39,508 results match your criteria Angewandte Chemie International ed. in English[Journal]


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://dx.doi.org/10.1002/anie.201902910DOI Listing

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://dx.doi.org/10.1002/anie.201903749DOI Listing

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
3 Reads

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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Sr₆Cd₂Sb₆O₇S₁₀: Strong SHG Response Activated by Highly Polarizable Sb/O/S Groups.

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

Shanghai Institute of Ceramics, Chinese Academy of Science, State Key Laboratory of High Performance Ceramics and Superfine Microstructure, 1295 Ding-Xi Road, 200050, Shanghai, CHINA.

A new nonlinear optical (NLO) oxysulfide Sr₆Cd₂Sb₆O₇S₁₀ containing functional 5s²-electron [SbOxS5-x]7- (x = 0, 1) groups is synthesized by solid state reaction. This compound displays a four-times stronger phase-matchable second harmonic generation (SHG) response than AgGaS₂ (AGS) under the laser radiation of 2.09 μm. Read More

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http://doi.wiley.com/10.1002/anie.201902806
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http://dx.doi.org/10.1002/anie.201902806DOI Listing
April 2019
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Developing Through-Space Charge Transfer Polymers as A General Approach to Realize Full-Color and White Emission with Thermally Activated Delayed Fluorescence.

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

Chang Chun Institute of Applied Chemistry Chinese Academy of Sciences, Changchun, CHINA.

Different from through-bond charge transfer polymers with conjugated donor-acceptor architectures, here we report the development of through-space charge transfer polymers (TSCT-polymers) containing non-conjugated polystyrene backbone and spatially separated donor and acceptor units for solution-processed OLEDs with full-color and white emission. By tuning the charge transfer strength between donor and acceptors with different electron-accepting ability, emission color spanning from deep blue (455 nm) to red (616 nm) region can be achieved. Meanwhile, by incorporating two kinds of donor/acceptor pairs in one polymer to create duple through-space charge transfer channels, blue and yellow emission can be simultaneously obtained to realize white electroluminescence from a single polymer. Read More

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http://dx.doi.org/10.1002/anie.201902264DOI Listing

Gold(I)-Catalyzed Cascade Cyclization Reactions of Allenynes for the Synthesis of Fused Cyclopropanes and Acenaphthenes.

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

Kyoto University, Graduate School of Pharmaceutical Sciences, Sakyo-ku, 606-8501, Kyoto, JAPAN.

Gold-catalyzed reaction of phenylene-tethered allenynes with a benzofuran gave 1-(naphth-1-yl)cyclopropa[b]benzofuran derivatives, whereas the reaction of 1-allenyl-2-ethynyl-3-methylbenzene derivatives in the absence of benzofuran gave acenaphthenes in good yields. These results can be rationalized by nucleophilic attack of the alkyne moiety to an activated allene to form a vinyl cation intermediate.. Read More

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http://dx.doi.org/10.1002/anie.201903384DOI Listing

Metalloradicals Supported by a meta-Carborane Ligand.

Angew Chem Int Ed Engl 2019 Apr 14. Epub 2019 Apr 14.

CHINA.

In this work, a pincer type complex [Cp*Ir-(SNPh)(SNHPh)(C2B10H9)] (2) has been synthesized and its reactivity has been studied in detail. Interestingly, molecular hydrogen can induce the transformation between the metalloradical [Cp*Ir-(SNPh)2(C2B10H9)] (5•) and the complex 2. A mixed-valence complex [(Cp*Ir)2-(SNPh)2(C2B10H8)] (7•+) is also synthesized by one-electron oxidation. Read More

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http://dx.doi.org/10.1002/anie.201903467DOI Listing

Synthesis, Structures, and Near-IR Absorption of Heterole-fused Earring Porphyrins.

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

Hunan Normal University, Chemistry, Yue Lu Qu Lushan Road 36, 410081, Changsha, CHINA.

A reaction sequence of regioselective peripheral bromination, Suzuki-Miyaura coupling with 2-borylated thiophene or pyrrole, and oxidative ring-closure with FeCl3 allowed the synthesis of heterole-fused earring porphyrins 4Pd and 9Pd from the parent earring porphyrin 1. Differently pyrrole-fused porphyrins 5H and 6H and their PdII complexes 5Pd and 6Pd were also synthesized. The structures of 4Pd, 5H, 6Pd, and 8Pd have been revealed by X-ray analysis to be roughly coplanar but considerably twisted due to constraints imposed by heterole-fused structures. Read More

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http://dx.doi.org/10.1002/anie.201903446DOI Listing

Molecular swings as extremely active ion transporters.

Angew Chem Int Ed Engl 2019 Apr 14. Epub 2019 Apr 14.

SINGAPORE.

