Spotlights on our sister journals: Angew. Chem. Int. Ed. 29/2018.
Authors: PMID: 29992781 [PubMed - in process] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 13, 2018 Category: Chemistry Tags: Angew Chem Int Ed Engl Source Type: research

Corrigendum: Degradable Vanadium Disulfide Nanostructures with Unique Optical and Magnetic Functions for Cancer Theranostics.
PMID: 29992782 [PubMed - in process] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 13, 2018 Category: Chemistry Authors: Chen Y, Cheng L, Dong Z, Chao Y, Lei H, Zhao H, Wang J, Liu Z Tags: Angew Chem Int Ed Engl Source Type: research

Synthesis and Reactivity of Multiple PR2-Functionalized Nonagermanide Clusters.
TF Abstract Herein we report on the synthesis of the first multiple phosphine-substituted nonagermanide clusters in a one-step reaction from K4Ge9. Their reactions towards various transition metal complexes show a large variety of reactive sites. The novel threefold phosphine-functionalized [Ge9] clusters [Ge9{PRRI}3]- {R: NiPr2; RI: NiPr2 (1a) or tBu (2a)} are obtained by reaction of pristine [Ge9]4- clusters with the respective chlorophosphines. Subsequent reactions with NHCDippCuCl yield neutral compounds (NHCDippCu)[Ge9{P(NiPr2)2}3] (3) and (NHCDippCu)[Ge9{P(NiPr2)tBu}3] (4), respectively. The reaction of neu...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Geitner FS, Klein W, Fässler TF Tags: Angew Chem Int Ed Engl Source Type: research

Rapid and Mild Synthesis of Amino Acid N-Carboxy Anhydrides Using Basic-to-Acidic Flash Switching in a Micro-flow Reactor.
Abstract Polymerization of N-carboxy anhydrides (NCAs) is the primary process used to prepare polypeptides. The synthesis of various pure NCAs is a key to the efficient synthesis of polypeptides. The only practical method that can be used to synthesize NCAs requires harsh acidic conditions that make acid-labile substrates unusable and results in an undesired ring opening of NCAs. We used "basic-to-acidic flash switching" and subsequent "flash dilution" technology in a micro-flow reactor to demonstrate synthesis of NCAs that is both rapid (0.1 s) and mild (20 °C) and includes versions contai...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Otake Y, Nakamura H, Fuse S Tags: Angew Chem Int Ed Engl Source Type: research

Dynamic covalent identification of an efficient heparin ligand.
Abstract Despite heparin being the most widely used macromolecular drug, the design of small-molecule ligands to modulate its effects has been hampered by the structural properties of this polyanionic polysaccharide. In this work we used a dynamic covalent selection approach to identify a new ligand for heparin, assembled from extremely simple building blocks. The amplified molecule strongly binds to heparin (KD in the low μM range, ITC) by a combination of electrostatic, hydrogen bonding and CH-π interactions as shown by NMR and molecular modeling. Moreover, this ligand reverts the inhibitory effect of hepa...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Corredor M, Carbajo D, Domingo C, Perez Y, Bujons J, Messeguer A, Alfonso I Tags: Angew Chem Int Ed Engl Source Type: research

Elastically Flexible Crystals have Disparate Mechanisms of Molecular Movement Induced by Strain and Heat.
Abstract Elastically flexible crystals are an emerging class of materials that exhibit a range of notable properties. Here, we compare the mechanism of thermal expansion in flexible crystals of bis(acetylacetonato)copper(II) with the mechanism of molecular motion induced by bending and show that they are distinct. Upon bending individual molecules within the crystal structure reversibly rotate, while thermal expansion results predominantly in an increase in intermolecular separations with only minor changes to molecular orientation through rotation. PMID: 29998602 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Brock AJ, Whittaker JJ, Powell JA, Pfrunder MC, Grosjean A, Parsons S, McMurtrie JC, Clegg JK Tags: Angew Chem Int Ed Engl Source Type: research

Helmuth M öhwald (1946-2018).
Helmuth Möhwald (1946-2018). Angew Chem Int Ed Engl. 2018 Jul 12;: Authors: von Klitzing R, Zemb TN Abstract Helmuth Möhwald, Founding Director of the Max Planck Institute for Colloids and Interfaces, Potsdam-Golm, passed away on March 27, 2018, at the age of 72. Möhwald's scientific achievements included the development of the layer-by-layer (LbL) technique to prepare ultrathin organized organic films, and its application in the coating of colloidal particles. PMID: 29999218 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: von Klitzing R, Zemb TN Tags: Angew Chem Int Ed Engl Source Type: research

