39,525 results match your criteria Angewandte Chemie International Edition [Journal]


Large SHG Effect and High LIDT Observed Coexisting in Gallium Selenide: a Simple but Perfect Case.

Angew Chem Int Ed Engl 2019 Apr 19. Epub 2019 Apr 19.

CHINA.

A big challenge for nonlinear optical materials is the application in high power lasers, which needs the simultaneous occurrence of large second harmonic generation (SHG) and high laser induced damage threshold (LIDT). This work reports the preparation of a new Ga2Se3 phase, which shows the SHG intensities of around 2.3 times and the LIDT of around 16. Read More

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http://dx.doi.org/10.1002/anie.201902839DOI Listing

Subcellular duplex DNA and G-quadruplex interaction profiling of a hexagonal Pt(II) metallacycle.

Angew Chem Int Ed Engl 2019 Apr 19. Epub 2019 Apr 19.

Donostia International Physics Center, Chemistry, Manuel Lardizabal Ibilbidea, 4, 20018, Donostia, SPAIN.

Metal-driven self-assembly afforded a multitude of fascinating supramolecular coordination complexes (SCCs) with applications as catalysts, host-guest and stimuli-responsive systems. However, the interest in SCCs' biological applications is only starting to emerge and thorough characterization of their behaviour in biological milieus is still lacking. Here, we report on the synthesis and detailed in-cell tracking of a Pt2L2 metallacycle. Read More

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http://dx.doi.org/10.1002/anie.201900934DOI Listing

Activity of Atomically Precise Titania Nanoparticles in CO Oxidation.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Institute of Chemistry Chinese Academy of Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, ZHONGGUANCUN NORTH FIRST STREET 2, 100190, BEIJING, CHINA.

Understanding the property evolution of atomically precise nanoparticles along the continuous change of size atom by atom is critical for selecting potential candidates to assemble nanomaterials with desirable functionality, but it is very experimentally challenging especially for the systems having mixtures of elements such as metal oxides. In this work, the capability to oxidize carbon monoxide has been experimentally measured for titania nanocluster anions of (TiO2)nOm- (-3 ≤ m ≤ 3) across a rather broad size range in gas phase. The stoichiometric (TiO2)nO- exhibits superior oxidative activity over other clusters of (TiO2)nOm- (m ≠ 1) even when the cluster dimensions upsize to n = 60, indicating that each atom still counts in the chemical behaviour of titania nanoparticles composed of ~180 atoms. Read More

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http://dx.doi.org/10.1002/anie.201902008DOI Listing

Cobalt-Catalyzed Allylic Alkylation Enabled by Organophotoredox Catalysis.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Hokkaido University, Faculty of Pharmaceutical Sciences, Kita-ku, Lab of Synthetic Organic Chemistry, 060-0812, Sapporo, JAPAN.

Co-catalyzed allylic substitution reactions have long received little attention arguably because no characteristic advantage of Co catalysis over Rh or Ir catalysis was ever known. Here we describe a general and regioselective Co-catalyzed allylic alkylation using an in situ catalyst activation by organophotoredox catalysis. This noble-metal-free catalytic system exhibited unprecedentedly high reactivity and regioselectivity for the allylation with an allyl sulfone, for the first time representing a unique synthetic utility of a Co-catalyzed method compared to the related Rh- or Ir-catalyzed reactions. Read More

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http://dx.doi.org/10.1002/anie.201902509DOI Listing

Biocompatible SuFEx Click Chemistry: Thionyl Tetrafluoride (SOF4) Derived Connective Hubs For Bioconjugation to DNA and Proteins.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Scripps Research Institute, Department of Chemistry, 10550 N. Torrey Pines Road, 92037, La Jolla , UNITED STATES.

We report here the development of a suite of biocompatible SuFEx transformations from the SOF4-derived iminosulfur oxydifluoride-hub in aqueous buffer conditions. Thes biocompatible SuFEx reactions of iminosulfur oxydifluorides (R-N=SOF2) with primary amines give sulfamides (8 examples, up to 98%), while the reaction with secondary amines furnish sulfuramidimidoyl fluoride products (8 examples, up to 97%). Likewise, under mild buffered conditions, phenols react with the iminosulfur oxydifluorides (Ar-N=SOF2) to produce sulfurofluoridoimidates (13 examples, up to 99%), which can themselves be further modified by nucleophiles. Read More

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http://dx.doi.org/10.1002/anie.201902489DOI Listing

Transition-Metal Free Deconstructive Lactamization of Piperidines.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

MEXICO.

One of the major synthetic challenges in organic synthesis is the activation or deconstructive functionalization of unreactive C(sp3)-C(sp3) bonds. This requires using transition or precious metal catalysts. However, we present here a deconstructive lactamization of piperidines without using transition metal catalysts. Read More

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http://doi.wiley.com/10.1002/anie.201903880
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http://dx.doi.org/10.1002/anie.201903880DOI Listing
April 2019
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Gold Difluorocarbenoid Complexes: Spectroscopic and Chemical Profiling.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

GERMANY.

