TM LDH Meets Birnessite: A 2D-2D Hybrid Catalyst with Long-term Stability for Water Oxidation at Industrial Operating Conditions.
Abstract Efficient noble-metal free electrocatalyst for oxygen evolution reaction (OER) is critical for large-scale hydrogen production via water splitting. Inspired by Nature's oxygen evolution cluster in photosystem II and the highly efficient artificial OER catalyst of NiFe layered double hydroxide (LDH), we designed an electrostatic 2D-2D assembly route and successfully synthesized a 2D LDH(+)-Birnessite(-) hybrid. The as-constructed LDH(+)-Binessite(-) hybrid catalyst showed advanced catalytic activity and excellent stability towards OER under a close to industrial hydrogen production condition (85 ºC an...
Source: Angewandte Chemie - January 23, 2021 Category: Chemistry Authors: Long X, Chen Z, Ju M, Sun M, Jin L, Cai R, Wang Z, Dong L, Peng L, Huang B, Yang S Tags: Angew Chem Int Ed Engl Source Type: research

Ultrafast Size Expansion and Turn-on Luminescence of Atomically Precise Silver Clusters by Hydrogen Sulfide.
Abstract The formation of high-nuclearity silver(I) clusters remains elusive and their potential applications are still underdeveloped. Herein, we firstly prepared a chain-like thiolated Ag(I) complex {[Ag18(StBu)10(NO3)8(CH3CN)2(H2O)2]·[Ag18(StBu)10(NO3)8(CH3CN)6]}n (abbreviated as Ag18) in which two similar Ag18 clusters are assembled by NO3- anions. The solution containing Ag18 reacted with hydrogen sulfide with controlled concentration, promptly producing another identifiable and bright red-emitting high-nuclearity silver(I) cluster, Ag62(S)13(StBu)32(NO3)4 (abbreviated as Ag62). We tracked the transfor...
Source: Angewandte Chemie - January 23, 2021 Category: Chemistry Authors: Zang SQ, He WM, Zhou Z, Han Z, Li S, Zhou Z, Ma LF Tags: Angew Chem Int Ed Engl Source Type: research

Enantioselective Reductive Cyanation and Phosphonylation of Secondary Amides by Ir and Chiral Thiourea Sequential Catalysis.
Abstract The combination of transition metal catalysis and organocatalysis increasingly offers chemists opportunities to realize diverse unprecedented chemical transformations. By combining iridium with thiourea catalysis, direct enantioselective reductive cyanation and phosphonylation of secondary amides have been accomplished for the first time for the synthesis of enantioenriched chiral α-aminonitriles and α-aminophosphonates. The protocol is highly efficient and enantioselective, providing a novel route to the synthesis of optically active α-functionalized amines from the simple, readily avai...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Chen DH, Sun WT, Zhu CJ, Lu GS, Wu DP, Wang AE, Huang PQ Tags: Angew Chem Int Ed Engl Source Type: research

Covalent Organic Frameworks Enabling Site-Isolation of Viologen-Derived Electron Transfer Mediators for Stable Photocatalytic Hydrogen Evolution.
Abstract Electron-transfer is the rate-limiting step in photocatalytic water splitting. Viologen and its derivatives are able to act as electron transfer mediators (ETMs) to facilitate the rapid electron transfer from photosensitizers to active sites. Nevertheless, the electron-transfer ability often suffers from the formation of stable dipole structure through the coupling between cationic-radical-containing viologen-derived ETMs, by which the electron-transfer process becomes restricted. Herein, cyclic diquats, a kind of viologen-derived ETM, are integrated into a 2,2'-bipyridine-based covalent organic framework...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Mi Z, Zhou T, Weng W, Unruangsri J, Hu K, Yang W, Wang C, Zhang KAI, Guo J Tags: Angew Chem Int Ed Engl Source Type: research

Ambient-Stable Two-Dimensional Titanium Carbide (MXene) Enabled by Iodine Etching.
Abstract MXene (e.g. Ti3C2) represents an important class of two-dimensional (2D) materials owing to its unique metallic conductivity and tunable surface chemistry. However, the mainstream synthetic methods rely on the chemical etching of MAX powders (e.g. Ti3AlC2) using hazardous HF or alike, leading to MXene sheets with fluorine termination and poor ambient stability in colloidal dispersions. Here, we demonstrate a fluoride-free, iodine (I2) assisted etching route for preparing 2D MXene (Ti3C2Tx, T = O, OH) with oxygen-rich terminal groups and intact lattice structure. More than 71 % of sheets are thinner...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Shi H, Zhang P, Liu Z, Park S, Lohe MR, Wu Y, Shaygan Nia A, Yang S, Feng X Tags: Angew Chem Int Ed Engl Source Type: research

Metal-Organic Framework-Supported Molecular Electrocatalysis for the Oxygen Reduction Reaction.
We report herein metal-organic framework (MOF)-supported Co porphyrins for the oxygen reduction reaction (ORR) with improved activity and selectivity. Co porphyrins can be grafted on MOF surfaces through ligand exchange. A variety of porphyrin@MOF hybrids were made using this method. Grafted Co porphyrins showed boosted ORR activity with large (> 70 mV) anodic shift of the half-wave potential compared to ungrafted porphyrins. By using active MOFs for peroxide reduction, the number of electrons transferred per O 2  increased from 2.65 to 3.70, showing significantly improved selectivity for the 4e ORR. We demonstrate...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Liang Z, Guo H, Zhou G, Guo K, Wang B, Lei H, Zhang W, Zheng H, Apfel UP, Cao R Tags: Angew Chem Int Ed Engl Source Type: research

