Angewandte Chemie International Edition in English

Cover image for Vol. 32 Issue 2

February 1993

Volume 32, Issue 2

Pages 131–312

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 2/1993)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199301311

      Thumbnail image of graphical abstract

      The cover picture shows a model of the cluster [Cu29Te16(PiPr3)12], whose structure can be described with the Frank–Kasper polyhedra known for intermetallic phases. A red Te15 Frank–Kasper polyhedron with 26 triangular faces is penetrated by the blue Cu29 cluster, and in the center of the total cluster the sixteenth Te atom is situated, to which three of the copper atoms are bound. The PiPr3 bound Cu atoms are located above twelve of the Te triangular faces, a further fourteen lie below the other faces. More about the diversity of clusters obtained from CuCl, Te(SiMe3)2, and phosphanes is reported by D. Fenske and J.-C. Steck on pages 238 ff. – In this issue an analysis of the referee system of “Angewandte Chemie” by H.-D. Daniel can be found on pages 234 ff., which is certainly of interest for all chemists.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Sequential Transformations in Organic Chemistry: A Synthetic Strategy with a Future (pages 131–163)

      Prof. Dr. Lutz F. Tietze and Dr. Uwe Beifuss

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199301313

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      Simple, efficient, highly selective, and resource saving are syntheses of complex organic compounds in which several transformations are combained to sequences like domino, tandem, or cascade reactions, and for which intermediates need not be isolated. The tandem Knoevenagel hetero-Diels–Alder reaction of aldehyde 1 with Meldrum's acid 2 via 3 to 4 is an example of the sequential transformations which are systematically classified in this review.

    2. Chemistry of and with Highly Reactive Metals (pages 164–189)

      Univ. Doz. Dr. Alois Fürstner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199301641

      What happens in heterogeneous reactions at the molecular level? In contrast to homogeneous reactions very little is known about these. This review is concerned with the solid-state chemistry aspect of metal-induced processes. It also describes how to approach the maximum reactivity of a metal by simple means and described applications of activated metals in organic synthesis. Since the high reactivity of a metal is not automatically associated with poor selectivity, many heterogeneous reactions are also applicable in natural product chemistry and for polyfunctional compounds.

    3. Aminoacyl-tRNA Synthetases: The Division into Two Classes Predicted by the Chemistry of Substrates and Enzymes (pages 190–200)

      Prof. Dr. Friedrich Cramer and Dr. Wolfgang Freist

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199301901

      With modified substrates and affinity labeling, information about the properties and structures of enzyme active sites can be obtained even before their exact structure has been determined by gene sequencing and X-ray structure analysis, as shown, for example, for the aminoacyl-tRNA synthetases. In these enzymes individual, important amino acid residues of the active site could be identified by affinity labeling, and even the classification of the enzymes into two classes with different phytogenetic evolutionary trees could be predicted.

    4. Computer-Assisted Solution of Chemical Problems—The Historical Development and the Present State of the Art of a New Discipline of Chemistry (pages 201–227)

      Prof. Dr. Ivar Ugi, Dr. Johannes Bauer, Dr. Klemens Bley, Dr. Alf Dengler, Dipl.-Chem. Andreas Dietz, Dr. Eric Fontain, Dr. Bernhard Gruber, Dr. Rainer Herges, Dr. Michael Knauer, Dipl.-Chem. Klaus Reitsam and Dipl.-Chem. Natalie Stein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302011

      Can new reactions be discovered by computer? The authors of this review describe their attempts to develop computer programs that generate structures and reactions without recourse to data banks. They compare their approach with that of empirical and semiformal synthesis design and describe the first preparative successes stimulated by the results of their programs IGOR and RAIN.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Extending the Metal Cluster–Metal Surface Analogy (pages 228–229)

      Prof. Dr. Bruce C. Gates

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302281

      Reactivity and catalytic properties–are there analogies between metal clusters and metal surfaces here too? In the 1980s the conclusion had been reached that such analogies could only be formulated about structure and bonding. But new work from Yates et al. and Chisholm et al. has given rise to new hope. They studied CO dissociation on sparsely covered Mo surfaces and in tetranuclear tungsten clusters, respectively. These reactions proceed in a similar fashion; however, their rate-determining steps and reaction rates differ.

