Angewandte Chemie International Edition in English

Cover image for Vol. 28 Issue 8

August 1989

Volume 28, Issue 8

Pages 969–1146

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 8/1989)

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198909691

      Thumbnail image of graphical abstract

      The cover picture shows the framework of (tBuCP)4, the first tetraphosphacubane, together with its surprisingly straightforward route of formation. This phosphorus-carbon compound was simply obtained by heating tBuC[TRIPLE BOND]P at ca. 130°C. This thermal cyclooligomerization of a phosphaalkyne offers a new perspective on the diverse reactivity of this class of compounds. Furthermore, the chemistry of polycyclic polyphosphorus hydrocarbons now appears to be developing apace with that of polyphosphanes and of the well-investigated polycyclic hydrocarbons. These developments promise to provide new insights into the structure and bonding of main-group compounds. Further details on (tBuCP)4 are reported by M. Regitz et al. on page 1013 ff. Cover design: Dipl.-Ing. Klaus Müller, Kaiserslautern.

    2. Graphical Abstract (Angew. Chem. Int. Ed. Engl. 8/1989)

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198909692

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. The Stereoselectivity of Intermolecular Free Radical Reactions [New Synthetic Methods (78)] (pages 969–980)

      Prof. Dr. Bernd Giese

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198909693

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      Inteamolecular free radical reactions have long been a part of the arsenal of B. Giese methods used by preparative organic chemists. Recently, intermolecular free radical reactions have also been employed in syntheses. In the reactions of five- and six-membered ring radicals with alkenes, the diastereoselectivity may be controlled by steric and stereoelectronic effects. For example, free radicals 1–3, bearing two or three substituents arranged in a cis fashion, afford products arising exclusively from anti attack of acrylonitrile or acrylate esters.

    2. Calorimetric Studies of Biopolymers and Aggregates of Phospholipids (pages 981–991)

      Prof. Dr. Theodor Ackermann

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198909811

      Thumbnail image of graphical abstract

      Calorimetric studies are often useful for the preliminary characterization of the structural transformations of polynucleotides, peptides, proteins, and lipids in aqueous solution. Information on the stability of the initial states and on the cooperativity of the overall processes are thereby obtained. Recent improvements in methods and apparatus have proved especially valuable in such studies. The picture on the right shows a differential power scanning calorimeter developed in the author's laboratory.

    3. Covalent versus Dative Bonds to Main Group Metals, a Useful Distinction (pages 992–1007)

      Prof. Arne Haaland

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198909921

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      A useful aid in understanding the structures of main-group metal compounds is the classification of bonds as covalent or dative. This approach helps to explain, for example, the different positions of the N substituents in 1 and 2 and the dramatic difference in the lengths of the N[BOND]Si bonds in 3 and 4, the average Si[BOND]C distances of which are not significantly different.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. The First Heterodinuclear Complexes with Bis(cyclopentadienyl)methane Bridges (pages 1008–1009)

      Dr. Peter Härter, Günther Boguth, Dr. Eberhardt Herdtweck and Jürgen Riede

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910081

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      The systematic study of metal–metal interactions in heterodinuclear complexes requires a straightforward and general synthetic route to such species. Compound 1, the key intermediate in a new approach, reacts via 2 to give complexes whose metal centers are bridged by a bis(cyclopentadienyl)methane moiety.

    2. Hydrooligomerization of Alkynes, a New Catalytic Reaction Promoted by [Co(py)6] in the Presence of H2 (pages 1009–1011)

      Dr. Paolo Biagini, Prof. Dr. Anna M. Caporusso, Dr. Tiziana Funaioli and Prof. Dr. Giuseppe Fachinetti

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910091

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      Pyridine-assisted H2 addition to cationic cobaltacycles such as 1 might explain why alkynes mainly undergo reductive oligomerization in the presence of H2 and [Co(py)6], whereas [Co(py)6] alone catalyzes their cyclotrimerization to arenes. For example, 2-butyne afforded the conjugated diene 2, a conjugated triene, and tetraene 3.

    3. [{Ph2PCH2C(CF3)2O}NiH(PCy3)]: Support for a Nickel Hydride Mechanism in Ethene Oligomerization** (pages 1011–1013)

      Dr. Ulrich Müller, Prof. Dr. Wilhelm Keim, Dr. Carl Krüger and Dr. Peter Betz

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910111

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      The formation of α-olefins from ethylene in the presence of homogeneous catalysts is of great industrial importance. How does this reaction proceed? Model experiments support the nickel hydride mechanism. Complexes 1 and 2 could be trapped with tricyclohexylphosphane (PCy3).

