Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Upcoming Hot Papers
Hot Papers are chosen by the Editors for their importance in a rapidly evolving field of high current interest. Many of the "Very Important Papers" (VIPs) would certainly qualify to be included here, but such a duplication is avoided.
Base-Promoted Coupling of Carbon Dioxide, Amines, and N-Tosylhydrazones: A Novel and Versatile Approach to Carbamates
Wenfang Xiong, Dr. Chaorong Qi, Haitao He, Lu Ouyang, Prof. Dr. Min Zhang and Prof. Dr. Huanfeng Jiang
Carbene intermediate? No! An unprecedented strategy for the synthesis of a range of organic carbamates through the coupling of carbon dioxide, amines, and N-tosylhydrazones is reported. The base-promoted reaction is proposed to proceed via a carbocation intermediate and is characterized by excellent functional group tolerance and a wide substrate scope.
Photocatalytic H2 Production
Palladium versus Platinum: The Metal in the Catalytic Center of a Molecular Photocatalyst Determines the Mechanism of the Hydrogen Production with Visible Light
Michael G. Pfeffer, Dr. Bernhard Schäfer, Dr. Grigory Smolentsev, Dr. Jens Uhlig, Dr. Elena Nazarenko, Dr. Julien Guthmuller, Dr. Christian Kuhnt, Dr. Maria Wächtler, Prof. Dr. Benjamin Dietzek, Prof. Dr. Villy Sundström and Prof. Dr. Sven Rau
Show your metal: The mechanism of the visible light-driven hydrogen production with an intramolecular photocatalyst depends on the nature of the catalytically active metal center. In Ru–M systems, where M=Pt or Pd, palladium forms metal colloids as initial step, whereas platinum shows a high stability and there is no change in the (N^N)PtCl2 coordination sphere.
Natural Product Synthesis
Total Synthesis of (−)-Caprazamycin A
Hugh Nakamura, Dr. Chihiro Tsukano, Motohiro Yasui, Shinsuke Yokouchi, Dr. Masayuki Igarashi and Prof. Dr. Yoshiji Takemoto
Abra‘capraza’: Caprazamycin A has significant antibacterial activity against Mycobacterium tuberculosis (TB). The first total synthesis is herein reported and features the scalable preparation of the syn-β-hydroxy amino acid with a thiourea-catalyzed diastereoselective aldol reaction, construction of a diazepanone with an unstable fatty-acid side chain, and global deprotection with hydrogenation.
Heterogeneous Water Oxidation: Surface Activity versus Amorphization Activation in Cobalt Phosphate Catalysts
Diego González-Flores, Irene Sánchez, Dr. Ivelina Zaharieva, Katharina Klingan, Jonathan Heidkamp, Dr. Petko Chernev, Dr. Prashanth W. Menezes, Prof. Dr. Matthias Driess, Prof. Dr. Holger Dau and Dr. Mavis L. Montero
The complete transformation during catalytic operation of crystalline and surface-active Co3(PO4)2⋅8 H2O into amorphous and volume-active cobalt oxide reveals basic features of heterogeneous water oxidation catalysis, which is discussed as a convolution of three phenomena: surface catalysis, volume catalysis, and restructuring of the material under operation.
Gas-Separation Membranes Loaded with Porous Aromatic Frameworks that Improve with Age
Dr. Cher Hon Lau, Dr. Kristina Konstas, Dr. Aaron W. Thornton, Dr. Amelia C. Y. Liu, Dr. Stephen Mudie, Dr. Danielle F. Kennedy, Dr. Shaun C. Howard, Dr. Anita J. Hill and Dr. Matthew R. Hill
Like red wine, membranes can improve with age. Small cavities of a permeable membrane (PIM-1) are prevented from collapsing using PAF-1 nanoparticles. Larger cavities however collapse over time. The result is that as the membrane ages, the transport of small gas molecules over larger gas molecules is preferred. Thus the membrane’s gas-separation properties improve with age.
Tunable Release of Multiplex Biochemicals by Plasmonically Active Rotary Nanomotors
Xiaobin Xu, Kwanoh Kim and Prof. Dr. Donglei Fan
Motorized nanomotor sensors are used to tune the release rate of biochemicals and allow their real-time detection. The nanomotor sensors are assembled from designed nanoentities and can be rotated controllably. Both single and multiple biochemicals can be released from the rotating nanomotor sensors in a tunable fashion.
Nickel-Catalyzed Monoarylation of Ammonia
Dr. Andrey Borzenko, Nicolas L. Rotta-Loria, Preston M. MacQueen, Christopher M. Lavoie, Dr. Robert McDonald and Prof. Dr. Mark Stradiotto
Lighten Up: The substrate scope of the title reaction includes (hetero)aryl chloride, bromide, and tosylate electrophiles. The versatility and potential scalability of the reported protocol is demonstrated by the use of either commercially available stock solutions of ammonia or ammonia gas.
