Angewandte Chemie International Edition in English

Cover image for Vol. 31 Issue 11

November 1992

Volume 31, Issue 11

Pages 1399–1540

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 11/1992)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199213991

      Thumbnail image of graphical abstract

      The cover picture shows a model of the trigonal-monopyramidal comlex [V{[(tBuMe2Si)NCH2CH2]3N}] with V in yellow, N in red, and Si in blue. This unusual coordination geometry is enforced by the triamido ligand, whose sterically demanding trialkylsilyl substitutents also shield the empty coordination site. Complexes with this geometry could reversibly bind a series of substrates at the free coordination site and thus function catalytically. More about the synthesis and characterization of the vanadium complex as well as the titanium, chromium, manganese, and iron analogues is reported by R. R. Schrock et al. on p. 1501 ff.

    2. Graphical Abstract (Angew. Chem. Int. Ed. Engl. 11/1992)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199213992

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. Corrigenda
    1. The Photochemistry of Stilbenoid Compounds and Their Role in Materials Technology (pages 1399–1420)

      Prof. Dr. Herbert Meier

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199213993

      Stilbenoid compounds and light: the details of the photophysical and chemical principles are still hardly understood, even for the apparently simple process of the Z/E isomerization of stilbenes. That, however, does not stand in the way of the increasing number of industrial uses for the optical, electrical, and optoelectrical properties of these compounds. Applications of derivatives of the diaminostilbene disulfonic acid as optical brighteners, for example for textiles, began in the forties. More recent applications already exploited or in development are found in the fields of laser dyes, optical information storage, photo-conductors, and photo-crosslinked polymers. Parallel to these developments, methods such as laser spectroscopy in the pico- and femtosecond ranges are yielding new information on the fundamentals of the processes.

    2. Cubanes: Starting Materials for the Chemistry of the 1990s and the New Century (pages 1421–1436)

      Prof. Philip E. Eaton

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214211

      From an academic curiosity to industrial material—cubane derivatives, often amazingly stable, have not yet reached the end of their development; applications as pharmaceuticals, fuels, and explosives are currently under investigation. The major obstacle in the new cubane chemistry, the controlled functionalization of the cubane framework, was overcome by metalation and transmetalation. Subsequent modifications of functional groups on the cubane framework can be performed by classical synthetic methods without difficulty.

    3. Oxoniobates Containing Metal Clusters (pages 1437–1456)

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

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214371

      Thumbnail image of graphical abstract

      Octahedral Nb6 units, as discrete entities or condensed to form one-, two-, or three-dimensional aggregates, are found in reduced oxoniobates. The end member of this family of structures is NbO, in which the Nb6 octahedrons are interlinked through all vertices. By analysis of the bonding relationships, electrons can be assigned to different types of Nb atoms (see picture). Thus quantitative predictions of the optimal concentrations of valence electrons can be made, and a deeper understanding of the electronic properties of these compounds is possible.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. Corrigenda
    1. Proteins from the D-Chiral World (pages 1457–1459)

      Prof. Dr. Günther Jung

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214571

      The chiroptical properties and substrate specificity of the D-enantiomer of the naturally occurring HIV protease synthesized by Kent et al. demonstrate that the three-dimensional structures of D- and L-enzymes really are mirror images of one another—that is, identical amino acid sequences actually fold in the same way in the tertiary structure. Interest in D-proteins goes beyond basic research, as the enzymatic stability may allow important medical applications; additional areas of application include protein crystallography.

    2. Asymmetric Deprotonation as an Efficient Enantioselective Preparation of Functionalized Secondary Alcohols (pages 1459–1461)

      Prof. Dr. Paul Knochel

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214591

      Thumbnail image of graphical abstract

      A reaction with organolithium compounds and the chiral amine (—)-sparteine deprotonates carbamates such as 1 in the α-position forming chiral lithio compounds 2, as shown by D. Hoppe et al. [Eq. (a)]. These react with high stereoselectivity with a variety of electrophiles to yield nonracemic, chiral compounds (see also the communication on p. 1505ff). R1 = alkenyl, R2 = C(O)NiPr2, R3 = nBuLi.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. Corrigenda
    1. The Structure of Pentamethyltantalum (pages 1462–1464)

      Prof. Thomas A. Albright and Huang Tang

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214621

      Thumbnail image of graphical abstract

      Unexpected structures for pentacoordinate d0 metal complexes were revealed in these theoretical and experimental studies. Ab initio calculations on [TaH5] and [Ta(CH3)5] (1) show that square-pyramidal coordination is preferred over trigonal-bipyramidal in both cases. This was also confirmed for the pentamethyl complex by gas-phase electron diffraction experiments. In contrast, the main group element compound [Sb(CH3)5] (2) has a trigonal-bipyramidal geometry which is, however, separated from the square-pyramidal form by only a small energy barrier.

