Chemistry - A European Journal

Cover image for Vol. 12 Issue 5

February 1, 2006

Volume 12, Issue 5

Pages 1299–1559

    1. Cover Picture: Controlled Self-Assembly of Amphiphilic Oligopeptides into Shape-Specific Nanoarchitectures (Chem. Eur. J. 5/2006) (page 1299)

      Tomoyuki Koga, Masahiro Higuchi, Takatoshi Kinoshita and Nobuyuki Higashi

      Article first published online: 23 JAN 2006 | DOI: 10.1002/chem.200690014

      Fine tuning of peptide sequence, reaction time, and solution pH enabled the construction of novel three-dimensional nanoarchitectures by controlled self-assembly of peptide building blocks (shown in the cover picture). Several self-assembled structures, such as β-sheet plates, β-sheet fibers, α-helix particles, and α-helix plates, were fabricated on the nanometer scale, and their conformation and self-assembling mechanisms studied. As suggested by N. Higashi et al. on page 1360 ff., this controlled self-assembly should elucidate the mechanism of peptide aggregation, and be useful in the design of novel biorelated nanomaterials.

    2. Acceleration of Organic Reactions through Aqueous Solvent Effects (pages 1312–1317)

      Michael C. Pirrung

      Article first published online: 28 SEP 2005 | DOI: 10.1002/chem.200500959

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      Water everywhere, but not a drop to drink. Using water as the medium for reactions of nonpolar reactants gives them a “green light.”

    3. Giant Porphyrin Wheels with Large Electronic Coupling as Models of Light-Harvesting Photosynthetic Antenna (pages 1319–1327)

      Takaaki Hori, Naoki Aratani, Akihiko Takagi, Takuya Matsumoto, Tomoji Kawai, Min-Chul Yoon, Zin Seok Yoon, Sung Cho, Dongho Kim and Atsuhiro Osuka

      Article first published online: 9 JAN 2006 | DOI: 10.1002/chem.200501373

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      Record breakers! The present report describes what is clearly the world record holder for porphyrin-based ring systems with the largest discrete porphyrin wheel (see figure). It could well be the record for any ring of purely synthetic origin. This could be important for the construction of porphyrin arrays with ample electronic interactions as a model of light-harvesting antenna.

    4. Proteo-Dendrimers Designed for Complementary Recognition of Cytochrome c: Dendrimer Architecture toward Nanoscale Protein Complexation (pages 1328–1338)

      Dharam Paul, Hiroyuki Miyake, Satoshi Shinoda and Hiroshi Tsukube

      Article first published online: 25 NOV 2005 | DOI: 10.1002/chem.200501131

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      Complementing nature: Proteo-dendrimers, in which polyanionic hepta(glutamic acids), fluorescent zinc porphyrinate cores, hydrophilic polyether surfaces, and nonpeptide hydrophobic dendrons are combined (see scheme), were developed for protein recognition. They undergo electrostatic interactions with cytochrome c in aqueous solution, and block its complexation with cytochrome b5.

    5. One-Armed Artificial Receptors for the Binding of Polar Tetrapeptides in Water: Probing the Substrate Selectivity of a Combinatorial Receptor Library (pages 1339–1348)

      Carsten Schmuck and Martin Heil

      Article first published online: 28 NOV 2005 | DOI: 10.1002/chem.200501062

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      Efficient binding even in water of polar tetrapeptides such as N-Ac-D-Glu-L-Lys-D-Ala-D-Ala-OH (EKAA) was observed for one-armed artificial receptors 1. Using the inverse substrate AAKE to probe the selectivity of a combinatorial receptor library, both on-bead and in free solution, reveals interesting insights into the structural requirements for efficient peptide complexation by this receptor class.

