Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
The following papers are very important in the opinion of two referees.
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Breathing Pores on Command: Redox-Responsive Spongy Membranes from Poly(ferrocenylsilane)s
Kaihuan Zhang, Xueling Feng, Dr. Xiaofeng Sui, Dr. Mark A. Hempenius and Prof. G. Julius Vancso
Redox-active porous membranes were synthesized from poly(ferrocenylsilane) PFS-based poly(ionic liquid)s (see picture; pore formation using ammonia/water). Reversible switching between more open and more closed porous structures, induced by oxidation and reduction, was demonstrated.
Scanning Electrochemical Microscopy of Individual Catalytic Nanoparticles
Tong Sun, Yun Yu, Brian J. Zacher and Prof. Michael V. Mirkin
Tip size matters: Extremely small polished platnium electrodes were used as scanning electrochemical microscopy tips to attain spatial resolution higher than that of ordinary atomic force microscopy imaging or super-resolution optical techniques. Electron transfer and catalytic hydrogen evolution at individual metal nanoparticles were visualized (HOPG=highly ordered pyrolytic graphite).
Ruthenium–Porphyrin-Catalyzed Diastereoselective Intramolecular Alkyl Carbene Insertion into CH Bonds of Alkyl Diazomethanes Generated In Situ from N-Tosylhydrazones
Annapureddy Rajasekar Reddy, Cong-Ying Zhou, Zhen Guo, Jinhu Wei and Prof. Dr. Chi-Ming Che
Nose to tail: With a ruthenium–porphyrin catalyst, alkyl diazomethanes generated in situ from N-tosylhydrazones underwent efficient intramolecular C(sp3)H insertion to give substituted tetrahydrofurans and pyrrolidines (see scheme) in a reaction that can be viewed as a reductive coupling between CO and CH bonds to form a new CC bond. This transformation was applied in a concise synthesis of (±)-pseudoheliotridane.
Preparation of Stereoregular Isotactic Poly(mandelic acid) through Organocatalytic Ring-Opening Polymerization of a Cyclic O-Carboxyanhydride
Dr. Antoine Buchard, Dr. David R. Carbery, Prof. Matthew G. Davidson, Dr. Petya K. Ivanova, Dr. Ben J. Jeffery, Dr. Gabriele I. Kociok-Köhn and Dr. John P. Lowe
Controlling tactic(s): The use of pyridine alone as organocatalyst of the ring-opening polymerization (ROP) of a cyclic O-carboxyanhydride resulted in atactic poly(mandelic acid) (PMA), however, a well-defined pyridine/mandelic acid adduct enabled excellent control over the ROP, providing highly isotactic chiral PMA with an enhanced heat resistance. Tg=glass-transition temperature.
Formation of Dianions in Helium Nanodroplets
Andreas Mauracher, Matthias Daxner, Stefan E. Huber, Johannes Postler, Michael Renzler, Stephan Denifl, Paul Scheier and Andrew M. Ellis
Electron donation from He− to fullerene clusters inside liquid helium nanodroplets has led to the production of doubly charged anions. The evidence suggests that the dianions are made by a concerted two-electron transfer from He−, which is a new way of making dianions that may be applicable to other molecules and clusters.
Coexistence of 3d-Ferromagnetism and Superconductivity in [(Li1−xFex)OH](Fe1−yLiy)Se
Ursula Pachmayr, Fabian Nitsche, Dr. Hubertus Luetkens, Sirko Kamusella, Felix Brückner, Dr. Rajib Sarkar, Prof. Dr. Hans-Henning Klauss and Prof. Dr. Dirk Johrendt
Opposites united: Superconductivity and ferromagnetism are antagonistic phenomena, and their coexistence is extremely rare. In [(Li1−xFex)OH](Fe1−yLiy)Se superconductivity emerges in iron selenide layers at 43 K, while iron atoms in hydroxide layers exhibit ferromagnetic ordering at 10 K and generate a spontaneous vortex phase.
Manipulating Nanowire Assembly for Flexible Transparent Electrodes
Dr. Jian-Wei Liu, Jin-Long Wang, Zhi-Hua Wang, Wei-Ran Huang and Prof. Shu-Hong Yu
Nano networking: Silver nanowires and Te nanowires are co-assembled by the Langmuir–Blodgett technique. Etching away the Te nanowires leaves Ag nanowire networks in which the spacing between the Ag wires is controlled by the Te nanowires. By manipulating the spacing between nanowires the optical transparency and electrical conductivity of flexible Ag nanowire electrodes can be precisely tailored.