    2. Pentazole and Other Nitrogen Rings (pages 230–232)

      Prof. Dr. Rudolf Janoschek

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302301

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      Nitrogen rings and cages are kinetically labile systems extremely high in energy that can nevertheless be assigned to minima on the appropriate energy surfaces. Experimenters are therefore challenged in this highlight to find conditions under which compounds such as the unsubstituted pentazole 1 can be prepared and characterized.

    3. Enantioselective Transition Metal-Catalyzed Hydrogenation for the Asymmetric Synthesis of Amines (pages 232–233)

      Dr. Carsten Bolm

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302321

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      The great preparative potential of chiral transition metal complexes is again illustrated by the homogeneous asymmetrical hydrogenation of C[DOUBLE BOND]N bonds which so far–in contrast to the hydrogenation of functionalized olefins or ketones–could be carried out with only a moderate selectivity. Both with the catalyst system RhI-1 and also with the ansa-titanocene complex 2 optically active amines could be produced in high enantiomeric excesses.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. An Evaluation of the Peer Review Process at Angewandte Chemie (pages 234–238)

      Priv.-Doz. Dr. Hans-Dieter Daniel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302341

      Criticism on the referee system—and of course of the referees—also filters through all too often to the editorial office of Angewandte Chemie. So we were glad when in 1990 H.-D. Daniel received permission from the Gesellschaft Deutscher Chemiker to examine our referee system under the auspices of the priority program “Research on Science” of the Deutsche Forschungsgemeinschaft. Of course, strict anonymity for authors and referees was observed. A concise selection of the results that will nevertheless provide much material for discussion in presented here. [The results will appear in full in summer in a book published by VCH.]

    2. New Cu[BOND]Te Clusters (pages 238–242)

      Prof. Dr. Dieter Fenske and Dipl.-Chem. Jörg-Christian Steck

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302381

      Thumbnail image of graphical abstract

      Frank–Kasper polyhedrons suitable for the description of the structures of intermetallic phases can also be used to describe the structures of the Cu-rich clusters, which are among the compounds formed by the reactions of CuCl with phosphanes and Te(Si[BOND]Me3)2. The Cu-poor compound 1 in contrast contains a Cu4 butterfly cluster with two μ4-Temath image ligands (structure shown right).

    3. New Phosphido-Bridging Copper Clusters (pages 242–245)

      Dipl.-Chem. Andreas Eichhöfer, Prof. Dr. Dieter Fenske and Dipl.-Chem. Werner Holstein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302421

      Thumbnail image of graphical abstract

      The way to polymeric copper phosphides is probably marked by multinuclear Cu clusters accessible from copper chloride and functionalized phosphanes. One of the multitude of new compounds with unusual structures prepared from these starting materials is [Cu12(PPh)6(PPh3)6], whose central Cu[BOND]P framework is shown here.

    4. Synthesis and Characterization of a High Molecular Weight Stiff Dendrimer (pages 246–248)

      Zhifu Xu and Prof. Jeffrey S. Moore

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302461

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      94 Monomeric units make up 1, the largest pure hydrocarbon yet characterized (C1134H1146). The compound which, thanks to its di-tert-butyl-phenyl groups, is extremely soluble in pentane (!) was obtained from the monodendron precursor and triiodobenzene with a Pd catalyst in 37% yield. Elemental analysis and 1H NMR spectra clearly prove its structure. The benzene rings are shown as filled circles; the lines in between represent C[TRIPLE BOND]C units.

    5. Self-Assembly and Liquid Crystal Formation of Folic Acid Salts (pages 248–250)

      Dr. Stefania Bonazzi, Dr. Monica Miranda DeMorais, Prof. Giovanni Gottarelli, Dr. Paolo Mariani and Prof. Gian Piero Spada

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302481

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      Even at concentrations of only 1 wt%, macromolecular aggregates can be proven in a solution of dipotassium folate in water. Their probable structure is in agreement with the results from studies of solutions of higher concentrations, some of which show liquid crystalline behavior. In these molecular aggregates are found hexagonally arranged columns of stacked folate tetramers.