    2. The Structures of Pentamethyltantalum and -Antimony: One Square Pyramid and One Trigonal Bipyramid (pages 1464–1467)

      Prof. Arne Haaland, Dr. Andreas Hammel, Dr. Kristin Rypdal, Hans Peter Verne, Ing. Hans Vidar Volden and Dr. Colin Pulham

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214641

      Thumbnail image of graphical abstract

      Unexpected structures for pentacoordinate d0 metal complexes were revealed in these theoretical and experimental studies. Ab initio calculations on [TaH5] and [Ta(CH3)5] (1) show that square-pyramidal coordination is preferred over trigonal-bipyramidal in both cases. This was also confirmed for the pentamethyl complex by gas-phase electron diffraction experiments. In contrast, the main group element compound [Sb(CH3)5] (2) has a trigonal-bipyramidal geometry which is, however, separated from the square-pyramidal form by only a small energy barrier.

    3. Perfluorotriethylamine: An Amine with Unusual Structure and Reactivity (pages 1467–1468)

      Dipl.-Chem. Markus Gaensslen, Dr. Udo Gross, Prof. Dr. Heinz Oberhammer and Dr. Stephen Rüdiger

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214671

      Thumbnail image of graphical abstract

      An almost planar NC3 frame, widening of the N-C-C angles, and a marked increase in the N[BOND]C and C[BOND]C bond lengths—these are the results of the dense packing of fluorine atoms in the title compound, whose structure (shown here) was determined by electron diffraction in the gas phase. The structural properties directly reflect the chemical behavior of this amine.

    4. Product Predictions for Nucleophilic Additions toC70 (pages 1468–1470)

      Priv.-Doz. Dr. Heinrich R. Karfunkel and Dr. Andreas Hirsch

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214681

      Thumbnail image of graphical abstract

      Considerably more complex than for C60 is the product distribution in the addition of nucleophiles NuH to higher fullerenes such as C70—hundreds of C70NuH isomers are conceivable. An efficient, reliable search for the stable isomers is possible with semiempirical calculations (Nu = H, Me, tBu). The results specify the “2/2” isomer (shown here) as the most stable isomer, but 1,4-addition products have only slightly higher energy.

    5. Paramagnetic Chiral Smectic C Materials: A New Class of Ferroelectric Liquid Crystals (pages 1471–1472)

      Dr. Mercedes Marcos, Dr. José Luis Serrano, Dr. Teresa Sierra and María José Giménez

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214711

      Thumbnail image of graphical abstract

      Cu2+ and VO2+ are the paramagnetic centers of the ferroelectric complexes ML2 that both display a Smath image mesophase. The spontaneous polarization of these first paramagnetic ferroelectric liquid crystals is 23 and 20 nCcm−2, respectively.

    6. Solving the Structure of a Metal-Substituted Aluminum Phosphate Catalyst by Electron Microscopy, Computer Simulation, and X-ray Powder Diffraction (pages 1472–1475)

      Dr. Paul A. Wright, Dr. Srinivasan Natarajan, Prof. Sir. John Meurig Thomas, Dr. Robert G. Bell, Dr. Pratibha L. Gai-Boyes, Dr. Richard H. Jones and Dr. Jiesheng Chen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214721

      A new method for the solution of solid-state structures—especially if the compounds can only be obtained as powders—is reported. A combination of electron microscopy, electron diffraction, and computer simulation of the lowest energy structure allowed the determination of the structure of the Mg- and Zn-substituted forms of the catalytically active aluminophosphate MeALPO-36. This novel structure has kinships with those of the aluminophosphate ALPO-5 and the zeolite cancrinite Na6[Al6Si6O24]CaCO3 · 2H2O.