Mechanistic Studies on the Organocatalytic α-Chlorination of Aldehydes: the Role and Nature of Off-Cycle Intermediates.
Mechanistic Studies on the Organocatalytic α-Chlorination of Aldehydes: the Role and Nature of Off-Cycle Intermediates. Angew Chem Int Ed Engl. 2018 Jul 12;: Authors: Christmann M, Ponath S, Menger M, Grothues L, Weber M, Lentz D, Strohmann C Abstract Herein we report the isolation and characterization of aminal intermediates in the organocatalytic α-chlorination of aldehydes. These species are stable covalent ternary adducts of the substrate, the catalyst and the chlorinating reagent. NMR-assisted kinetic studies and isotopic labeling experiments with the isolated intermediate did not sup...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Christmann M, Ponath S, Menger M, Grothues L, Weber M, Lentz D, Strohmann C Tags: Angew Chem Int Ed Engl Source Type: research

High-throughput metabolomics by 1D NMR.
Abstract Metabolomics deals with the whole ensemble of metabolites (the metabolome). As one of the -omic sciences, it relates to biology, physiology, pathology and medicine; but metabolites are chemical entities, small organic molecules or inorganic ions. Therefore, their proper identification and quantitation in complex biological matrices requires a solid chemical ground. With respect to e.g. DNA, metabolites are much more prone to oxidation or enzymatic degradation: we can reconstruct large parts of a mammoth's genome from a small specimen, but we are unable to do the same with its metabolome, which was probabl...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Vignoli A, Ghini V, Meoni G, Licari C, Takis PG, Tenori L, Turano P, Luchinat C Tags: Angew Chem Int Ed Engl Source Type: research

Surface-assisted self-assembly of a hydrogel by proton diffusion.
Abstract Controlling supramolecular growth at solid surfaces is of great importance to expand the scope of supramolecular materials. Here we describe a dendritic benzene-1,3,5-tricarboxamide peptide conjugate whose assembly can be triggered by a pH jump. Stopped flow kinetics and mathematical modeling provide a quantitative understanding of the nucleation, elongation, and fragmentation behavior in solution. To assemble the molecule at a solid-liquid interface, we use proton diffusion from the bulk. The latter needs to be slower than the lag phase of nucleation in order to progressively grow a hydrogel outwards fro...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Spitzer D, Marichez V, Formon G, Besenius P, Hermans T Tags: Angew Chem Int Ed Engl Source Type: research

Highly Emissive Self-Trapped Excitons in Fully Inorganic Zero-Dimensional Tin Halides.
alenko MV Abstract The spatial localization of charge carriers to promote the formation of bound excitons and concomitantly enhance radiative recombination has long been a goal for luminescent semiconductors. Zero-dimensional materials structurally impose carrier localization and result in the formation of localized Frenkel excitons. Here we report that the fully inorganic, perovskite-derived zero-dimensional Sn(II) material Cs4SnBr6 exhibits room temperature, broad-band photoluminescence centred at 540 nm with a quantum yield (QY) of 15±5%. A series of analogous compositions following the general formula C...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Benin BM, Dirin DN, Morad V, Wörle M, Yakunin S, Rainò G, Nazarenko O, Fischer M, Infante I, Kovalenko MV Tags: Angew Chem Int Ed Engl Source Type: research

Advances in Materials and Structures for Ingestible Electromechanical Medical Devices.
Abstract Ingestible biomedical devices that can diagnose, prevent, and treat a wide range of diseases has been a dream of engineers and clinicians for decades. The increasing apparent importance of gut health on overall health and the prevalence of many gastrointestinal diseases have renewed focus on this emerging class of medical devices. Several prominent examples of commercially successful ingestible medical devices exist. However, many technical challenges remain before ingestible medical devices can achieve their full clinical potential. This minireview summarizes recent discoveries in this interdisciplinary ...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Bettinger CJ Tags: Angew Chem Int Ed Engl Source Type: research

Adsorbed Intermediates in Oxygen Reduction on Platinum Nanoparticles Observed by In situ IR Spectroscopy.
Abstract The sluggish kinetics of oxygen reduction to water remains a significant limitation in the viability of proton exchange membrane fuel cells, yet details of the four electron oxygen reduction reaction remain elusive. Here we apply in situ infrared spectroscopy to probe surface chemistry of a commercial carbon-supported Pt nanoparticle catalyst during oxygen reduction. Infrared spectra show potential dependent appearance of adsorbed superoxide and hydroperoxide intermediates on Pt. This strongly supports an associative pathway for oxygen reduction. Analysis of the adsorbates alongside the catalytic current ...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Nayak S, McPherson IJ, Vincent KA Tags: Angew Chem Int Ed Engl Source Type: research

