Angewandte Chemie International Edition in English

Cover image for Vol. 32 Issue 10

October 1993

Volume 32, Issue 10

Pages 1377–1500

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 10/1993)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199313771

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      The cover picture shows the three-dimensional scanning force microscopic image of the supercoiling of a pBR322-DNA molecule. The height information is coded by shades of purple (the lighter, the higher). The two turns of the DNA chains about the superhelical axis and the right-handedness of the supercoiling are well distinguished. Supercoiled and relaxed circular DNA molecules are now routinely imaged by scanning force microscopy; however, the three-dimensional resolution of the images now achieved was previously not possible. Scanning force microscopy should also allow the imaging of the three-dimensional structure of polymers other than DNA. More about the possibilities and problems with the technique is reported by B. Samori et al, on p. 1461 ff. That double-helical structures play a role not only in biochemistry but also in complex chemistry is demonstrated in the communications by A. F. Williams et al. (p. 1463 ff.) and E. C Constable et al. (p. 1465 ff.).

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. The Battle of Calicheamicin γmath image (pages 1377–1385)

      Prof. Dr. K. C. Nicolaou

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199313773

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      Not exactly from the elements but nevertheless from simple precursors, the total synthesis of calicheamicin γmath image (1) was achieved in a remarkably short time. The definitive, highly complicated structure was only determined in 1987/1988. For chemists engaged in natural product synthesis this compound presented a challenge matched previously, perhaps, only by that of vitamin B12 and palytoxin; thus, it is not surprising that several research groups entered into a race that was packed with excitement and drama. Apropos simple components, the Greek word chaliche (χαλιξ) means “pebble made of limestone” more about this in this very personal recollection.

    2. Organoelement Compounds with Al[BOND]Al, Ga[BOND]Ga, and In[BOND]In Bonds (pages 1386–1397)

      Prof. Dr. Werner Uhl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199313861

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      Trialkylaluminum compounds and elemental aluminum were for a long time the only products obtained from attempts to synthesize organoelement compounds with Al in the oxidation state II and with one Al[BOND]Al bond. With the synthesis [see Eq. (a)] of 1, the first compound of this type that could be fully characterized, and other tetraalkyldielement compounds R2E[BOND]ER2 (E [DOUBLE BOND] Al, Ga, In), the chemical properties of this class of compound and, in particular, the reactivity of the metal–metal bond can now be studied in detail.

    3. Bacteria and the Biodegradation of Chemicals Achieved Naturally, by Combination, or by Construction (pages 1398–1408)

      Prof. Dr. Gerhard Gottschalk and Prof. Dr. Hans-Joachim Knackmuss

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199313981

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      Bacteria's natural potential for degrading synthetic compounds is greater than typically assumed—it extends even to heteroarenes, chlorinated arenes, and, as shown below, highly toxic nitrophenols. Only when the aromatic ring is multisubstituted or has a specific substitution pattern are these compounds transformed into xenobiotics that are difficult or impossible to degrade further. In this case, the process may be directed or the cooperation of several bacterial strains may be employed for complete degradation. As a last resort, hybrid metabolic pathways may be constructed by gene transfer. TCA [DOUBLE BOND] tricarboxylic acid cycle.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Triplet States in Organic Chemistry (pages 1409–1411)

      Prof. Dr. Harry Kurreck

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314091

      The investigation of organic multispin systems—with the triplet state as the initial member—has contributed considerably to the understanding of chemical bonding and to the examination of quantum mechanical model concepts. Structural information is accessible from the form and strength of the interaction between unpaired electrons in triplet ground states; in photochemistry triplet excited states play an important role both from a mechanistic and a preparative point of view. Besides triplet states, spin states of higher multiplicity (that is, molecules with more than two unpaired electrons) are attracting increasing interest. One way to superparamagnetic organic molecules has been shown by the synthesis of a branched nonacarbene with 18 unpaired electrons (S = 9 state).

    2. Fast Solid-State Chemistry: Reactions under the Influence of Microwaves (pages 1411–1412)

      Prof. Dr. Rüdiger Kniep

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314111

      Solid-state synthesis by microwave irradiation allows the “fascinatingly simple” preparation of crystalline CuInS2 from the elements. The product is not of “semiconductor quality” and can therefore not be used directly for solar cells. The method, however, which has been established for a long time in solvent and molecular chemistry, should rapidly find wider applications in solid-state chemistry.

