Iodine redox chemistry in rechargeable batteries.
Abstract In contrast with the classic ion intercalation, halogens have been coupled with metal anodes in a single cell to develop novel rechargeable batteries on the basis of the extrinsic redox reactions.  Since the commercial introduction of lithium-iodine primary battery in 1972, the iodine-based batteries exhibit high potential to match with high-rate performance, large energy density, and good safety in comparison with other halogen-based batteries. Along with the prosperous development of metal anodes (e.g., Li, Zn), one of the actual challenges lies in preparing the electrochemically active and reliabl...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Ma J, Liu M, He Y, Zhang J Tags: Angew Chem Int Ed Engl Source Type: research

A Unified Strategy for Arylsulfur(VI) Fluorides from Aryl Halides: Access to Ar-SOF3 Compounds.
Abstract A convenient protocol to selectively access various arylsulfur(VI) fluorides from commercially available aryl halides in a divergent fashion is presented. Firstly, a novel sulfenylation reaction with the electrophilic N -(chlorothio)phthalimide (Cl-S-Phth) and arylzinc reagents afforded the corresponding Ar-S-Phth compounds. Subsequently, the S(II) atom was selectively oxidized to distinct fluorinated sulfur(VI) compounds under mild conditions. Slight modifications on the oxidation protocol permit the chemoselective installation of 1, 3 or 4 fluorine atoms at the S(VI) center, affording the corresponding ...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Wang L, Cornella J Tags: Angew Chem Int Ed Engl Source Type: research

Bandgap Engineering of Hydroxyl-Functionalized Borophene for Superior Photo-Electrochemical Performance.
In this study, hydroxyl-functionalized borophene (borophene-OH) with tunable bandgap was fabricated by liquid-phase exfoliation using 2-butanol solvent. Surface energy matching between boron and 2-butanol produced smooth borophene, and the exposed unsaturated B sites generated by B-B bond breaking during exfoliation coordinated with OH groups to form semiconducting borophene-OH, enabling a tunable bandgap of 0.65-2.10 eV by varying its thickness. Photoelectrochemical (PEC) measurements demonstrated that the use of borophene-OH to fabricate working electrodes for PEC-type photodetectors significantly enhanced the photocurre...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Wang X, Liang J, You Q, Zhu J, Fang F, Xiang Y, Song J Tags: Angew Chem Int Ed Engl Source Type: research

Rhodium-Catalyzed Cyclisation of Terminal and Internal Allenols: An Atom Economic and Highly Stereoselective Access Towards Tetrahydropyrans Johannes P. Schmidt, Bernhard Breit.
Abstract A comprehensive study of a diastereoselective Rh-catalyzed cyclization of terminal and internal allenols is reported. The methodology allows the atom economic and highly syn -selective access to synthetically important 2,4-disubstituted, respectively 2,4,6-trisubstituted tetrahydropyrans (THP). Furthermore, its utility and versatility is demonstrated by a great functional group compatibility and the enantioselective total synthesis of (-)-centrolobine. PMID: 32940396 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Breit B, Schmidt J Tags: Angew Chem Int Ed Engl Source Type: research

The 2-Pyridyl Problem: Challenging Nucleophiles in Cross-Coupling Arylations.
Abstract Azine containing biaryls are ubiquitous scaffolds in many areas of chemistry, and efficient methods for their synthesis are continually desired. Pyridine rings are prominent amongst these motifs. Transition metal catalysed cross-coupling reactions have been widely used for their synthesis and functionalisation as they often provide a swift and tuneable route to related biaryl scaffolds. However, 2-pyridine organometallics are capricious coupling partners and 2-pyridyl boron reagents in particular are notorious for their instability and poor reactivity in Suzuki-Miyaura cross-coupling reactions. The synthe...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Willis MC, Cook XAF, de Gombert A, McKnight J, Pantaine LRE Tags: Angew Chem Int Ed Engl Source Type: research

A New Class of NIR-II Gold Nanoclusters Based Protein Biolabels for In Vivo Tumor-Targeted Imaging.
Abstract Photoluminescence imaging in the second near-infrared window (NIR-II) has recently emerged as a promising technique for in vivo deep-tissue imaging. However, it remains a challenge to design bright NIR-II luminescent nanomaterials that enable efficient labelling of proteins without disturbing their physiological properties in vivo . Herein, we developed an efficient strategy to synthesize bright NIR-II gold nanoclusters (Au NCs) protected by biocompatible cyclodextrin (CD). Leveraging on the ultrasmall size feature of Au NCs (
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Song X, Zhu W, Ge X, Li R, Li S, Chen X, Song J, Xie J, Chen X, Yang H Tags: Angew Chem Int Ed Engl Source Type: research