Antibody Activation using DNA-Based Logic Gates
Brian M. G. Janssen, Martijn van Rosmalen, Lotte van Beek and Dr. Maarten Merkx
Logic antibody locks: Bivalent peptide–DNA conjugates are presented as generic, noncovalent, and easily applicable molecular locks that allow the control of antibody activity using toehold-mediated strand displacement. By connecting antibody-based molecular recognition and DNA-based computing, this new approach allows the introduction of autonomous signal-processing in antibody-based targeting.
Ratiometric Fluorescence Imaging of Cellular Polarity: Decrease in Mitochondrial Polarity in Cancer Cells
Na Jiang, Jiangli Fan, Feng Xu, Prof. Xiaojun Peng, Huiying Mu, Prof. Jingyun Wang and Xiaoqing Xiong
… and BOB’s your uncle: A fluorescent probe of mitochondrial polarity, termed BOB, showed a linear ratiometric fluorescence response to solution polarity. Various mitochondria of normal cells and cancer cells were examined, and it was found that mitochondrial polarity tends to be lower in cancer cells than in normal cells. The detection of mitochondrial polarity could thus be used as a method to distinguish cancer cells from normal cells.
Indolo-Phakellins as β5-Specific Noncovalent Proteasome Inhibitors
Dr. Philipp Beck, Theresa A. Lansdell, Nicole M. Hewlett, Prof. Dr. Jetze J. Tepe and Prof. Dr. Michael Groll
Nonpeptidic ligands: Inhibitors with new mechanisms of action are needed to tackle the ineffectiveness of currently marketed peptidic proteasome blockers for the treament of solid tumors. The crystal structure of the yeast 20S proteasome in complex with a natural product inspired alkaloid reveals an unexpected binding action. The presented compound provides an ideal scaffold for the structure-based design of subunit-specific, nonpeptidic proteasome-blockers.
Sensitive and Multiplexed On-chip microRNA Profiling in Oil-Isolated Hydrogel Chambers
Dr. Hyewon Lee, Rathi L. Srinivas, Ankur Gupta and Prof. Patrick S. Doyle
miRNA profiling: A versatile hydrogel-based microfluidic approach and novel amplification scheme were used for entirely on-chip, sensitive, and highly specific miRNA detection (let-7a, miR-145, and miR-21; see picture) without the risk of sequence bias. The approach uses photopolymerized hydrogel microposts for miRNA capture and labeling with a universal sequence. Fluorescence products are concentrated into the completely isolated gel posts.
The Nature of Photocatalytic “Water Splitting” on Silicon Nanowires
Dong Liu, Leilei Li, Yang Gao, Dr. Chengming Wang, Prof. Jun Jiang and Prof. Yujie Xiong
The production of hydrogen gas by photocatalytic water splitting on silicon nanowires was investigated. It occurs through cleavage of SiH bonds and formation of SiOH bonds; the surface dangling bonds have a great impact on charge separation.
A Small-Molecule Protein–Protein Interaction Inhibitor of PARP1 That Targets Its BRCT Domain
Zhenkun Na, Bo Peng, Shukie Ng, Sijun Pan, Prof. Dr. Jun-Seok Lee, Prof. Dr. Han-Ming Shen and Prof. Dr. Shao Q. Yao
Array and break: By establishing a high-throughput microplate-based assay for screening potential inhibitors of protein–protein interactions of the PARP1 BRCT domain, (−)-gossypol was found to possess novel PARP1 inhibitory activity both in vitro and in cancer cells, presumably by acting as a chemical dimerizer of the PARP1 BRCT domain, which causes disruption of protein–protein interactions and leads to inhibition of the enzymatic activity.
Atomically Thin Arsenene and Antimonene: Semimetal–Semiconductor and Indirect–Direct Band-Gap Transitions
Dr. Shengli Zhang, Prof. Zhong Yan, Prof. Dr. Yafei Li, Prof. Dr. Zhongfang Chen and Prof. Haibo Zeng
Unlike black phosphorus, both arsenic and antimony are typical semimetals in their natural, layered bulk state. However, monolayered arsenene and antimonene are indirect wide-band-gap semiconductors, and under strain, they become direct band-gap semiconductors. Owing to these band-gap transitions, these materials could find applications in nano- and optoelectronic devices.
Hydrogen Evolution Reaction
Enhanced Electron Penetration through an Ultrathin Graphene Layer for Highly Efficient Catalysis of the Hydrogen Evolution Reaction
Jiao Deng, Pengju Ren, Dehui Deng and Xinhe Bao
An advanced electrocatalyst consists of uniform CoNi nanoalloys that are encapsulated by ultrathin graphene shells (1–3 layers) and exhibits high activity and stability in the hydrogen evolution reaction (HER) in acidic medium. This study paves the way for the design of high-performance, low-cost HER electrocatalysts and other catalysts that can be employed under harsh conditions.