Gold carbenes of the general type [LAu=CR2]+ are sufficiently long-lived for spectroscopic inspection only if the substituents R compensate for the largely missing stabilization of the carbene center by the [LAu]+ fragment. pi-Donation by two fluorine substituents (R = F) is insufficient; rather, difluorocarbene complexes are so deprived in electron density that they sequester even weakly coordinating anions such as triflate or triflimide. This particular bonding situation translates into unmistakable carbenium ion chemistry upon reaction with stilbene as a model substrate. Read More

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http://doi.wiley.com/10.1002/anie.201903957
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http://dx.doi.org/10.1002/anie.201903957DOI Listing
April 2019
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A Photochemical Route towards Metal Sulfide Nanosheets from Layered Metal Thiolate Complexes.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences (CAS), Key Laboratory of Photochemical Conversion and Optoelectronic Materials, No.29 Zhongguancun East Road, Haidian District,, 100190, Beijing, CHINA.

Synthesizing nanomaterials with anisotropic architectures, especially two-dimensional (2D) nanosheets (NSs), is a key focus of materials science research. Metal sulfide nanosheets (MSNSs) are typically obtained involving exfoliation of bulk metal sulfides with layered structures. The synthesis of NSs of intrinsically non-layered metal sulfides has received relatively less attention. Read More

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http://doi.wiley.com/10.1002/anie.201902791
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http://dx.doi.org/10.1002/anie.201902791DOI Listing
April 2019
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How Many Phosphoric Acid Units Are Required to Ensure Uniform Occlusion of Sterically-Stabilized Nanoparticles within Calcite?

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

The University of Sheffield, Chemistry, UNITED KINGDOM.

Polymerization-induced self-assembly (PISA) mediated by reversible addition-fragmentation chain transfer (RAFT) polymerization offers a platform technology for the efficient and versatile synthesis of well-defined sterically-stabilized block copolymer nanoparticles. Herein we synthesize a series of such nanoparticles with tunable anionic charge density within the stabilizer chains, which are prepared via statistical copolymerization of anionic 2-(phosphonooxy)ethyl methacrylate (P) with non-ionic glycerol monomethacrylate (G). Systematic variation of the P/G molar ratio enables elucidation of the minimum number of phosphate groups per copolymer chain required to promote nanoparticle occlusion within a model inorganic crystal (calcite). Read More

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http://dx.doi.org/10.1002/anie.201901307DOI Listing

Interfacial Coordinational Coupled Defect Engineering Boosted Portable Zinc-Air Battery with Broad Work Temperature.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Lanzhou University, 222 South Tianshui Rd, Lanzhou, CHINA.

Atomic-thick interfacial dominated bifunctional catalyst NiO/CoO transition interfacial nanowires (TINWs) with abundant coordinational defective sites display high electroactivities and durabilities in the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). Density functional theory (DFT) calculations unravel that the excellent OER/ORR performance arises from the electron-rich interfacial region coupled with coordinational defective sites, thus endows the fast-redox rate with lower activation barrier for fast electron transfer. When assembled as air-electrode, NiO/CoO TINWs delivered the high specific capacity of 842. Read More

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http://dx.doi.org/10.1002/anie.201903879DOI Listing

Copper-Catalyzed N-F Bond Activation for Uniform Intramolecular C-H Amination to Pyrrolidines and Piperidines.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

SPAIN.

The dual function of the N-F bond as an effective oxidant and subsequent nitrogen source in intramolecular aliphatic C-H functionalization reactions is explored. Copper catalysis is demonstrated to exercise full regio- and chemoselectivity control, which opens new synthetic venues to nitrogenated heterocycles with predictable ring size. For the first time, a uniform catalysis manifold has been identified for the construction of both pyrrolidine and piperidine cores. Read More

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http://dx.doi.org/10.1002/anie.201902716DOI Listing

A general treatment to study molecular complexes stabilized by hydrogen, halogen and carbon bond networks: Experiment and theory of (CH2F2)n···(H2O)m.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Universidad del Pais Vasco, Química Física, Barrio Sarriena s/n, Facultad de Ciencia y Tecnología, 48940, Leioa, SPAIN.

Rotational spectra of several difluomethane water adducts have been observed using two broadband chirped pulse Fourier transform microwave (CP FTMW) spectrometers. The experimental structures of (CH2F2)···(H2O)2, (CH2F2)2···(H2O), (CH2F2)···(H2O)3 and (CH2F2)2···(H2O)2 were unambiguously identified with the aid of 18 isotopic substituted species. A subtle competition between hydrogen, halogen and carbon bonds is observed and a detailed analysis was performed on the complex network of non-covalent interactions, which stabilize each cluster. Read More

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http://dx.doi.org/10.1002/anie.201902753DOI Listing

Cross-peaks in simple 2D NMR experiments from chemical exchange of transverse magnetization.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

UNITED KINGDOM.