    3. The Mechanism of Fullerence Formation (pages 1412–1415)

      Prof. Dr. Helmut Schwarz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314121

      “Next to nothing is known about how fullerenes actually grow and form.” This statement was published in spring. Soon thereafter Bowers et al. published a series of articles that seem to be the light at the end of the tunnel. According to these studies, in graphite vaporization primarily Cmath image, clusters form from single C atoms. These species are linear (for Cmath image to Cmath image), monocyclic (for Cmath image to Cmath image), and planar-bicyclic cations (for Cmath image to about Cmath image); fullerenes are also present above Cmath image. The most important new insight is that the mono- and bicyclic Cmath image species isomerize directly to fullerenes on addition of energy; „cooling” of the „excited” fullerenes takes place by loss of C1, C2, or C3 units.

    4. The Solution of the Sherman Paradox or the Successful Search for the Huntington Gene (pages 1415–1418)

      Prof. Dr. Ernst-L. Winnacker

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314151

      With the help of reverse genetics the gene whose changes cause Huntington chorea, also known as St. Vitus's dance, was identified from a 500 000 base-pair sequence of the short arm of chromosome 4 several months ago. This rare hereditary disease usually breaks out between the ages of 35 and 50, and is characterized by disturbances of the motor and neural systems, and inevitably leads to death. The genetic reason appears to be repetitions of a certain base triplet; the greater their number, the earlier the disease breaks out. How this “molecular disease” was tracked down is described in an intelligible and absorbing way.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Synthesis and Structure of Bis(tri-tert-butylphenyl)iminohalogenphosphoranes X[BOND]P([DOUBLE BOND]NtBu3C6H2)2 (pages 1419–1420)

      Dr. Alexander Ruban, Dr. Martin Nieger and Prof. Dr. Edgar Niecke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314191

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      The hitherto unknown exo/exo conformation for bis(imino)phosphoranes is exhibited by the halogen derivatives X[BOND]P([DOUBLE BOND]NtBu3C6H2)2 (X [DOUBLE BOND] Cl, Br, I([DOUBLE BOND]1)). The P atom is in a trigonal-planar environment, and the phenyl rings are orthogonal to the N2PI plane. The crystal structure of 1 is shown below.

    2. The Coupled Activation of Molecular Oxygen and C[BOND]H and C[BOND]C Bonds in Gas-Phase Reactions of [M(C2H4)]+ (M [DOUBLE BOND] Sc[BOND]Zn) with O2 (pages 1420–1422)

      Dr. Detlef Schröder and Prof. Dr. Helmut Schwarz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314201

      Fe+ is the only cation that mediates the activation of molecular oxygen as well as that of the C[BOND]H and C[BOND]C bonds of the olefin when the complexes [M(C2H4)]+ of the transition metals (M [DOUBLE BOND] Sc[BOND]Zn) are allowed to react with O2 under single-collision conditions in the gas phase. This unique behavior parallels the role of iron complexes in important condensed-phase processes in many chemical and biological systems.

    3. Chromatographic Separation of the Four Possible Structural Isomers of a Tetrasubstituted Phthalocyanine: Tetrakis(2-ethylhexyloxy)phthalocyaninatonickel(II) (pages 1422–1424)

      Prof. Dr. Michael Hanack, Gabriele Schmid and Michael Sommerauer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314221

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      As a result of their different symmetry, the four structural isomers of the title compound (the C4h isomer 1 is depicted on the right) could be characterized by 1H NMR spectroscopy. With these complexes the complete chromatographic separation of the four structural isomers of tetrasubstituted metal phthalocyanines was achieved for the first time. R [DOUBLE BOND] 2-EtC6H12O.

    4. Sterically Controlled, Metal-Induced Synthesis of a 1-Thia-2, 4-diphosphole (pages 1424–1426)

      Prof. Dr. Ekkehard Lindner, Dipl.-Chem. Cornelius Haase, Dr. Hermann A. Mayer, Dipl.-Chem. Martin Kemmler, Dr. Riad Fawzi and Manfred Steimann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314241

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      Cleavage of the P[DOUBLE BOND]S bond of an R2P[DOUBLE BOND]S function (R [DOUBLE BOND] cyclohexyl), bound in a η2 fashion to Mn(CO)4, through insertion of R1C[TRIPLE BOND]P, followed by subsequent [2+2] cycloaddition of the product and a second molecule of R1C[TRIPLE BOND]P, leads to the thiadiphosphole 1. By decreasing the size of R stepwise ([RIGHTWARDS ARROW] Ph [RIGHTWARDS ARROW] Me), the bicycle 2 and the pentacycle 3 can be formed. [Mn] [DOUBLE BOND] Mn(CO)3, R1 [DOUBLE BOND] tBu.