    4. Tetra-tert-butyltetraphosphacubane: The First Thermal Cyclooligomerization of a Phosphaalkyne (pages 1013–1014)

      Dipl.-Chem. Thomas Wettling, Dipl.-Chem. Jürgen Schneider, Dipl.-Chem. Oliver Wagner, Prof. Dr. Cornelius G. Kreiter and Prof. Dr. Manfred Regitz

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910131

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      A previously unknown reaction of phosphaalkynes, the thermal cyclotetramerization of 1, leads in one step to the title compound 2 (65 h at 130°C in a glass pressure tube, neat). Compound 2 is pale yellow and air stable. The NMR signals of the cage atoms are unusual: δ(13C)= −29.07, δ(31P)= + 257.4.

    5. A Phosphane–Dithioformate Adduct as a Five-Electron Bridging Ligand [Mn2(CO)6{S2C(H)P(cyclo-C6H11)3}2] (pages 1014–1016)

      Dr. Daniel Miguel, Dr. Jesús A. Miguel, Prof. Dr. Víctor Riera and Prof. Dr. Xavier Soláns

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910141

      Thumbnail image of graphical abstract

      The two dithio ligands in 2, which is obtained by reaction of 1 with NaBH4, are simultaneously η2-chelating and η1-bridging ligands. The electron count reveals that the adduct [Cy3P[BOND]CHS2] must serve as a five-electron ligand. The cisoid arrangement of the ligands in 2 is presumably favored by attractive interactions between the H atoms and the Mn and S atoms (Cy = cyclo-C6H11).

    6. Formation and Reactivity of Silicon–Sulfur and Silicon–Selenium Double Bonds. The First X-Ray Structure of a Silanethione (pages 1016–1018)

      Dr. Prabhat Arya, Dr. Jacqueline Boyer, Dr. Francis Carré, Prof. Dr. Robert Corriu, Dr. Gérard Lanneau, Prof. Dr. Jacques Lapasset, Myriam Perrot and Christian Priou

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910161

      Thumbnail image of graphical abstract

      Silanethione 2a and silaneselenone 2b—stabilized by intramolecular Si [LEFTWARDS ARROW] N coordination— are obtained as shown below. The X-ray structure analysis of 2a, 1-naphthyl instead of phenyl, reveals strong zwitterionic character, which might explain the unexpectedly low reactivity toward nucleophiles and electrophiles (a, X = S; b, X = Se).

    7. [Mes2SbCu(PMe3)2]2: The First CuI Antimonide (pages 1018–1019)

      Prof. Alan H. Cowley, Prof. Richard A. Jones, Dr. Christine M. Nunn and Donald L. Westmoreland

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910181

      Thumbnail image of graphical abstract

      A planar Cu2Sb2 framework characterizes the structure of the title complex 1, which is moderately stable in the crystalline form in the absence of light and air, but rapidly decomposes in solution. The Cu1 antimonide was prepared by lithiation of Mes2SbH with nBuLi followed by reaction with CuCI and Me3P in THF. Mes2SbH, the structure of which was also determined, is obtained from Mes3Sb by reduction with lithium powder and protonation with Me3NHCl.

    8. One-Dimensional Metal Chains in a Chiral Environment — The Crystal Structure of Helical Bis(dicarbonylrhodium(I))-3,3′-hexafluoroglutarylbis-(1R)-camphorate (pages 1019–1021)

      Prof. Dr. Volker Schurig, Hans Gaus, Dipl.-Chem. Peter Scheer, Dr. Leonhard Walz and Prof. Dr. Hans Georg von Schnering

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910191

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      Interesting effects were observed in the molecular stacking of the chiral Binuclear rhodium(i) complex 1. Both rhodium atoms are incorporated into a single one-dimensional “rhodium chain”. The stacks consist alternately of two P and two M helices. Owing to stereoisomerism in the solid state, energetically different diastereoisomers, (1R)-(P)(1R) and (1R)-(M)-(1R), are present.

    9. Isolation, Synthesis, and Absolute Configuration of Filbertone – the Principal Flavor Component of the Hazelnut (pages 1022–1023)

      Dipl.-Chem. Johann Jauch, Dipl.-Chem. Dieter Schmalzing, Prof. Dr. Volker Schurig, Dr. Roland Emberger, Dr. Rudolf Hopp, Dr. Manfred Köpsel, Dr. Wilhelm Silberzahn and Dr. Peter Werkhoff

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910221

      Thumbnail image of graphical abstract

      The aliphatic enone filbertone 2, the active constituent of the flavor of hazelnuts, is a natural product with low and source-dependent enantiomeric purity. (ee = 55–63%). To assign the (predominant) absolute configuration (S), (S)-2 was synthesized from (S)-1. The configuration of 2 has a decisive influence on the smell.