Two-dimensional correlation measurements such as COSY, NOESY, HMQC and HSQC experiments are central to small molecule and biomolecular NMR spectroscopy, and commonly form the basis of more complex experiments designed to study chemical exchange occurring during additional mixing periods. However, exchange occurring during chemical shift evolution periods can also influence the appearance of such spectra. While this is often exploited through one-dimensional lineshape analysis ('dynamic NMR'), the analysis of exchange across multiple chemical shift evolution periods has received less attention. Read More

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http://doi.wiley.com/10.1002/anie.201903245
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http://dx.doi.org/10.1002/anie.201903245DOI Listing
April 2019
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Ionophore-based biphasic chemical sensing in droplet microfluidics.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

University of Michigan, UNITED STATES.

Droplet microfluidics is an enabling platform for high-throughput screens, single cell studies, low-volume chemical diagnostics, and microscale material syntheses. Analytical methods for real-time and in situ detection of chemicals in the droplets will greatly benefit these applications, but they remain limited. Herein, we report a novel heterogeneous chemical sensing strategy based on functionalization of the oil phase with rationally combined sensing reagents. Read More

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http://doi.wiley.com/10.1002/anie.201902960
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http://dx.doi.org/10.1002/anie.201902960DOI Listing
April 2019
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Selenium-Modified Microgels as Bio-Inspired Oxidation Catalysts.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

DWI at RWTH Aachen, Macromolecular Chemistry, Pauwelsstrasse 8, 52056, Aachen, GERMANY.

Active colloidal catalysts inspired by the glutathione peroxidase (GPx) were synthesized by integration of catalytically active selenium (Se) moieties into aqueous microgels. Diselenide crosslinker (Se X-linker) was successfully synthesized and incorporated into microgels through precipitation polymerization, along with conventional crosslinker N,N´-Methylenebis(acrylamide) (BIS). Diselenide bonds inside the microgels were cleaved through oxidation by H2O2 and converted to seleninic acid whilst maintaining the microgel microstructure intact. Read More

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http://doi.wiley.com/10.1002/anie.201901161
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http://dx.doi.org/10.1002/anie.201901161DOI Listing
April 2019
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C-Terminal Bioconjugation of Peptides through Photoredox Catalyzed Decarboxylative Alkynylation.

Angew Chem Int Ed Engl 2019 Apr 18. Epub 2019 Apr 18.

Ecole Polytechnique Federale de Lausanne, ISIC - Laboratory of Catalysis and Organic Synthesis, EPFL BCH 4306 Batiment chimie UNIL, 1015, Lausanne, SWITZERLAND.

We report the first decarboxylative alkynylation of the C-terminus of peptides starting from free carboxylic acids. The reaction is fast, metal-free and proceeds cleanly to afford alkynylated peptides with a broad tolerance for the C-terminal amino acid. Through the use of hypervalent iodine reagents, the introduction of a broad range of functional groups was successful. Read More

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http://dx.doi.org/10.1002/anie.201901922DOI Listing

Activation of a nonheme Fe(III)-OOH by a second Fe(III) to hydroxylate strong C-H bonds: possible implications for sMMO.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

University of Minnesota Twin Cities, Chemistry, 207 Pleasant St. SE, 55455, Minneapolis, UNITED STATES.

Nonheme iron oxygenases contain either mono-iron or di-iron active sites, and the role of the second iron in the latter enzymes is a topic of particular interest, especially for soluble methane monooxygenase (sMMO). Herein we report the activation of a nonheme FeIII-OOH intermediate in a synthetic mono-iron system using FeIII(OTf)3 to form a high-valent oxidant capable of effecting cyclohexane and benzene hydroxylation within seconds at -40 °C. Our results show that the second iron acts as a Lewis acid to activate the iron-hydroperoxo intermediate, leading to the formation of a powerful FeV=O oxidant - a possible role for the second iron in sMMO. Read More

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http://doi.wiley.com/10.1002/anie.201903465
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http://dx.doi.org/10.1002/anie.201903465DOI Listing
April 2019
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Asymmetric Synthesis of Alkyl Fluorides: Hydrogenation of Fluorinated Olefins.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Stockholm University, Dept. of Organic Chemistry, 106 91, 106 91, Stockholm, SWEDEN.

The development of new general methods for the synthesis of chiral fluorine-containing molecules is important for several scientific disciplines. By the Ir-catalyzed asymmetric hydrogenation of tri-substituted vinyl-fluorides, a straightforward preparation of chiral organofluorine molecules is disclosed. The developed method represents a catalytic asymmetric process that enables the synthesis of chiral fluorine molecules with or without carbonyl framework. Read More

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http://dx.doi.org/10.1002/anie.201903954DOI Listing

Peptide-Directed DNA-Templated Protein Labelling for The Assembly of a Pseudo-IgM.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Aarhus University, Centre for DNA Nanotechnology at the Dept. of Chemsitry and iNANO, Gustav Wieds Vej 14, 8000, Aarhus, DENMARK.