Controlling the Stacking Modes of Metal-Organic Framework Nanosheets through Host-Guest Noncovalent Interactions.
Abstract The tuning of metal-organic framework (MOF) nanosheet stacking modes from molecular level was rarely explored although it significantly affected the properties and applications of nanosheets. Here, the different stacking modes of Zr-1, 3, 5-(4-carboxylphenyl)-benzene framework nanosheets were synthesized through the induction of different host-guest noncovalent interactions. The solvents of methyl benzene and ethyl acetate induced twisted stacking of nanosheets with the specific rotation angles of 12 o , 18 o , 24 o and 6 o , 18 o , 24 o , 30 o , respectively, which was in agreement with theoretical ...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Tang WQ, Zhao YJ, Xu M, Xu JY, Meng SS, Yin YD, Zhang QH, Gu L, Liu DH, Gu ZY Tags: Angew Chem Int Ed Engl Source Type: research

Tetraimido sulfuric acid H2S(NtBu)4 - valence isoelectronic to H2SO4.
r R Abstract The valence isoelectronic imido analogue H 2 S(N t Bu) 4 ( 1 ) of sulfuric acid H 2 SO 4 was synthesized, isolated and characterized by NMR spectroscopy and high-resolution X-ray charge density analysis. The latter reveals strongly polarized S δ+ -N δ- bonds with virtually no double bond character. The easy-to-polarize S-N bonds are an advantageous and versatile feature of sulfur nitrogen ligands to adapt to different electron requirements of various metal cations. PMID: 33480147 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Stalke D, Jung J, Münch A, Herbst-Irmer R Tags: Angew Chem Int Ed Engl Source Type: research

Organelle-Specific Photoactivation of DNA Nanosensors for Precise Profiling of Subcellular Enzymatic Activity.
Abstract Design of sensors with controllable localization for in situ imaging of subcellular levels of enzymatic activity is particularly challenging, despite the importance in understanding of their functions in diverse cellular processes. We introduce herein a spatiotemporally-controlled sensor technology that permits in situ localization and photoactivated imaging of human apurinic/apyrimidinic endonuclease 1 (APE1) within an intracellular organelle of choice (e.g., mitochondria and nucleus). The hybrid sensor platform is constructed by photoactivatable engineering of a DNA-based fluorescent probe and further c...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Shao Y, Zhao J, Yuan J, Zhao Y, Li L Tags: Angew Chem Int Ed Engl Source Type: research

One Polyketide Synthase, Two Distinct Products: Trans-Acting Enzyme-Controlled Product Divergence in Calbistrin Biosynthesis.
Abstract Calbistrins are fungal polyketides consisting of the characteristic decalin and polyene moieties. Although the biosynthetic gene cluster of calbistrin A was recently identified, the pathway of calbistrin A biosynthesis has largely remained uninvestigated. Herein, we investigated the mechanism by which the backbone structures of calbistrins are formed, by heterologous and in vitro reconstitution of the biosynthesis and a structural biological study. Intriguingly, our analyses revealed that the decalin and polyene portions of calbistrins are synthesized by the single polyketide synthase (PKS) CalA, with the...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Abe I, Tao H, Mori T, Wei X, Matsuda Y Tags: Angew Chem Int Ed Engl Source Type: research

Bubble-propelled Janus Gallium/Zinc Micromotors for Active Treatment of Bacterial Infection.
We report a bubble-propelled Janus gallium/zinc (Ga/Zn) micromotor with good biocompatibility and biodegradability for active target treatment for bacteria, as a robust antibacterial platform. The Janus Ga/Zn micromotors are fabricated by asymmetrically coating liquid metal Ga on Zn microparticles, and display self-propelling movement in the imitative gastroenteric acid (pH 0.5) at a speed of up to 383 μm s -1 under the propulsion of hydrogen bubbles generated by the zinc-acid reaction. This motion of Ga/Zn micromotors is enhanced by the Ga-Zn galvanic effect. The produced Ga(III) cations due to the degradation of Ga/Zn...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Lin Z, Gao C, Wang D, He Q Tags: Angew Chem Int Ed Engl Source Type: research

Giant Optical Activity in 2D Hybrid Copper Halides: Novel Material for Second Harmonic Generation.
Abstract Hybrid organic-inorganic metal halides have emerged as highly promising materials for a wide range of applications in optoelectronics. Incorporating chiral organic molecules into metal halides allows for the expansion of their unique optical and electronic properties to chiral optics. Herein, using chiral R- or S-methylbenzylamine (R-/S-MBA) as the organic component, we present the synthesis of chiral hybrid copper halides, (R-/S-MBA) 2 CuCl 4 , and investigate their optical activity for the first time. Thin films of this material show a record anisotropic g-factor as high as ~0.06. Additionally, we ...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Guo Z, Li J, Wang C, Liu R, Liang J, Gao Y, Cheng J, Zhang W, Zhu X, Pan R, He T Tags: Angew Chem Int Ed Engl Source Type: research