Carbon Dioxide Fixation
Visible-Light-Driven CO2 Reduction with Carbon Nitride: Enhancing the Activity of Ruthenium Catalysts
Ryo Kuriki, Dr. Keita Sekizawa, Prof. Dr. Osamu Ishitani and Prof. Dr. Kazuhiko Maeda
A heterogeneous photocatalyst that is based on a carbon nitride material modified by a ruthenium complex enables the reduction of CO2 into formic acid with a high turnover number (>1000) and a good apparent quantum yield (5.7 % at 400 nm). These are the highest values that have been reported for CO2 reduction by heterogeneous photocatalysts under visible-light irradiation to date (TEOA=triethanolamine).
Application of Fragment-Based Screening to the Design of Inhibitors of Escherichia coli DsbA
Dr. Luke A. Adams, Dr. Pooja Sharma, Dr. Biswaranjan Mohanty, Olga V. Ilyichova, Dr. Mark D. Mulcair, Dr. Martin L. Williams, Ellen C. Gleeson, Dr. Makrina Totsika, Dr. Bradley C. Doak, Dr. Sofia Caria, Dr. Kieran Rimmer, Dr. James Horne, Dr. Stephen R. Shouldice, Mansha Vazirani, Dr. Stephen J. Headey, Brent R. Plumb, Prof. Jennifer L. Martin, Dr. Begoña Heras, Dr. Jamie S. Simpson and Dr. Martin J. Scanlon
Combating bacterial virulence: DsbA is an oxidoreductase enzyme and a key mediator of virulence in Escherichia coli. Using fragment-based screening, compounds were developed that inhibit DsbA activity in vitro and E. coli motility in a cell-based assay. Crystal structures of the compounds in complex with DsbA provide a rationale for their activity.
Unraveling the Intrinsic Color of Chlorophyll
Dr. Bruce F. Milne, Dr. Yoni Toker, Prof. Angel Rubio and Prof. Steen Brøndsted Nielsen
Taking chlorophylls out of leaves: From a combination of gas-phase spectroscopy and theoretical calculations, the intrinsic colors of chlorophyll a and b reveal themselves. The two molecules isolated in vacuo absorb further to the blue than when in a solution or located within a protein pocket of photosynthesis systems, unequivocally demonstrating red-shifting effects of the microenvironment.
The Phosphinoboration Reaction
Erika N. Daley, Christopher M. Vogels, Dr. Stephen J. Geier, Dr. Andreas Decken, Dr. Simon Doherty and Prof. Dr. Stephen A. Westcott
Phosphine machine: Phosphinoboronate esters containing a reactive PB bond were synthesized. These compounds add to aldehydes, ketones, aldimines, and α,β-unsaturated ketones in the absence of a catalyst or strong base and to CC multiple bonds in the first examples of transition-metal-catalyzed phosphinoboration reactions.
Generation of a Genetically Encoded, Photoactivatable Intein for the Controlled Production of Cyclic Peptides
M. Sc. Jana K. Böcker, M. Sc. Kristina Friedel, M. Sc. Julian C. J. Matern, M. Sc. Anne-Lena Bachmann and Prof. Dr. Henning D. Mootz
Split inteins provide a powerful approach to cyclic peptides and libraries thereof, but the spontaneous nature of the protein splicing reaction prevents a convenient purification from cellular mixtures. A novel photoactivatable intein that can be purified from E. coli cells to produce the cyclic product in a controlled fashion is now reported and expected to facilitate screening and lead identification.
Excluded-Volume Effects in Living Cells
David Gnutt, Mimi Gao, Oliver Brylski, Dr. Matthias Heyden and Prof. Dr. Simon Ebbinghaus
Crowding in cells: A FRET-labeled homopolymer serves as a sensor to study macromolecular crowding in single living cells. Contrary to expectations, the cellular environment does not lead to a compression of the sensor. The sensor is further utilized to probe sub-cellular heterogeneities and crowding changes upon osmotic stress.
Krebs Cycle Metabolon: Structural Evidence of Substrate Channeling Revealed by Cross-Linking and Mass Spectrometry
Fei Wu and Prof. Shelley Minteer
Enzymes and channels: Part of the structure of the Krebs cycle metabolon was probed by mass spectrometry. Rational protein docking with cross-link constraints proposed an association of enzymes giving a two-fold symmetric octamer composed of two mMDH dimers and two ACON monomers bound to one CS dimer as the core. The electrostatic channels formed by enzyme association are favorable for direct transport of intermediates between active sites.