    6. The Application of Au55 Clusters as Quantum Dots (pages 250–254)

      Dipl.-Chem. Ulrich Simon, Prof. Dr. Günter Schön and Prof. Dr. Günter Schmid

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302501

      The beginning–or the end—of the metallic state is attained in ligand-stabilized Au55 clusters. As quantum dots with two last “switchable” electrons they are the nonpareils of electronic miniaturization and can be used as microelectronic quantum devices.

    7. Superconductivity and Phase Separation in NaxNbO2 (x < 1) (pages 254–255)

      Maria A. Rzeznik, Dr. Margret J. Geselbracht, Dr. Mark S. Thompson and Prof. Dr. Angelica M. Stacy

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302541

      Below 4.2 K is the onset of superconductivity in sodium niobates NaxNbO2 for values of x between 0.65 and 0.9. The samples studied all contain two phases, a sodium-rich phase, which is isostructural with NaNbO2, and a sodium-poor phase with a related layered structure. The latter phase exhibits superconductivity.

    8. A New Layered Ternary Sulfide: Formation of Cu2WS4 by Reaction of WSmath image and Cu+ Ions (pages 256–257)

      Eugene A. Pruss, Dr. Barry S. Snyder and Prof. Dr. Angelica M. Stacy

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302561

      Thumbnail image of graphical abstract

      Intact tetrathiotungstate units, which are linked into layers by copper(I) ions, are found in the title compound. This can be prepared from [Cu(CH3CN)4]BF4 and (NH4)2 WS4 under very mild reaction conditions (135 °C, in solution). The structure of this ternary sulfide was determined by X-ray powder diffraction. ⊕ = Cu, ○ = S, • = W.

    9. Cyanosulfines: An Unexpected Reaction of N,N-bis(trimethylsilyl)ynamines (pages 258–259)

      Dipl.-Chem. Thomas Schmid, Prof. Dr. Michael Hanack, Dr. Cäcilia Maichle and Prof. Dr. Joachim Strähle

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302581

      Thumbnail image of graphical abstract

      Cyanosulfines 2 and not the expected alkynylsulfinylamines 3, which might serve as precursors to alkenediazonium ions and alkynyl cations, arise in the reaction of bissilylated ynamines 1 with thionyl chloride. R [DOUBLE BOND] Ph, tBu, nPr, cyclohexyl.

    10. Selective Photolabeling near the Middle of Bilayers with a Photosensitive Transmembrane Probe (pages 259–261)

      Masakuni Yamamoto, Dr. William A. Warnock, Prof. Alain Milon, Prof. Yoichi Nakatani and Prof. Guy Ourisson

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302591

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      The efficient study of the inside of a membrane should no longer be a problem, thanks to the investigations described here. In vesicles from phospholipids, incorporated 1 (X [DOUBLE BOND] H,D) reacts upon irradiation with a selectivity up to 90% at positions ω −1 and ω −2 of the phospholipid chains, when, at the same time, cholesterol is a constituent of the membrane in normal bioconcentrations.

    11. Polyoxovanadium–Organophosphonates—Properties and Structure of an Unusual Pentavanadate Species with a V[DOUBLE BOND]O Group Directed Toward the Interior of the Molecular Cavity (pages 261–263)

      Dr. Qin Chen and Prof. Jon Zubieta

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302611

      Thumbnail image of graphical abstract

      An unsymmetrical bowllike [V3O5(PhPO3)4] framework (V2–V4, P1–P4), on whose surface a VO unit (V1) is “condensed”, and which is capped by octahedrally coordinated V atom (V5), is formed by the anion of 1 · CH3OH. A terminal oxo group (O23) is encapsulated in this cavity (phenyl substituents at P1, P3, P4 are omitted from the structure shown right).