    6. Facile Synthesis and Optimization of Conductive Copolymer Nanoparticles and Nanocomposite Films from Aniline with Sulfodiphenylamine (pages 1349–1359)

      Xin-Gui Li, Qiu-Feng Lü and Mei-Rong Huang

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500486

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      Good conduct: Pure nanoparticles of electrically conductive aniline (AN) copolymers were synthesized by oxidative polymerization in acidic media without external stabilizer. Instead, a sulfodiphenylamine (SDP) comonomer unit was used as an internal stabilizer (see figure). The structures and properties of the copolymer nanoparticles were optimized.

    7. Controlled Self-Assembly of Amphiphilic Oligopeptides into Shape-Specific Nanoarchitectures (pages 1360–1367)

      Tomoyuki Koga, Masahiro Higuchi, Takatoshi Kinoshita and Nobuyuki Higashi

      Article first published online: 15 SEP 2005 | DOI: 10.1002/chem.200500611

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      A controlled self-assembly of amphiphilic oligopeptides into shape-specific nanoarchitectures was developed in aqueous media. A wide variety of self-organized three-dimensional architectures with well-defined conformations and nanostructures were obtained by tuning the peptide sequence and environmental conditions, as shown in the graphic.

    8. Solid-Phase Synthesis and Biological Activity of a Combinatorial Cross-Conjugated Dienone Library (pages 1368–1376)

      Makoto Kitade, Hiroshi Tanaka, Sho Oe, Makoto Iwashima, Kazuo Iguchi and Takashi Takahashi

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500793

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      A combinatorial library of cross-conjugated dienones based on clavulones has been synthesized and the biological activity of the compounds synthesized has been investigated. Combinatorial synthesis of a small library with twelve halides and eight aldehydes resulted in 76 desired compounds from 98 candidates (see graphic), and were detected by their mass spectra. Antiproliferative effects of crude compounds showed that eleven samples demonstrated strong antitumor activity; the purified samples showed strong cytotoxicity against five tumor cell lines comparable to that of adriamycin except for one case.

    9. Water-Soluble Fluorescent Boronic Acid Compounds for Saccharide Sensing: Substituent Effects on Their Fluorescence Properties (pages 1377–1384)

      Yanling Zhang, Xingming Gao, Kenneth Hardcastle and Binghe Wang

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500982

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      A lighter view of sugar: Four boronic acid based fluorescent sensors (14) were synthesized and studied. Compound 1 shows ratiometric fluorescence changes upon addition of a sugar, while compounds 2 and 3 show a very large fluorescence intensity increase (about 70-fold). The fluorescence color changes of 13 are also visible to the naked eye.

    10. A Family of Ferro- and Antiferromagnetically Coupled Decametallic Chromium(III) Wheels (pages 1385–1396)

      David M. Low, Gopalan Rajaraman, Madeleine Helliwell, Grigore Timco, Joris van Slageren, Roberta Sessoli, Stefan T. Ochsenbein, Roland Bircher, Christopher Dobe, Oliver Waldmann, Hans-Ulrich Güdel, Mark A. Adams, Eliseo Ruiz, Santiago Alvarez and Eric J. L. McInnes

      Article first published online: 28 NOV 2005 | DOI: 10.1002/chem.200501041

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      Exchange within wheels: Decametallic chromium(III) wheels are reported, [Cr10(OR)20(O2CR′)10] (see picture), in which the Cr⋅⋅⋅Cr exchange can be ferromagnetic or antiferromagnetic depending on the choice of the bridging alkoxides.

    11. A Simple and Efficient Approach to 1,3-Polyols: Application to the Synthesis of Cryptocarya Diacetate (pages 1397–1402)

      Pradeep Kumar, Priti Gupta and S. Vasudeva Naidu

      Article first published online: 25 NOV 2005 | DOI: 10.1002/chem.200501029

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      Practicality is the key! A short and practical enantioselective synthesis of cryptocarya diacetate (see scheme) has been achieved with high diastereomeric excess by using Jacobsen's hydrolytic kinetic resolution (HKR), diastereoselective iodine-induced electrophilic cyclization, and ring-closing metathesis (RCM) as the key steps.