    5. Hydrolysis to a Complex with a Central, Octahedral (μ6-O)In6 Unit (pages 1426–1428)

      Dr. Kaspar Hegetschweiler, Dipl.-Chem. Michele Ghisletta, Dr. Thomas F. Fässler and Prof. Reinhard Nesper

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314261

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      Hitherto unknown for main group elements was the structural element M6O13, which has now been found in the cation 1, taci = 1,3,5-triamino-1,3,5-trideoxyinositol. In the In6O13 core with a μ6-oxo center and approximate Oh symmetry, the OIn6 unit is completely shielded by the six-coordinate (taci–3 H) ligands, which explains the surprising stability of 1 toward further hydrolysis.

    6. [AltBu]math image: EPR Spectroscopic Evidence and Ab Initio Calculations (pages 1428–1430)

      Dipl.-Chem. Carsten Dohmeier, Dipl.-Chem. Mario Mocker, Prof. Dr. Hansgeorg Schnöckel, Priv.-Doz. Dr. Albert Lötz, Dipl.-Chem. Uwe Schneider and Prof. Dr. Reinhart Ahlrichs

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314281

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      An aluminum polyhedron with six equivalent Al atoms occurs in the radical anion [AltBu]math image according to the EPR spectrum. Ab initio calculations reveal that the Al framework has a distorted octahedral structure with D3d symmetry (picture shown on the right).

    7. The Structures of Tris(8-dimethylaminol-naphthyl)phosphane and Tris[2-(dimethylaminomethyl)phenyl]phosphane: Crystallographic Evidence of Seven-Coordinate Phosphorus (pages 1430–1432)

      Dr. Claude Chuit, Prof. Dr. Robert J. P. Corriu, Pascal Monforte, Dr. Catherine Reyé, Prof. Dr. Jean-Paul Declercq and Dr. Antoine Dubourg

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314301

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      A pseudo seven-coordinate central phosphorus atom is observed in the phosphanes 1 and 2. In solution this coordination is retained in the rigid phosphane 1, whereas in 2 an equilibrium exists between the opened and closed forms; as a result, MeI reacts with 1 at the P atom, but with 2 at the N atom.

    8. Synthesis and Pairing Properties of Decanucleotides from (3′S,5′R)-2′-Deoxy-3′, 5′-ethanoβ-D-ribofuranosyladenine and -thymine (pages 1432–1434)

      Dr. Markus Tarköy and Dr. Christian Leumann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314321

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      A lower change in entropy upon duplex formation and a higher propensity for the triplex formation with complementary natural DNA, together with a higher resistance to degradation by phosphodiesterases are the main characteristics of the novel DNA analogues 1 and 2. The concept of reducing pairing entropy by reducing the conformational flexibility of an oligonucleotide single strand (preorganization) may be useful in “antisense” research.

    9. Multiring Catenanes with a Macrobicyclic Core (pages 1434–1437)

      Dr. Christiane Dietrich-Buchecker, Bruno Frommberger, Dr. Ingo Lüer, Dr. Jean-Pierre Sauvage and Prof. Dr. Fritz Vögtle

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314341

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      Up to three Cu1 ions and three catenane rings can be interlocked on the arms of the bicyclic central unit (shown schematically on the right); thus, the first multiring catenanes not based on macromonocycles, but on macrobicycles are formed. The synthesis of these supramolecular complexes uses the three-dimensional template effect of the Cu1 ions.