A mechanism based approach to screening metagenomic libraries for discovery of unconventional glycosidases.
Abstract Functional metagenomics has opened up exciting new opportunities for enzyme discovery. To take advantage of the full potential of this new tool, the design of suitable, selective screens is essential, especially when searching for rare enzymes. In order to identify novel glycosidases that employ cleavage strategies other than the conventional Koshland mechanisms, we needed a suitable screen. Focusing initially on the unsaturated glucuronidases (UGLs) we showed that use of simple aryl glycoside substrates did not allow sufficient discrimination against β-glucuronidases, which are widespread in bacteri...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Withers S, Nasseri S, Betschart L, Opaleva D, Rahfeld P Tags: Angew Chem Int Ed Engl Source Type: research

Metal-Free Synthesis of Pharmaceutically Important Biaryls by Photosplicing.
We report a novel, metal-free cross-coupling reaction that involves the tethering of two phenyl groups by a temporary, traceless sulfonamide linker that directs a photochemical aryl fusion into a single coupling product. The perfect regio- and chemoselectivity of the reaction could be rationalized by a cyclic intermediate, which fragments into the biaryl and volatile side products. Using a flow reactor, we synthesized numerous substituted biaryl building blocks for important therapeutics in high yields, such as antibiotics, antitumor, neuroprotective and cholesterol-lowering agents as well as antiarthritic non-steroidal an...
Source: Angewandte Chemie - July 12, 2018 Category: Chemistry Authors: Kloss F, Neuwirth T, Haensch V, Hertweck C Tags: Angew Chem Int Ed Engl Source Type: research

Multiphase-Assembly of Siloxane Oligomers with Improved Mechanical Strength and Water-Enhanced Healing.
Abstract Self-healable silicone materials have great technical impacts in coatings, smart actuators and flexible electronics, however, current self-healable silicone materials are lack of mechanical tunability. Here, we designed and synthesized a new type of self-healable silicones through hydrogen-bond assisted multiphase assembly of siloxane oligomers. Besides the enhanced mechanical strength, unique water-enhanced healing was observed in the polymer network which is due to the fast and reversible dissociation/association of multivalent hydrogen bonds in the presence of water. PMID: 29993173 [PubMed - as su...
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Liu M, Liu P, Lu G, Xu Z, Yao X Tags: Angew Chem Int Ed Engl Source Type: research

Metal-Free Direct C-H Cyanation of Alkenes.
Abstract A metal-free direct alkene C-H cyanation is described. Directing groups are not required and the mechanism involves electrophilic activation of the alkene by a cyano iodine(III) species generated in situ from a [bis(trifluoroacetoxy)iodo]arene and trimethylsilyl cyanide as the cyanide source. This C-H functionalization can be conducted at gram-scale and for non-cyclic 1,1- and 1,2-disubstuted alkenes high stereoselectivity is achieved, rendering the method highly valuable. PMID: 29995341 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Wang X, Studer A Tags: Angew Chem Int Ed Engl Source Type: research

Fluorescence blinking beyond nano-confinement: Spatially synchronous intermittency of entire perovskite micro-crystals.
Abstract Abrupt fluorescence intermittency or blinking is long recognized to be characteristic of single nano-emitters. Extended quantum-confined nanostructures also undergo spatially heterogeneous blinking, however, there is no such precedence in dimensionally unconfined (bulk) materials. Here, we report multi-level blinking of entire individual organo-lead bromide perovskite micro-crystals (volume 0.1-3 µm³) under ambient conditions. Extremely high spatiotemporal correlation (>0.9) in intra-crystal emission intensity fluctuations signifies effective communication amongst photogenerated carriers at ...
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Pathoor N, Halder A, Mukherjee A, Mahato J, Sarkar SK, Chowdhury A Tags: Angew Chem Int Ed Engl Source Type: research

Surprising Antibacterial Activity and Selectivity of Hydrophilic Polyphosphoniums Featuring Sugar and Hydroxyl Substituents.
Abstract There is currently an urgent need for the development of new antibacterial agents to combat the spread of antibiotic resistant bacteria. We explored the synthesis and antibacterial activities of novel, sugar-functionalized phosphonium polymers. While these compounds exhibited antibacterial activity, we unexpectedly found that a control polymer poly(tris(hydroxypropyl)vinylbenzylphosphonium chloride) had very high activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and very low haemolytic activity against red blood cells. These results challenge the conventional wis...
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Cuthbert TJ, Hisey B, Harrison TD, Trant JF, Gillies ER, Ragogna PJ Tags: Angew Chem Int Ed Engl Source Type: research