Chiral Near-Infrared Fluorophores by Self-Promoted Oxidative Coupling of Cationic Helicenes with Amines / Enamines.
Abstract In one pot, tertiary alkyl amines are oxidized to enamines by cationic dioxa [6]helicene, which further reacts as electrophile and oxidant to form mono or bis donor-π-acceptor coupling products. This original and convergent synthetic approach provides a strong extension of conjugation yielding chromophores that absorb intensively in far-red or NIR domains (λ max up to 791 nm) and fluoresce in the NIR as well (λ max up to 887 nm). Intense ECD properties around 790 nm with a |Δε| value up to 60 M -1 cm -1 are observed. PMID: 33481294 [PubMed - as supplied by publisher] (S...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Bosson J, Labrador GM, Besnard C, Jacquemin D, Lacour J Tags: Angew Chem Int Ed Engl Source Type: research

Decarboxylative Polyfluoroarylation of Alkylcarboxylic Acids.
Abstract Polyfluoroarenes are useful building blocks in several areas such as drug discovery, materials, and crop protection. Herein, we report the first polyfluoroarylation of aliphatic carboxylic acids via photoredox decarboxylation. The method proceeds with broad substrate scope and high functional group tolerance. Moreover, small complex molecules such as natural products and drugs can be modified by late-stage modification. PMID: 33481305 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Ritter T, Sun X Tags: Angew Chem Int Ed Engl Source Type: research

ZIF-8 Membrane Permselectivity Modification by Manganese(II) Acetylacetonate Vapor Treatment.
Abstract Vapor phase treatment of ZIF-8 membranes with manganese(II) acetylacetonate (Mn(acac) 2 )   allows permselectivity tuning. Propylene/propane selectivity increases from 31 to 210 after the Mn(acac) 2 treatment at 165°C for 30 min, while selectivities increase from 14.6 to 242 for H 2 /CH 4 , from 2.9 to 38 for CO 2 /CH 4 , from 2.4 to 29 for CO 2 /N 2 , from 2.9 to 8 for O 2 /N 2 , after Mn(acac) 2 treatment at 175°C for 30 min. Stable equimolar propylene/propane mixture selectivity of 168 at ambient temperature, and 4 bar equimolar feed with a propylene flux of 8.3 x 10 -3 mol m -2 s -1 ...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Hayashi M, Lee DT, Dorneles de Mello M, Boscoboinik A, Tsapatsis M Tags: Angew Chem Int Ed Engl Source Type: research

Nitrogen-Doped Amorphous Zn-Carbon Multichannel Fibers for Stable Lithium Metal Anodes.
Abstract Lithium metal has drawn wide attention as a competitive anode candidate for next-generation high energy density rechargeable batteries. However, the application of lithium metal anodes for practical batteries is still impeded by safety issues and low Coulombic efficiency caused mainly by the uncontrollable growth of lithium dendrites. Herein, two types of free-standing nitrogen-doped amorphous Zn-carbon multichannel fibers are synthesized as multifunctional hosts for lithium accommodation. The three-dimensional (3D) macroporous structures endow effectively reduced local current density, and the lithiophil...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Lou XD Tags: Angew Chem Int Ed Engl Source Type: research

Formation of nanoscale [Ge4O16Al48(OH)108(H2O)24]20+ from condensation of ε-GeAl128+ Keggin polycations.
Formation of nanoscale [Ge4O16Al48(OH)108(H2O)24]20+ from condensation of ε-GeAl128+ Keggin polycations. Angew Chem Int Ed Engl. 2021 Jan 22;: Authors: Shohel M, Bjorkjund JL, Smith JA, Kravchuk DV, Mason SE, Forbes T Abstract Keggin-type polyaluminum cations belong to a unique class of compound with their large positive charge, hydroxo bridges, and divergent isomerization/oligomerization. Previously reports indicate that oligomerization of this species can only occur through one isomer (δ), but herein we report the isolation of largest Keggin-type cluster that occurs through self-conden...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Shohel M, Bjorkjund JL, Smith JA, Kravchuk DV, Mason SE, Forbes T Tags: Angew Chem Int Ed Engl Source Type: research

Iron oxidation in Escherichia coli bacterioferritin ferroxidase centre, a site designed to react rapidly with H2O2 but slowly with O2.
ko DA Abstract Both O 2 and H 2 O 2 can oxidise iron at the ferroxidase centre (FC) of Escherichia coli bacterioferritin (EcBfr) but mechanistic details of the two reactions need clarification. UV-vis, EPR and Mössbauer spectroscopies have been used to follow the reactions when apo-EcBfr, pre-loaded anaerobically with Fe 2+ , was exposed to O 2 or H 2 O 2 . We show that O 2 binds di-Fe 2+ FC reversibly, two Fe 2+ ions are oxidised in concert and a H 2 O 2 molecule is formed and released to solution. This peroxide molecule further oxidises another di-Fe 2+ FC, at a rate ~1000 faster than O 2 , ensuring an over...
Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Pullin J, Wilson MT, Clémancey M, Blondin G, Bradley JM, Moore GR, Le Brun NE, Lučić M, Worrall JAR, Svistunenko DA Tags: Angew Chem Int Ed Engl Source Type: research