    10. The Active Site of Glutathione Reductase: An Example of Near Transition-State Structures (pages 1023–1025)

      Prof. Dr. Refiner Sustmann, Dipl.-Ing. Willi Sicking and Prof. Dr. Georg E. Schulz

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910231

      Interactions in the active site of glutathione reductase were calculated at the MNDO level (PM3 parametrization). The reaction partners were found to be arranged in an ideal geometry for hydride transfer from NADPH to FAD and for nucleophilic opening of the protein disulfide bridge by FADH. The X-ray structure analysis alone would have been insufficient for such an interpretation.

    11. Are Lithiosulfones Configurationally Stable? (pages 1025–1028)

      Prof. Dr. Hans-Joachim Gais, Dipl.-Ing. Gunther Hellmann, Prof. Dr. Harald Günther, Dr. Fernando Lopez, Prof. Dr. Hans J. Lindner and Dr. Sigmar Braun

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910251

      Thumbnail image of graphical abstract

      The configurational stability of lithio(trifluoromethyl)sulfones such as 1 and 2 is appreciably higher than that of their analogues containing Ph instead of CF3. Compound 1, the first optically active lithiosulfone (Cα probably tetrahedrally coordinated), is optically stable at low temperatures. The synthesis from the sulfone and the protonation proceed with retention of configuration. [2ċTMEDA]2 (Cα planar-coordinated) has a very short Cα[BOND]S bond.

    12. Addition of Free Me2Ge: to Alkenes and Alkynes on Glass Surfaces in the Presence of Water (pages 1028–1029)

      Prof. Dr. Wilhelm P. Neumann, Prof. Dr. Hideki Sakurai, Dipl.-Chem. Gilbert Billeb, Dipl.-Chem. Hartmut Brauer, Dr. Jürgen Köcher and Dipl.-Chem. Sabine Viebahn

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910281

      Thumbnail image of graphical abstract

      Traces of water on glass surfaces (even after heating) can decisively influence the course of a reaction. This is shown by the reactions of Me2Ge: with alkenes such as acrylonitrile and alkynes such as phenylacetylene in “anhydrous” medium. These reactions afforded poor yields of 1 and 2, respectively. On the other hand, reaction in the presence of water and silica gel gave 1 and 2 in nearly quantitative yield; the presence of water alone did not increase the yield. These findings indicate that acidic H atoms, formed on the silica surface, are essential for the reaction of the expected products with water.

    13. Visualization of Chromatographic Separations by NMR Imaging (pages 1029–1032)

      Prof. Dr. Ernst Bayer, Dr. Winfried Müller, Martin Ilg and Dr. Klaus Albert

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910291

      NMR imaging allows in-situ observation of interactions between eluant and stationary phase in chromatographic columns. This method, referred to as magnetic resonance tomography in medicine, has been little used so far in chemistry. It provides information on the state of the column (e.g., packing quality and density, flow profile) and allows substances to be observed as they pass through the column.

    14. Insertion of Cr(CO)3 into Asmath image to Form [As7Cr(CO)3]3⊖: An Inorganic Nortricyclane-to-Norbornadiene Conversion (pages 1032–1033)

      Dr. Bryan W. Eichhorn, Dr. Robert C. Haushalter and Dr. John C. Huffman

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910321

      Thumbnail image of graphical abstract

      A four-electron-donor, norbornadiene-like Asmath image fragment is a component of the orange-red transition-metal cluster anion 1, obtained by reaction of Rb3As7 with tricarbonyl(η6-mesitylene)chromiur. Low CO stretching frequencies in the IR spectrum and short Cr[BOND]C bonds indicate that a significant amount of the electron density is transferred to the Cr atom.

    15. Trigonal-Bipyramidal Lanthanoid Complexes with Interstitial Oxygen Atoms (pages 1033–1035)

      Prof. Dr. Herbert Schumann, Dr. Pil Ryul Lee and Dipl.-Chem. Jörg Loebel

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910331

      Thumbnail image of graphical abstract

      Two axial sodium and three equatorial lanthanoid atoms around the interstitial oxygen atom are the salient features of the trigonalbipyramidal lanthanoid complex 1, formed from lanthanoid trichlorides and dimethylpyrazolesodium in a solvent containing traces of water.