    12. Density Functional Studies of Dicobalt Octacarbonyl-Mediated Azobenzene Formation from 4-Ethynylaniline (pages 1403–1412)

      Yi-Luen Huang and Fung-E Hong

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500744

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      Azobenzene formation: Two reaction pathways mediated by [Co2(CO)8] are proposed for the formation of azobenzene (C6H5N[DOUBLE BOND]NC6H5) from the primary amine (NH2C6H5) (see scheme). The validity of the mechanism is examined by utilizing density functional theory methods. Hydride-migration steps are established as the most energy-demanding processes.

    13. New Insights into the Mechanism of Proton Transfer to Hydride Complexes: Kinetic and Theoretical Evidence Showing the Existence of Competitive Pathways for Protonation of the Cluster [W3S4H3(dmpe)3]+ with Acids (pages 1413–1426)

      Andrés G. Algarra, Manuel G. Basallote, Marta Feliz, M. Jesús Fernández-Trujillo, Rosa Llusar and Vicent S. Safont

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500695

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      How does proton transfer to tungsten hydride clusters occur? Kinetic, NMR and theoretical studies indicate that the reaction of [W3S4H3(dmpe)3]+ (dmpe=1,2-bis(dimethylphosphanyl)ethane) with acids in CH2Cl2 may occur through two competitive pathways. The kinetic studies reveal that one of the pathways shows an unprecedented second-order dependence with respect to the acid. The theoretical calculations indicate that the role of the HX molecules is to form hydrogen-bonded adducts (see picture) that evolve to the final product through dihydrogen complexes as transition states.

    14. Decacyclene as Complexation Manifold: Synthesis, Structure and Properties of Its Fe2 and Fe4 Slipped Triple-Decker Complexes (pages 1427–1435)

      Jörg J. Schneider, Dirk Spickermann, Christian W. Lehmann, Jörg Magull, Hans-Jörg Krüger, Jürgen Ensling and Philipp Gütlich

      Article first published online: 7 NOV 2005 | DOI: 10.1002/chem.200500100

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      Two out of three naphthalene subunits of decacyclene can coordinate two or four {(η5-(Me4EtC5)Fe} fragments. These metal–ligand fragments decorate in an alternating fashion different sides of the π perimeter, which adopts a gently twisted propeller geometry (see picture). Cyclic voltammetry revealed a strong electronic interaction of the coordinated iron centers across the decacyclene ligand.

    15. A Designed Well-Folded Monomeric Four-Helix Bundle Protein Prepared by Fmoc Solid-Phase Peptide Synthesis and Native Chemical Ligation (pages 1436–1447)

      Gunnar T. Dolphin

      Article first published online: 11 NOV 2005 | DOI: 10.1002/chem.200500458

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      A monomeric 90-residue-long native-like four-helix bundle protein (see picture) has been prepared by thiol chemical ligation and standard fluorenylmethoxycarbonyl (Fmoc) chemistry. Its design, total chemical synthesis, and structural characterization are described.

    16. Hollow Silica Spheres with an Ordered Pore Structure and Their Application in Controlled Release Studies (pages 1448–1456)

      Nicole E. Botterhuis, Qianyao Sun, Pieter C. M. M. Magusin, Rutger A. van Santen and Nico A. J. M. Sommerdijk

      Article first published online: 25 NOV 2005 | DOI: 10.1002/chem.200500588

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      Hollow silica spheres with a defined porous wall structure are prepared by the mineralization of a trimethylbenzene emulsion stabilized by a b-poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO–PPO–PEO) block copolymer (see picture). These spheres can be used for the encapsulation and controlled release of both hydrophilic and hydrophobic dye molecules.

