Angewandte Chemie International Edition in English

Cover image for Vol. 30 Issue 3

March 1991

Volume 30, Issue 3

Pages 217–342

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1991)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102171

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      The cover picture shows how aesthetically appealing the results of modern analytical methods can be. The method is pulsed ESR spectroscopy, which now, long after NMR spectroscopy was revolutionized by pulsed methods, could also lead to a notable improvement in the experimental possibilities of ESR spectroscopy. The result shown in the cover picture is the response signal which was obtained after stochastic excitation of a cobalt complex containing N,O-ligands. The modulation pattern observed after adding together data from many individual measurements is caused by interaction between the spin of the unpaired electron and the spins of 14N nuclei. From the frequencies of these oscillations, hyperfine and nuclear quadrupole couplings of the 14N nuclei may be derived. More about the present state-of-the-art of pulsed ESR spectroscopy is reported by A. Schweiger on p. 265.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Iminophosphanes: Unconventional Compounds of Main Group Elements (pages 217–237)

      Prof. Dr. Edgar Niecke and Dr. Dietrich Gudat

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102173

      Multiple-bond systems involving elements of higher periods and phosphorus compounds with low coordination numbers have introduced a renaissance of main group chemistry. Iminophosphanes, which display both properties, are synthetically valuable starting compounds, and are of particular interest not only because of their markedly diverse chemical behavior but also from the point of view bond theory. By cycloadditions, for example, heterocycles with varying ring sizes and number of heteroatoms can be prepared.

    2. 3-Amino-2H-Azirines. Synthons for α,α-Disubstituted α-Amino Acids in Heterocycle and Peptide Synthesis [New Analytical Methods (43)] (pages 238–264)

      Prof. Dr. Heinz Heimgartner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102381

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      Parallel with the renewed impetus in peptide chemistry there has also been a notable increase in the interest shown in non-proteinogenic amino acids, particularly in Aib (2-aminoisobutyric acid). Amino acids of this type favor the formation of specific secondary structures in the peptide chain. Ideal starting materials for the synthesis of oligopeptides and related compounds, which contain such α,α-disubstituted α-amino acids, are the 3-amino-2 H-azirines 1. The presence of the ring strain in these molecules means that they can be used in peptide coupling without the need for additional activating reagents. The azirines 1 are also especially suitable for the synthesis of heterocycles.

    3. Pulsed Electron Spin Resonance Spectroscopy: Basic Principles, Techniques, and Examples of Applications [New Analytical Methods (43)] (pages 265–292)

      Priv.-Doz. Dr. Arthur Schweiger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102651

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      Shorter measuring times, higher sensitivity, better resolution and simpler spectra, are some of the advantages of pulsed ESR spectroscopy over the continuous wave ESR methods currently in use. Thus, for example, by hyperfine-selective ENDOR spectroscopy, the ENDOR spectrum of the 14N nucleus of CuII picolinate (bottom) can be extracted from the total ENDOR spectrum (top).

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Spontaneous Resolution by Stirred Crystallization (pages 293–295)

      Prof. J. Michael McBride and Randall L. Carter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102931

      New insights into the mechanism of crystal nucleation emerge from a study by Kondepudi et al., on the crystallization of NaClO3 from a stirred solution. Rectangular prisms of the chiral space group P213 precipitate from aqueous solutions of the achiral ions. If the solution is not stirred, crystals of both enantiomorphic forms precipitate in equal amounts—exactly as was reported almost one hundred years ago. However, when the NaClO3 solution is stirred, then almost exclusively only right-handed or only left-handed crystals are formed. There is a simple explanation for this extremely surprising and obviously reproducible phenomenon.

    2. The Rationality of Random Screening—Efficient Methods of Selection of Peptides and Oligonucleotide Ligands (pages 296–298)

      Priv. Doz. Dr. Andreas Plückthun and Dr. Liming Ge

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102961

      The rapid automatic synthesis of oligonucleotides enables the production of a large number of variants in a single step. The oligonucleotides with random base composition can then serve either as ligands or receptors or encode peptide ligands or protein receptors. After selection, in which readily binding ligands are separated from nonbinding or poorly binding ligands, the desired compounds can be multiplied from virtually single molecules, either in vivo (by transfection or transformation of bacteria with this DNA) or in vitro by a polymerase chain reaction. Such strategies will play an increasingly important role in the investigation of molecular interactions of biochemical relevance. Random screening may be the most rational approach for solving many problems.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Novel Strategies for the Construction of Complex Polycyclic Ether Frameworks. Stereocontrolled Synthesis of the FGHIJ Ring System of Brevetoxin A (pages 299–303)

      K. C. Nicolaou, C. A. Veale, C.-K. Hwang, J. Hutchinson, C. V. C. Prasad and W. W. Ogilvie

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199102991

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      Almost one hindered steps were necessary to synthesize the FGHIJ ring framework 1 of brevetoxin A in its naturally occurring enantiomeric form from the readily accessible carbohydrates D-mannose, 2-deoxy-D-ribose, and tri-O-acetyl-D-glucal. Despite the large number of steps the synthesis is highly convergent, which makes the efficiency even more impressive.