The development of methods for conjugation of DNA to proteins is of high relevance for integration of protein function and DNA structures. Here, we demonstrate that protein binding peptides can direct a DNA-templated reaction, furnishing DNA-protein conjugates selectively with one DNA label. Quantitative conversion of oligonucleotides is achieved at low stoichiometries and the reaction can be performed in complex biological matrixes such as cell lysates. Read More

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http://dx.doi.org/10.1002/anie.201903134DOI Listing

Scalable biosynthesis of the seaweed neurochemical kainic acid.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

University of California at San Diego, Scripps Institution of Oceanography, 9500 Gilman Dr., 92093-0204, La Jolla, UNITED STATES.

Kainic acid, the flagship member of the kainoid family of natural neurochemicals, is a widely used neuropharmacological agent that helped unravel the key role of ionotropic glutamate receptors, including the kainate receptor, in the central nervous system. Worldwide shortages of this seaweed natural product in 2000 prompted numerous chemical syntheses that now number in excess of 70, including scalable preparations with as few as six-steps. Herein we report the discovery and characterization of the concise two-enzyme biosynthetic pathway to kainic acid from L-glutamic acid and dimethylallyl pyrophosphate in red macroalgae and show that the biosynthetic genes are co-clustered in genomes of Digenea simplex and the edible Palmaria palmata. Read More

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http://doi.wiley.com/10.1002/anie.201902910
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http://dx.doi.org/10.1002/anie.201902910DOI Listing
April 2019
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Chemistry of Layered Pnictogens: Phosphorus, Arsenic, Antimony, and Bismuth.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic.

Materials with few layers have been subjected to extensive research for the last few decades owing to their remarkable properties as for example catalysts, optical and electrical devices, or sensors. The properties and electronic structure of these materials can be tailored by the introduction of substituents. In the case of more reactive species, the modification also can improve stability, which is also an important factor with respect to device fabrication. Read More

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http://doi.wiley.com/10.1002/anie.201900811
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http://dx.doi.org/10.1002/anie.201900811DOI Listing
April 2019
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β-Selective Aroylation of Activated Alkenes by Photoredox Catalysis.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Department of Chemistry and Institute of Chemical Biology and Drug Discovery, The State University of New York at Stony Brook, Stony Brook, NY, 11794, USA.

Late-stage synthesis of α,β-unsaturated aryl ketones remains an unmet challenge in organic synthesis. Reported herein is a photocatalytic non-chain-radical aroyl chlorination of alkenes by a 1,3-chlorine atom shift to form β-chloroketones as masked enones that liberate the desired enones upon workup. This strategy suppresses side reactions of the enone products. Read More

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http://doi.wiley.com/10.1002/anie.201901874
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http://dx.doi.org/10.1002/anie.201901874DOI Listing
April 2019
2 Reads

Valence-to-Core X-ray Emission Spectroscopy as a Probe of O-O Bond Activation in Cu2O2 complexes.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

MPI CEC, Molecular Theory and Spectroscopy, Stidtstr. 34-36, 45470, Muelheim an der Ruhr, GERMANY.

Valence-to-Core (VtC) X-ray emission spectroscopy (XES) was used to directly detect the presence of an O-O bond in a complex comprising the [Cu2(II)(µ-η2:η2-O2)]2+ core relative to its isomer with a cleaved O-O bond having a [Cu(III)2(µ-O)2]2+ unit. The experimental studies are complemented by DFT calculations, which show that the unique VtC XES feature of the [Cu2(II)(µ-η2:η2-O2)]2+core corresponds to the copper stabilized in-plane 2p π peroxo molecular orbital. These calculations illustrate the sensitivity of VtC XES for probing the extent of O-O bond activation in µ-η2:η2-O2 species and highlight the potential of this method for time-resolved studies of reaction mechanisms. Read More

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http://doi.wiley.com/10.1002/anie.201903749
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http://dx.doi.org/10.1002/anie.201903749DOI Listing
April 2019
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Optical multiplexed bioassays improve biomedical diagnostics.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

CHINA.

Conventional analytical methods based on single detection to determine one disease marker are usually not sufficient and accurate because the progression of disease generally involves multiple chemicals and biomolecules. The drive for simultaneous analysis of multiple targets, which plays a key role in both basic biomedical research and clinical applications, demands the development of multiplexed bioassays with high-throughput. In this minireview, we systematically summarize the recent progress of optical multiplexed analytical techniques to improve biomedical diagnostics, in which fluorescence and surface enhanced Raman scattering (SERS) with distinctive optical features are chosen as the main readout signals. Read More

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http://dx.doi.org/10.1002/anie.201901964DOI Listing

Mitochondria-Targeting Intracellular Delivery of Native Proteins by Using Biodegradable Silica Nanoparticles.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

National University of Singapore, Department of Chemistry, 3 Science Dr., 117543, Singapore, SINGAPORE.