    16. Nickel(O)-Catalyzed Preparation of Isomeric Carboxamides Ligand-Controlled β-H or β′-H Elimination (pages 1035–1036)

      Prof. Dr. Heinz Hoberg and Dipl.-Chem. Dieter Guhl

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910351

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      Isocyanates and monosubstituted alkenes undergo C[BOND]C bond formation on (Lig)NiO to give azanickelacycles such as 1. Variation of the ligands (Lig) and exploitation of steric and/or electronic effects allows either the β-H atom on the ring or the exocyclic β′-H atom to be activated; in the ensuing reactions, the two isomeric carboxamides 2 and 3 are formed catalytically with high selectivity.

    17. Selective 1:3 Coupling of Norbornene and Iodobenzene: A Facile Synthesis of Benzo[e]pyrenes with Annelated Cycloaliphatic Moieties (pages 1037–1038)

      Dipl.-Chem. Oliver Reiser, Martin Weber and Prof. Dr. Armin de Meijere

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910371

      Thumbnail image of graphical abstract

      Pd(OAc)2/Bu4NBr/K2CO3 and dimethylformamide - these are the reaction conditions under which norbornene reacts selectively with three molecules of iodobenzene to give the hydrocarbon 1 containing a 4-phenyl-9,10-dihydrophenanthrene moiety annelated to the norbornane framework. Photocyclization and two dehydrogenation steps transform 1 in high yield into the norbornene-annelated benzo[e]pyrene 2. Analogous domino Heck couplings were also observed with deltacyclene, indene, and [2.2]paracyclophane-l,9-diene.

    18. Synthesis, Characterization, and Complexation of an Unusual P2Si2 Bicyclobutane with Butterfly-Structure: 2,2,4,4-Tetramesityl-1,3-diphospha-2,4-disilabicyclo[1.1.0]butane (pages 1038–1040)

      Dr. Matthias Driess, Alan D. Fanta, Dr. Douglas R. Powell and Robert West

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910381

      Thumbnail image of graphical abstract

      Reaction of white phosphorus with dimesityldisilene in toluene at 40°C affords an 87% yield of the P2Si2 bicyclobutane 1, which reacts further with [(PPh3)2Pt(C2H4)] to give hetero[1.1.1]propellane 2.

    19. N-Arylation and N,N-Dibenzylation of Coordinated N2 with Organic Halides; Differences in the Reactivity of trans-[Mo(N2)2(Me8[16]aneS4)] and Its Phosphane Analogues (pages 1040–1042)

      Prof. Dr. Toshikatsu Yoshida, Tomohiro Adachi, Tatsuo Ueda, Manabu Kaminaka, Nobuyoshi Sasaki, Prof. Dr. Taiichi Higuchi, Takayuki Aoshima, Izumi Mega, Dr. Yasushi Mizobe and Prof. Dr. Masanobu Hidai

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910401

      Thumbnail image of graphical abstract

      The N2 ligand in the title complex (M8[16]anS4 = 3,3,7,7,11,11,15,15-octamethyl-1,5,9,13-tetrathiacyclohexadecane) displays unprecedented reactivity. It reacts with aryl halides and benzyl bromide in toluene at room temperature without irradiation to give MoII aryldiazenido and dibenzylhydrazido complexes, respectively. Its reaction with methanol and acetone affords NH3 and Me2C[DOUBLE BOND]N[BOND]N[DOUBLE BOND]CMe2, respectively. Phosphane analogues of the title complex do not undergo such reactions. The structure of trans [MoI(N2-p-C6H4CO2Me)(Me8[16]anS4)], the diazenido complex, is shown on the right.

    20. The 7-Norbornadienyl Cation: An NMR/IGLO Validation of its ab initio Structure (pages 1042–1044)

      Dr. Matthias Bremer, Dr. Karl Schötz, Prof. Dr. Paul von Ragué Schleyer, Dipl.-Chem. Ulrich Fleischer, Dr. Michael Schindler, Prof. Dr. Werner Kutzelnigg, Dr. Wolfram Koch and Prof. Dr. Peter Pulay

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910421

      Thumbnail image of graphical abstract

      The energetically favored structure of the 7-norbornadienyl cation is only Cs symmetric according to ab initio calculations. The 13C NMR chemical shifts calculated from the theoretical structural parameters are in good agreement with the experimental values for both 1 and the norbornenyl cation 2.