    2. Intermediates in Nitrogenase Models: N2H3 and N2H4 as η2-Coordinated Ligands (pages 303–304)

      Dipl.-Chem. Sabine Vogel, Dipl.-Chem. Annette Barth, Prof. Dr. Gottfried Huttner, Dipl.-Chem. Thomas Klein, Dr. Laszlo Zsolnai and Dr. Reinhard Kremer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103031

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      The complex cations 1 and 2 have model character for the active centers of nitrogenases even though neither phosphane ligand nor cobalt occur in the known nitrogenases. Nevertheless, these cations show how a quite specific ligand environment can facilitate the fixation to metal centers of the N2H3 and N2H4 intermediates said to be formed on N2 reduction.

    3. Chloride-Induced Conversion of [Mn4O2(OAc)6(py)2(dbm)2] to [Mn4O3Cl(OAc)3(dbm)3]: Potential Relevance to Photosynthetic Water Oxidation (pages 305–306)

      Sheyi Wang, Dr. Kirsten Folting, Dr. William E. Streib, Edward A. Schmitt, James K. McCusker, Professor Dr. David N. Hendrickson and Prof. Dr. George Christou

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103051

      Further insights into the function of chloride in the water-oxidizing enzyme system of photosynthesis are provided by the title reaction, in which an Mnmath image-complex is converted into an Mnmath imageMnIV complex, as given formally in Equation (a). Thus, the redox process S1 [RIGHTWARDS ARROW] S2 taking place in the active state in nature is copied, and suggests that also the biological relevance of Cl could lie in the stabilization of a higher oxidized Mn aggregates.

      • equation image
    4. 1,3-(C [RIGHTWARDS ARROW] O) Silyl Shift in α-Diazo α-Silyl Ketones: Cycloaddition Reactions and Kinetic Proof for the β-Siloxydiazoalkene Intermediate (pages 306–308)

      Dipl.-Chem. Rainer Munschauer and Prof. Dr. Gerhard Maas

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103061

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      The 1 : 1 cycloadducts 3 and 4 with norbornene and N-phenylmaleimide (NPM), respectively, can be regarded as direct trapping products of the diazoalkenes 2. A kinetic analysis of the trapping reaction with NPM rules out a [3+2] cycloaddition of the diazoketone 1 with formation of 5 and spontaneous silylketone–silyl enol ether isomerization to 4. The conversion of 1 into 2 already takes place at 25–60°C. R [DOUBLE BOND] tBu or p-NO2C6H4.

    5. Diphosphonio Isophosphindoles, Phospholes with a Planar Phosphorus (pages 308–310)

      Prof. Dr. Alfred Schmidpeter and Dipl.-Chem. Martin Thiele

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103081

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      Which resonance formula is correct? The protonation of 1 to the symmetrical dication 2 is certainly most plausible from the indicated phosholide structure, which confers distinct basic character on the ring phosphorus. The bonding of the system 2 stable at room temperature, a phosphole with P[BOND]H group, is however best explained by the phosphorane structure 2b. Certain is, that the reactivity and stability of these systems are understandable only in terms of the interplay of phosphonio substituents and annelated benzene ring.

    6. Cooligomerization of Phosphaalkynes and Alkynes in the Coordination Sphere of Rhodium Complexes (pages 310–312)

      Prof. Dr. Paul Binger, Dipl.-Chem. Josef Haas, Dipl.-Chem. Albert T. Herrmann, Dipl.-Chem. Franz Langhauser and Prof. Dr. Carl Krüger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103101

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      The 1-phospha-2-rhodacyclobutene 2 is formed upon reaction of the vinylidene complex 1 with tert-butylphosphaacetylene and subsequent ligand substitution. In the crystal, 2 can be described as a slightly distorted tetragonal bipyramid with a free coordination site.

    7. The First Metallobis(methylene)phosphoranes—Unexpected Isomerization to a Phosphaferrocene (pages 312–313)

      Dipl.-Chem. Hans Jürgen Metternich and Prof. Dr. Edgar Niecke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103121

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      The synthesis of a phospholyl ligand in the coordination sphere of a transition metal was achieved by rearrangement of the ferriophosphane 1 to the phosphaferrocene 2. Compound 1 could be prepared by metalation of the choro-substituted phosphorane with K [CpFe(CO)2]. R [DOUBLE BOND] SiMe3.