Porous ionic liquids or liquid metal-organic frameworks ?
Abstract Liquids with permanent porosity can be created by incorporating empty cavities into liquid phases hence adding novel functionalities to conventional fluid absorbents and opening new perspectives for a range of applications including separations, catalysis and drug delivery. The preparation of porous liquids is difficult, especially in the case where they consist of a neat fluid composed by molecular entities containing empty cavities (type I porous liquid) or when these molecular entities are dissolved in sterically hindered solvents (type II porous liquids). Amongst the synthetic approaches proposed so f...
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Costa Gomes M, Pison L, Červinka C, Padua A Tags: Angew Chem Int Ed Engl Source Type: research

Strain-Induced Double Carbon-Carbon Bond Activations of Cycloparaphenylenes (CPPs) by a Platinum Complex and Its Application for the Synthesis of Cyclic Diketones.
Abstract The carbon-carbon (C-C) bond activation of [n]cycloparaphenylenes ([n]CPPs) by a transition metal complex is herein reported. A Pt⁰ complex, Pt(PPh₃)₄, regioselectively cleaved two C-C σ bonds of [5] and [6]CPPs giving cyclic dinuclear platinum complexes in high yields. Theoretical calculations reveal that the relief of ring strain drives the reaction. The cyclic complex was further transformed into a cyclic diketone by a CO insertion reaction. PMID: 29998548 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Kayahara E, Hayashi T, Takeuchi K, Ozawa F, Ashida K, Ogoshi S, Yamago S Tags: Angew Chem Int Ed Engl Source Type: research

Probing Interfacial Electronic and Catalytic Properties on Well-Defined Surfaces Using In Situ Raman Spectroscopy.
Abstract Heterogeneous metal interfaces play a key role in determining the mechanism and performance of catalysts. However, in situ characterization of such interfaces at the molecular level is challenging, yet necessary for clearly elucidating the catalytic mechanism. Herein, two types of model interfaces, namely Pd and Pt overlayers on Au single crystals, were precisely constructed. The electronic structures of these interfaces as well as effects of crystallographic orientation on them were analyzed by shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) using phenyl isocyanide (PIC) as a probe mole...
Source: Angewandte Chemie - July 11, 2018 Category: Chemistry Authors: Wang YH, Zhang YJ, Liang MM, Chen S, Radjenovic P, Zhang H, Yang ZL, Zhou XS, Tian ZQ, Li JF Tags: Angew Chem Int Ed Engl Source Type: research

Ultrasound Promoted Step-Growth Polymerization and Polymer Crosslinking Via Copper Catalyzed Azide-Alkyne 'Click' (CuAAC) Reaction.
Abstract Mechano-activated chemistry is a powerful tool for remodeling of synthetic polymeric materials, however few reactions are currently available. Here we show that using piezochemical reduction of a Cu(II)-based pre-catalyst, a step-growth polymerization occurs via the Copper Catalyzed Azide-Alkyne cycloaddition (CuAAC) reaction to form a linear polytriazole. Furthermore, we show that a linear polymer can be cross-linked mechanochemically using the same chemistry to form a solid organogel. We envision that this chemistry can be used to harness mechanical energy for constructive purposes in polymeric material...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Mohapatra H, Ayarza J, Sanders E, Scheuermann AM, Griffin P, Esser-Kahn AP Tags: Angew Chem Int Ed Engl Source Type: research

A fully automated continuous-flow platform for fluorescence quenching studies and Stern-Volmer analysis.
Abstract Herein, we report the first fully automated continuous-flow platform for fluorescence quenching studies and Stern-Volmer analysis. All the components of the platform were automated and controlled by a self-written Python script. A user-friendly software allows even inexperienced operators to perform automated screening of novel quenchers or Stern-Volmer analysis, thus accelerating and facilitating both reaction discovery and mechanistic studies. The operational simplicity of our system affords a time and labor reduction over batch methods, while increasing the accuracy and reproducibility of the data prod...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Kuijpers K, Bottecchia C, Cambie D, Drummen K, Koenig N, Noel T Tags: Angew Chem Int Ed Engl Source Type: research