      • equation image
    12. Cobalt Tetra(hydroquinone)porphyrin: An Efficient Electron Transfer Reagent in Aerobic Pd-Catalyzed 1,4-Diacetoxylation of 1,3-Cyclohexadiene (pages 263–264)

      Dr. Helena Grennberg, Sylvie Faizon and Prof. Dr. Jan-E. Bäckvall

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302631

      Thumbnail image of graphical abstract

      An efficient bifunctional catalyst for the title reaction is cobalt tetra(hydroquinone)porphyrin 1. The oxidized form of 1 (shown right, R = hydroquinone) has one unit for the interaction with molecular O2, and another for the interaction with the Pd catalyst. Thus, electrons can be transferred rapidly from the Pd complex to O2.

    13. Surprising Differences in the Cycloaddition Reactions of Cumulenes and Heterocumulenes to Vinylidenetitanocene: Formation of Four- or Five-Membered Titanacycles (pages 264–266)

      Dr. Rüdiger Beckhaus, Isabelle Strauß, Trixie Wagner and Dr. Paul Kiprof

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302641

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      Liberation of ethylene from titaniumcyclobutane 1 generates the corresponding metallaallene, Cpmath imageTi[DOUBLE BOND]C[DOUBLE BOND]CH2, which surprisingly behaves differently in trapping reactions with various compounds. In the presence of carbon dioxide, ketenes, and isocyanates the four-membered titanacycles 2 (X [DOUBLE BOND] O, CR2, and NR, respectively) form, whereas with metal carbonyls [LnMCO] the products are the Fischer carbene complexes 3, which have a planar metallacyclopentene unit. Cp* [DOUBLE BOND] η5-C5Me5.

    14. η6-(1,2-Dioxocyclobutabenzene)tricarbonyl-chromium(0): Starting Material for Double Anionic Oxy-Cope Rearrangements under Very Mild Conditions (pages 267–269)

      Dipl.-Chem. Michael Brands, Dr. Richard Goddard, Dr. Hans G. Wey and Priv.-Doz. Dr. Holger Butenschön

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302671

      Thumbnail image of graphical abstract

      Certainly one of the most strained arene complexes known, the title compound 1 is described here. Its reactivity is characterized by the differentiation of the sides of attack at the bicyclic ligand. On addition of alkenyl metal reagents this leads to an ideal configuration for double anionic oxy-Cope rearrangements, providing access to benzoannelated cyclooctan-1,4-dione derivatives.

    15. S-Glycosylated Cyclic Peptides (pages 269–271)

      Dr. Manfred Gerz, Dr. Hans Matter and Prof. Dr. Horst Kessler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302691

      The high chemical and enzymatic stability of thioglycosides stimulated the synthesis of S-glycosylated cyclopeptides. The structural properties of this new class of compounds were established by conformational analysis with 2D NMR methods and molecular dynamics calculations. These substances are of interest for the development of site-specific drugs.

    16. Two New High-Pressure Modifications of NaOH (pages 271–272)

      Prof. Dr. Horst P. Beck and Dr. Gunda Lederer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302711

      Only stable under pressure, two new high-pressure modifications of NaOH were structurally characterized for the first time by refined X-ray diffraction methods. Both structures proved to be interesting variants of common types and result from the nonspherical symmetry of the OH groups.

    17. A Simple Route from Glucal to Cerny Epoxides (pages 272–273)

      Dipl.-Chem. Gilbert Lauer and Dr. Franz Oberdorfer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302721

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      Previously difficult to obtain, dianhydropyranoses 1 and 2 can now be synthesized from the pseudoglucal derivative 3 in one step with surprising ease and in good yields. The bridged glucoside 3 is prepared from glucal by an intramolecular ring-closure novel for this type of compound. R [DOUBLE BOND] H.

    18. Total Synthesis of (−)-Pyrimidoblamic Acid and Deglycobleomycin A2 (pages 273–275)

      Prof. Dale L. Boger, Royce F. Menezes and Takeshi Honda

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302731

      Thumbnail image of graphical abstract

      Bleomycin is an important antibiotic for the treatment of cancer. Now the completion of the total synthesis of the aglycon 1 from bleomycin A2, the major component of bleomycin, has been achieved. The decisive steps are the construction of the pyrimidine part by an inverse-electron-demand Diels–Alder reaction and the diastereoselective addition of a stannous enolate to an imine group.