    10. Oxoferryl π-Cation Radical of β-Pyrrole Octachlorinated meso-Tetramesitylporphyrin: Electronic and Structural Properties (pages 1437–1439)

      Dipl.-Chem. Philippe Ochsenbein, Dr. Dominique Mandon, Prof. Dr. Jean Fischer, Prof. Dr. Raymond Weiss, Dipl.-Chem. Rachel Austin, Dr. Karupiah Jayaraj, Prof. Dr. Avram Gold, Prof. Dr. James Terner, Dr. Eckhard Bill, Dipl.-Phys. Markus Müther and Prof. Dr. Alfred X. Trautwein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314371

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      Despite significantly different molecular structures and redox potentials, the electronic properties of the oxoferryl cation radical of 1 (M [DOUBLE BOND] FeIV O instead of M [DOUBLE BOND] FeIIICl, obtained by oxidation of 1 with m-chloroperoxyben zoic acid), which shows saddle-shaped distortions as a result of its peripheral chloro substituents, are similar to those of the corresponding cation radical of the unsubstituted “planar” porphyrin. These results help in the understanding of the different chemoand regioselectivities of halogenated and halogen-free iron porphyries in the catalytic hydroxylation of alkanes. R [DOUBLE BOND] 2,4,6 Me3C6H2.

    11. The Dimeric Tris(lithioarsino)germane tBuGe[As(SiiPr3)Li]3: A Self Assembled, Solvent Free Lithium–Main Group Element Aggregate with a Ge2As6Li6 Rhombododecahedral Frame work (pages 1439–1440)

      Dr. Laszlo Zsolnai, Prof. Dr. Gottfried Huttner and Dr. habil. Matthias Driess

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314391

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      Without problems and from “within”, that is, by Li–As multicenter bonds and Li[BOND]H[BOND]C interactions, is the description of how the electronic stabilization of the Li atoms appears to function in the Ge2As6Li6 framework of 1, which is shielded by bulky tBu and SiiPr3 substituents. The lithium-rich main group element aggregate 1 is formed in the reaction of tBuGeF3 with LiAs(SiiPr3)H in the presence of tBuLi. • [DOUBLE BOND]As, equation image [DOUBLE BOND]Ge, ◯[DOUBLE BOND]Li, ⊗ [DOUBLE BOND] R1 [DOUBLE BOND] SiiPr3, ⊙ [DOUBLE BOND] R2 [DOUBLE BOND] tBu.

    12. Relative Significance of Electrostatic- and Hydrophobic-Induced pKa Shifts in a Model Protein: The Aspartic Acid Residue (pages 1440–1442)

      Prof. Dan W. Urry, Shao Q. Peng, Timothy M. Parker, D. Channe Gowda and Roland D. Harris

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314401

      Unusual pKa values for amino acids in the active sites of proteins play a large role in their function. A new explanation for these pKa shifts, which considers not electrostatic but mainly hydrophobic interactions as the cause, is presented here. This is substantiated by the correlation between the titrimetrically determined pKa values of a family of polypentapeptides containing aspartic acid and the aspartic acid content in the polypeptide.

    13. High-Pressure Synthesis of LiSi: Three-Dimensional Network of Three-Bonded Si Ions (pages 1442–1444)

      Priv.-Doz. Dr. Jürgen Evers, Gilbert Oehlinger and Dr. Gerhard Sextl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314421

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      4 GPa pressure, 600 °C, and a reaction time of 5 minutes—under these conditions LiSi can be prepared from the elements. Like the homologous silicides MSi (M [DOUBLE BOND] Na[BOND]Cs), which have been known for a long time, LiSi also belongs to the Zintl phases. The Si ions form a three-dimensional network in a structure comprising puckered Si8 rings. Li+ ions are located in the cavities (shown on the right). ⊗ [DOUBLE BOND] Si, ◯ [DOUBLE BOND] Li.

    14. Vitamin D3 Synthetic Studies: Enantiospecific Synthesis of the CD Ring Fragment (pages 1444–1446)

      Martin C. Clasby, Dr. Donald Craig and Andrew Marsh

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314441

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      The activity of highly oxygenated derivatives of vitamin D3 in cancer and psoriasis therapies makes these compounds attractive synthetic goals. Here the vitamin D3 building block 3 was synthesized enantiospecifcally from (+)-(R)pulegone (1). The intramolecular cycloaddition of 2 is a key step in the reaction.

    15. Carbonyl–Metal Complexes of Diphosphadiboretane (mesB–PtBu)2 and of Triphosphatriborinanes (mesB[BOND]PtBu)3 (pages 1446–1448)

      Dipl.-Chem. Bernhard Kaufmann, Prof. Dr. Heinrich Nöth, Prof. Dr. Robert T. Paine, Prof. Kurt Polborn and Dr. Martina Thomann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314461

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      Formulated as an η3 complex, compound 2 is synthesized from the centrosymmetric ligand 1 and [Fe2(CO)9]. On photolysis 2 evolves CO and is converted into 3, in which the P atoms have an almost planar coordination environment. mes [DOUBLE BOND] 2,4,6-Me3C6H2.