Regiodivergent copper catalyzed borocyanation of 1,3-dienes.
We report a regiodivergent process that allows a switch between 1,4-borocupration and 4,1-borocupration of 1,3-dienes upon a simple change in ligand. The subsequently generated allyl coppers are trapped in an electrophilic cyanation to selectively generate densely functionalized and synthetically versatile 1,2- or 4,3- borocyanation products. PMID: 29992705 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Jia T, He Q, Ruscoe RE, Pulis AP, Procter DJ Tags: Angew Chem Int Ed Engl Source Type: research

The Chaotropic Effect as an Assembly Motif in Chemistry.
Abstract Following up on scattered reports on interactions of conventional chaotropic ions (e.g., I-, SCN-, ClO4-) with macrocyclic host molecules, biomolecules, and hydrophobic neutral surfaces in aqueous solution, the chaotropic effect has recently emerged as a generic driving force for supramolecular assembly, orthogonal to the hydrophobic effect. The chaotropic effect becomes most effective for very large ions that extend beyond the classical Hofmeister scale, and that can be referred to as superchaotropic ions (e.g., borate clusters and polyoxometalates). In this review, we present a continuous scale of water...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Nau WM, Assaf K Tags: Angew Chem Int Ed Engl Source Type: research

Surface Immobilization of Redox-Labile Fluorescent Probes Enables Single-Cell Co-Profiling of Aerobic Glycolysis and Oncogenic Protein Signaling Activities.
We describe an analytical method for profiling lactate production in single cells, via the use of coupled enzyme reactions on surface-grafted resazurin molecules. The immobilization of the redox-labile probes was achieved through chemical modifications on resazurin, followed by bio-orthogonal click reactions. The lactate detection scheme was demonstrated to be sensitive and specific. The method was incorporated into the single cell barcode chip platform for simultaneous quantification of aerobic glycolysis activities and oncogenic signaling phosphoproteins in cancer. We interrogated the interplay between glycolysis and onc...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Li Z, Cheng H, Shao S, Lu X, Li M, Tsang J, Zeng P, Guo Z, Wang S, Nathanson DA, Heath JR, Wei W, Xue M Tags: Angew Chem Int Ed Engl Source Type: research

Electrostatic-driven Dynamic Jamming of 2D Nanoparticles at Interfaces for Controlled Molecular Diffusion.
Abstract Dynamically engineering interfacial interaction of nanoparticles has emerged as a new approach for bottom-up fabrication of smart systems to tailor molecular diffusion and controlled release. Here we report Janus "zwitterionic" nanoplates that can be switched between a "lock" and "unlock" state at interfaces upon changing surface charge, allowing manipulation of interfacial properties in a fast, flexible, and switchable manner. Combining experimental and modeling studies, we established an unambiguous correlation among the electrostatic energy, the interface geometry, and the...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Luo J, Zeng M, Peng B, Tang Y, Zhang L, Wang P, He L, Huang D, Wang L, Wang X, Chen M, Lei S, Lin P, Chen Y, Cheng Z Tags: Angew Chem Int Ed Engl Source Type: research

On the mechanism of the reactivity of 1,3-dialkylimidazolium salts under basic to acidic conditions: a combined kinetic and computational study.
l;lä K Abstract Comprehensive spectroscopic kinetic studies illustrate an alternative mechanism for the traditional free-carbene intermediated H/D exchange reaction of 1,3-dialkylimidazolium salts under neutral (D2O) and acidic conditions (DCl/D2O 35 wt % solution). The deuteration of high purity [bmim]Cl in D2O is studied at different temperatures, in absence of catalyst or impurities, to yield an activation energy. DFT transition-state modelling, of a small water cluster and [bmim] cation, also yields an activation energy which strongly supports the proposed mechanism. The presence of basic impurities are s...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Rico Del Cerro D, Mera Adasme R, King AWT, Perea Buceta JE, Heikkinen S, Hase T, Sundholm D, Wähälä K Tags: Angew Chem Int Ed Engl Source Type: research

Gold(I)-Catalyzed Tandem Cycloisomerization of 1,5-Enyne Ethers via Hydride Transfer.
Abstract A novel gold-catalyzed tandem protocol, initiated by hydride transfer in the presence of catalytic (C6F5)3PAuCl/AgSbF6, towards the formation of fused polycyclic ring systems has been achieved. This tandem reaction provides a rapid access to various fused polycyclic species in a single chemical operation, leading to stereospecific formation of two carbon-carbon bonds and three rings. PMID: 29989283 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Wong HNC, Lu XL, Lyu MY, Peng XS Tags: Angew Chem Int Ed Engl Source Type: research