    21. A New Coordinating Chiral Lithium Amide (pages 1044–1047)

      Dr. Donald Barr, David J. Berrisford, Dr. Raymond V. H. Jones, Alexandra M. Z. Slawin, Dr. Ronald Snaith, Dr. J. Fraser Stoddart and Dr. David J. Williams

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910441

      Thumbnail image of graphical abstract

      The C2-symmetric (R,R)-di(α-methoxymethylbenzyl)amine 1, synthesized from (R)-phenylglycinol and α-methoxyacetophenone, yields a lithium amide 2 upon lithiation with nBuLi. In the solid state and in solution, 2 is present as a dimer. 4-tert-Butylcyclohexanone could be asymmetrically deprotonated with this lithium amide.

    22. Platinum Complexes of the Anions Se2Nmath image and Se2N2H; X-Ray Structure Analysis of [Pt(Se2N2H) (PMe2Ph)2]Cl (pages 1047–1049)

      Dr. Paul F. Kelly, Ivan P. Parkin, Alexandra M. Z. Slawin, Dr. David J. Williams and Dr. J. Derek Woollins

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910471

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      A renewed interest in Se[BOND]N chemistry might be the consequence of this synthesis of complex-stabilized Se[BOND]N compounds in liquid ammonia; working with isolated, very unstable Se4N4 is avoided. Addition of complexes such as 1 to a reaction solution of SeCl4 in liquid ammonia and allowing the reaction mixture to warm to room temperature leads to the isolation of Se[BOND]N metallacycles such as 2, which may be protonated, for example, with HBF4. The X-ray structure analysis of the related complex 3 revealed essentially planar P2PtSe2N2 units stacked in a parallel and overlapping fashion.

    23. N-Analogues of Metal Acetylacetonates: Bis(1,2,6,7-tetracyano-3, 5-diimino-3, 5-dihydropyrrolizinido)metal(II), (Metal = Fe, Ni, Cu, Zn); Crystal Structure of the Copper Derivative (pages 1049–1050)

      Prof. Mario Bonamico, Dr. Vincenzo Fares, Dr. Alberto Flamini, Dr. Patrizia Imperatori and Nicola Poli

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910491

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      The title compounds 2 contain new complex ligands. These compounds are formed from anion 1, which isomerizes in a metal-promoted reaction. An X-ray structure analysis was carried out for 2 (M = Cu). Complex 2 (M = Fe) can easily be reduced to the analogous diaminopyrrolizidine FeII complex.

    24. Tri-tert-butyl(trimethylsilyl)tricyclo[1.1.0.02, 4]-butane–a Second Tetrahedrane Derivative (pages 1050–1052)

      Prof. Dr. Günther Maier and Dipl.-Chem. Dieter Born

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910501

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      A surprisingly high stability, which cannot be explained in terms of the “corset effect” alone, characterizes the new tetrahedrane 1 (

      ), which melts at 162°C and is transformed into the cyclobutadiene 2 at ca. 180°C. The SiMe3 group is presumably crucial for the stabilization. Moreover, it allows further functionalization of the tetrahedrane.

    25. p-Quinodimethane Analogues of Tetrathiafulvalene (pages 1052–1053)

      Prof. Dr. Yoshiro Yamashita, Yasuo Kobayashi and Prof. Dr. Tsutomu Miyashi

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910521

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      The quinonoid analogues of TTF are better electron donors than TTF itself. Their prototype 4 has now been synthesized for the first time. Wittig–Horner reaction of the dithiol derivative 1 with the cyclopentadiene adduct of benzoquinone, 2, gives 3, which undergoes retro-Diets–Alder reaction to yield 4 as dark red crystals. TTF undergoes oxidation at + 0.28 and + 0.64 V (vs. SCE), whereas 1 is oxidized at −0.11 and −0.04 V (vs. SCE).

    26. 2-Isocyanato-2-alkenoates–Synthesis and Reactions (pages 1053–1055)

      Prof. Dr. Franz Effenberger, Dr. Christan Baumgartner and Dr. Jürgen Kühlwein

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910531

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      The perrhenate-catalyzed decomposition of α-azidocarboxylate esters 1 with phosgene or diphosgene provides a simple approach to 2-isocyanato-2alkenoate esters 2. The latter undergo the usual addition reactions at the isocyanate group. In addition, the ester with R = R1 = H undergoes radical polymerization and can be used as a dienophile in Diets–Alder reactions. R, R1, e.g., H, Me, Ph.