    16. Titanated Methoxyallene as Novel Homoaldol Equivalent for Diastereoselective Additions to Chiral Amino Aldehydes (pages 1449–1450)

      Dr. Stephan Hormuth, Prof. Dr. Hans-Ulrich Reissig and Dr. Dieter Dorsch

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314491

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      The versatile building block, methoxyallene reveals another a new facet: The titanium derivative 1 derived from it reacts with aldehydes at the γ position. Thus the methoxyalkynes anti-3 arise with high anti-selectivity on reaction of 1 with α-N,N-dibenzylamino aldehydes 2. These activated carboxylic acid derivatives can be transformed into the homostatine lactones anti-4 by hydrolysis. R [DOUBLE BOND] CH3, CH2Ph, CH2CHMe2.

    17. Formation of Monomeric Terminal Chalcogenides by Template-Induced Disilylchalcogenide Elimination; the Crystal Structures of [ETa{(Me3SiNCH2CH2)3N}] (E [DOUBLE BOND] Se, Te) (pages 1450–1452)

      Dr. Victor Christou and Prof. Dr. John Arnold

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314501

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      Ever more useful is the triamido ligand [(Me3Si)NCH2CH2]3N3−, which now has shown its worth in stabilizing a terminal selenido and telluride unit at a tantalum center. Treatment of the dichloride 1 with (thf)2LiESi(SiMe3)3, E [DOUBLE BOND] Se or Te, affords the stable complexes 2 and 3 in good yield. The products can be characterized by spectroscopy and X-ray crystallography.

    18. Linear Total Synthesis of (–)-ACRL Toxin III B (pages 1452–1454)

      Prof. Dr. Johann Mulzer, Dipl.-Chem. Susanne Dupré, Dr. Jürgen Buschmann and Prof. Dr. Peter Luger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314521

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      Enantio- and diastereomerically pure samples of the methyl ether 1 of ACRL toxin IIIA can be prepared in 16 or 20 steps from methyl 3-hydroxy-2-methylpropionate. As an alternative to the aldol method the anti-configurated propionate units are stereoselectively produced by carbanion-aldehyde addition with a subsequent oxidation–reduction sequence.

    19. Ba44Cu48(CO3)6O87.9: The Structure of “BaCuO2” from Simultaneous X-ray and Neutron Powder Diffraction (pages 1454–1456)

      Dr. Miguel A. G. Aranda and Dr. J. Paul Attfield

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314541

      “BaCuO2” is not a simple ternary oxide but a complex oxocarbonate. It is a common component of superconducting oxocuprates. The complete elucidation of the structure by simultaneous X-ray and neutron powder diffraction on samples of “BaCuO2” gave a statistically disordered carbonate group at the heart of the structure and resulted in the composition of this supposed oxide given in the title.

    20. Synthesis and Reactivity of Hexafluoro-1,2-diisocyanocyclobutanechromium Complexes (pages 1456–1458)

      Priv.-Doz. Dr. Dieter Lentz, Frank Nowak, Dr. Dagmar Preugschat and Markus Wasgindt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314561

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      A perfluorinated diisocyanide was stabilized for the first time in complex 1 (cis form is depicted). The carbon atoms of the isocyanides are susceptible to nucleophilic attack, and 1 reacts with Me2NH with the elimination of a [Cr(CO)5] substituent to give an imidazole derivative with an annelated fluoro-substituted four-membered ring.

    21. A Light-Induced Molecular Shuttle Based on a [2]Rotaxane-Derived Triad (pages 1459–1461)

      Dr. Andrew C. Benniston and Dr. Anthony Harriman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314591

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      Light-induced charge separation, rapid intrarotaxane electron transfer over a short distance, migration of the two rotaxane components relative to each other, and a slow intrarotaxane electron transfer over a longer distance are the steps that enable molecular shuttle motion (see scheme on the right). Ferrocene, bipyridinium, and dialkoxybenzene units play a crucial role in this process.