DNA-Templated [2+2] Photocycloaddition: A Straightforward Entry into the Aplysinopsin Family of Natural Products.
Abstract Biosynthetic considerations inspired us to harness the template properties offered by DNA to promote a [2+2] photo-induced cycloaddition. The method was developed based on the dimerization of (E)-aplysinopsin, which was previously shown to be unproductive in solution. In sharp contrast, exposure of this tryptophan-derived olefin to light in the presence of salmon testes DNA (st-DNA) reproducibly afforded the corresponding homo-dimerized spiro-fused cyclobutane in excellent yields. DNA provides unique templating interactions enabling a singular mimic of the solid-state aggregation necessary for the [2+2] p...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Duchemin N, Skiredj A, Mansot J, Leblanc K, Vasseur JJ, Beniddir MA, Evanno L, Poupon E, Smietana M, Arseniyadis S Tags: Angew Chem Int Ed Engl Source Type: research

Overcoming volume selectivity of dipolar recoupling in biological solid-state NMR.
Abstract Dipolar recoupling in solid state NMR is an essential method for establishing correlations between nuclei that are close in space. In applications on protein samples, the traditional experiments like ramped and adiabatic DCP suffer from the fact that dipolar recoupling occurs only within a limited volume of the sample. This selection is dictated by the radiofrequency (rf) field inhomogeneity profile of the excitation solenoidal coil. We employ optimal control strategies to design dipolar recoupling sequences with substantially larger responsive volume and increased sensitivity. We show that it is essentia...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Tosner Z, Sarkar R, Becker-Baldus J, Glaubitz C, Wegner S, Engelke F, Glaser SJ, Reif B Tags: Angew Chem Int Ed Engl Source Type: research

Post-synthetic ligand exchange in zirconium-based metal-organic frameworks: beware of the defects!
Abstract Post-synthetic ligand exchange in the prototypical zirconium-based metal-organic framework UiO-66 was investigated by in situ solution 1H nuclear magnetic resonance. Samples of UiO-66 having different degrees of defectivity were exchanged using solutions of several terephthalic acid analogues in a range of conditions. Linker exchange only occurred in defect-free UiO-66, whereas monocarboxylates grafted at defective sites were found to be preferentially exchanged with respect to terephthalic acid over the whole range of conditions investigated. A 1:1 exchange ratio between the terephthalic acid analogue an...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Taddei M, Wakeham RJ, Koutsianos A, Andreoli E, Barron AR Tags: Angew Chem Int Ed Engl Source Type: research

Exploration of the Synthetic Potential of Electrophilic Trifluoromethylthiolating and Difluoromethylthiolating Reagents.
Abstract Electrophilicity parameters (E) of some popular trifluoromethylthiolating and difluoromethylthiolating reagents were determined by following the kinetics of their reactions with a series of enamines and carbanions with known nucleophilicity parameters (N, sN), using the linear free-energy relationship log k2 = sN(N + E). The electrophilic reactivities of these reagents cover a range of 17 orders of magnitude, with Shen and Lu's reagent 1a being the most reactive and Billard's reagent 1h the least reactive electrophile. While the observed electrophilic reactivities (E) of the amido-derived trifluoromethylt...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Xue XS, Zhang J, Yang JD, Zheng H, Mayr H, Cheng JP Tags: Angew Chem Int Ed Engl Source Type: research

Lord of The Crowns: A New Precious In The Kingdom of Clustomesogens.
Abstract Replacing pure inorganic materials by functional organic-inorganic hybrid ones to lower production costs has become a major challenge, in particular for the optoelectronic industry. Adding nanostructuration abilities meanwhile preserving homogeneity is even more challenging for this class of new materials. Here we show that Red-NIR emissive ternary molybdenum cluster salts can be assembled to liquid crystalline 15C5 crown ethers. The resulting hybrids are homogeneous and stable up to high temperature despite the weakness of the supramolecular interactions binding both components. These are illustrated by ...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Guy K, Ehni P, Paofai S, Roiland C, Amela-Cortes M, Cordier S, Laschat S, Molard Y Tags: Angew Chem Int Ed Engl Source Type: research

Exploration into the Syntheses of Gallium- and Indiumborates under Extreme Conditions: M5B12O25(OH) (M = Ga, In) - Structure, Luminescence, and Surprising Photocatalytic Properties.
z H Abstract Explorative solid state chemistry led to the discovery of the two new compounds Ga5B12O25(OH) and In5B12O25(OH). Extreme synthetic conditions within the range of 12 GPa and a temperature of 1450 °C realized in a Walker-type multianvil apparatus resulted in the formation of an unprecedented tetragonal structure with the exclusive presence of condensed BO4 tetrahedra, forming cuboctahedral cavities. Successful doping of these cavities with Eu3+ in In5B12O25(OH) yielded in an orange-red luminescence. A highly exciting result was observed in photocatalytic tests of In5B12O25(OH) revealing a hydrogen p...
Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Vitzthum D, Wurst K, Pann JM, Brüggeller P, Seibald M, Huppertz H Tags: Angew Chem Int Ed Engl Source Type: research