    7. Decamethylcucurbit[5]uril (pages 1475–1477)

      Dr. Anthony Flinn, Gordon C. Hough, Prof. J. Fraser Stoddart and Dr. David J. Williams

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214751

      Thumbnail image of graphical abstract

      Patience is a virtue in chemistry too! This is demonstrated once again by the synthesis of the title compound 1 from dimethylglycoluril and formaldehyde in boiling nitric acid, and the structural investigation of this new molecular receptor. The crystallization of 1 from dilute nitric acid took twelve months!

    8. The [(μ3-WSe4)33-Se)2 (Cu3)2]4− Anion, an Inorganic Cluster with a Pin wheel Shape (pages 1477–1478)

      Christopher C. Christuk, Dr. Mohammad A. Ansari and Prof. Dr. James A. Ibers

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214771

      Thumbnail image of graphical abstract

      A structure incorporating two eclipsed Cu3 triangles, three bridging μ3-WSemath image units, and two capping μ3-Se atoms is formed from a cubane-like Cu[BOND]Se[BOND]W cluster on treatment with Li2Se. This product pictured here (one Se atom is omitted at each W atom) exemplifies one of the structural possibilities for the little-studied selenidometalates.

    9. Synthesis of Esterase-resistant 9-O-Acetylated Polysialoside as Inhibitor of Influenza C Virus Hemagglutinin (pages 1478–1481)

      Prof. Dr. René Roy, Dr. Fredrik O. Andersson, Günter Harms, Dr. Sørge Kelm and Prof. Dr. Roland Schauer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214781

      Thumbnail image of graphical abstract

      N-acrylolated thioglycosides of sialic acid, for example 1, can be treated with acrylamide to give glycopolymers. These new thioglycosides hinder the adhesion of influenza C virus to the host cell, but are resistant to viral esterases, which makes them interesting in the design of medication against influenza C infections. X = S, R = H, R′ = Me.

    10. N-Perbenzylation of Oligopeptides with P4-Phosphazene Base; A New Protecting-Group Technique for Modification and Solubilization of Peptides in Apolar Organic Solvents (pages 1481–1482)

      Dipl.-Chem. Thomas Pietzonka and Prof. Dr. Dieter Seebach

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214811

      Thumbnail image of graphical abstract

      Even sparingly soluble peptides can be perbenzylated with P4-phosphazene base/benzyl bromide. The products of type A are readily soluble in organic solvents and can be used for further modifications of the peptide framework. Debenzylation is achieved by treatment with sodium in liquid nitrogen.

    11. Crosslinking of Adjacent Guanine Residues in an Oligonucleotide by cis-[Pt(NH3)2(H2O)2]2+: Kinetic Analysis of the Two-Step Reaction (pages 1483–1485)

      Florence Gonnet, Dr. Jiři Kozelka and Dr. Jean-Claude Chottard

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214831

      Thumbnail image of graphical abstract

      Why does cisplatin bind preferentially to GG units in oligonucleotides? The development of a new method which enables the determination of the four rate constants of the two-step reaction between an oligonucleotide containing a GpG unit and cis-[Pt(NH3)2(H2O)2]2+ has brought us closer to the solution of this puzzle.

    12. Stable Cyclic Germanediyls (“Cyclogermylenes”): Synthesis, Structure, Metal Complexes, and Thermolyses (pages 1485–1488)

      Prof. Dr. Wolfgang A. Herrmann, Dr. Michael Denk, Dr. Joachim Behm, Wolfgang Scherer, Franz-Robert Klingan, Prof. Dr. Hans Bock, Dr. Bahman Solouki and Dr. Matthias Wagner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214851

      Thumbnail image of graphical abstract

      The new germandiyls 1 and 2 which sublime at 50 °C are monomeric in the solid state, in solution, and in the gas phase. They are available from germanium dichloride · 1,4-dioxane and the appropriate lithium diamides in high yields, and react smoothly with [Ni(CO)4] to give 3 and 4. According to ab initio calculations, the π electrons in 2 are delocalized. cod = cyclooctadiene.