    22. DNA Supercoiling Imaged in Three Dimensions by Scanning Force Microscopy (pages 1461–1463)

      Prof. Bruno Samori, Dr. Carmelo Nigro, Valerio Armentano, Salvatore Cimieri, Giampaolo Zuccheri and Prof. Carla Quagliariello

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314611

      Until now only planar projections of the molecular shape of supercoiled circular DNA molecules could be imaged with scanning force microscopy (SFM). In the three-dimensional image of a supercoiled pBR322 DNA molecule in this report, the chirality and writhing number can be “read” directly. Local changes in the supercoiling in individual DNA molecules can be monitored, which should be important for our understanding of biological processes such as DNA transcription.

    23. Structure of a One-Dimensional Infinite Double-Helical Copper(I) Complex (pages 1463–1465)

      Dr. Riccardo F. Carina, Dr. Gérald Bernardinelli and Dr. Alan F. Williams

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314631

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      Not intra-, but intermolecular stacking interactions between imidazole rings are responsible for the self assembly of the ainuclear Cu1 complex [Cu2L2]2+ to an infinite double-helical polymer (picture on the right) in the solid state. In recent years a range of double-helical complexes of low-molecular weight has been prepared; however, [Cu2L2]math image is the first polymeric complex of this type.

    24. The First Structurally Characterized Heterodinuclear Double-Helicate Complex (pages 1465–1467)

      Dr. Edwin C. Constable, Dr. Andrew J. Edwards, Dr. Paul R. Raithby and Juliet V. Walker

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314651

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      The head-to-head self assembly of two [CoAgL2]3+ units in the solid state results in a tetranuclear complex (shown on the right), which is not held together by Ag[BOND]Ag interactions, but by stacking interactions between pyridine rings. This and the preceeding communication show that supramolecular complex chemistry is booming.

    25. Rotation about the C[BOND]Se Bond as the Rate-Determining Step in the Racemization of α-Selenium-Substituted Alkyllithium Compounds (pages 1467–1468)

      Dipl.-Chem. Thomas Ruhland, Dipl.-Chem. Ruprecht Dress and Prof. Dr. Reinhard W. Hoffmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314671

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      New possibilities for increasing the stability of the configuration of α-heteroatomsubstituted alkyllithium compounds follow from the unexpected finding that ortho methyl groups influence the rate of racemization of α-arylselenoalkyllithium compounds. According to this observation, rotation about the C[BOND]X bond (X [DOUBLE BOND] Se) [Eq. (a)] can be the rate-determining step.

    26. Effects of Ion Pair Separation on Inversion and Rotation of Sulfur-, Selenium-, and Silicon-Stabilized Organolithium Reagents (pages 1469–1470)

      Prof. Dr. Hans J. Reich and Robert R. Dykstra

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314691

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      What affects the configurational stability of chiral organolithium reagents? It is frequently proposed that ion pair separation plays a key role in the configurational inversion of alkyllithium compounds. But NMR studies of 1 and 2 show that the configurational stability of the solvent-separated ion pair is greater than that of the contact ion pair.

    27. The Search for an Isolable Silyl Cation Must Continue (pages 1471–1473)

      Prof. Dr. Paul von Ragué Schleyer, Peter Buzek, Dr. Thomas Müller, Prof. Dr. Yitzhak Apeloig and Prof. Dr. Hans-Ullrich Siehl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314711

      Evidently a σ complex and not a free uncomplexed silyl cation is present in the crystals of 1· toluene. This follows from ab initio studies into the structure of the cationic complexes [Me3Si[BOND]toluene]+, [Me3Si[BOND]benzene]+, and [H3Si[BOND]benzene]+ as well as from IGLO calculations of the δ(29Si) values of these complexes. The differences between these and σ complexes with alkyl groups can be ascribed to the more effective C[BOND]Si hyperconjugation. Compound 1. toluene was recently described as “the first free silyl cation”.

      • equation image
    28. Non-Twisted Tetrakis(organosilyl)ethene (pages 1473–1475)

      Dr. Masahiro Murakami, Dr. Michinori Suginome, Kenzo Fujimoto and Prof. Dr. Yoshihiko Ito

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314731

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      Intramolecular bissilylation under high pressure yields the ethene derivative 1, whose structure is not twisted about the C[DOUBLE BOND]C bond. Its UV spectra and crystal structure suggests that the weak absorption at 361 nm is attributable to the fourfold Si substitution and not, as previously suggested for tetrakis(organosilyl)ethenes, from twisting.