Highly Reactive and Tracelessly Cleavable Cysteine-Specific Modification of Proteins via 4-Substituted Cyclopentenone.
Abstract A rapid and cysteine-specific modification of proteins using 4-substituted cyclopentenone via a Michael addition tandem elimination reaction was developed. Compared to the classical method, this reaction featured fast kinetics with a stable product. More importantly, this conjugation could be tracelessly removed by exchange with a Michael addition donor. The conjugation and regeneration process not only exhibited little change to the structures or conformations of the proteins but also exhibited little disturbance to their biological functions, such as their enzymatic activities. PMID: 29984549 [PubM...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Yu J, Yang X, Sun Y, Yin Z Tags: Angew Chem Int Ed Engl Source Type: research

From Electron Crystallography to Single Particle CryoEM (Nobel Lecture).
Abstract Pictures are a key to knowledge: The development of electron microscopy from its beginnings to modern single particle cryo-EM is described by R. Henderson in his Nobel lecture. Shown is the first projection structure at 7 Å resolution of the purple membrane from October 1974. PMID: 29984560 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Henderson R Tags: Angew Chem Int Ed Engl Source Type: research

On the Development of Electron Cryo-Microscopy (Nobel Lecture).
Abstract An electron microscope must operate under vacuum which means that any observed biological specimen must be dry. When water is removed, however, the molecules stick to each other. J. Dubochet describes in his Nobel lecture the solution to this dilemma that paved the way to electron-cryo microscopy: suspension of the specimen in vitrifying water. PMID: 29984876 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Dubochet J Tags: Angew Chem Int Ed Engl Source Type: research

Enantioconvergent Biocatalytic Redoxisomerization.
Abstract Alcohol dehydrogenases can act as powerful catalysts in the preparation of optically pure γ-hydroxy-δ-lactones by means of an enantioconvergent dynamic redoxisomerization of readily available Achmatowicz-type pyranones. Imitating the traditionally metal-mediated borrowing hydrogen approach to shuffle hydrides across molecular architectures and interconvert functional groups, this chemoinspired and purely biocatalytic interpretation effectively expands the enzymatic toolbox and provides new opportunities in the assembly of multi-enzyme cascades and tailor-made cellular factories. PMID: 299...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Liu YC, Merten C, Deska J Tags: Angew Chem Int Ed Engl Source Type: research

HFIP-assisted C-H functionalization by Cp*Co(III): Promoted Access to Key Reactive Cobaltacycles and Implication in Catalysis.
ro JM Abstract Herein, we describe our synthetic approach to access two of the most widely invoked cationic cobaltacycles in Cp*Co(III)-catalyzed C-H functionalization reactions via C-H activation. We take advantage of the unique stabilizing capability of MeCN to surmount the previously proposed reversible nature of the C-H metalation step. Moreover, we also uncover the boosting effect of HFIP in the metalation step and in the reactivity, under catalytic conditions, between N-pyrimidinylindole and diphenylacetylene. PMID: 29984879 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Perez-Temprano MH, Sanjosé-Orduna J, Sarria Toro JM Tags: Angew Chem Int Ed Engl Source Type: research

Mechanistic Insights into Visible-Light Photocatalysis for C(sp3)-H Fluorination by Uranyl.
Abstract The uranyl dication shows photocatalytic activity towards C(sp3 )-H bonds of aliphatic compounds, but not towards those of alkylbenzenes or cyclic ketones. Theoretical insights into the corresponding mechanisms are still limited. Multi-configurational ab initio calculations including relativistic effects reveal the inherent electron transfer mechanism for the uranyl catalyzed C-H fluorination under blue light. Along the reaction path of the triplet state it was found that the hydrogen atom abstraction triggered by the electron-rich oxygen of the uranyl moiety is the rate-limiting step. The subsequent step...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Wu L, Cao X, Chen X, Fang W, Dolg MF Tags: Angew Chem Int Ed Engl Source Type: research