    19. Iodine Azide (pages 275–277)

      Dipl.-Chem. Peter Buzek, Priv.-Doz. Dr. Thomas M. Klapötke, Prof. Dr. Paul von Ragué Schleyer, Dr. Inis C. Tornieporth-Oetting and Dr. Peter S. White

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302751

      Very pure and crystalline, iodine azide IN3 (1) can be obtained by reaction of silver azide and iodine in CFCl3 and subsequent sublimation. According to the results of the X-ray structure analysis in the solid state IN3 consists of layers of chains, which contain twofold coordinated iodine atoms. The structural parameters of the IN3 unit are in good agreement with the results of an ab initio calculation for IN3.

    20. Nickel(III)-Promoted DNA Cleavage with Ambient Dioxygen (pages 277–278)

      Chien-Chung Cheng, Prof. Steven E. Rokita and Prof. Cynthia J. Burrows

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302771

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      Oxygen-sensitive nickel(II) complexes with macrocyclic ligands promote DNA cleavage without additional oxidants, initiators, or irradiation. The reaction does not involve OH radicals, but superoxido[BOND]NiIII complexes may play a role. The reactivity of the nickel complexes is highly dependent on the substituents on the ligands, which may allow fine-tuning for in vivo applications. R1,R2 e.g. F, H.

    21. Propionyl-Aza(dethia)coenzyme A as Pseudosubstrate of the Biotin-Containing Transcarboxylase (pages 278–280)

      Dr. Harald Martini and Prof. Dr. János Rétey

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302781

      How is the carboxyl group of 1′-N-carboxybiotin transferred to the substrate? To resolve the controversy surrounding the mechanism the title compound was used as substrate for propionyl-CoA-oxaloacetate transcarboxylase. It was not carboxylated in the reaction, but induced the decarboxylation of oxaloacetate. This communication gives a plausible explanation for this observation.

    22. Ca2PN3: A New Phosphorus(V) Nitride with One-Dimensional Infinite Chains of Corner-Sharing PN4 Tetrahedra (pages 280–281)

      Priv.-Doz. Dr. Wolfgang Schnick and Dipl.-Chem. Verena Schultz-Coulon

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302801

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      Low-dimensional coupling analogous to that in chainlike silicates can also occur in phosphorus(V) nitrides. Infinite chains of corner-sharing PN4 tetrahedra (schematically shown below) are present in the complex anion Ca2PN3.

    23. Reductive Ring-Opening of Oxabicyclic Compounds with Diisobutylaluminum Hydride. Application to the Synthesis of the C17–C23 Subunit of Ionomycin (pages 281–283)

      Prof. Mark Lautens, Pauline Chiu and John T. Colucci

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302811

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      Not acetate aldol reactions but the reductive ring-opening of oxabicyclic compounds with diisobutylaluminum hydride (DIBAH) paved the way to the synthesis of important precursors to natural products. The reactions summarized in Equation (a) show the potential of the method with simple examples. TBDMS = tBuMe2Si.

    24. Novel Arsaalkenes from an Arsasilene Derivative and Isocyanides (pages 283–285)

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

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302831

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      The conversion of a Si[DOUBLE BOND]As bond into a C[DOUBLE BOND]As bond is surprisingly simple by the reaction of the arsasilene 1 with organic isocyanides, from which the arsaalkenes 2 are formed. These react with Brønsted acids with the elimination of iPr3SiX (X [DOUBLE BOND] F, Cl) to give the cyclic arsaalkenes 3. Is = 2,4,6-iPr3C6H2; R [DOUBLE BOND] c-C6H11, 2,4,6-Me3C6H2.

    25. Synthesis of 4-Oxo-L-proline and cis-4-Hydroxy-L-proline Derivatives from L-Aspartic Acid (pages 285–287)

      Prof. Dr. Klaus Burger, Dr. Martin Rudolph and Dipl.-Chem. Susanna Fehn

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302851

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      When hexafluoroacetone is used to generate a protecting group for L-aspartic acid, the diazacarbonyl compound 1 can be prepared and subsequently converted into the bicyclic proline derivative 2 with Rh catalysis. Because of the concave shape of 2, new chiral centers can be made with high stereoselectivity; 4-oxo-L-proline, unsubstituted and substituted in the 5 position, cis-4-hydroxy-L-proline, and other derivatives are readily accessible. R [DOUBLE BOND] H, CO2Et.

