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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Bipolar Tribocharging Signal During Friction Force Fluctuations at Metal–Insulator Interfaces
Dr. Thiago A. L. Burgo and Dr. Ali Erdemir
Friction force fluctuation and tribocurrent generation at metal–insulator interfaces show a strong correlation during sliding contacts. The reported results suggest that these two phenomena have a common origin that must be associated with the occurrence of strong electrostatic interactions at the interface.
Unravelling the Correlation between the Aspect Ratio of Nanotubular Structures and Their Electrochemical Performance To Achieve High-Rate and Long-Life Lithium-Ion Batteries
Dr. Yuxin Tang, Dr. Yanyan Zhang, Jiyang Deng, Dr. Dianpeng Qi, Wan Ru Leow, Jiaqi Wei, Dr. Shengyan Yin, Prof. Zhili Dong, Prof. Rachid Yazami, Prof. Zhong Chen and Prof. Xiaodong Chen
A new aspect: When titanate-based nanotubes are used to fabricate electrode materials, the aspect ratio of the nanostructures correlates with the electrochemical performance in lithium-ion batteries. These insights should be useful in the development of efficient energy devices based on nanomaterials.
Sustainable Electrical Energy Storage through the Ferrocene/Ferrocenium Redox Reaction in Aprotic Electrolyte
Dr. Yu Zhao, Yu Ding, Dr. Jie Song, Dr. Gang Li, Prof. Guangbin Dong, Prof. John B. Goodenough and Prof. Guihua Yu
The redox couple ferrocene/ferrocenium is applied for the construction of a liquid cathode Li-ion redox battery for electrical energy storage. The redox reaction is highly reversible and efficient. Even after 250 full charge/discharge cycles the capacity maintains ca. 90 % of the initial value and the Coulombic efficiency reaches 98–100 %.
Exceptional Isotopic-Substitution Effect: Breakdown of Collective Proton Tunneling in Hexagonal Ice due to Partial Deuteration
Dr. Christof Drechsel-Grau and Prof. Dr. Dominik Marx
Ab initio simulations clarify the effects of H/D isotopic substitution on the mechanism of the collective tunneling of six protons within proton-ordered cyclic water hexamers that are contained in proton-disordered ice. At the transition state, isotopic substitution leads to a Zundel-like [HO⋅⋅⋅D⋅⋅⋅OH] complex with localized ionic defects and thus inhibits perfectly correlated proton tunneling.
Highly Diastereoselective and Enantiospecific Allylation of Ketones and Imines Using Borinic Esters: Contiguous Quaternary Stereogenic Centers
Dr. Jack L.-Y. Chen and Prof. Dr. Varinder K. Aggarwal
Goldilocks reactivity: 3,3-Disubstituted allylic borinic esters possess the perfect balance between reactivity and configurational stability to react with both ketones and ketimines, allowing facile access to adjacent quaternary stereocenters with full stereocontrol. Synthesis of all possible stereoisomers of a quaternary-quaternary motif is demonstrated. TFAA=trifluoroacetic anhydride.
A Lightweight Polymer Solar Cell Textile that Functions when Illuminated from Either Side
Zhitao Zhang, Xueyi Li, Guozhen Guan, Shaowu Pan, Zhengju Zhu, Dayong Ren and Prof. Huisheng Peng
A polymer solar cell textile has been developed by sandwiching a metal textile electrode between two ultrathin, transparent, and conducting carbon nanotube sheets. Because of its unique structure, the resulting solar cell textile shows the same energy conversion efficiency regardless of which side it is irradiated from. Furthermore, its energy conversion efficiencies were maintained even after 200 bending cycles.
Core/Shell Au/MnO Nanoparticles Prepared Through Controlled Oxidation of AuMn as an Electrocatalyst for Sensitive H2O2 Detection
Huiyuan Zhu, Aruna Sigdel, Dr. Sen Zhang, Dr. Dong Su, Zheng Xi, Dr. Qing Li and Prof. Shouheng Sun
Cell sensing: AuMn alloy nanoparticles were synthesized through hydride reduction of manganese acetylacetonate in the presence of Au nanoparticles and were subsequently converted into Au/MnO nanoparticles through air annealing. The Au/MnO nanoparticles are active catalysts for the electrochemical reduction of H2O2 and can be used to measure the H2O2 levels from different types of cells for cancer detection.
Long-Lived Trifluoromethanide Anion: A Key Intermediate in Nucleophilic Trifluoromethylations
Prof. Dr. G. K. Surya Prakash, Dr. Fang Wang, Zhe Zhang, Prof. Dr. Ralf Haiges, Dr. Martin Rahm, Prof. Dr. Karl O. Christe, Dr. Thomas Mathew and Prof. Dr. George A. Olah
Rather persistent: For more than 60 years, the trifluoromethanide anion has been widely believed to exist only as an extremely transient species in the condensed phase, and to undergo swift decomposition to difluorocarbene and fluoride. The trifluoromethanide anion has now been successfully prepared, observed, and characterized for the first time in solution. Contrary to previous assumptions, the anion possesses considerable lifetime at subambient temperatures.
Chiral Amine Synthesis Using ω-Transaminases: An Amine Donor that Displaces Equilibria and Enables High-Throughput Screening
Dr. Anthony P. Green, Prof. Nicholas J. Turner and Dr. Elaine O'Reilly
ω-Transaminases (ω-TA) are employed as biocatalysts in a simple and efficient process for the synthesis of chiral amines. A dual-function diamine donor (ortho-xylylenediamine) serves to displace challenging reaction equilibria towards product formation whilst generating intensely colored by-products, which have allowed the development of liquid-phase and colony-based assays.