    27. A Polymeric Technetium Compound of the Composition [Tc2O3(C5Me5)]n (page 1055)

      Prof. Dr. Basil Kanellakopulos, Dr. Bernd Nuber, Dipl.-Chem. Konstantinos Raptis and Prof. Dr. Manfred L. Ziegler

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910551

      Thumbnail image of graphical abstract

      The polymeric “polydecker compounds” 1, not the expected [Cp*TcO3], are obtained upon reaction of [Cp*Tc(CO)3] with H2O2—in contrast to the analogous rhenium compound, which gives [Cp*ReO3]. In the structure of 1, three μ-oxo ligands each bridge two Tc atoms. The distance between the Tc atoms is extremely short. The coordination of the Tc atoms is completed by the Cp* rings (Cp* = C5Me5).

    28. Energy Wells of Diradicals; 4-Methylene-1,3-cyclopentanediyl (pages 1056–1057)

      Prof. Dr. Wolfgang R. Roth, Frank Bauer, Karsten Braun and Rolf Offerhaus

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910561

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      In the intramolecular recombination of diradicals, the energy barrier depends strongly on structure. A barrier of only 2.4 kcal mol−1 was found for the title diradical 2 by use of the oxygen trapping reaction. This is the first time that such a small energy, barrier has been measured exactly.

    29. Addition of Carboxamides to Alkynyl Trifluoromethyl Sulfones (pages 1057–1059)

      Prof. Dr. Michael Hanack and Dipl.-Chem. Bärbl Wilhelm

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910571

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      “Push-pull” compounds 4 are obtained in good yields in an unusual way by addition of carboxamides 2 to the extremely reactive alkynyl trifluoromethyl sulfone 1. A crucial feature of this reaction is the activation of the triple bond in 1 by the F3CSO2 group. Dimethyl sulfoxide also adds spontaneously to 1.

    30. A Systematic Entry to Butterfly-Type [M4(CO)124-XY)] Clusters (pages 1059–1060)

      Dipl.-Chem. Harald Bantel, Prof. Dr. Bernhard Hansert, Dr. Anne K. Powell, Dr. Miklos Tasi and Prof. Dr. Heinrich Vahrenkamp

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910591

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      The photochemical generation of M(CO)3 fragments from simple carbonyl complexes and their addition to X = Y-bridged trinuclear clusters provides a general route to tetranuclear clusters having butterfly structures. The detailed structure depends on the kind of unsaturated ligands XY and their electron count (see picture). Such a cluster expansion should change the reactivity of the ligands XY, thereby allowing preparatively useful transformations.

    31. Di(1-pyridinio)- and Di(1-bipyridindiio)-dihydrodibenzotetraaza[14]annulenes (pages 1060–1063)

      Dipl.-Chem. Florian Adams, Prof. Dr. Rudolf Gompper and Dr. Eckardt Kujath

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910601

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      Tetraaza[14] annulenes have properties similar to those of porphyries and phthalocyanines, but they can be more easily substituted with cationic groups. In the title compounds 1, R is an N-bonded pyridyl cation or a 4,4′-bipyridinyl dication. Compound 1 and its metal complexes might be useful as new redox systems or as models for organic superconductors.

    32. Di(4-pyridinio)-, Di(2-benzothiazolio)-, Di(2-[1,3-dithiolylio])- and Diformyltetraaza[14]annulenes and Tetraaza[14]annulenylene-Homologous Tetrathiafulvalenes (pages 1063–1065)

      Dipl.-Chem. Florian Adams and Prof. Dr. Rudolf Gompper

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910631

      Thumbnail image of graphical abstract

      A possible route to new donors for the preparation of organic and metallic superconductors is provided by the title compounds. In contrast to the preceding communication, the cationic substituents in 1(see above) are joined to the ring through a C atom. Deprotonation of 1, X = [BOND]S[BOND]CH[DOUBLE BOND]CH[BOND]S[BOND], affords a homologue (shown on the right) of tetrathiafulvalene, the archetypal donor.

    33. A Novel Approach to Ferroelectric Liquid Crystals: the First Organotransition Metal Compound Displaying This Behavior (pages 1065–1066)

      Prof. Dr. Pablo Espinet, Dr. Jesús Etxebarría, Dr. Mercedes Marcos, Dr. Joaquina Pérez, Dr. Angel Remón and Dr. José Luis Serrano

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910651

      Thumbnail image of graphical abstract

      A novel type of mesogenic molecule and a new way of introducing chirality into liquid-crystalline compounds are both realized in roof shaped 1, obtained as a mixture of three diastereoisomers. Compound 1 forms an Smath image mesophase between 102 and 119°C, and its electro-optic switching behavior in an electric field fits the law characteristic of ferroelectric liquid crystals.