    13. Quest for Higher Ladderanes: Oligomerization of a Cyclobutadiene Derivative (pages 1488–1490)

      Prof. Goverdhan Mehta, M. Balaji Viswanath, G. Narahari Sastry, Prof. Eluvathingal D. Jemmis, Dr. D. Sivakumar K. Reddy and Dr. Ajit C. Kunwar

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214881

      Thumbnail image of graphical abstract

      Successive [4 + 2] cycloadditions of dimethyl 1,2-cyclobutadienedicarboxylate (1), first with itself and then with the next highest adducts 2 and 3, result in the [7]-ladderane 4. The [n]-ladderanes 24 are of interest because of their weak σ framework and the very different polarities of the two sides of the molecule. R = CO2Me.

    14. Ether-Soluble Ti0 and Bis(η6-arene)titanium(0) Complexes from the Reduction of TiCl4 with Triethylhydroborate (pages 1490–1492)

      Prof. Dr. Helmut Bönnemann and Dr. Barbara Korall

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214901

      The first preparation of bis (η6-arene)titanium(0) complexes was achieved by reduction of TiCl4 with the borate [BEt3H] in the appropriate arene solvent. In contrast the same reduction in THF leads to soluble “TiH2”, which loses H2 when dried to give a substance which can be formulated as Ti · 0.5 THF with various amounts of residual hydrogen. X-ray photoelectron spectroscopy and EXAFS analysis support the assumed oxidation state of zero for the titanium.

    15. High-Yield Synthesis of Lipid Systems with Giant Rings (pages 1492–1493)

      Prof. Dr. Fredric M. Menger, Stephen Brocchini and Xiangyang Chen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214921

      Thumbnail image of graphical abstract

      A high-temperature Glaser coupling reaction is the key to the efficient synthesis of lipids with “giant rings” as exemplified by reaction (a) (77% yield). Macrocyclic compounds are usually considered to have rings with twelve to twenty members; the term “giant rings” refers to compounds with even larger rings.

    16. Arborols Based on Luminescent and Redox-Active Transition Metal Complexes (pages 1493–1495)

      Dr. Scolastica Serroni, Prof. Dr. Gianfranco Denti, Dr. Sebastiano Campagna, Prof. Dr. Alberto Juris, Dr. Mauro Ciano and Prof. Dr. Vincenzo Balzani

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214931

      Thumbnail image of graphical abstract

      Not an electronic circuit, but a chemical formula of a huge metal complex is depicted here. The circles stand for metal centers, the zigzags for bridging ligands, and the dashes for terminal ligands. The Ru22 complex, which belongs to the class of cascade compounds (arborols/dendrimers), is the largest Werner-type complex so far.

    17. A New Approach to Bis(arene)titanium(0) and -titanium(–I) Complexes; Structure of Bis(arene)titanates(1–) (pages 1495–1498)

      David W. Blackburn, Prof. Dr. Doyle Britton and Prof. Dr. John E. Ellis

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214951

      The reduction of titanium tetrachloride with arene radical anions (such as biphenyl or 4,4′-di-tert-butylbiphenyl potassium), as summarized in Equation (a), affords the corresponding bis(arene)titanates(l—) K[1] and K[2] in high yields, which were structurally characterized as K[2.2.2]cryptand complexes. The oxidation of K[1] and K[2] with I2 leads to the corresponding neutral bis(arene)titanium complexes. Such metallocenes were previously accessible only by metal atom–ligand cocondensation or sonochemical reactions.

      • equation image
    18. Molecular Switching by Electron Transfer—the Spiroperimidine/Quinonimine System (pages 1498–1500)

      Dr. Josef Salbeck, Dr. Vitaly N. Komissarov, Prof. Dr. Vladimir I. Minkin and Prof. Dr. Jörg Daub

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199214981

      Thumbnail image of graphical abstract

      The isomerization between spiroperimidine 1 and quinonimine 2 is reversibly switchable in a multistep process. The forward reaction takes place by electron transfer, while the reverse reaction is a thermal process. The intermediate radical anions and dianions were identified and the mechanism was elucidated.