    8. A Cluster with the Triply Facially Bridging Trimethylenemethane Ligand: Structure and Bonding of [{Rh(cod)}33-H){μ3-C(CH2)3}] (pages 313–315)

      Prof. Dr. Gerhard E. Herberich, Dr. Ulli Englert, Dr. Lars Wesemann and Prof. Dr. Peter Hofmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103131

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      An equilaterial triangle of Rh atoms, capped on one side by an almost planar trimethylenemethane (TMM) and on the other by a hydrido ligand, is present in the title compound 1. The structure of 1 in the crystal deviates markedly from ideal C3v symmetry: the TMM ligand and the Rh3 triangle are not exactly congruent, and the COD ligands are tilted away from the TMM ligand and rotated about their C2 axis. This arrangement prevents too close an H[BOND]H contact between the endo H atoms of the C[DOUBLE BOND]C units of the COD ligands on the hydrido side of the cluster.

    9. Interaction of Hydrophobically-Modified Poly-N-isopropylacrylamides with Model Membranes—or Playing a Molecular Accordion (pages 315–318)

      Prof. Dr. Helmut Ringsdorf, Dipl.-Chem. Joachim Venzmer and Dr. Françoise M. Winnik

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103151

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      The thermoreversible coil-globule transition of polymers at the lower critical demixing temperature is a popular theme in polymer chemistry. Here, this phenomenon is exploited to induce a reversible contraction/expansion by temperature changes in a membrane-achored N-isopropylacrylamide copolymer (shown schematically below). With this liposome-anchored “molecular accordion” the dynamics of the cytoskeleton of biological systems can be roughly simulated.

    10. RS-P[DOUBLE BOND]S in the Gas Phase—First Generation of (Organothio)thioxophosphanes (pages 318–320)

      Dr. Helmut Keck, Prof. Dr. Wilhelm Kuchen, Dipl.-Chem. Heike Renneberg, Prof. Dr. Johan K. Terlouw and Herman C. Visser

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103181

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      A two-coordinate, trivalent phosphorus atom is present in the title compounds 1 (R [DOUBLE BOND] CH3, C6H5), which are formed by electron collision ionization of the corresponding dithiadiphosphetane disulfides 2. Collision activation and neutralization-reionization mass spectroscopy show that the isomeric dithioxophosphoranes 3 rearrange to 1.

    11. Enantioselective Metabolism of (±)-α-l,2,3,4,5,6-Hexachlorocyclohexane in Organs of the Eider Duck (pages 320–321)

      Roland Kallenborn, Dr. Heinrich Hühnerfuss and Prof. Dr. Wilfried A. König

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103201

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      Also enantiomers of synthetic pollutants can be “recognized” in enzymatic degradation reactions. This is demonstrated by the enantioselective metabolization of technical α-HCH, a highly chlorinated, chiral hydrocarbon, in the liver of eider ducks. Extracts of this organism contain almost exclusively (+)-α-HCH, i.e. the (−)-isomer is degraded much more rapidly.

    12. η1-(1S, 2E)-1-(N,N-diisopropylcarbamoyloxy)-3-trimethylsilylallyllithium([BOND])-Sparteine: Structure of a Chiral, Carbamoyloxy-substituted Allyllithium Compound (pages 321–323)

      Michael Marsch, Dr. Klaus Harms, Dipl.-Chem. Oliver Zschage, Prof. Dr. Dieter Hoppe and Prof. Dr. Gernot Boche

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103211

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      Configurationally stable lithium compounds such as 1, which are substituted by oxygen in the α-position, are useful reagents for the stereoselective synthesis of homoallyl alcohols. Solid-state structure and reactivity of 1 are in harmony: the preferred silylation at C1 and the steroselective reaction with aldehydes at C3 are understandable from the η1-coordination of the Li atom at the allyl unit. Furthermore, the unusually long C1[BOND]O1 distance (147.6 pm) confirms earlier ab initio studies.

    13. The Structure of IFmath image (pages 323–324)

      Dipl.-Chem. Ali Reza Mahjoub and Prof. Dr. Konrad Seppelt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103231

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      The structure of the IFmath image ion can be described as a distorted octahedron with C3v, symmetry, and thus-—in contrast to that of BrFmath image—it is in keeping with the electron pair repulsion model. Whereas IFmath image in crystals of (CH3)4NIF6 forms a dimer by weak fluorine bridges (see Figure), in the case of a smaller cation a tetramer is found, in analogy to the isoelectronic XeF6.