    34. Carbohydrates as Chiral Templates: Stereoselective Tandem Mannich-Michael Reactions for the Synthesis of Piperidine Alkaloids (pages 1067–1068)

      Prof. Dr. Horst Kunz and Dr. Waldemar Pfrengle

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910671

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      Pure diastereomers in high yields can be obtained by the reaction sequence shown below followed by crystallization or chromatography. The stereochemical course of the reaction is shown for R = n-propyl, p-chlorophenyl, and 2-furyl. Compound 1, R = 3-pyridyl, requires two equivalents of ZnCl2 for catalysis and reacts stereochemically in the opposite fashion. This reaction can be used to obtain enantiomerically pure (S)-coniine and (S)-anabasine

      .

    35. Carbohydrates as Chiral Templates: Stereoselective Synthesis of β-Amino Acids (pages 1068–1069)

      Prof. Dr. Horst Kunz and Dipl.-Chem. Dirk Schanzenbach

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910681

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      The asymmetric synthesis of chiral N-unsubstituted β-amino acids, which are of interest as components of antibiotics and natural products, may be achieved with high induction when Schiff bases (see 1 in the preceding communication) are allowed to react with silylketene acetals. The esters thereby obtained (see right) may be hydrolyzed to β-amino acids containing free amino groups.

  3. Book Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
  4. Corrigenda

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. You have free access to this content
      Corrigendum (page 1074)

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910741

  5. Editorial Essay

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Materials Science and Engineering in Britain (pages 1077–1078)

      Prof. Colin Humphreys

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910771

      Editorial Essay: The funding of the materials science research effort in British universities and polytechnics has recently been reorganized with the founding of the Materials Science and Engineering Commission of the SERC. The chairman of the commission assesses Britain's performance in materials science and outlines the aims and objectives of the funding bodies in the UK. The recent increase in the importance of advanced materials has resulted in a surge of research activity but have the funding levels kept pace?

  6. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Advanced Catalysts: Interfaces in the Physical and Biological Sciences (pages 1079–1088)

      John M. Thomas

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910791

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      Review: The presidential address to the chemistry section of the British Association for the Advancement of Science (BAAS) to be given in Sheffield in September, by John M. Thomas (see picture) concentrates on the roles that catalysts play in chemical synthesis both in industry and in a biological environment. The future of catalysts rests in the hands of interdisciplinary scientists and engineers who, when faced with the problem of developing a new catalytic system, can call upon experience from such diverse fields as solid state physics and biology.

    2. Materials for the Next Millenium (pages 1088–1097)

      Dr. Ernest D. Hondros and Dr. Edward Bullock

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910881

      Review: The future of mankind will be influenced by our attitudes towards the overuse of today's materials and to the development and exploitation of new ones. Current supply and demand trends are analyzed and themes of future significance are examined, which include microstructure control and the design of functional materials.

    3. Tailoring Semiconductor Crystals to Atomic Dimensions (pages 1098–1103)

      Prof. Bruce A. Joyce

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198910981

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      Review: Semiconductor properties resulting from quantum confinement effects can be engineered using molecular beam epitaxy (MBE), a method of depositing materials in thin films. The dynamics of thin film growth are examined, the production of quantum wells, superlattices and quantum wires is described and recent modifications to the method, based on flux interruption, are reported.

    4. Structure-Directed Synthesis of New Organic Materials (pages 1103–1110)

      Dr. Franz H. Kohnke, Mr. John P. Mathias and Dr. J. Fraser Stoddart

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911031

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      Review: The synthesis of molecular cages, belts and strips opens up new areas of technology for exploitation. Solvent specific sensors are one possible use of cage molecules called carcerands (see figure). A series of Diels-Alder reactions under tight stereochemical control are used in a remarkably efficient manner to produce the structures.

    5. Metal Organic Chemical Vapor Deposition (MOCVD) Perspectives and Prospects (pages 1110–1120)

      Prof. John O. Williams

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911101

      Review: Thin film epitaxial semiconductor structures of widely varying but controlled compositions and thickness can be prepared using MOCVD. The performance of the method is gauged against molecular beam epitaxy (MBE) and spray pyrolysis, and comment is made on the direction in which this area of research is going, for example, towards the processing of high-Tc superconductors and ferroelectric oxides.