    19. Trigonal-Monopyramidal MIII Complexes of the Type [M(N3N)] (M = Ti, V, Cr, Mn, Fe; N3N = [(tBuMe2Si)equation imageCH2CH2]3N) (pages 1501–1503)

      Christopher C. Cummins, Jenny Lee, Prof. Dr. Richard R. Schrock and Dr. William D. Davis

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215011

      Thumbnail image of graphical abstract

      The bulkiness and multidenticity of the ligands stabilize the unusual trigonal-monopyramidal coordination geometry of the title complexes, which were prepared by “reductive” (Ti, V), “direct” (Cr, Fe), and “oxidative” (Mn) routes. The V complex was characterized by X-ray crystallography (structure shown here).

    20. Cateholates as σ- and π-Donationg Ligands: The Synthesis and Structure of (Et4N)2[W(CO)4(O2C6H4)] and the “Sixteen Electron” Analogue Resulting from CO Dissociation (pages 1503–1504)

      Prof. Dr. Donald J. Darensbourg, Dipl.-Chem. Kevin K. Klausmeyer, Dr. Brian L. Mueller and Dr. Joseph H. Reibenspies

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215031

      Thumbnail image of graphical abstract

      Alkoxo ligands with strong π-donor character stabilize coordinatively unsaturated organometallic compounds. This is confirmed by the two complexes 2 (each formally 16-electron species), which are in equilibrium with the starting materials 1. When R = tBu, 1 exists in the pure state only under a CO atmosphere, and 2 can even be characterized by X-ray crystallography. R = H, tBu.

    21. Stereoselective Generation of 1-Acyloxy-2-amino Carbanions by Deprotonation; Synthesis of Enantiomerically and Diastereomerically Pure β-Amino Alcohols (pages 1505–1507)

      Dipl.-Chem. Jörg Schwerdtfeger and Prof. Dieter Hoppe

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215051

      Thumbnail image of graphical abstract

      Activation of the oxygen-substituted C atom so that it functions as a nucleophile—this is the key to the preparation of the stereoisomeric β-amino alcohols in pure form. The stereochemical outcome of the reactions of O-carbamate derivatives of achiral 2-(dibenzylamino)alcohols (e.g. 1 [RIGHTWARDS ARROW] 2) is determined by the reagent. If, on the other hand, a stereogenic center is in the β position, the stereochemistry of the deprotonation and the substitution is determined by the substrate. In both cases, the configurationally stable α-acyloxy-β-amino carbanion is the intermediate. El = electrophile.

    22. 99mTc Labeled Biotin Conjugate in a Tumor “Pretargeting” Approach with Monoclonal Antibodies (pages 1507–1509)

      Dipl.-Chem. Peter Koch and Prof. Dr. Helmut Robert Mäcke

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215071

      Thumbnail image of graphical abstract

      Very stable in vitro and in vivo, the complex of 99mTc and the biotin derivative 1 shows, like biotin, a high affinity for the glycoprotein avidin. It was successfully used to diagnose brain tumors when the patients were treated three days previously with an unlabeled conjugate of a tumor-specific monoclonal antibody and avidin.

    23. Enantioselective Polymerization of 1,2-Diisocyanoarenes—Synthesis of Optically Active, Helical Poly(quinoxaline-2,3-diyl)s (pages 1509–1510)

      Prof. Dr. Yoshihiko Ito, Eiji Ihara and Dr. Masahiro Murakami

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215091

      Thumbnail image of graphical abstract

      The helical pentamer 1, active in polymerizations, was obtained from the appropriate 1,2-dgaiisocyanoarene and the chiral Pd complex trans-[PdBr(CH3)Lmath image]. With diastereomerically pure 1 as the polymerization initiator helical polyquinoxalinediyls can be prepared enantioselectively from 1,2-diisocyanoarene. L* = PPh[(S)-2-methylbutyl]2.

    24. Triphosphatrisilacyclohexanes as Tridentate Coronands in Cr and Mo Complexes: Activation of Si[BOND]H in an Early Stage versus Phosphane Coordination (pages 1510–1513)

      Dr. Matthias Driess, Dipl.-Chem. Michael Reisgys and Dr. Hans Pritzkow

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215101

      Thumbnail image of graphical abstract

      The Si[BOND]H bond ousts a phosphorus atom in the coordination to the metal center of the chromium complex 1. This is the surprising result of the reaction of the hexaorganosubstituted P3Si3 ligand 2 with [Cr(CO)3] (• = SiHMes in 1 and 2). The Si,H,Cr three-center two-electron bond in 1 represents a case of very weak Si[BOND]H activation. The crucial factor determining the unusual complexation is the mesityl substitution at the tiny metal center. This is confirmed by the formation of complexes 3, in which Cr is replaced by Mo and/or mesityl by phenyl groups.