Mitochondria are key organelles in mammalian cells whose dysfunctions are linked to various diseases. Drugs targeting mitochondrial proteins thus provide a highly promising strategy for potential therapeutics. Current methods of mitochondria-targeting delivery of small molecule drugs are available, but not suitable for macromolecules such as proteins (including antibodies). Read More

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http://dx.doi.org/10.1002/anie.201901699DOI Listing

A Single Atom Change Facilitates the Membrane Transport of Green Fluorescent Proteins in Mammalian Cells.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Indian Institute of Science, Bangalore, 560012, Bangalore, INDIA.

Direct delivery of proteins into mammalian cells is a challenging problem in biological and biomedical applications. The most common strategies for the delivery of proteins into the cells include the use of cell-penetrating peptides or supercharged proteins. Herein, we show for the first time that a single atom change, hydrogen to halogen, at one of the tyrosine residues can increase the cellular entry of 28 kDa green fluorescent protein (GFP) in mammalian cells. Read More

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http://dx.doi.org/10.1002/anie.201902347DOI Listing

Induced Fit of C2H2 in a Flexible MOF through Cooperative Action of Open Metal Sites.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Jinan University, Chemistry, 601 Huangpu Avenue W, 510632, Guangzhou, CHINA.

Porous materials that can undergo pore structure adjustment to better accommodate specific molecules are ideal for separation and purification. Here we report a stable microporous metal-organic framework, JNU-1, featuring one-dimensional diamond-shaped channels with high-density of open metal sites arranged on the surface for cooperative binding of acetylene. Together with its framework flexibility and appropriate pore geometry, JNU-1 exhibits an induced-fit behavior for acetylene. Read More

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http://dx.doi.org/10.1002/anie.201904160DOI Listing

Oxygen evolution electrocatalysis of a single MOF-derived composite nanoparticle on the tip of a nanoelectrode.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Ruhr-Universitat Bochum, Analytische Chemie, Universitätsstr 150, 44780, Bochum, GERMANY.

Determination of the intrinsic electrocatalytic activity of nanomaterials by means of conventional macroelectrode techniques is compromised by ensemble and film effects. Here, a unique 'particle at the stick' approach is used to grow a single metal-organic frame-work (MOF) nanoparticle (ZIF-67) on a nanoelectrode surface which is subsequently pyrolyzed to generate a cobalt/nitrogen-doped carbon (CoN/C) composite nanoparticle that exhibits extremely high catalytic activity towards the oxygen evolution reaction (OER) with a current density of up to 230 mA cm-2 at 1.77 V (vs. Read More

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http://dx.doi.org/10.1002/anie.201903283DOI Listing
April 2019
11.261 Impact Factor

Functional Polyion Complex Vesicles enabled by Supramolecular Reversible Coordination Polyelectrolytes.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

East China University of Science and Technology, School of Chemical Engineering, Meilong Road 130, 200237, Shanghai, CHINA.

PICsomes (vesicles formed by polyelectrolyte complexation) have attracted attention as delivery systems for bio-cargo because they have walls consisting of hydrophilic yet insoluble polymer material, which may endow them with unique properties regarding permeability. So far, controlled formation of PICsomes seemed to require pairs of diblock copolymers with carefully length-matched anionic and cationic blocks, which is synthetically rather demanding. Here, we report a new class of PICsomes in which the anionic/neutral diblock copolymer is replaced by an anionic, reversible, supramolecular polyelectrolyte based on metal-ligand coordination. Read More

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http://dx.doi.org/10.1002/anie.201903513DOI Listing

A Peanut-Shaped Polyaromatic Capsule: Solvent-Dependent Transformation and Electronic Properties of a Non-Contacted Fullerene Dimer.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Tokyo Institute of Technology, Laboratory for Chemistry and Life Science, Institute of Innovative Research, 4259-R28, Nagatsuta, Midori-ku, 226-8503, Yokohama, JAPAN.

Synthesis of molecular containers capable of incorporating multiple fullerenes, for the study of the nanocluster properties, remains challenging. Here we report that room-temperature mixing of metal ions with W-shaped bispyridine ligands featuring polyaromatic panels results in the quantitative formation of a peanut-shaped M2L4 capsule. The polyaromatic capsule reversibly converts into two molecules of an ML2 double tube in response to changes in the solvent. Read More

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http://doi.wiley.com/10.1002/anie.201903117
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http://dx.doi.org/10.1002/anie.201903117DOI Listing
April 2019
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Organic Photodynamic Nanoinhibitor for Synergistic Cancer Therapy.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Nanyang Technological University, School of Chemical and Biomedical Engieering, 70 Nanyang Drive, 637457, Singapore, SINGAPORE.