Visible Light-Mediated Metal-Free Synthesis of Trifluoromethylselenolated Arenes: Scope and Mechanism.
ili A Abstract The first visible light-mediated synthesis of trifluromethylselenolated arenes under metal free conditions is reported herein. The use of an organic photocatalyst allows the trifluoromethylselenolation of arene diazonium salts using a shelf-stable reagent, trifluoromethyl tolueneselenosulfonate at room temperature. The reaction does not require the presence of any additive and shows a large functional group tolerance covering a very broad scope of starting materials. Mechanistic investigations, including EPR, fluorescence and cyclic voltammetry allow the rationalisation of the reaction mechanism. ...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Ghiazza C, Debrauwer V, Monnereau C, Khrouz L, Médebielle M, Billard T, Tlili A Tags: Angew Chem Int Ed Engl Source Type: research

Electrocatalytic 5-(hydroxymethyl)furfural oxidation using high surface area nickel boride.
This study does not only report a low cost active electrocatalyst material for the electro¬chemical oxidation of HMF to FDCA, but additionally provides new insight into the reaction pathway. PMID: 29985550 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Barwe S, Weidner J, Cychy S, Morales DM, Dieckhöfer S, Hiltrop D, Masa J, Muhler M, Schuhmann W Tags: Angew Chem Int Ed Engl Source Type: research

The Arene-Limited Nondirected C-H Activation of Arenes.
Abstract The nondirected C(sp²)-H activation of simple arenes has advanced significantly in recent years through the discovery of new catalyst systems that are able to perform transformations with the arene as the limiting reagent. Important developments in catalyst and ligand design to increase reactivity and selectivity are reviewed. PMID: 29985551 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Wedi P, van Gemmeren M Tags: Angew Chem Int Ed Engl Source Type: research

A Supramolecular [10]CPP Junction Enables Efficient Electron Transfer in Modular Porphyrin-[10]CPP-Fullerene Complexes.
Abstract [10]Cycloparaphenylene ([10]CPP) has recently been shown to be an excellent supramolecular receptor for C60 and C70. Here we report efficient photoinduced electron transfer across a [10]CPP moiety that serves as a modular, yet rigid, non-covalent bridge between a zinc porphyrin and a diverse range of fullerenes. The first preparation of iodo-[10]CPP is the cornerstone of our synthesis of a porphyrin-[10]CPP conjugate, which was found to bind C60, C70, (C60)2 and other fullerenes with association constants beyond 105 M-1. Fluorescence and pump-probe spectroscopy revealed intramolecular energy transfer betw...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: von Delius M, Xu Y, Wang B, Kaur R, Minameyer M, Bothe M, Drewello T, Guldi D Tags: Angew Chem Int Ed Engl Source Type: research

Mixed-valent molecular triple-deckers.
Abstract Two phenothiazine (PTZ) moieties were connected via naphthalene spacers to a central arene to result in stacked PTZ-arene-PTZ structure elements. Benzene and tetramethoxybenzene units served as central arenes mediating electronic communication between the two PTZ units. Based on cyclic voltammetry, UV-Vis-NIR absorption, EPR spectroscopy, and computational studies, the one-electron oxidized forms of the resulting compounds behave as class II organic mixed-valence species in which the unpaired electron is partially delocalized over both PTZ units. The barrier for intramolecular electron transfer depends on...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Schmidt HC, Guo X, Richard PU, Neuburger M, Palivan CG, Wenger OS Tags: Angew Chem Int Ed Engl Source Type: research

Regiodivergent Synthesis of 1,3- and 1,4-Enynes through Kinetically Favored Hydropalladation and Ligand-Enforced Carbopalladation.
Abstract Pd-catalyzed hydroalkynylations were developed that involve ligand-enabled regiodivergent addition of an alkyne to an allenamide, giving branched and linear products stereoselectively and facilitated by the neighboring amide group. Regioselectivity was achieved with the use of (o-OMePh)3 P and BrettPhos, which allowed the functionalization of various alkynes, including steroids, carbohydrates, alkaloids, chiral ligands, and vitamins. Based on the experimental results, it was proposed that hydro- and carbopalladation processes operated during the formations of the branched and linear products, respectively...
Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Pradhan TR, Kim HW, Park JK Tags: Angew Chem Int Ed Engl Source Type: research

Corrigendum: Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere.
idis J, Savage GP, Williams CM PMID: 29975016 [PubMed - in process] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 6, 2018 Category: Chemistry Authors: Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanakt Tags: Angew Chem Int Ed Engl Source Type: research

Spotlights on our sister journals: Angew. Chem. Int. Ed. 28/2018.
Authors: PMID: 29975017 [PubMed - in process] (Source: Angewandte Chemie)
Source: Angewandte Chemie - July 6, 2018 Category: Chemistry Tags: Angew Chem Int Ed Engl Source Type: research