    25. Multifield Saturation Magnetization Measurements of Oxidized and Reduced Ribonucleotide Reductase from Escherichia coli (pages 1513–1515)

      Mohammed Atta, Corinne Scheer, Dr. Pascal H. Fries, Prof. Marc Fontecave and Dr. Jean-Marc Latour

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215131

      Thumbnail image of graphical abstract

      A diiron(II) center doubly bridged by carboxylate groups (see sketch) is present in reduced ribonucleotide reductase according to magnetization measurements: the strong anti-ferromagnetic coupling of the oxidized diiron(III) site consistent with an oxo bridge is no longer observed. Protonation of the oxo bridge during the reduction is postulated. The loss of the resulting aqua bridge then leads to the structural unit shown here.

    26. Mono- and Binuclear Molybdenum Complexes Incorporating 4-(4-Hydroxyphenyl)pyridine: Metal–Metal Interactions Across an Asymmetric Bridging Ligand (pages 1515–1518)

      Dr. Amitava Das, Dr. John C. Jeffery, Dr. John P. Maher, Prof. Jon A. McCleverty, Erik Schatz, Dr. Michael D. Ward and Gerd Wollermann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215151

      Thumbnail image of graphical abstract

      Localization versus delocalization: in the binuclear asymmetric Mo complex 1, a facile one-electron reduction with cobaltocene is sufficient to convert a system with localized electrons to one with delocalized electrons. Whereas according to the EPR spectrum the unpaired electron in the 17e–16e complex 1 is localized at the Mo center coordinated to N, in the 17e–17e diradical 1 a rapid site exchange of the two unpaired electrons occurs for which a rate of 4 × 107 Hz was determined. L* = hydro-tris(3,5-dimethylpyrazolyl)borate.

    27. Se3N2Cl2, a Novel Selenium–Nitrogen Chloride: Reinvestigation of “Se4N2 (pages 1518–1519)

      Jari Siivari, Prof. Tristram Chivers and Prof. Risto Laitinen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215181

      Not the binary compound tetraselenium dinitride, as previously reported, but rather Se3N2Cl2 (1) is the product of the reaction of trimethylsilyl azide and selenium monochloride in dichloromethane [Eq. (a)]. Compound 1 can also be obtained quantitatively in a pure form from selenide 2 and selenium tetrachloride/selenium monochloride [Eq. (b)], and is of interest as a synthetic building block in the little developed Se[BOND]N chemistry.

      • equation image
      • equation image
    28. The New Subnitride NaBa3N; an Extension of Alkali Metal Suboxide Chemistry (pages 1519–1521)

      Dr. Paul E. Rauch and Prof. Dr. Arndt Simon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215191

      Thumbnail image of graphical abstract

      Chains of face-sharing, N-centered, trigonal Ba6 antiprisms (shown here) with Na atoms between the chains is a description of the structure of the title compound. The columns of Ba atoms ([Ba2+]3N3−)3e centered by N atoms show ionic bonding within, but metallic bonding on the “skin” as well as between the columns and the Na atoms, leading to the overall metallic character of the compound.

    29. Enantioselective Complexation of Chiral Dicarboxylic Acids in Clefts of Functionalized 9,9′-Spirobifluorenes (pages 1521–1523)

      Dr. Victoria Alcazar and Prof. Dr. François Diederich

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215211

      Thumbnail image of graphical abstract

      The 9,9′-spirobifluorene receptors (R)- and (S)-1 with amidopyridine groups in the 2 and 2′ positions complex chiral dicarboxylic acids enantioselectively in chloroform by hydrogen bonding. Interestingly, the N-protected acidic amino acids, L-aspartic and L-glutamic acid, prefer binding to different hosts. In contrast, 1,1′-binaphthyl receptors with similar functionality in the major groove show hardly any enantioselectivity in the complexation of chiral dicarboxylic acids.