Despite its great potential in cancer treatment, photodynamic therapy (PDT) often exacerbates hypoxia and subsequently compromises its therapeutic efficacy. To overcome this issue, an organic photodynamic nanoinhibitor (OPNi) is synthesized to have additional ability to counteract carbonic anhydrase IX (CA-IX), a molecular target in hypoxia-mediated signalling cascade. OPNi is composed of a metabolizable semiconducting polymer as the photosensitizer and a CA-IX antagonist-conjugated amphiphilic polymer as the matrix. Read More

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http://dx.doi.org/10.1002/anie.201903968DOI Listing

Iridium-Catalyzed Distal Hydroboration of Aliphatic Internal Alkenes.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, State Key Laboratory for Oxo Synthesis and Selective Oxidation, No. 18 Tianshui Middle Road, 730000, Lanzhou, CHINA.

Regioselective hydroboration of aliphatic internal alkenes remains a great challenge. Reported here is an iridium-catalyzed hydroboration of aliphatic internal alkenes, providing distal borylated products in good to excellent yields with high regioselectivity (up to 99:1). We also demonstrated that the C-B bond of the distal borylated product could be converted facilely to other functionalities. Read More

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http://doi.wiley.com/10.1002/anie.201902464
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http://dx.doi.org/10.1002/anie.201902464DOI Listing
April 2019
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Regio- and Enantioselective Formal Hydroamination of Enamines for the Synthesis of 1,2-Diamines.

Authors:
Lu Yu Peter Somfai

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Organic Chemistry, CAS, Getingevägen 69, 22100, Lund, SWEDEN.

The asymmetric formal hydroamination of enamines using Cu-H catalyst is reported. The method provides a straightforward and efficient approach for the synthesis of chiral 1,2-dialkyl amines in good yields with high level of enantioselectivities for a broad range of substrates, and should have significant value for the preparation of molecules bearing a 1,2-diamine motif. Read More

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http://dx.doi.org/10.1002/anie.201902642DOI Listing

Unidirectional presentation of membrane proteins in nanoparticle-supported liposomes.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Harvard Medical School, BCMP, 250 Longwood Ave, SGM 105, 02115, Boston, UNITED STATES.

Presentation of membrane proteins to host immune systems has been a challenging problem due to complexity arising from the poor in vivo stability of the membrane-mimetic media often used for solubilizing the membrane proteins. We report the use of functionalized, biocompatible nanoparticles as substrates to guide the formation of proteoliposomes that can present many copies of membrane proteins in a unidirectional manner. The approach was demonstrated to present the membrane-proximal region of the HIV-1 envelope glycoprotein. Read More

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http://doi.wiley.com/10.1002/anie.201903093
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http://dx.doi.org/10.1002/anie.201903093DOI Listing
April 2019
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Recent Advances on Electrochemical Biosensing Strategies toward Universal Point of Care Systems.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Case Western Reserve University, Chemical and Biomolecular Engineering, 10900 Euclid Ave, 44106, Cleveland, UNITED STATES.

A number of very recently developed electrochemical biosensing strategies are promoting electrochemical biosensing systems into practical point-of-care applications. Focus of research endeavors in biosensing community has transferred from detection of a specific analyte to the development of general biosensing strategies that can be applied for a single category of analytes, such as nucleic acid, protein and cell. In this review, we describe most recent cutting-edge researches on electrochemical biosensing strategies. Read More

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http://doi.wiley.com/10.1002/anie.201901879
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http://dx.doi.org/10.1002/anie.201901879DOI Listing
April 2019
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Concerted Nucleophilic Aromatic Substitution Reactions.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Nanyang Technological University, Division of Chemistry and Biological Chemistry, SINGAPORE.

Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSNAr),1,2 rather than classical two-step, SNAr mechanisms. Whereas traditional SNAr reactions require substantial activation of the aromatic ring by electron-withdrawing substituents, such activating groups are not mandatory in the concerted pathways. At this crucial stage of growth in understanding of these reactions, our aim is to review the current state of knowledge on CSNAr reactions. Read More

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http://dx.doi.org/10.1002/anie.201902216DOI Listing
April 2019
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Synthesis, Properties and Application of Tetrakis(pentafluoroethyl)gallate, [Ga(C2F5)4].

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Universität Bielefeld, Fakultät für Chemie, Universitätsstr. 25, 33615, Bielefeld, GERMANY.

Weakly coordinating anions (WCA) are important for academic reasons as well as for technical applications. Tetrakis(pentafluoroethyl)gallate, [Ga(C2F5)4]-, a new WCA, is accessible by treatment of [GaCl3(dmap)] (dmap = 4-dimethylaminopyridine) with LiC2F5. The anion [Ga(C2F5)4]- proved to be reluctant towards deterioration by aqueous hydrochloric acid or lithium hydroxide. Read More

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http://dx.doi.org/10.1002/anie.201904197DOI Listing
April 2019
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Lipase-powered mesoporous silica nanomotors for triglyceride degradation.