Observation of Transition from Ferroelasticity to Ferroelectricity by Solvent Selective Effect in Anilinium Bromide.
Abstract Organic ferroelectrics are highly desirable for their lightweight, mechanical flexibility and biocompatibility. However, the rational design of organic ferroelectrics has always been faced with great challenges. Anilinium bromide (AB) has two structures reported in the Cambridge Crystallographic Data Centre, which might be an mmm F2/ m type ferroelastic (AB-1). When we studied its ferroelasticity, we were surprised to discover that there was another crystal (AB-2) in H 2 O besides this one, and they were very difficult to separate. By changing the solvent, we found that AB-1 crystals could be formed in et...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Fu DW, Gao JX, Huang PZ, Ren RY, Shao T, Han LJ, Liu J, Gong JM Tags: Angew Chem Int Ed Engl Source Type: research

Perovskite Nanosheet Hydrogels with Mechanochromic Structural Color.
Abstract Structural color colloidal sols of perovskite nanosheets were synthesized and were immobilized in a polymer hydrogel film by in-situ photopolymerization, leading to a novel mechanochromic material. Visible absorption spectroscopy, polarized optical microscopy and small-angle X-ray scattering revealed that the nanosheets are aligned parallel to the film surface with the periodic distance of up to ca. 300 nm, giving the structural color tunable over full color range. The present structural color gel showed reversible mechanochromic response that detects weak stress of 1 kPa with the quick response time less...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Yang W, Yamamoto S, Sueyoshi K, Inadomi T, Kato R, Miyamoto N Tags: Angew Chem Int Ed Engl Source Type: research

Boosting the Electrocatalysis of MXene by  Plasmon-induced Thermalization and Hot-electron Injection.
Boosting the Electrocatalysis of MXene by Plasmon-induced Thermalization and Hot-electron Injection. Angew Chem Int Ed Engl. 2021 Jan 21;: Authors: Wu X, Wang J, Wang Z, Sun F, Liu Y, Wu K, Meng X, Qiu J Abstract The MXenes attract great interest in catalytic and energy applications but suffer from inferior redox activity. An efficient strategy is presented to boost the intrinsic electrochemical activity of MXenes for electrocatalysis in varied chemical environments by utilizing their plasmonic response to electromagnetic waves. The plasmonic MXenes induce a significant thermoplasmonic effect to ...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Wu X, Wang J, Wang Z, Sun F, Liu Y, Wu K, Meng X, Qiu J Tags: Angew Chem Int Ed Engl Source Type: research

Responsive Emulsions for Sequential Multienzyme Cascades.
Abstract Multienzyme cascade biocatalysis is an efficient synthetic process, avoiding the isolation/purification of intermediates and shifting the equilibria of unfavourable steps. However, multienzyme systems are often limited by their incompatibility and cross-reactivity. Herein, we report a multi-responsive emulsion to proceed multienzyme reactions sequentially for high reactivity. The emulsion is achieved using a CO 2  , pH, and thermo-responsive block copolymer as a stabilizer, allowing the on-demand control of emulsion morphology and phase composition. Applying this system to a three-step cascade reacti...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Sun Z, Zhao Q, Haag R, Wu C Tags: Angew Chem Int Ed Engl Source Type: research

Site Selective Chlorination of C(sp3)-H Bonds Suitable for Late-Stage Functionalization.
We report a method for the highly selective chlorination of tertiary and benzylic C( sp 3 )-H bonds to produce the corresponding chlorides, generally in high yields. The reaction occurs with a mixture of an azidoiodinane, which generates a selective H-atom abstractor under mild conditions, and a readily-accessible and inexpensive copper(II) chloride complex, which efficiently transfers a chlorine atom. The reaction's exceptional functional group tolerance is demonstrated by the chlorination of>30 diversely functionalized substrates and the late-stage chlorination of a dozen derivatives of natural products and active pha...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Hartwig JF, Fawcett A, Keller MJ, Herrera Z Tags: Angew Chem Int Ed Engl Source Type: research

Vacancy-Enabled O3 Phase Stabilization for Manganese-rich Layered Sodium Cathodes.
Abstract Manganese-rich layered oxide materials hold great potential as low-cost and high-capacity cathodes for Na-ion batteries. However, they usually form P2 phase and suffer from fast capacity fade. In this work, an O3 phase sodium cathode has been developed out of a Li and Mn-rich layered material by leveraging the creation of transition metal (TM) and oxygen vacancies and the electrochemical exchange of Na and Li. The Mn-rich layered cathode material remains primarily O3 phase during sodiation/desodiation and can have a full sodiation capacity of ~220 mAh/g. It delivers ~160 mAh/g specific capacity between 2-...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Xiao B, Wang Y, Tan S, Song M, Li X, Zhang Y, Lin F, Han KS, Omenya F, Amine K, Yang X, Reed D, Hu Y, Xu GL, Hu E, Li X, Li X Tags: Angew Chem Int Ed Engl Source Type: research

Surface Modification of Black Phosphorus with Group 13 Lewis Acids for Ambient Protection and Electronic Tuning.
Abstract Herein we introduce a facile, solution-phase protocol to modify the Lewis basic surface of few-layer black phosphorus (bP) and demonstrate its effectiveness at providing ambient stability and tuning of electronic properties. Commercially available group 13 Lewis acids that range in electrophilicity, steric bulk, and Pearson hard/soft-ness are evaluated. The nature of the interaction between the Lewis acids and the bP lattice is investigated using a range of microscopic (optical, atomic force, scanning electron) and spectroscopic (energy dispersive, X-ray photoelectron) methods. Al and Ga halides are most ...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Tofan D, Sakazaki Y, Walz Mitra K, Peng R, Lee S, Li M, Velian A Tags: Angew Chem Int Ed Engl Source Type: research