    17. Origin of Stereoinduction by Chiral Aminophosphane Phosphinite Ligands in Enantioselective Catalysis: Asymmetric Hydroformylation (pages 1457–1467)

      Jorge J. Carbó, Agustí Lledós, Dieter Vogt and Carles Bo

      Article first published online: 28 NOV 2005 | DOI: 10.1002/chem.200500606

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      Different substrate–ligand interactions with the substituents of the stereogenic center at the aminophosphane P atom in axial position are responsible for stereodifferentiation in Rh-catalyzed asymmetric hydroformylation with aminophosphane phosphinite ligands according to hybrid QM/MM and pure DFT calculations. Thus the pro-S transition state for styrene insertion into the Rh[BOND]H bond (picture, left) is favored over its pro-R counterpart (right), because the π–π interaction of the former is stronger than the CH–π interaction of the latter.

    18. Synthesis and Photophysical Properties of Annulated Dinuclear and Trinuclear Phthalocyanines (pages 1468–1474)

      Sergey Makarov, Christian Litwinski, Eugeny A. Ermilov, Olga Suvorova, Beate Röder and Dieter Wöhrle

      Article first published online: 25 NOV 2005 | DOI: 10.1002/chem.200500617

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      Stick together: Metal-free mono-, di-, and trinuclear phthalocyanines were synthesised. The phthalocyanine units of the dimer and trimer were connected through common annulated benzene rings and contain a totally delocalized π-electron system leading to long wavelength shifts of the Q band absorption (see figure).

    19. Controlling the Nature of Mixed (Phthalocyaninato)(porphyrinato) Rare-Earth(III) Double-Decker Complexes: The Effects of Nonperipheral Alkoxy Substitution of the Phthalocyanine Ligand (pages 1475–1485)

      Rongming Wang, Renjie Li, Yong Li, Xianxi Zhang, Peihua Zhu, Pui-Chi Lo, Dennis K. P. Ng, Na Pan, Changqin Ma, Nagao Kobayashi and Jianzhuang Jiang

      Article first published online: 28 NOV 2005 | DOI: 10.1002/chem.200500733

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      Controlling the nature of heteroleptic rare-earth(III) sandwich complexes. An in-depth study of the influence of alkoxy-substitution of the phthalocyanine ligand on the formation of (phthalocyaninato)(porphyrinato) rare-earth(III) double-decker complexes. The protonated and nonprotonated forms are indicated in the scheme.

    20. Unprecedented Stereoselective Synthesis of Catalytically Active Chiral Mo3CuS4 Clusters (pages 1486–1492)

      Marta Feliz, Eva Guillamón, Rosa Llusar, Cristian Vicent, Salah-Eddine Stiriba, Julia Pérez-Prieto and Mario Barberis

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500907

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      Chiral catalysts: An efficient strategy for preparing enantiomerically pure heterodimetallic cubane-type clusters of the general formula [Mo3CuS4(diphosphane)3Cl4]+ has been developed. NMR spectroscopy, X-ray crystallography, and circular dichroism analyses (see figure) confirmed their chiral purity. Catalytic activity/selectivity performance of the clusters was also investigated.

    21. Unusual High-Temperature Structural Behaviour in Ferroelectric Bi2WO6 (pages 1493–1499)

      Neil A. McDowell, Kevin S. Knight and Philip Lightfoot

      Article first published online: 28 NOV 2005 | DOI: 10.1002/chem.200500904

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      Edge-sharing octahedral chains are a key element of the high-temperature paraelectric phase of Bi2WO6 (shown here). This contrasts dramatically with all other members of the Aurivillius family of ferroelectrics and has never been seen in related families of layered perovskites.