    14. Solvent-free Tris(trimethylsilyl)methyllithium (pages 324–326)

      Dr. Wolfgang Hiller, Marcus Layh and Dr. Werner Uhl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103241

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      nBuLi first reacts with Br[BOND]Hg[BOND]C(SiMe3), at 65–700C in the melt to give the title compound within an hour. This is monomeric in solution and dimeric in the crystal (structure on the right), a novel structural type for solvent-free alkyllithium compounds. Apart from the two direct bonds from Li to the carbanionic C-atoms there are also agostic interactions with two H atoms of the SiMe3 substituents, so that each Li atom is coordinated altogether in a distorted tetrahedral fashion.

    15. [InAs3]6⊖ and [AlSb3]6⊖, Trigonal Planar Anions in Cs6InAs3 and Cs6AlSb3 (pages 326–328)

      Dipl.-Ing. Wolfgang Blase, Dr. Gerhard Cordier, Dr. Karl Peters, Dr. Mehmet Somer and Prof. Dr. Hans Georg von Schnering

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103261

      The anions of the complex salts Cs6InAs3 and Cs6AlSb3 are isosteric with borates. Both salts can be obtained as shiny metallic crystals directly from the elements. In the crystal the Cs atoms form a bundle of four chains of trigonal prisms which are centered by the atoms of the trigonal planar anions: math image{Cs12/2[MX3]}. The In[BOND]As and Al[BOND]Sb bond lengths (261.5 and 263.7 pm, respectively) fall in the range typical for single bonds.

    16. Synthesis and Crystal Structure of Brmath imageMFmath image (M = As, Sb) (pages 328–329)

      Prof. Dr. Hans Hartl, Dipl.-Chem. Joachim Nowicki and Prof. Dr. Rolf Minkwitz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103281

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      The cation of the compounds Brmath imageMFmath image (M [DOUBLE BOND] As, Sb), which are formed in the reaction of Br2 with XeFMFmath image, is Z-shaped and planar. This corresponds to an AX2E3 coordination, as predicted by the electron pair repulsion model for pentahalogen( + 1) ions. In addition, layers are formed by interionic contacts between four fluorine atoms of the MF6 octahedron and Brmath image.

    17. (I3O6), a Novel Polyoxo Cation of Iodine (pages 329–330)

      Dipl.-Chem. Anette Rehr and Prof. Dr. Martin Jansen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103291

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      A ribbon of pyramidal IO3 units and square-planar IO4 units, which are coupled via common oxygen atoms, is present in the title compound. The presence of Iv - and IIII-containing structural groups would suggest that the overall structure be formulated as I(IO3)math image, which supports the constitution I(IO3)3 postulated for the pseudobinary oxide I4O9.

    18. The Neutral Transition Metal Thiolates [M(SAr)2]2 (M [DOUBLE BOND] Mn, Fe or Co, Ar [DOUBLE BOND] 2,4,6-t-Bu3C6H2) (pages 330–332)

      Prof. Philip P. Power and Steven C. Shoner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103301

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      Not a polymeric structure, but discrete molecules are present in the thiolate complexes [{M(SAr)2}2] (M [DOUBLE BOND] Mn, Fe (1). Co; Ar [DOUBLE BOND] 2,4,6-tBu3C6H2). The central [M2S2] unit is planar, the metal atoms are surrounded in an almost trigonal planar fashion. Thiolato transition-metal complexes are relevant as models for investigating the active centers in metalloproteins.

    19. 1,3,5,7-Tetrakis(diethylamino)-s-indacenediylium-bis(tetrafluoroborate)—a Stable s-Indacene Dication (pages 332–334)

      Prof. Dr. Rudolf Gompper, Dr. Kurt Polborn, Dipl.-Chem. Christian Seifert and Dr. Hans-Ulrich Wagner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103321

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      A combination of two vinamidinium units and an interconnecting benzene ring characterizes the title compound 1 according to an X-ray structure analysis. Although there is no delocalization of the positive charges over the whole indacene system, the blue compound absorbs at remarkably long wavelength (λmax = 630 nm).

    20. 2,3a,5,6a-Tetrapentalene Dications and Tetraamino-1,3,5,7-tetrazocine (pages 334–336)

      Dipl.-Chem. Stefan Ehrenberg, Prof. Dr. Rudolf Gompper, Dr. Kurt Polborn and Dr. Hans-Ulrich Wagner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103341

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      Salts of the tetraazapentalenediylium ions 1 are readily accessible by reaction of the 3,5-bis(dialkylamino)-1,2,4-triazoles with 1,3-dichloro-2-azavinaamidinium salts. According to theoretical predictions they are best described as largely delocalized, almost planar 8π-electron systems. Reduction with zinc afforded the 1,3,5,7-tetrazocines 2, whose structure corresponds to that of octamethylcyclooctatetraene.

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Book Review: Electrophilic Aromatic Substitution. By R. Taylor (page 337)

      Christian Reichardt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103371

    2. Book Review: Lectins. By N. Sharon and H. Lis (pages 338–339)

      Hans-Joachim Gabius

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199103381

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