Angew Chem Int Ed Engl 2019 Apr 16. Epub 2019 Apr 16.

Institute for Bioengineering of Catalonia (IBEC), Smart Nano Bio Devices, Baldiri Reixac 10-12, 08028, Barcelona, SPAIN.

We report lipase-based nanomotors, capable of enhanced Brownian motion over long periods in triglyceride solution and of degrading triglyceride droplets that mimic 'blood lipids'. We achieved about 40 minutes of enhanced diffusion of lipase modified mesoporous silica nanoparticles (MSNPs) through a biocatalytic reaction between lipase and its corresponding water-soluble oil substrate (triacetin) as fuel, which resulted in an enhanced diffusion coefficient (i.e. Read More

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http://dx.doi.org/10.1002/anie.201900697DOI Listing

Geochemical Sources and Availability of Amidophosphates on the Early Earth.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

UNITED STATES.

Phosphorylation of (pre)biotically relevant molecules in aqueous medium leading to sugar-phosphates, (oligo)nucleotides, (oligo)peptides and lipids/vesicles has recently been demonstrated by the use of water-soluble diamidophosphate (DAP). Naturally, questions arise relating to the prebiotic plausibility and availability of DAP and other amidophosphosphorus species on the early earth. Herein, we demonstrate that DAP and other amino-derivatives of phosphates/phosphite are generated when Fe3P (surrogate of mineral schreibersite), condensed phosphates and reduced oxidation state phosphorus compounds that could be available on early earth are exposed to aqueous ammonia solutions. Read More

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http://doi.wiley.com/10.1002/anie.201903808
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http://dx.doi.org/10.1002/anie.201903808DOI Listing
April 2019
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Facile Preparation of Spirolactones by an Alkoxycarbonyl Radical Cyclization Cross-Coupling Cascade.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

UNITED STATES.

An alkoxycarbonyl radical 5-exo cyclization cross-coupling cascade has been developed that allows functionalized γ-butyrolactones to be prepared in one step from simple tertiary alcohol-derived homoallylic oxalate precursors. The reaction succeeds with aryl and vinyl electrophiles and is compatible with heterocyclic fragments in both coupling partners. This chemistry allows for the rapid construction of spirolactones, which are of interest in drug discovery endeavors. Read More

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http://dx.doi.org/10.1002/anie.201903353DOI Listing

Charge Transport through Self-assembled Monolayers of Monoterpenoids.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

Harvard University, Department of Chemistry, 12 Oxford Street, 02138, Cambridge, UNITED STATES.

The nature of the processes at the origin of life that selected specific classes of molecules for broad incorporation into cells is controversial. Among those classes selected were polyisoprenoids and their derivatives. This paper tests the hypothesis that polyisoprenoids were early contributors to membranes in part because they (or their derivatives) could facilitate charge transport by quantum tunneling. Read More

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http://doi.wiley.com/10.1002/anie.201902997
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http://dx.doi.org/10.1002/anie.201902997DOI Listing
April 2019
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The rise of fiber electronics.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

Fudan University, Deptm. of Macromolecular Science, 2205 Songhu Road, 200438, Shanghai, CHINA.

As a new direction of applied chemistry, fiber electronics allow configuration changes from three to two dimensions and then to one dimension in electronic devices. The resulting fiber devices have unique properties, such as ultraflexibility, tissue adaptability and weavability, enabling their use in a variety of applications, particularly in various emerging fields related to implantable devices and wearable systems. Here, we summarize the different types of fiber electrode materials based on the one-dimensional configuration and their distinctive interfaces, various devices and promising applications and highlight the remaining challenges and future directions. Read More

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http://dx.doi.org/10.1002/anie.201902425DOI Listing

Biomimetic chiral photonic crystals.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

The National Center for Nanoscience and Technology, No 11, Beiyitiao, Zhongguancun, 100190, Beijing, CHINA.

Although it is well known that the amazing iridescent colors from the cuticle of beetles reflect intricate nanoscale organization of bio-fibers, artificial inorganic materials with comparable optical response have not yet been synthesized with abiotic nano-building blocks. Such materials have broad applications including circular polarizers, circularly polarized luminescence, lasers, etc. Here, we describe a general method to fabricate biomimetic chiral photonic crystals via Langmuir-Schaefer assembly of colloidal inorganic nanowires. Read More

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http://dx.doi.org/10.1002/anie.201903264DOI Listing
April 2019
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Vibrational Signatures of Chirality Recognition Between alpha-Pinene and Alcohols for Theory Benchmarking.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

Universität Göttingen, Institut für Physikalische Chemie, Tammannstr. 6, 37077, Göttingen, GERMANY.