    22. Nucleic Acid Intercalators and Avidin Probes Derived from Luminescent Cyclometalated Iridium(III)–Dipyridoquinoxaline and –Dipyridophenazine Complexes (pages 1500–1512)

      Kenneth Kam-Wing Lo, Chi-Keung Chung and Nianyong Zhu

      Article first published online: 22 NOV 2005 | DOI: 10.1002/chem.200500885

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      The intercalative binding of a new class of luminescent iridium(III)–dipyridoquinoxaline and –dipyridophenazine complexes to double-stranded DNA and synthetic oligonucleotides has been studied by using absorption and emission titrations. The avidin-binding properties of the biotin-containing complexes (one of which is shown in the figure) have also been investigated.

    23. Phospholipase Cleavage of D- and L-chiro-Glycosylphosphoinositides Asymmetrically Incorporated into Liposomal Membranes (pages 1513–1528)

      Julia B. Bonilla, M. Belén Cid, F.-Xabier Contreras, Félix M. Goñi and Manuel Martín-Lomas

      Article first published online: 28 NOV 2005 | DOI: 10.1002/chem.200500833

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      Substrate specificity: The nature of chiro-inositol-containing inositolphosphoglycans, putative insulin mediators, was studied by examination of the substrate specificities of phosphatidylinositol-specific phospholipase C (PI-PLC) and glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) by using a series of synthetic D- and L-chiro-glycosylphosphoinositides, asymmetrically incorporated into phospholipid bilayers in the form of large unilamellar vesicles.

    24. Ruthenium-Cluster-Mediated Activation of All Bonds of a Methyl Group of 6,6′-Dimethyl-2,2′-bipyridine and 2,9-Dimethyl-1,10-phenanthroline: Transformation of the Latter into a 2-Alkenyl-9-methyl-1,10-phenanthroline Ligand (pages 1529–1538)

      Javier A. Cabeza, Ignacio del Río, Lorena Martínez-Méndez and Daniel Miguel

      Article first published online: 22 NOV 2005 | DOI: 10.1002/chem.200500813

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      Activation of all the bonds of a C-bound methyl group of 6,6′-dimethyl-2,2′-bipyridine and 2,9-dimethyl-1,10-phenanthroline transforms this methyl carbon atom into a carbide. This process was observed during the study of the reactivity of [Ru3(CO)12] with these methylated ligands and has allowed the preparation of 2-alkenyl-9-methyl-1,10-phenanthroline ligands (some examples of the isolated products are shown).

    25. Synthesis of Strained Tricyclic β-Lactams by Intramolecular [2+2] Cycloaddition Reactions of 2-Azetidinone-Tethered Enallenols: Control of Regioselectivity by Selective Alkene Substitution (pages 1539–1546)

      Benito Alcaide, Pedro Almendros, Cristina Aragoncillo, María C. Redondo and M. Rosario Torres

      Article first published online: 18 NOV 2005 | DOI: 10.1002/chem.200500807

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      Fine tune your chemistry! Just by a subtle variation in the substitution pattern of the alkene component, the regioselectivity of thermal [2+2] cycloaddition reactions of 2-azetidinone-tethered enallenols can be tuned to afford a vast array of structurally novel, strained tricyclic β-lactams (see scheme).

    26. Control of Metal-Ion Composition in the Synthesis of Ternary II-II′-VI Nanoparticles by Using a Mixed-Metal Cluster Precursor Approach (pages 1547–1554)

      Marty W. DeGroot, Harald Rösner and John F. Corrigan

      Article first published online: 30 NOV 2005 | DOI: 10.1002/chem.200501081

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      Zinc into it! Ternary Zn-Cd-Se and Zn-Cd-Te molecular nanoclusters have been employed as single-source precursors for the synthesis of high-quality ZnxCd1−xSe and ZnxCd1−xTe (illustrated) nanocrystals, respectively. The thermolysis of the molecular precursors in hexadecylamine solvent provides a route in which the inherent metal-ion stoichiometry of the clusters is retained in the nanocrystalline materials.

    27. Preview: Chem. Eur. J. 5/2006 (page 1559)

      Article first published online: 23 JAN 2006 | DOI: 10.1002/chem.200690016