Ions get transported across membrane mostly via carrier or channel mechanisms. We report herein a unique class of molecular machine-inspired membrane transporters, termed molecular swings that utilize a previously unexplored swing mechanism for promoting ion transport in a highly efficient manner. In particular, the molecular swing, which carries a 15-crown-5 unit as the ion-binding and transporting unit, exhibits extremely high ion transport activities with EC50 values of 46 nM (a channel:lipid molar ratio of 1:4800 or 0. Read More

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http://dx.doi.org/10.1002/anie.201901833DOI Listing

Collective Total Synthesis of the Prostaglandins Family via Stereocontrolled Organocatalytic Baeyer-Villiger Oxidation.

Angew Chem Int Ed Engl 2019 Apr 14. Epub 2019 Apr 14.

CHINA.

A new protocol for the synthesis of prostaglandins using a stereocontrolled organocatalytic Baeyer-Villiger (B-V) oxidation was described for the first time. The key B-V oxidation of racemic cyclobutanone with aqueous hydrogen peroxide has enabled an early stage construction of bicyclic lactone skeleton in high enantiomeric excess (up to 99%). The generated bicyclic lactone is fully primed with two desired stereocenters and enabled the assembly of the entire family of prostaglandins. Read More

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http://dx.doi.org/10.1002/anie.201902371DOI Listing

Mechanochromism, Twisted/Folded Structures Determination, and Derivatization of N-Phenyl Fluorenylidene-Acridane.

Angew Chem Int Ed Engl 2019 Apr 14. Epub 2019 Apr 14.

The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, JAPAN.

N-phenyl fluorenylidene-acridane (Ph-FA) compounds with electron-withdrawing and -donating substituents (H, MeO, Ph, NO2, Br, F) at the para position of the phenyl group were successfully synthesized by the Barton-Kellogg reaction of N-aryl thioacridones and diazofluorene. By using the substituent on nitrogen to alter electronic properties, both the folded and twisted conformers of p-NO2-C6H4-FA were crystallographically characterized to understand charge transfer from the electron-donating acridane moiety to the electron-accepting fluorenylidene moiety. Ground state mechanochromism, thermochromism, vapochromism, and proton-induced chromism were demonstrated by utilizing folded/twisted conformational change between the conformers. Read More

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http://dx.doi.org/10.1002/anie.201902636DOI Listing

New Mechanistic Insight into the Reaction of Organic Acids with SO3 at the Air-Water Interface.

Angew Chem Int Ed Engl 2019 Apr 13. Epub 2019 Apr 13.

University of Pennsylvania, Department of Earth and Environmental Science and Department of Chemistry, 251 Hayden Hall, 240 South 33rd Street, 19104-6316, Philadelphia, UNITED STATES.

The gas-phase reaction of organic acids with SO3 has been recognized as essential in promoting aerosol particle formation. However, this reaction at the air-water interface is poorly understood. Herein, we performed systematic Born-Oppenheimer molecular dynamics (BOMD) simulations to study the reaction of various organic acids with SO3 on the surface of a water droplet. Read More

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http://dx.doi.org/10.1002/anie.201900534DOI Listing

NIR Light Activated Combination Therapy with Precisely Integrated Photosensitizer and Prodrug by a Host-Guest Strategy.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

CHINA.

Co-delivery of photosensitizers with reactive oxygen species (ROS) sensitive prodrugs for light triggered ROS generation and cascaded prodrug activation has drawn tremendous attention. However, the absence of a feasible method to deliver the two components with a precise ratio has impaired the application potential. Herein, we report an efficient method to fabricate a nanosized delivery platform with an optimized ratio of the two components by the means of host-guest strategy for maximizing the combination therapy efficacy in the cancer treatment. Read More

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http://dx.doi.org/10.1002/anie.201900886DOI Listing

meta- and para-Phenylenediamine-fused Porphyrin Dimers: Synthesis and Magnetic Interactions in Their Dication Diradicals.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

JAPAN.

meta- and para-Phenylenediamine-fused NiII-porphyrin dimers were synthesized by SNAr reaction of meso,β,β-trichloro NiII-porphyrin with meta- and para-phenylenediamines and subsequent Pd-catalyzed intramolecular C-H arylation. Their tetrachlorinated dication diradicals were very stable, allowing SQUID magnetometry that revealed clear open-shell characters for both meta- and para-isomers with ferro- and anti-ferromagnetic interactions, respectively. Nitrogen analogue of Thiele's hydrocarbon usually displays predominant closed-shell nature but its hidden diradical characters increase in a twisted conformation or upon insertion of an additional phenylene spacer. Read More

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http://dx.doi.org/10.1002/anie.201901939DOI Listing

Negative Charging of Au Nanoparticles during Methanol Synthesis from CO₂/H₂ on a Au/ZnO Catalyst: Insights from Operando Infrared and Near-ambient Pressure XPS and XAS.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg, 4-6, 14195, Berlin, GERMANY.