High-Performance Liquid-Catalyst Fuel Cell for Direct Biomass-into-Electricity Conversion
Wei Liu, Wei Mu and Prof. Dr. Yulin Deng
Plant light: The liquid-catalyst fuel cell is catalyzed solely by a polyoxometalate solution without any noble-metal components. Raw biomass, such as cellulose, starch, and even grass or wood powders, can be directly converted into electricity. High performance and a robust catalyst hold the key to achieving a breakthrough in direct biomass fuel-cell technology.
A Hexameric Peptide Barrel as Building Block of Amyloid-β Protofibrils
Dr. Christofer Lendel, Dr. Morten Bjerring, Dr. Anatoly Dubnovitsky, Robert T. Kelly, Dr. Andrei Filippov, Prof. Dr. Oleg N. Antzutkin, Prof. Dr. Niels Chr. Nielsen and Prof. Dr. Torleif Härd
Amyloid-β protofibrils are precursors to amyloid fibrils found in plaques in the brains of patients with Alzheimer’s disease. A stable form of Aβ protofibrils was engineered and studied by solid-state NMR spectroscopy. The structural model of hexameric building block oligomers clarifies biochemical issues related to the formation of protofibrils.
Dynamic Mirror-Symmetry Breaking in Bicontinuous Cubic Phases
Christian Dressel, Prof. Dr. Feng Liu, Dr. Marko Prehm, Dr. Xiangbing Zeng, Prof. Dr. Goran Ungar and Prof. Dr. Carsten Tschierske
Cubics with a twist: Polycatenar 5,5′-diphenyl-2,2′-bithiophenes (see picture) form two types of bicontinuous cubic phases. Though the molecules are achiral the cubic phase is always chiral, while the phase is achiral. The explanation is that in the phase the opposing chiralities of the two enantiomorphic networks cancel, but not so in the three-networks phase.
The Formation of Imidazolium Salt Intimate (Contact) Ion Pairs in Solution
Marcileia Zanatta, Dr. Anne-Lise Girard, Nathalia M. Simon, Prof. Gunter Ebeling, Prof. Hubert K. Stassen, Prof. Paolo R. Livotto, Prof. Francisco P. dos Santos and Prof. Jairton Dupont
Remote pKa control is the result of the formation of intimate contact ion pairs in CDCl3 and CD3CN of 1-n-butyl-2,3-dimethyl imidazolium ionic liquids associated with HCO3 or prolinate anions. These salts are effective neutral catalysts for the H/D exchange reaction from CDCl3 to substrates containing acidic H.
Bowl-like SnO2@Carbon Hollow Particles as an Advanced Anode Material for Lithium-Ion Batteries
Jin Liang, Dr. Xin-Yao Yu, Han Zhou, Hao Bin Wu, Prof. Shujiang Ding and Xiong Wen (David) Lou
Super Bowl: A bowl-like hybrid hollow nanostructure of SnO2@carbon is designed and fabricated as an anode material for lithium-ion batteries. With advantages of the unique architecture, the bowl-like SnO2@carbon particles are able to deliver a high discharge capacity of 963 mAh g−1 even after 100 cycles at a current density of 0.4 A g−1.
Photo-Organocatalysis of Atom-Transfer Radical Additions to Alkenes
Dr. Elena Arceo, Dr. Elisa Montroni and Prof. Dr. Paolo Melchiorre
Light and simple: An organic molecule as simple as p-anisaldehyde can efficiently catalyze the intermolecular atom-transfer radical addition of a variety of haloalkanes onto olefins. The protocol requires irradiation from a household 23 W compact fluorescent light (CFL) bulb to proceed, and ambient temperature is sufficient to functionalize olefins in a synthetically useful fashion.
Ultrahigh Energy Density Realized by a Single-Layer β-Co(OH)2 All-Solid-State Asymmetric Supercapacitor
Shan Gao, Dr. Yongfu Sun, Fengcai Lei, Liang Liang, Jiawei Liu, Wentuan Bi, Prof. Bicai Pan and Prof. Yi Xie
An atomically thin β-Co(OH)2 sheet electrode was used to fabricate an all-solid-state asymmetric supercapacitor with high energy density. The β-Co(OH)2 layers are characterized by 100 % exposed hydrogen atoms, thus facilitating efficient Faradaic redox reactions. The energy density of 98.9 Wh kg−1 can compete with the world’s highest energy density for supercapacitors.