    29. A Nickel-Anthracene Complex Having η3 and η4 Coordination in One Crystal (pages 1475–1477)

      Priv.-Doz. Dr. Roland Boese, Dr. Amnon Stanger, Dipl.-Chem. Peter Stellberg and Anat Shazar

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314751

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      Two independent isomeric molecules in one crystal. This was the surprising result of the X-ray structural analysis of 1. Both molecules can be considered as representatives of transition states of the η2 ⇇η2 rearrangement that is common in Nio–arene complexes.

    30. Synthesis, Structure, and Reactivity of Stable PN Heterocycles with Two and Six Methyleneamine Units: [H2C[DOUBLE BOND]N[BOND]N(Me)]2 P(S)(Ph) and [H2C[DOUBLE BOND]N[BOND]N(Me)]6P3N3 (pages 1477–1479)

      Christophe Galliot, Dr. Anne-Marie Caminade, Dr. Françoise Dahan and Dr. Jean Pierre Majoral

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314771

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      Since it remains unchanged after several days in air and several months under H2O-free argon, the hydrazone 1 is unexpectedly stable; however, methyleneamines R[BOND]N[DOUBLE BOND]CH2 rapidly di-, tri-, or polymerize. Compound 1 reacts with (iPr2N)math imageCF3SOmath image as an imine not as a hydrazone-and affords the cationic heterocycles 2 and 3 (counterion is CF3math image).

    31. Carbenerhodium Complexes with Diaryl- and Aryl(alkyl)carbenes as Ligands: The Missing Link in the Series of the Double Bond Systems trans-[RhCl{[DOUBLE BOND] C([DOUBLE BOND]C)nRR′}(L)2] Where n [DOUBLE BOND] 0, 1, and 2 (pages 1480–1482)

      Dipl.-Chem. Peter Schwab, Dipl.-Chem. Norbert Mahr, Dr. Justin Wolf and Prof. Dr. Helmut Werner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314801

      Thumbnail image of graphical abstract

      That compounds bearing homologous ligands—here PiPr3 and SbiPr3—can behave differently is underlined by the synthesis of the first carbenerhodium(i) complexes in which the carbene is not stabilized by a heteroatom. Compound 1 (characterized by X-ray structural analysis) undergoes a variety of interesting ligand displacement reactions, giving, for example, 2 (L [DOUBLE BOND] SbiPr3, CO, CNtBu) and 3. Diphenylketene is obtained by coupling of the carbene ligand with CO.

    32. Synthesis and Structure of Surprisingly Stable Tetrakis(trifluoromethyl)cuprate(III) Salts (pages 1482–1483)

      Prof. Dr. Dieter Naumann, Dipl.-Chem. Thomas Roy, Dr. Karl-Friedrich Tebbe and Dipl.-Chem. Wolfgang Crump

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314821

      Thumbnail image of graphical abstract

      CF3 groups stabilize the CuIII center in the complex anion [Cu(CF3)4] (1). Salts of 1 with large cations are easy to prepare by oxidation of CuI-CF3 compounds with, for example, I2. The CuIII center in 1 has approximately square-planar coordination geometry, and the F atoms form one planar hexagon above the CuC4 plane and one below. • [DOUBLE BOND]Cu, ◯ [DOUBLE BOND] C, equation image [DOUBLE BOND] F.

    33. Synthesis and Structure of a Sixteen-Membered (AINCO)4 Ring (pages 1483–1484)

      Craig M. Bird, Catherine Breheny, Matthew G. Davidson, Dr. Andrew J. Edwards, S. Clare Llewellyn, Dr. Paul R. Raithby and Dr. Ronald Snaith

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314831

      Thumbnail image of graphical abstract

      The unprecedented ring size in tetramer 1 arises from the alternation of the

      • equation image

      coordinating units in the sixteen-membered macrocycle. This alternation spaces out the ring components of the OxO ligands, and the flat aromatic rings of the ligands align themselves in near-parallel pairs (shown on the right). Tetramer 1 is prepared from Me3A1 and OxOH in toluene.

      • equation image
    34. The First Example of an Increase in the Enantioselectivity of a Chemical Reaction in the Presence of a Chiral Lewis Acid under High Pressure (pages 1485–1486)

      Prof. Dr. Lutz F. Tietze, Dipl.-Chem. Christian Ott, Kerstin Gerke and Prof. Dr. Michael Buback

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314851

      Thumbnail image of graphical abstract

      The enantioselectivity increases from 4.5 to 20.4% ee in favor of the (–)-enantiomer in the intramolecular hetero-Diels-Alder reaction of 1, which provides 2 and 3 when the pressure is increased from 1 to 5000 bar. A chiral Lewis acid is also employed in this reaction.