    30. The Uncatalyzed Transfer Hydrogenation of α-Methylstyrene by Dihydroanthracene or Xanthene—a Radical Reaction (pages 1523–1525)

      Prof. Christoph Rüchardt, Dipl.-Chem. Matthias Gerst and Dipl.-Chem. Margot Nölke

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215231

      Thumbnail image of graphical abstract

      Cumene (3) is formed almost quantitatively from α-methylstyrene (1) by hydrogen transfer from dihydroanthracene (2a) or xanthene (2b) at 270–310 °C. The initial step in this reaction is the first example of a stoichiometric, bimolecular, molecule-induced formation of radicals in solution (proven by ESR) by hydrogen transfer. This type of reaction has been postulated for the initiation of chain reactions such as the thermal polymerization of styrene.

    31. Novel Binuclear Phosphinidene Compounds by Dimerization of the P[BOND]H-Functional Phosphenium Complexes [C5R5(CO)2W[DOUBLE BOND]PH(Mes)] (R = H, Me) (pages 1525–1527)

      Prof. Dr. Wolfgang Malisch, Dr. Ulrich-Andreas Hirth, Dr. Theresa A. Bright, Dr. Harald Käb, Dr. Teja Sebastian Ertel, Dipl.-Chem. Sabine Hückmann and Prof. Dr. Helmut Bertagnolli

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215251

      Thumbnail image of graphical abstract

      A 15- and a 17-electron metal complex fragment stabilize the MesP unit (Mes = 2,4,6-trimethylphenyl) in the binuclear complexes 1 (R = H, Me). These are formed as the dimerization product of the PH-functional phosphe-nium complexes 2, which can be trapped with Me3P as metalliophosphanes 3.

    32. A Paramagnetic, Mononuclear Organometallic Iridium(II) Complex: [Ir(C6Cl5)2(cod)] (pages 1527–1529)

      Dr. María P. García, Dipl.-Chem. M. Victoria Jiménez, Prof. Dr. Luis A. Oro, Dr. Fernando J. Lahoz and Prof. Dr. Pablo J. Alonso

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215271

      Unexpectedly stable, 2 is the first mononuclear IrII complex whose ligands are bound exclusively through C atoms. Complex 2, prepared by oxidation of 1 with I2 or Ag+, is close to square planar. The phenyl rings are almost perpendicular to the metal's coordination plane; the ortho Cl atoms are quite close to the Ir metal center, which could explain the remarkable stability of 2. cod = 1,5-cyclooctadiene.

      • equation image
    33. Formate-Driven, Non-Enzymatic NAD(P)H Regeneration for the Alcohol Dehydrogenase Catalyzed Stereoselective Reduction of 4-Phenyl-2-butanone (pages 1529–1531)

      Dipl.-Chem. Von Dorothée Westerhausen, Dr. Sabine Herrmann, Priv.-Doz. Dr. Werner Hummel and Prof. Dr. Eberhard Steckhan

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215291

      (2,2′-Bipyridyl)(pentamethylcyclopentadienyl)rhodium complexes are homogeneous catalysts for the formate-driven, in situ regeneration of the cofactors NADH and NADPH in enantioselective, enzymatic reductions of carbonyl compounds. A non-enzymatic cofactor regeneration scheme in combination with four NAD(P)H-dependent alcohol dehydrogenases was tested with the reduction of 4-phenyl-2-butanone. High turnovers and high enantioselectivities were achieved for the formation of the (R) and (S) alcohols.

    34. Induction of Ferroelectricity in Polymeric Systems through Hydrogen Bonding (pages 1531–1533)

      Dr. Uday Kumar, Prof. Dr. Jean M. J. Fréchet, Dr. Takashi Kato, Seiji Ujiie and Prof. Kazuyoshi Timura

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215311

      Thumbnail image of graphical abstract

      Achiral polysiloxanes with para-alkoxybenzoic acid side chains can bind many molecules of an optically active trans-stilbazole with hydrogen bonds. The resulting, self-assembling system 1 has ferroelectric properties which can be regulated by the number of stilbazole units per polymer molecule and the length of the (CH2)n spacer.

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. Corrigenda
    1. Book Review: Molecular Electronics. Edited by G. J. Ashwell. (page 1536)

      Hans Christoph Wolf

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215361

  5. Corrigenda

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    6. Corrigenda
    1. You have free access to this content
      Corrigenda (page 1540)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199215401

SEARCH

SEARCH BY CITATION