  7. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Siloxane Copolymers with Laterally and Terminally Attached Mesogenic Side Chains (pages 1120–1122)

      Prof. G. W. Gray, Dr. J. S. Hill and Dr. D. Lacey

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911201

      Thumbnail image of graphical abstract

      Communication: Liquid crystals based on polysiloxane copolymers (see figure) with well defined physical characteristics have been synthesized by varying the type and ratio of the laterally attached mesogenic side chains. Applications in integrated optics and optical storage are envisaged.

    2. Polymers with a High Refractive Index and Low Optical Dispersion (pages 1122–1123)

      Dr. Hans-U. Simmrock, Dr. Alfred Mathy, Dr. Ligia Dominguez, Dr. Wolfgang H. Meyer and Prof. Gerhard Wegner

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911221

      Thumbnail image of graphical abstract

      Communication: Organic Polyelectrolytes (I–VII) known as Ionenes, with unique combinations of high refractive index (ND) and high Abbe number (VD, see figure) now compete with inorganic glasses for application in optics. Variation of the counterions allows the tuning of their chemical and optical properties.

  8. Research News

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Gauge Theory—A New Outlook on Solid State Dynamics (pages 1124–1126)

      Prof. Stanley Clough

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911241

      Research News: The hitherto mysterious relationship between the quantum and classical descriptions of solid state dynamic processes has been reexamined recently. It has been found that quantum theory has been missing important features such as symmetry breaking and Berry's phase, the incorporation of which does away with the rather fuzzy Copenhagen interpretation and rationalizes solid state behavior.

    2. Imaging Organic Molecules with the Scanning Tunneling Microscope (pages 1127–1128)

      Dr. Jürgen P. Rabe

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911271

      Research News: The lack of electrical conductivity and the constant molecular mobility of organic molecules have, in the past, restricted the successful imaging of these systems by STM. Recently, however, a number of new organic systems have been imaged. Jürgen Rabe reports on these new developments and in the future will write regularly for ADVANCED MATERIALS on surface analysis techniques especially scanning microscopy methods.

    3. Phase Equilibria under Stress (pages 1128–1130)

      Prof. Robert W. Cahn

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911281

      Research News: A slight mismatch between the lattice parameters of two intergrown “coherent” phases can cause internal stresses within a two phase alloy which can modify the shapes of the dispersed phase particles. Recent studies by both metallurgists and geologists have been aimed at understanding this and other stress related phenomena.

    4. Networks Composed of Rigid Rod Polymers (pages 1130–1131)

      Dr. Matthias Ballauff

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911301

      Thumbnail image of graphical abstract

      Research News: Rubber elasticity in macro-molecules on which the tire industry (for example) relies is the result of the arrangement of the polymer chains as shown in the figure, crosslinked, and connected by flexible hinges. In two recent publications a theory describing this elasticity has been proposed. Matthias Ballauff reviews this new work and will, in the future, run a regular column in ADVANCED MATERIALS on polymer related topics.

  9. Conference Report

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Joining Ceramics, Glass and Metal in Bad Nauheim (pages 1132–1134)

      Mr. Graham Partridge

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911321

      Conference Report: G. Partridge (GEC) reports on a meeting which concerned the joining of ceramics, glass, and metals and E. Marinero and T. Sizuki (IBM) on two major symposia from the spring meeting of MRS, on magnetic and magneto-optic thin films and multilayers.

    2. Magnetic and Magneto-Optic Thin Films and Multilayers in San Diego (pages 1134–1136)

      Dr. Ernesto Marinero and Dr. Takao Suzuki

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911341

      Conference Report: G. Partridge (GEC) reports on a meeting which concerned the joining of ceramics, glass, and metals and E. Marinero and T. Sizuki (IBM) on two major symposia from the spring meeting of MRS, on magnetic and magneto-optic thin films and multilayers.

  10. Book Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Book Review: Super Conductors: The Breakthrough. By R. M. Hazen (pages 1139–1140)

      Peter Gregory

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911391

    2. Book Review: Side Chain Liquid Crystal Polymers. Edited by C. B. McArdle (page 1140)

      Hans-Werner Schmidt

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911401

  11. Conference Calendar

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    5. Corrigenda
    6. Editorial Essay
    7. Reviews
    8. Communications
    9. Research News
    10. Conference Report
    11. Book Reviews
    12. Conference Calendar
    1. Conference Calender (pages 1141–1146)

      Article first published online: 30 DEC 2003 | DOI: 10.1002/anie.198911411

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