Interplay Between a Foldamer Helix and a Macrocycle in a Foldarotaxane Architecture.
Abstract The design and synthesis of a novel rotaxane/foldaxane hybrid architecture is reported. The winding of an aromatic oligoamide helix host around a dumbbell-shaped thread-like guest, or axle, already surrounded by a macrocycle was evidenced by NMR and X-ray crystallography. The process proved to depend on the position of the macrocycle along the axle and to the associated steric hindrance. The macrocycle thus behaves as a switchable shield that modulates the affinity of the helix for the axle. Reciprocally, the foldamer helix acts as a supramolecular auxiliary that compartmentalizes the axle. In some cases,...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Gauthier M, Koehler V, Clavel C, Kauffmann B, Huc I, Ferrand Y, Coutrot F Tags: Angew Chem Int Ed Engl Source Type: research

An Organic-inorganic Hybrid Electrolyte as Cathode Interlayer for Efficient Organic Solar Cells.
Abstract An organic-inorganic hybrid electrolyte based on a cylic Ti-oxo cluster as inorganic core and naphthalene based organic ammonium bromide salts as electrolyte was developed with easy synthesis and low cost. The new hybrid electrolyte exhibits excellent solubility in methanol, aligned work function, good conductivity and amorphous state in thin film, enabling its successful application as cathode interlayer into organic solar cells with a high-power conversion efficiency of 17.19%. The studies in this work demonstrate that the hybrid electrolytes are a new kind of semiconductors, exhibiting promising applic...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Zhao C, Zhang Z, Han F, Xia D, Xiao C, Fang J, Zhang Y, Wu B, You S, Wu Y, Li W Tags: Angew Chem Int Ed Engl Source Type: research

Fe-catalyzed anaerobic Mukaiyama-type hydration of alkenes using nitroarenes.
Abstract Hydration of alkenes using first row transition metals (Fe, Co, Mn) under oxygen atmosphere (Mukaiyama-type hydration) is highly practical for alkene functionalization in complex synthesis. Different hydration protocols have been developed, however, control of the stereoselectivity remains a challenge. Herein, highly diastereoselective Fe-catalyzed anaerobic Markovnikov-selective hydration of alkenes using nitroarenes as oxygenation reagents is reported. The nitro moiety is not well explored in radical chemistry and nitroarenes are known to suppress free radical processes. Our findings show the potential ...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Bhunia A, Bergander K, Daniliuc CG, Studer A Tags: Angew Chem Int Ed Engl Source Type: research

Frequency-upconverted Stimulated Emission by Up to Six-photon Excitation from Highly Extended Spiro-fused Ladder-type Oligo(p-phenylene)s.
Abstract The frequency-upconverted fluorescence and stimulated emission induced by multi-photon absorption (MPA) have attracted much interest. As compared with low-order MPA process, the construction of high-order MPA process is highly desirable and rather attractive, yet remains a formidable challenge due to its inherent low transition probability. Herein, we report the observation of the first experimental frequency-upconverted fluorescence and stimulated emission by simultaneous six-photon excitation in organic molecular system. The well designed organic conjugated system based on cross-shaped spiro-fused ladde...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Jiang Y, Li KF, Gao K, Lin H, Tam HL, Liu YY, Shu Y, Wong KL, Lai WY, Cheah KW, Huang W Tags: Angew Chem Int Ed Engl Source Type: research

Development of High-Performance Pyrimidine Nucleoside and Oligonucleotide Diarylethene Photoswitches.
uml;schke A Abstract Nucleosidic and oligonucleotidic diarylethenes (DAEs) are an emerging class of photochromes with high application potential. However, their further development is hampered by the poor understanding of how the chemical structure modulates the photochromic properties. Here we synthesized 26 systematically varied deoxyuridine- and deoxycytidine-derived DAEs and analyzed reaction quantum yields, composition of the photostationary states, thermal and photo-chemical stability, and reversibility. This analysis identified two high-performance photoswitches with near-quantitative, fully reversible back...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Kolmar T, Büllmann SM, Sarter C, Höfer K, Jäschke A Tags: Angew Chem Int Ed Engl Source Type: research

Synthesis of Ketones by C-H Functionalization of Aldehydes with Boronic Acids under Transition-Metal-Free Conditions.
Abstract A method for the synthesis of ketones from aldehydes and boronic acids via a transition-metal-free C-H functionalization reaction is reported. The method employs nitrosobenzene as a reagent to drive the simultaneous activation of the boronic acid as a boronate and the activation of the C-H bond of the aldehyde as an iminium species that triggers the key C-C bond-forming step via an intramolecular migration from boron to carbon. These findings constitute a practical, scalable, and operationally straightforward method for the synthesis of ketones. PMID: 33476411 [PubMed - as supplied by publisher] (Sou...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Csaky AG, Roscales S Tags: Angew Chem Int Ed Engl Source Type: research

Strain-Modulated Reactivity: an Acidic Silane.
Abstract Compounds of main-group elements such as silicon are attractive candidates for green and inexpensive catalysts. For them to compete with state-of-the-art transition metal complexes, new reactivity modes must be unlocked and controlled, which can be achieved through strain. Using a tris(2-skatyl)methylphosphonium ([TSMPH 3 ] + ) scaffold, we prepared the strained cationic silane [TSMPSiH] + . In stark contrast with the generally hydridic Si-H bond character, it is acidic with an experimental pK a DMSO within 4.7-8.1, lower than in phenol, benzoic acid and the few hydrosilanes with reported pK a 's. We show...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Moret ME, Tretiakov S, Witteman L, Lutz M Tags: Angew Chem Int Ed Engl Source Type: research