    35. The Behavior of Cp*MoBr/Br2 Redox Systems: The Unusual Structure of [(Cpmath imageMo2Br4)2(Cp*MoBr4)3], a Compound Containing MoIII, MoIV, and MoV (pages 1486–1488)

      Dr. Jahanvi U. Desai, Dr. John C. Gordon, Dr. Heinz-Bernhard Kraatz, Dr. Beth E. Owens-Waltermire, Prof. Rinaldo Poli and Prof. Arnold L. Rheingold

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314861

      Thumbnail image of graphical abstract

      A MoIV anion, a neutral MoV complex, and a mixed-valence MoIII/MoIV cation are found within the same crystal of the title compound 1, which is prepared by the reaction of [(Cp*MoBr2)2] with bromine in benzene. The coexistence of three oxidation states of molybdenum within 1 and the formation of 1 is rationalized based on the particular redox behavior of the individual constituents of the redox system Cp*MoBr/Br2. The anion [Cp*MoBr4] in 1 is shown on the right. Cp* [DOUBLE BOND] η5-C5Me5.

      • equation image
    36. Coherence Selection by Gradients without Signal Attenuation: Application to the Three-Dimensional HNCO Experiment (pages 1489–1491)

      Dipl.-Chem. Jürgen Schleucher, Dipl.-Chem. Michael Sattler and Prof. Dr. Christian Griesinger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314891

      Maximum sensitivity and excellent suppression of the water signal is achieved in 3D triple-resonance NMR experiments by the application of a heteronuclear gradient echo in phase-modulating pulse sequences. This principle is demonstrated for an HNCO experiment applied to a complex of a uniformly 13C/15Nlabeled protein (calmodulin) and a peptide (C2OW).

    37. Amination of Methane and Ethane by Mercury Photosensitization in the Presence of Ammonia (pages 1491–1492)

      Dr. Demetrius Michos, Caroline A. Sassano, Dr. Paul Krajnik and Prof. Dr. Robert H. Crabtree

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314911

      When the primary products are condensed in a cold trap to prevent further reaction, CH4/NH3 and C2H6/NH3 mixtures can be converted into imines in the presence of Hg vapor on UV irradiation [Eq. (a)]. Slowing the gas circulation rate during the photolysis leads to C[BOND]C bond formation; for example, CH3CH[DOUBLE BOND]NH is formed from CH4/NH3. R [DOUBLE BOND] H, CH3.

      • equation image
    38. A New Type of Paratungstate (pages 1492–1494)

      Prof. Dr. Hans Hartl, Rosemarie Palm and Prof. Dr. Joachim Fuchs

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314921

      Thumbnail image of graphical abstract

      For 65 years it has been discussed whether hexatungstate ions exist. Now the confirmation of their existence and the structural analysis of Na5[H3W6O22] · 18H2O have been achieved; in aqueous solution the latter is probably in equilibrium with the known [W7O24]6− ion. The polyhedral representa tion of the structure of [H3W6O22]5− is shown on the right.

    39. β-Na3Hg: A Solid with a Quasi-Fluid Sodium Substructure between 36 and 60°C (pages 1494–1495)

      Prof. Dr. Hans-Jörg Deiseroth and Dipl.-Chem. Matthias Rochnia

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314941

      The higher melting component of β-Na3Hg, namely the Na atoms, are mobile in the solid at relatively low temperature (36–60 °C) throughout the range of existence of this structural modification. In contrast, the Hg atoms show no unusual mobility. β-Na3Hg crystallizes in a distorted rhombohedral Li3Bi-type structure.

    40. Tetranuclear Silver(I) Clusters Linked by Bridging Succinate Anions in a Three-Dimensional Network: Crystal Structure of Succinatodisilver(I) (pages 1495–1497)

      Dr. Adonis Michaelides, Vangelis Kiritsis, Dr. Stavroula Skoulika and Dr. Andre Aubry

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314951

      Silver nitrate and succinic acid react to form the pale yellow prisms of succinatodisilver(I) (1). The structure of 1 (shown on the right) contains Ag4 clusters parallel to the ac plane, each of which are bound to four other clusters through succinato bridges.

      • equation image
  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Book Review: Organic Peroxides. Edited by W. Ando (page 1498)

      Axel G. Griesbeck

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199314981