Chirality recognition between largely rigid molecules can be applied as a benchmark for the description of intermolecular forces by theoretical methods because one constituent is merely mirrored so that other deficits of the methods, such as neglect of anharmonicity, should mostly cancel. To test this approach, mixed OH···pi bridged dimers between the enantiomers of the bicyclic monoterpene alpha-pinene and the chiral secondary alcohols borneol, alpha-fenchol, isopinocampheol and 1-phenylethanol were formed in a supersonic jet and probed by linear FTIR spectroscopy. With borneol and alpha-fenchol, pronounced shifts in the hydroxyl stretching frequencies upon exchange of the handedness are observed. Read More

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http://dx.doi.org/10.1002/anie.201901687DOI Listing
April 2019
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Cobalt-Catalyzed Enantioselective Hydroboration/Cyclization of 1,7-Enynes: Asymmetric Synthesis of Chiral Quinolinones Containing Quaternary Stereogenic Centers.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

National University of Singapore, Chemistry, 3 Science Drive 3, 117543, Singapore, SINGAPORE.

An asymmetric cobalt-catalyzed hydroboration/cyclization of 1,7-enynes to synthesize chiral six-membered N-heterocyclic compounds was developed. A variety of aniline-tethered 1,7-enynes react with pinacolborane to afford the corresponding chiral boryl-functionalized quinoline derivatives in high yields with high enantioselectivity. This cobalt-catalyzed asymmetric cyclization of 1,7-enyens provides a general approach to access a series of chiral quinoline derivatives containing quaternary stereocenters. Read More

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http://dx.doi.org/10.1002/anie.201903377DOI Listing

Oxygen Evolution Reaction at Carbon Edge Sites: Activity Evolution and Structure-Function Relationships Clarified by Polycyclic Aromatic Hydrocarbons.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

Max Planck Institute for Chemical Energy Conversion, Heterogeneous Reactions, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, GERMANY.

The abundant surface chemical information and edge structures of carbon materials have attracted tremendous interest in catalysis. For the oxygen evolution reaction (OER), edge effects of carbon materials have been rarely studied in detail due to the complexity of various coexisting edge configurations and the controversy between carbon corrosion and carbon catalysis. In the present work, the exact roles of common carbon active edge sites in OER using polycyclic aromatic hydrocarbons (PAHs) with designated configurations (zigzag and armchair) as model probe molecules were interrogated with the focus on structure-function relationships. Read More

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http://dx.doi.org/10.1002/anie.201902884DOI Listing

Heterodiatomic Multiple Bonding in Group 13: A Complex with a B-Al π Bond Reduces CO2.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

Julius-Maximilians-Universitat Wurzburg, Department of Chemistry, Am Hubland, 97074, Würzburg, GERMANY.

Heterodiatomic multiple bonds have never been observed within group 13. In this contribution, we disclose a method that generates [(CAAC)PhB=AlCp3t] (1), a complex featuring π bonding between boron and aluminum through the association of singlet fragments. We present the properties of this multiple bond as well as the reactivity of the complex with carbon dioxide, which yields a boron CO complex via an unusual metathesis reaction. Read More

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http://doi.wiley.com/10.1002/anie.201902655
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http://dx.doi.org/10.1002/anie.201902655DOI Listing
April 2019
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Generating New Cross Relaxation Pathways by Coating Prussian Blue on NaNdF4 for Enhanced Photothermal Agents.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

Nanyang Technological University, School of Chemical and Biomedical Engineering, SINGAPORE.

Cross relaxation among sensitizers is commonly regarded as deleterious in fluorescent materials, while it is favorable in photothermal agents. In this work, we coated Prussian blue (PB) on NaNdF4 nanoparticles for the first time to fabricate core-shell nanocomplex to generate new cross relaxation pathways between the ladder-like energy levels of Nd3+ ions and continuous energy band of PB. The photothermal conversion efficiency was exceptionally improved and the mechanism of enhanced photothermal effect was investigated. Read More

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http://dx.doi.org/10.1002/anie.201904534DOI Listing

A gas phase CanMn4-nO4+ cluster model for the oxygen evolving complex of photosystem II.

Angew Chem Int Ed Engl 2019 Apr 15. Epub 2019 Apr 15.

UNITED STATES.

One of the fundamental processes in nature, the oxidation of water, is catalyzed by a small CaMn3O4·MnO cluster located in photosystem II (PSII). Herein, we report the first successful preparation of a series of isolated ligand-free tetrameric CanMn4-nO4+ (n = 0 - 4) cluster ions which are employed as structural models for the catalytically active site of PSII. Gas phase reactivity experiments with D2O and H218O in an ion trap reveal the facile deprotonation of multiple water molecules via hydroxylation of the cluster oxo-bridges for all investigated clusters. Read More

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http://doi.wiley.com/10.1002/anie.201903738
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http://dx.doi.org/10.1002/anie.201903738DOI Listing
April 2019
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