Chiral Self-sorting of Giant Cubic [8+12] Salicylimine Cage Compounds.
RR Abstract Chiral self-sorting is intricately connected to the complicated chiral processes observed in nature and no artificial systems of comparably complexity have been generated by chemists. However, only a few examples of purely organic molecules have been reported so far, where the self-sorting process could be controlled. Among those systems a handful of shape-persistent organic cages were studied and rarely narcisstic or social self-sorting could be controlled. Herein, we describe the chiral self-sorting of large cubic [8+12] salicylimine cage compounds based on a chiral TBTQ precursor. Out of 23 possibl...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Mastalerz M, Wagner P, Rominger F, Zhang WS, Gross JH, Elbert SM, Schröder RR Tags: Angew Chem Int Ed Engl Source Type: research

Colloidal Metal Nanocrystals with Metastable Crystal Structures.
Abstract In addition to the conventional knobs such as composition, size, shape, and defect structure, the crystal structure (or phase) of metal nanocrystals offers a new avenue for engineering their properties. Various strategies have recently been developed for the fabrication of colloidal metal nanocrystals in metastable phases different from their bulk counterparts. With a focus on noble metals, we begin with a brief introduction to their atomic packing, followed by a discussion about five major synthetic approaches to their colloidal nanocrystals in unconventional phases. We then highlight the success of synt...
Source: Angewandte Chemie - January 21, 2021 Category: Chemistry Authors: Janssen A, Nguyen QN, Xia Y Tags: Angew Chem Int Ed Engl Source Type: research

Tailoring electronic structure and size of ultrastable M-MOFs (M = Co, Ni) with enhanced electroconductivity for high-performance supercapacitor.
Abstract Metal-organic frameworks (MOFs) utilized as electrodes for energy storage/conversion has been a challenge due to their incompetent chemical stability and poor electrical conductivity in electrolyte. Here, a nanoscale MOF, Co 0.24 Ni 0.76 -bpa-200 , possessing ultrahigh stability with uncommon semiconductor behavior (σ = 4.2 × 10 -3 S m -1 ) was fabricated by a combination of robust hydrophobic paddlewheel, optimized Co/Ni ratio, MOF size and conjugated degree of coligand. DFT study reveals that the appropriate Ni 2+ doping reduces the activation energy of system and thus yields a higher carrie...
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Chen S, Xia Z, Jia X, Ge X, Ren C, Yang Q, Hu J, Chen Z, Han J, Xie G, Gao S Tags: Angew Chem Int Ed Engl Source Type: research

Regiodivergent Synthesis of Spirocyclic Compounds through Pd-Catalyzed Regio- and Enantioselective [3+2] Spiroannulation.
Abstract A novel Pd(0)-catalyzed highly regio- and enantioselective  [3+2] spiroannulation reaction has been developed for rapid assembly of a new class of [5,5] spirocyclic carbo- and heterocycles. Notably, the regioselectivity could be dominated by fine-tuning of the Pd-𝝅-allyl intermediate. An array of coupling partners could be well-tolerated with excellent regio-, and enantioselectivtities. Moreover, the potential application of this reaction was exemplified by several further transformations. PMID: 33474803 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Trost BM, Zuo Z Tags: Angew Chem Int Ed Engl Source Type: research

Intramolecular Electric Field Construction in Metal Phthalocyanine as Dopant-Free Hole Transporting Material for Stable Perovskite Solar Cells with > 21% Efficiency.
Intramolecular Electric Field Construction in Metal Phthalocyanine as Dopant-Free Hole Transporting Material for Stable Perovskite Solar Cells with>21% Efficiency. Angew Chem Int Ed Engl. 2021 Jan 20;: Authors: Yu Z, Wang L, Mu X, Chen CC, Wu Y, Cao J, Tang Y Abstract Low conductivity and hole mobility in the pristine metal phthalocyanines greatly limit their application in perovskite solar cells (PSCs) as the hole-transporting materials (HTMs). Here, we prepare a Ni phthalocyanine (NiPc) decorated by four methoxyethoxy units as HTMs. In NiPc, the two oxygen atoms in peripheral substituent have a m...
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Yu Z, Wang L, Mu X, Chen CC, Wu Y, Cao J, Tang Y Tags: Angew Chem Int Ed Engl Source Type: research

Efficient and Selective Interplay Revealed: CO2 Reduction to CO over ZrO2 by Light with Further Reduction to Methane over Ni0 by Heat Converted from Light.
This study paves the way for using first row transition metals for solar fuel generation and on-site fuel supply on planets using only UV-visible light. PMID: 33474813 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Izumi Y, Zhang H, Itoi T, Konishi T Tags: Angew Chem Int Ed Engl Source Type: research