Kinetic measurements in combination with time resolved operando infrared (DRIFTS), in situ near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and X-ray absorption near edge spectroscopy (XANES) measurements at the O K-edge together with high resolution electron microscopy were applied to evaluate the electronic and structural properties of Au/ZnO under industrial and idealized methanol synthesis conditions. CO adsorption during the reaction revealed the presence of negatively charged Au nanoparticles / Au sites under reaction conditions, which are formed during the initial phase of the reaction. Near ambient pressure XPS and XANES demonstrate the build-up of O-vacancies during the reaction, which goes along with a substantial increase in the methanol formation rate. Read More

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http://doi.wiley.com/10.1002/anie.201900150
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http://dx.doi.org/10.1002/anie.201900150DOI Listing
April 2019
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Magnesium-Catalyzed Hydroboration of Terminal and Internal Alkynes.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

Institute of Organic Chemistry, RWTH Aachen, Landoltweg 1, 52074, Aachen, Germany.

A magnesium-catalyzed hydroboration of alkynes providing good yields and selectivities for a wide range of terminal and symmetrical and unsymmetrical internal alkynes has been developed. The compatibility with many functional groups makes this magnesium catalyzed procedure attractive for late stage functionalization. Experimental mechanistic investigations and DFT calculations reveal insights into the reaction mechanism of the magnesium catalyzed protocol. Read More

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http://dx.doi.org/10.1002/anie.201902188DOI Listing

Mixed-Metal MOFs: Unique Opportunities in Metal-organic Framework Functionality and Design.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

Universidad Politécnica de Valencia, Instituto de Tecnología Química, Av. de los Naranjos s/n, 46022, Valencia, SPAIN.

Mixed-metal metal organic frameworks (MM-MOFs) can be considered those MOFs having two metals anywhere in the structure. The present review summarizes the various strategies reported for preparation of MM-MOFs and some of their applications in adsorption, gas separation and catalysis. It is shown that compared to homometallic MOFs, MM-MOFs bring about the opportunity to take advantage of the complexity and the synergism derived from the presence of different metal ions in the structure of MOFs. Read More

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http://doi.wiley.com/10.1002/anie.201902229
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http://dx.doi.org/10.1002/anie.201902229DOI Listing
April 2019
5 Reads

Transformation of Metal-Organic Frameworks into Stable Organic Frameworks with Inherited Skeletons and Catalytic Properties.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

310027, Hangzhou, CHINA.

Metal-organic frameworks (MOFs) are an emerging class of porous materials with attractive properties; however, their practical applications are heavily hindered by the fragile nature. We report herein an effective strategy to transform fragile coordination bonds in MOFs into stable covalent organic bonds under mild annealing decarboxylative coupling reaction conditions, which results in highly stable organic framework materials. This strategy endows successfully inherit the intrinsic framework skeletons, porosity and properties of the parent MOFs in the daughter organic framework materials which exhibit excellent chemical stability under harsh catalytic conditions. Read More

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http://doi.wiley.com/10.1002/anie.201903367
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http://dx.doi.org/10.1002/anie.201903367DOI Listing
April 2019
3 Reads

Atypical lone pair-π interaction with quinone methides in a series of imido-ferrociphenol anticancer drug candidates.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

Sorbonne Universite Campus Pierre et Marie Curie, IPCM, jussieu, 75005, paris, FRANCE.

Ferrociphenols, especially those possessing a heterocycle at the terminus of an aliphatic chain, display strong anticancer activity via a novel redox mechanism that generates active metabolites such as quinone methides (QMs). X-ray crystallography and UV-Vis spectroscopy reveal that the specific lone pair (lp)-π interaction between a carbonyl group of the imide and the quinone motif of the QM plays an important role in the exceptional cytotoxic behaviour of their imido-ferrociphenol precursors. This intramolecular lp-π interaction markedly enhanced the stability of the QMs and lowered the pKa values of the corresponding phenolates. Read More

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http://dx.doi.org/10.1002/anie.201902456DOI Listing

Covalent Inter-Carbon-Allotrope Architectures Consisting of the Endohedral Fullerene Sc3N@C80 and Single Walled Carbon Nanotubes.

Angew Chem Int Ed Engl 2019 Apr 12. Epub 2019 Apr 12.

GERMANY.

Using a reductive sidewall functionalization concept we prepared for the first time a covalent inter-carbon-allotrope hybrid consisting of single walled carbon nanotubes (SWCNTs) and the endohedral fullerene Sc3N@C80. The characterization of this new compound type was accomplished by a variety of techniques including absorption spectroscopy, Raman spectroscopy, TG-MS, TG-GC-MS and MALDI-TOF mass spectroscopy. HRTEM investigations were carried out to visualize this highly integrated architecture. Read More

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http://dx.doi.org/10.1002/anie.201902595DOI Listing