Reconfigurable Swarms of Nematic Colloids Controlled by Photoactivated Surface Patterns
Sergi Hernàndez-Navarro, Dr. Pietro Tierno, Prof. Joan Anton Farrera, Prof. Jordi Ignés-Mullol and Prof. Francesc Sagués
Swarming into focus: The assembly and transport of large ensembles of colloidal particles or droplets that are dispersed in a film of anisotropic fluid can be directly controlled by means of AC electrophoresis. Individual or collective particle steering is independently achieved by elastic modulation of the host nematic liquid crystal on a photosensitive confining surface.
A Designed Conformational Shift To Control Protein Binding Specificity
Dr. Servaas Michielssens, Dr. Jan Henning Peters, Dr. David Ban, Supriya Pratihar, Dr. Daniel Seeliger, Monika Sharma, Karin Giller, Dr. Thomas Michael Sabo, Dr. Stefan Becker, Dr. Donghan Lee, Prof. Dr. Christian Griesinger and Prof. Dr. Bert L. de Groot
Since protein dynamics is inextricably linked to protein function, protein functionality can be altered by manipulating protein dynamics. The specificity of protein–protein binding can be altered solely by a designed change in conformational preference, while leaving the binding interface untouched. This mechanism, which nature utilizes to control binding specificity, provides a novel route to designing protein function.
Switchable Bifunctional Stimuli-Triggered Poly-N-Isopropylacrylamide/DNA Hydrogels
Dr. Weiwei Guo, Dr. Chun-Hua Lu, Xiu-Juan Qi, Ron Orbach, Michael Fadeev, Prof. Huang-Hao Yang and Prof. Itamar Willner
All change! Nucleic acid-functionalized pNIPAM copolymers undergo bi-triggered phase transitions. In the presence of H+/OH− or Ag+/cysteamine, the polymers undergo cyclic and reversible gel-to-solution transitions. The hydrogels undergo further cyclic and reversible hydrogel/solid phase transitions upon heating and cooling the systems.
Reprogramming Nonribosomal Peptide Synthetases for “Clickable” Amino Acids
Dr. Hajo Kries, Rudolf Wachtel, Anja Pabst, Benedikt Wanner, David Niquille and Prof. Dr. Donald Hilvert
Pocketed: A single active site mutation reprograms the substrate specificity of nonribosomal peptide synthetase adenylation domains, enabling efficient incorporation of non-natural aromatic amino acids containing unique chemical functionality for bioorthogonal labeling.
An Easy Way To Prepare Monolithic Inorganic Oxide Aerogels
Dr. Lili Ren, Sumin Cui, Fengchao Cao and Qinghui Guo
Not cracking up: A drying method based on the sublimation of organic solvent allows the rapid synthesis of the monolithic inorganic oxide aerogels without cracks from wet gels. The method proceeds by endothermic evaporation of organic solvent at the outer surface followed by sublimation of solidified solvent (see picture).
Monitoring Morphology and Hydrogen Coverage of Nanometric Pt/γ-Al2O3 Particles by In Situ HERFD–XANES and Quantum Simulations
Agnes Gorczyca, Dr. Virginie Moizan, Dr. Celine Chizallet, Dr. Olivier Proux, William Del Net, Eric Lahera, Dr. Jean-Louis Hazemann, Dr. Pascal Raybaud and Dr. Yves Joly
Identifying the morphology of platinum nanoclusters supported on γ-alumina and the hydrogen coverage at a given temperature and hydrogen pressure is possible. The use of state-of-the-art methodologies combining high-resolution X-ray absorption near edge structure (XANES) in situ experiments, quantum molecular dynamics calculations, and XANES simulations gives unrivalled insights into catalyst characterization.
Integrating Perovskite Solar Cells into a Flexible Fiber
Longbin Qiu, Jue Deng, Xin Lu, Zhibin Yang and Prof. Huisheng Peng
Wearable perovskite solar cells with a fiber structure are synthesized by continuously winding an aligned carbon nanotube (CNT) sheet onto a stainless-steel wire; photoactive materials are incorporated in between them through a solution process. The fiber-shaped perovskite solar cell exhibits an energy conversion efficiency of 3.3 % and may be woven into electronic textiles.
Decay of FeV Nitride Complexes by a N–N Bond Coupling Reaction in Solution: A Combined Spectroscopic and Theoretical Analysis
Oliver Krahe, Eckhard Bill, and Frank Neese*
Cryogenically trapped FeV–nitride complexes with cyclam-based ligands were found to decay by bimolecular reactions, forming exclusively FeII compounds. Characterization of educts and products by Mössbauer spectroscopy, mass spectrometry, and spectroscopy-oriented DFT calculations showed that the reaction mechanism is reductive nitride coupling and release of dinitrogen (2FeV≡NFeII-N=N-FeII2FeII+N2). The reaction pathways, representing an "inverse" of the Haber–Bosch reaction, were computationally explored in detail, also to judge the feasibility that the converse would yield catalytically competent FeV(N). Implications for the photolytic cleavage of FeIII–azides used to generate high-valent Fe nitrides could be discussed.
Received March 20, 2014, published online May 18, 2014, DOI: 10.1002/anie.201403402 – read now.
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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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