

    7. A Triosmium Cluster Complex with a Carbene Ligand in an Unusual Coordination Mode (pages 1093–1094)

      Dr. Andrew J. Edwards, Dr. Mark A. Gallop, Dr. Brian F. G. Johnson, Dr. Jochem U. Köhler, Prof. Jack Lewis and Dr. Paul R. Raithby

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410931

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      The face-capping carbene ligand displays a chairlike conformation and unusual side-on bonding in the triosmium cluster 1. This air-stable compound reacts in the presence of Lewis bases with atmospheric oxygen to form 2, in which the cyclohexadienone ligand is coordinated in a new mode to the Os3 framework.

    8. Long-Lived ipso-Silylated p-Toluenium Ions: Evidence from a Kinetic Isotope Effect (pages 1094–1096)

      Dr. Maria Elisa Crestoni and Prof. Simonetta Fornarini

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410941

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      A sizeable hydrogen isotope effect arises from the competing abstractions of Me3Si+ and X (X = H, D) from the σ complex 1, which is formed by addition of gaseous Me3Si+ to toluene. This species may adequately describe the Et3Si+ -toluene pair recently reported in the solid state.

    9. Structure of a (4 + 4)-Coordinate Silicon Compound, a Precursor of Hypercoordinate Silyl Mono- and Dications (pages 1097–1099)

      Dr. Francis Carré, Dr. Claude Chuit, Prof. Dr. Robert J. P. Corriu, Ahmad Mehdi and Dr. Catherine Reyé

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410971

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      A tetracapped tetrahedron describes the geometry of the coordination environment of the silicon atom in 1; it is thus (4 + 4)-coordinate. Treatment of 1 with two equivalents of HC1 leads surprisingly to loss of H2 and formation of the corresponding chloride salt, whose centrosymmetric cation contains a six-coordinate silicon atom.

    10. Synthesis of Enediynes by Diels–Alder Addition (pages 1099–1100)

      Prof. Henning Hopf and Dipl.-Chem. Marcus Theurig

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199410991

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      The hex-3-ene-1,5-diyne unit, the reaction-initiating component of the enediyne antibiotics, was generated in the synthesis of compounds of type 3 by Diels–Alder reaction for the first time. The requisite diene 2 is easily obtained by coupling diene 1 with alkynyl Grignard reagents. Subsequent cycloaddition with dienophiles furnishes the target compounds 3.

    11. Stable Highly Concentrated Fluorocarbon Gels (pages 1100–1101)

      Dr. Marie-Pierre Krafft and Prof. J. G. Riess

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411001

      Highly viscous, transparent, and unchanged after one year of storage, concentrated gels with potential medical applications can be prepared from fluorocarbons, small amounts of water, and a fluorinated surfactant. These gels form polyhedral domains of fluorocarbon surrounded by thin shells of hydrated surfactant.

    12. Synthesis of a Biantennary Heptasaccharide by Regioselective Glycosylations (pages 1102–1104)

      Carlo Unverzagt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411021

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      A single protective group is sufficient at β-mannoside for the selective introduction of both side chains of A. The key glycosylations at the branching point proceed with high regioselectivity when 4,6-O-benzylidene acetal is used as a temporary protecting group. Protected heptasaccharide A was synthesized as a precursor of the undecasaccharide-asparagine found on glycoproteins and shown below.

    13. Combination of Superexchange and Spin-Polarization Mechanisms Leads to a Novel Hydrocarbon Tetraradical with a High-Spin Ground State (pages 1104–1106)

      Dr. S. Joshua Jacobs and Prof. Dr. Dennis A. Dougherty

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411041

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      Ferromagnetic coupling between the diradical units of 1 and superexchange within these units is apparent in the EPR spectra recorded at 4 K. Spectral analysis indicates unequivocally that 1 is in a quintet state, and the signal intensities at such a low temperature imply that this most likely corresponds to the ground state. This high-spin system resulted from the deliberate combination of components with particular spin properties.

    14. Tridentate β-Hydroperoxy Alcohols as Novel Oxygen Donors for the Titanium-Catalyzed Epoxidation of γ,δ-Unsaturated α,β-Diols: A Direct Diastereoselective Synthesis of Epoxy Diols (pages 1107–1108)

      Prof. Dr. Waldemar Adam, Dr. Karl Peters and Dipl.-Chem. Michael Renz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411071

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      An attractive direct route to epoxy diols 2 relies on the Ti-catalyzed epoxidation of enediols 1 with 2-hydroperoxy-2-phenylpropan-l-ol. Under conventional Sharpless epoxidation conditions (bidentate tBuOOH) diols 1 react very sluggishly; however, with the new tridentate oxygen donor these same diols undergo smooth reaction to give products 2 in high diastereoselectivity and without the use of protecting groups.

    15. Ozone Formation through Decomposition of CFCs in the Stratosphere (pages 1108–1110)

      Prof. Dr. Gustavo A. Argüello, Dipl.-Chem. Bernd Jülicher and Prof. Dr. Helge Willner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411081

      Both in a matrix and in the gas phase, the electronically excited state of CF2 reacts with O2 to form F2CO and ozone. These are the results of photolysis experiments with difluorodiazirine as CF2 source. The significance of this reaction (which has not previously been taken into account) for the chemistry of the stratosphere is discussed.

    16. [Cp*Fe(η5-P5)], a Sandwich Complex with Diverse Ligand Properties (pages 1110–1112)

      Dipl.-Chem. Michaela Detzel, Dipl.-Chem. Thomas Mohr, Prof. Dr. Otto J. Scherer and Dr. Gotthelf Wolmershäuser

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411101

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      Cleavage of a P[BOND]P bond is achieved when the cyclo-P5 part of the ferrocene analogue [Cp*FeP5] reacts with tantalum and iridium complex fragments. The bi-, tri-, and pentanuclear complexes formed in this way have novel structures. The central framework of [Cp*Fe(P5)TaCp ″] shown on the right is one example. Cp ″ + C5Me5, Cp ″ = C5H3rBu2.

    17. High-Pressure Synthesis of K2PtH6, a Saltlike Hydride with the K2PtCl6 Structure (pages 1112–1114)

      Prof. Dr. Welf Bronger and Dr. Gudrun Auffermann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411121

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      At H2 pressures of up to 2 kbar, new ternary transition metal hydride complexes can be synthesized in which the transition metal has the same high oxidation state as in the corresponding ternary halides. In K2PtH6, which was prepared by this method, the complex [PtH6]2− building unit 1 was observed.

    18. A Template Synthesis of Stable Conjugated Primary Enamines from Ketones, Nitriles, and Butadiene (pages 1114–1116)

      Dr. Luis López, Dipl.-Chem. Martin Berlekamp, Dipl.-Chem. Dorothee Kowalski and Prof. Dr. Gerhard Erker

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199411141

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      The energy of conjugation of butadiene is sufficient to favor the primary enamines 3 over the imine tautomers 2 under equilibrium conditions. They are now readily accessible by template synthesis via the imine intermediates 1. R1 = Ph, -CH2CH2-, CH3; R2 - Ph, tBu, p-CH3C6H4, p-NCC6H4, CH[DOUBLE BOND]CHCN.

  4. Book Reviews

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