Live-Cell Imaging of Endogenous mRNAs with a Small Molecule
Dr. Shin-ichi Sato, Dr. Mizuki Watanabe, Dr. Yousuke Katsuda, Dr. Asako Murata, Dr. Dan Ohtan Wang and Prof. Motonari Uesugi
Spatiotemporal imaging of specific non-engineered RNAs in living cells is reported. The used method combined a gene-specific RNA aptamer with a cell-permeable synthetic small molecule, the fluorescence of which is restored only when the RNA aptamer hybridizes with its cognitive target RNA.
Liquid-Phase Epitaxial Growth of Two-Dimensional Semiconductor Hetero-nanostructures
Chaoliang Tan, Dr. Zhiyuan Zeng, Dr. Xiao Huang, Dr. Xianhong Rui, Dr. Xue-Jun Wu, Dr. Bing Li, Dr. Zhimin Luo, Junze Chen, Bo Chen, Prof. Qingyu Yan and Prof. Hua Zhang
Epitaxial growth of metal sulfide nanoplates, including CuS, ZnS, and Ni3S2, on ultrathin TiS2 nanosheets is achieved by a simple electrochemical approach. Ultrathin triangular/hexagonal CuS nanoplates (50–120 nm) are grown on TiS2 nanosheets with perfect epitaxial alignment. The 2D CuS–TiS2 composite is used as anode in a lithium-ion battery, which exhibits high capacity and excellent cycling stability.
Hydrodeoxygenation of Vicinal OH Groups over Heterogeneous Rhenium Catalyst Promoted by Palladium and Ceria Support
Nobuhiko Ota, Dr. Masazumi Tamura, Dr. Yoshinao Nakagawa, Prof. Kazu Okumura and Prof. Keiichi Tomishige
Ultra-fast double cutting: High yields (>99 %), turnover frequencies (TOF, 300 h−1), and turnover numbers (TON, 10 000) are achieved in the simultaneous hydrodeoxygenation of 1,4-anhydroerythritol to tetrahydrofuran over heterogeneous ReOx–Pd/CeO2 catalyst. This catalyst can be applied to sugar alcohols; mono-alcohols and diols are obtained in high yields (≥85 %).
Phosphorus-Doped Graphitic Carbon Nitrides Grown in Situ on Carbon-Fiber Paper: Flexible and Reversible Oxygen Electrodes
Dr. Tian Yi Ma, Jingrun Ran, Prof. Sheng Dai, Prof. Mietek Jaroniec and Prof. Shi Zhang Qiao
Electrodes, on a roll: Flexible and reversible oxygen electrodes composed of nanostructured P-doped graphitic carbon nitrides grown on carbon-fiber paper exhibit outstanding catalytic activity and stability towards both oxygen reduction (ORR) and oxygen evolution reactions (OER) in different folded and rolled-up forms. They can be used as efficient air cathodes in Zn–air batteries.
Unusual Ultra-Hydrophilic, Porous Carbon Cuboids for Atmospheric-Water Capture
Dr. Guang-Ping Hao, Giovanni Mondin, Dr. Zhikun Zheng, Tim Biemelt, Stefan Klosz, René Schubel, Prof. Alexander Eychmüller and Prof. Stefan Kaskel
Thirsty materials: A new class of ultra-hydrophilic porous carbon cuboids shows the best performance for atmospheric-water capture among porous carbons to date. It may serve as a model material for research on carbon chemistry, a new material for water capture, and find use in applications requiring highly hydrophilic surfaces, porosity, and stability.
Renewable Carbon Sources
Cyclic Alkyl Amino Carbene (CAAC) Ruthenium Complexes as Remarkably Active Catalysts for Ethenolysis
Dr. Vanessa M. Marx, Alexandra H. Sullivan, Dr. Mohand Melaimi, Dr. Scott C. Virgil, Dr. Benjamin K. Keitz, Dr. David S. Weinberger, Prof. Guy Bertrand and Prof. Robert H. Grubbs
A new series of olefin-metathesis catalysts containing cyclic alkyl amino carbene (CAAC) ligands exhibit unprecedented activity in the ethenolysis of methyl oleate. This work advances the state-of-the-art of the ethenolysis reaction and is expected to find particular use in large-scale industrial applications.
Synthesis of Inorganic Structural Isomers By Diffusion-Constrained Self-Assembly of Designed Precursors: A Novel Type of Isomerism
Marco Esters, Matti B. Alemayehu, Zachary Jones, Dr. N. T. Nguyen, Dr. Michael D. Anderson, Corinna Grosse, Prof. Saskia F. Fischer and Prof. David C. Johnson
Just as organic molecules have isomers resulting from different interconnectivity (as shown for C4H8), layered compounds have similar structural isomers. The six possible structural isomers containing four Se-Nb-Se trilayers and four bilayers of PbSe were synthesized from designed precursors. Thus, thousands of new compounds may be selectively prepared from fragments of known compounds.