Photochemically Activated Dimagnesium(I) Compounds: Reagents for the Reduction and Selective C-H Bond Activation of Inert Arenes.
Abstract The photochemical activation of dimagnesium(I) compounds, and subsequent high yielding, regioselective reactions with inert arenes, are reported. Irradiating benzene solutions of [{( Ar Nacnac)Mg} 2 ] ( Ar Nacnac = [HC(MeCNAr) 2 ] - ; Ar = 2,6-diisopropylphenyl (Dip) or 2,4,6-tricyclohexylphenyl (TCHP)) with blue or UV light, leads to double reduction of benzene and formation of the "Birch-like" cyclohexadienediyl bridged compounds, [{( Ar Nacnac)Mg} 2 (μ-C 6 H 6 )]. Irradiation of [{( Dip Nacnac)Mg} 2 ] in toluene, and each of the three isomers of xylene, promoted completely regio- and chemo...
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Jones C, Jones DDL, Douair I, Maron L Tags: Angew Chem Int Ed Engl Source Type: research

Chiral Spiro-Axis Induced Blue Thermally Activated Delayed Fluorescence Material for Efficient Circularly Polarized OLEDs with Low Efficiency Roll-off.
Abstract This work presents a chiral spiro-axis strategy which not only introduced the circularly polarized luminescence (CPL) property into thermally activated delayed fluorescence (TADF) molecules but also enhanced the intramolecular through space charge transfer (TSCT) process. Spiral distributed phenoxazine and 2-(trifluoromethyl)- 9H -thioxanthen-9-one-10,10-dioxide act as donor and acceptor units, respectively. The resulting TADF enantiomers, (R/S)-OSFSO, display emission maxima at 470 nm, small singlet-triplet energy gap (ΔEST) of 0.022 eV and high photoluminescence quantum yield (PLQY) of 81.2% in co...
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Zhang YP, Liang X, Luo XF, Song SQ, Li S, Wang Y, Mao ZP, Xu WY, Zheng YX, Zuo JL, Pan Y Tags: Angew Chem Int Ed Engl Source Type: research

Efficient Infrared-Light-Driven CO2 Reduction Over Ultrathin Metallic Ni-doped CoS2 Nanosheets.
Abstract Converting CO 2 and H 2 O into carbon-based fuel by IR light is a tough task. Herein, compared with other single-component photocatalysts, the most efficient IR-light-driven CO 2 reduction is achieved by an element-doped ultrathin metallic photocatalyst-Ni-doped CoS 2 nanosheets (Ni-CoS 2 ). The evolution rate of CH 4 over Ni-CoS 2 is up to 101.8 μmol g -1 h -1 . The metallic and ultrathin nature endow Ni-CoS 2 with excellent IR light absorption ability. The PL spectra and Arrhenius plots indicate that Ni atoms could facilitate the separation of photo-generated carriers and the decrease of the activa...
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Xu J, Ju Z, Zhang W, Pan Y, Zhu J, Mao J, Zheng X, Fu H, Yuan M, Chen H, Li R Tags: Angew Chem Int Ed Engl Source Type: research

All-in-one photocatalyst for high performance H2 production: Ga doped polymeric carbon nitride.
Abstract A photocatalyst system is generally constructed by catalyst and cocatalyst to achieve light absorption, electron-hole separation, and surface reaction. It is a great challenge to develop a sole photocatalyst with all functions to lower the efficiency loss. Here, we integrate the active GaN4  site into polymeric carbon nitride (CN)   photocatalyst (GCN), which displays an excellent H2  production rate of 9904  μmol h-1 g-1. It is 162 and 3.3 times higher than that of  CN  with the absence  ( 61  μmolh-1 g-1)  and presence ( 2981  μmolh-1 g-1) of 1....
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Jiang W, Zhao Y, Zong X, Nie H, Niu L, An L, Qu D, Wang X, Kang Z, Sun Z Tags: Angew Chem Int Ed Engl Source Type: research

Electrooxidative Rhodium-Catalyzed [5 + 2] Annulations via C-H/O-H Activations.
Abstract Electrooxidative annulations involving mild transition metal-catalyzed C-H activation have emerged as transformative strategy for the rapid construction of five- and six-membered heterocycles. In contract, we herein describe the first electrochemical metal-catalyzed [5 + 2] cycloadditions to assemble valuable seven-membered benzoxepine skeletons by C-H/O-H activation. The efficient alkyne annulation featured ample substrate scope, using electricity as the only oxidant. Mechanistic studies provided strong support for a rhodium(III/I) regime, involving a benzoxepine coordinated rhodium(I) sandwich complex a...
Source: Angewandte Chemie - January 20, 2021 Category: Chemistry Authors: Wang Y, Oliveira JCA, Lin Z, Ackermann L Tags: Angew Chem Int Ed Engl Source Type: research

Vapochromic Behaviors of A Solid-State Supramolecular Polymer Based on Exo-Wall Complexation of Perethylated Pillar[5]arene with 1,2,4,5-Tetracyanobenzene.
Abstract The research for the solid-state supramolecular polymers with specific functions accelerates the development of supramolecular and materials sciences. Here, we discover the different complexation modes of perethylated pillar[5]arene ( EtP5 ) with 1,2,4,5-tetracyanobenzene ( TCNB ) in various solvents. Driven by charge-transfer interaction, TCNB is enclosed in the cavity of EtP5 in CHCl 3 , while TCNB complexes with EtP5 at the exo-wall of EtP5 in CH 2 Cl 2 . This is because the size of CH 2 Cl 2 matches the cavity of EtP5 , forcing TCNB to complex with the exo-wall of EtP5 . Furthermore, we fabricate a va...
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Wang M, Li Q, Li E, Liu J, Zhou J, Huang F Tags: Angew Chem Int Ed Engl Source Type: research