Semisynthesis of Biologically Active Glycoforms of the Human Cytokine Interleukin 6
Andreas Reif, Sebastian Siebenhaar, Andrea Tröster, Marina Schmälzlein, Carolin Lechner, Phanindra Velisetty, Karen Gottwald, Claudia Pöhner, Irene Boos, Volker Schubert, Prof. Stefan Rose-John and Prof. Carlo Unverzagt
The sequence matters: The human cytokine interleukin 6 (IL-6) was synthesized in two glycoforms by sequential native chemical ligation from two recombinant fragments (A, C) and a synthetic glycopeptide (B). Only one of the possible sequences of ligations efficiently led to the IL variants because of the susceptibility of the peptide chain and the folded glycoprotein to nonphysiological conditions.
De Novo 3D Structure Determination from Sub-milligram Protein Samples by Solid-State 100 kHz MAS NMR Spectroscopy
Dr. Vipin Agarwal, Susanne Penzel, Kathrin Szekely, Riccardo Cadalbert, Emilie Testori, Andres Oss, Jaan Past, Prof. Ago Samoson, Prof. Matthias Ernst, Dr. Anja Böckmann and Prof. Beat H. Meier
Smaller and faster: The 3D structure of a model protein was determined with a protein sample one-fortieth of the usual amount thanks to 100 kHz magic-angle-spinning NMR spectroscopy.
Nanocrystalline-Graphene-Tailored Hexagonal Boron Nitride Thin Films
Kang Hyuck Lee, Dr. Hyeon-Jin Shin, Dr. Brijesh Kumar, Han Sol Kim, Jinyeong Lee, Dr. Ravi Bhatia, Dr. Sang-Hyeob Kim, In-Yeal Lee, Dr. Hyo Sug Lee, Prof. Gil-Ho Kim, Prof. Ji-Beom Yoo, Dr. Jae-Young Choi and Prof. Sang-Woo Kim
A hexagonal boron nitride (h-BN) thin film with an atomically flat surface was obtained using unintentionally formed nanocrystalline graphene (nc-G). A wafer-scale dielectric h-BN thin film was synthesized on a bare sapphire substrate by assistance of nc-G, which prevented structural deformations during chemical vapor deposition. The sp3-hybridized edges of nc-G play a key role during these processes.
Watson–Crick Base Pairing Controls Excited-State Decay in Natural DNA
Dominik B. Bucher, Alexander Schlueter, Prof. Dr. Thomas Carell and Prof. Dr. Wolfgang Zinth
Shedding light on DNA: The excited-state dynamics of each nucleobase in calf thymus DNA following UV excitation could be determined with femtosecond IR spectroscopy. It was shown that the Watson–Crick base pairing opens up a new excited-state decay channel in double-stranded DNA, an effect that deactivates charge-transfer states.
Rate Coefficients of Criegee Intermediate (CH2OO and CH3CHOO) Reactions with Formic and Acetic Acid Are Close to Their Collision Limit: Direct Kinetics Measurements and Atmospheric Implications
Oliver Welz, Arkke J. Eskola, Leonid Sheps, Brandon Rotavera, John D. Savee, Adam M. Scheer, David L. Osborn, Douglas Lowe, A. Murray Booth, Ping Xiao, M. Anwar H. Khan, Carl J. Percival,* Dudley E. Shallcross,* and Craig A. Taatjes*
Rate coefficients for reactions of Criegee intermediates (carbonyl oxides, CI) with organic acids are in excess of 1x10-10 cm3 s-1, suggesting that reaction with carboxylic acids is a substantially more important loss process for CI than has been assumed. Implementing these rate coefficients in global atmospheric models shows that reactions between CI and organic acids make a substantial contribution to removal of these acids in terrestrial equatorial areas and in other regions where high CI concentrations occur such as high northern latitudes, and implies that sources of acids in these areas are larger than previously recognized.
Received January 28, 2014, published online March 25, 2014, DOI: 10.1002/anie.201400964 – read now.
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