    26. Ba[Si(OCH2CH2O)3], a Hexaalkoxysilicate Synthesized from SiO2 (pages 287–289)

      Martin L. Hoppe, Prof. Richard M. Laine, Jeffrey Kampf, Mark S. Gordon and Larry W. Burggraf

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302871

      The reaction of BaO, SiO2, and an excess of ethylene glycol provides [Ba-Si(OCH2CH2O)3] · 3.25 HO(CH2)2OH, the first amazingly stable hexaalkylsilicate, in 90% yield. This complex was characterized by X-ray crystallography. The reactions with MgO and CaO give analogous compounds; with alkali metal oxides pentacoordinate silicates are formed.

    27. A Hemerythrin Model Complex with Catalase Activity (pages 289–291)

      Dipl.-Chem. Bert Mauerer, Dr. Jonathan Crane, Dipl.-Chem. Jürgen Schuler, Prof. Dr. Karl Wieghardt and Dr. Bernhard Nuber

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302891

      The catalytic disproportionation of H2O2 to O2 and H2O is achieved with the asymmetric hemerythrin model complex 1, which has a reactive coordination site. The catalytic cycle proceeds via the oxyhemerythrin form with a coordinated hydrogenperoxo ligand. L [DOUBLE BOND] 1,4,7-trimethyl-1,4,7-triazacyclononane, bpy [DOUBLE BOND] 2,2′-bipyridine.

      • equation image
    28. 2,3,7,8,12,13,17,18-Octamethoxyporphyrin (pages 291–293)

      Prof. Dr. Andreas Merz, Dipl.-Chem. Roland Schropp and Dr. Johann Lex

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302911

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      An eightfold donor-substituted porphyrin with free meso positions 1 has been obtained for the first time. In the solid state one of the two methoxy groups on each pyrrole ring lies almost parallel to the porphyrin plane, thus allowing conjugation with the π-electron system of the macrocycle. Further evidence is provided by the spectroscopic properties of 1, which deviate significantly from those of the related octaalkylporphyrins.

    29. [Fe2Cl6]2−: A Discrete Form of Ferrous Chloride (pages 293–295)

      Prof. Kim R. Dunbar and Anne Quillevéré

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302931

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      Two edge-sharing FeCl4 tetrahedra with two terminal and two bridging Cl ligands per metal center describes the title anion 1 (structure shown) isolated as a phosphonium salt. The Fe…Fe distance in this unprecedented dinuclear iron(II) compound is 3.350(4) Å.

    30. 1-Hetero-3,4-diborolanes and Two New Routes to 1,2-Diboretanes** (pages 295–297)

      Dipl.-Chem. Ralf Littger, Prof. Dr. Heinrich Nöth, Dr. Martina Thomann and Dr. Matthias Wagner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302951

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      In sunlight, 1-plumba-3,4-diborolane 1 reacts to form the 1,2-diboretan derivative 2. This rearranges on warming to the thermodynamically more stable 1,3 isomer 3. Compound 2 is also accessible from the corresponding diboratabutadiene dianion by oxidative coupling.

    31. The First Octahedral Zintl Ion: Snmath image as a Ligand in [Sn6{Cr(CO)5}6]2− (pages 297–298)

      Dipl.-Chem. Berthold Schiemenz and Prof. Dr. Gottfried Huttner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199302971

      Thumbnail image of graphical abstract

      Not only aesthetically pleasing, anion 1 is chemically significant. Its isolation as a K[2.2.2]cryptand salt shows for the first time that octahedral main group element aggregates such as Snmath image—the first octahedral Zintl ion—can also exist.

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Book Review: Oxygen Chemistry. By D. T. Sawyer (pages 304–305)

      Bernard Meunier

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199303042