Iron-Catalyzed Radical Activation Mechanism for Denitrogenative Rearrangement Over C(sp3)-H Amination.
Abstract An iron-catalyzed denitrogenative rearrangement of 1,2,3,4-tetrazole is developed over the competitive C(sp 3 )-H amination. This catalytic rearrangement reaction follows an unprecedented metalloradical activation mechanism. Employing the developed method, a wide number of complex-N-heterocyclic product classes have been accessed. The synthetic utility of this radical activation method is showcased with the short synthesis of a bioactive molecule. Collectively, this discovery underlines the progress of radical activation strategy that should find wide application in the perspective of medicinal chemistry,...
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Chattopadhyay B, Roy S, Das SK, Khatua H, Das S, Singh KN Tags: Angew Chem Int Ed Engl Source Type: research

Sterilizing Immunity against SARS-CoV-2 Infection in Mice by a Single-Shot and Lipid Amphiphile Imidazoquinoline TLR7/8 Agonist-Adjuvanted Recombinant Spike Protein Vaccine.
saert M Abstract The search for vaccines that protect from severe morbidity and mortality as a result of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19) is a race against the clock and the virus. Here we describe the use of a novel amphiphilic imidazoquinoline (IMDQ-PEG-CHOL) TLR7/8 adjuvant, consisting of an imidazoquinoline conjugated to the chain end of a cholesterol-poly(ethylene glycol) macromolecular amphiphile. This amphiphile is water soluble and exhibits massive translocation to lymph nodes upon local administration, li...
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Jangra S, De Vrieze J, Choi A, Rathnasinghe R, Laghlali G, Uvyn A, Van Herck S, Nuhn L, Deswarte K, Zhong Z, Sanders N, Lienenklaus S, David S, Strohmeier S, Amanat F, Krammer F, Hammad H, Lambrecht BN, Coughlan L, García-Sastre A, de Geest B, Schotsaert Tags: Angew Chem Int Ed Engl Source Type: research

Transition Metal Complexes as Catalysts for the Electroconversion of CO2 : An Organometallic Perspective.
ner W Abstract The electrocatalytic transformation of carbon dioxide has been a topic of interest in the field of CO2 utilization for a long time. Recently, the area has seen increasing dynamics as an alternative strategy to catalytic hydrogenation for CO2 reduction. While many studies focus on the direct electron transfer to the CO2 molecule at the electrode material, molecular transition metal complexes in solution offer the possibility to act as catalysts for the electron transfer. C1 compounds such as carbon monoxide, formate, and methanol are often targeted as the main products, but more elaborate transformat...
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Kinzel NW, Werlé C, Leitner W Tags: Angew Chem Int Ed Engl Source Type: research

Highly Enantioselective Cobalt-Catalyzed (3 + 2) Cycloadditions of Alkynylidenecyclopropanes.
de;as JL, Lopez F Abstract Low-valent cobalt complexes equipped with chiral ligands can efficiently promote highly enantioselective (3+2) cycloadditions of alkyne-tethered alkylidenecyclopropanes. The annulation allows to assemble bicyclic systems containing five-membered rings in good yields and with excellent enantiomeric ratios. We also present a mechanistic discussion based on experimental and computational data, which support the involvement of Co(I)/Co(III) catalytic cycles. PMID: 33464693 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Da Concepción E, Fernández I, Mascareñas JL, Lopez F Tags: Angew Chem Int Ed Engl Source Type: research

Cryptic sulfur incorporation in thioangucycline biosynthesis.
Abstract Sulfur incorporation into natural products is a critical area of biosynthetic studies. Recently, a subset of sulfur-containing angucyclines has been discovered, and yet, the sulfur incorporation step is poorly understood. In this work, a series of thioether-bridged angucyclines were discovered, and a cryptic epoxide Michael acceptor intermediate was revealed en route to thioangucyclines (TACs) A and B. However, systematic gene deletion of the biosynthetic gene cluster (BGC) by CRISPR/Cas9 could not identify any gene responsible for the conversion of the epoxide intermediate to TACs. Instead, a series of&n...
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Cao M, Zheng C, Yang D, Kalkreuter E, Adhikari A, Liu YC, Rateb ME, Shen B Tags: Angew Chem Int Ed Engl Source Type: research

Carbene-Catalyzed Activation of Remote Nitrogen Atoms of (benz)imidazole-derived aldimines for Enantioselective Synthesis of Heterocycles.
Abstract A new mode of carbene-catalyzed heteroatom activation and asymmetric reactions is disclosed. The reaction starts with addition of a carbene catalyst to a (benz)imidazole-derived aldimine substrate. Subsequent oxidation and proton transfer lead to the formation of a catalyst-bound triaza-diene as the key intermediate, in which the nitrogen atom at a site remote to the catalyst-substrate bond is activated. This unusual triaza-diene intermediate then undergoes highly enantioselective reactions with activated ketones through a concerted asynchronous pathway, as supported by mechanistic studies and preliminary...
Source: Angewandte Chemie - January 19, 2021 Category: Chemistry Authors: Yang X, Xie Y, Xu J, Ren S, Mondal B, Zhou L, Tian W, Zhang X, Hao L, Jin Z, Chi YR Tags: Angew Chem Int Ed Engl Source Type: research