Activating chalcogen bonding (ChB) in alkylseleno/ alkyltelluroacetylenes toward ChB directionality control.
Abstract Activation of a deep electron-deficient area on chalcogen atoms (Ch = Se, Te) is demonstrated here in alkynyl chalcogen derivatives, in the prolongation of the (C≡)C-Ch bond. The solid-state structures of 1,4-bis(methylselenoethynyl)perfluorobenzene (1Se) show the formation of recurrent chalcogen-bonded (ChB) motifs. Association of 1Se and the tellurium analog 1Te with 4,4'-bipyridine and with the stronger Lewis base 1,4-di(4-pyridyl)piperazine gives 1:1 co-crystals with 1D extended structures linked by short and directional ChB interactions, comparable to those observed with the corresponding halog...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Fourmigue M, Dhaka A, Jeannin O, Jeon IR, Aubert E, Espinosa E Tags: Angew Chem Int Ed Engl Source Type: research

Fortified Coiled Coils: Enhancing Mechanical Stability with Lactam or Metal Staples.
P, Blank KG Abstract Coiled coils (CCs) are powerful supramolecular building blocks for biomimetic materials, increasingly used for their mechanical properties. Here, we introduce helix-inducing macrocyclic constraints, so-called staples, to tune thermodynamic and mechanical stability of CCs. We show that thermodynamic stabilization of CCs against helix uncoiling primarily depends on the number of staples, whereas staple positioning controls CC mechanical stability. Inserting a covalent lactam staple at one key force application point significantly increases the barrier to force-induced CC dissociation and reduces...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: López-García P, de Araujo AD, Bergues-Pupo AE, Tunn I, Fairlie DP, Blank KG Tags: Angew Chem Int Ed Engl Source Type: research

Post-Synthetic Modification: Systematic Study on a Simple Access to Nitridophosphates.
k W Abstract Nitridophosphates are a well-studied class of nitrides with diverse materials properties such as luminescence or ion conductivity. Despite the growing interest on this compound class, their synthesis mostly works through direct combination of starting materials. Herein, we present a systematic study on a promising method for post-synthetic modification by reacting pre-synthesized nitridophosphates with halides under elevated pressures and temperatures. In this work, we focus on the applicability of this approach to P/N compounds with different degrees of condensation. Accordingly, BaP2N4, Ba3P5N10Br, ...
Source: Angewandte Chemie - September 17, 2020 Category: Chemistry Authors: Wendl S, Seidl L, Schüler P, Schnick W Tags: Angew Chem Int Ed Engl Source Type: research

Modulating single-atom Pd sites with Cu for enhanced ambient ammonia electrosynthesis.
Abstract The electrochemical reduction of N 2 to NH 3 is emerging as a promising alternative for sustainable and distributed production of NH 3 . However, the development has been impeded by difficulties in N 2 adsorption, protonation of *NN and inhibition of competing hydrogen evolution. To address the issues, we design a catalyst with diatomic Pd-Cu sites on N-doped carbon by modulation of single-atom Pd sites with Cu. The introduction of Cu not only shifts the partial density states of Pd toward the Fermi level but also promote the d-2π* coupling between Pd and adsorbed N 2 , leading to enhanced N 2 chemisor...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Han L, Ren Z, Ou P, Cheng H, Rui N, Lin L, Liu X, Zhuo L, Song J, Sun J, Luo J, L Xin H Tags: Angew Chem Int Ed Engl Source Type: research

Zwitterionic Polydopamine Engineered Interface for In Vivo Sensing with High Biocompatibility.
Abstract Electrochemical sensing performance is often compromised by electrode biofouling (e.g., protein nonspecific binding) in complex biological fluids; however, the design and construction of a robust biointerface with superior antifouling ability and high tolerance of free radicals and excellent electrochemical performance remains a great challenge. Herein, inspired by nature, we demonstrate a robust polydopamine-engineered biointerfacing, to tailing zwitterionic molecules (i.e., sulfobetaine methacrylate, SBMA) through Michael Addition. The SBMA-PDA biointerface can resist nonspecific binding of proteins in ...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Zhang M, Feng T, Ji W, Zhang Y, Wu F, Tang Q, Wei H, Mao L Tags: Angew Chem Int Ed Engl Source Type: research

Activity-Based NIR Enzyme Fluorescent Probes for the Diagnosis of Tumors and Image-Guided Surgery.
Abstract Near-infrared (NIR) activatable fluorescent probes have been considered to be the effective edge tools for the investigation of cell biology and disease diagnosis because of their outstanding advantages. Related genes involved in tumorigenesis and progression regulate the overexpression of certain enzymes. Owing to the distinctive characteristics of quick reaction time and favorable pharmacokinetics, enzyme-reactive NIR optical probes have shown great potential in the diagnosis of tumorigenesis and in image-guided intraoperative surgeries with high signal-to-noise ratios. In this review, we mainly summari...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Yoon J, Li H, Kim D, Yao Q, Ge H, Chung J, Fan J, Wang J, Peng X Tags: Angew Chem Int Ed Engl Source Type: research

Plasmonic Hot Electrons from Oxygen Vacancies for Infrared Light-Driven Catalytic CO2 Reduction on Bi2O3-x.
Abstract Current plasmonic photocatalysts are mainly based on noble metal nanoparticles and rarely work in the infrared (IR) light range. Here, cost-effective Bi 2 O 3- x with oxygen vacancies was formed in situ on commercial bismuth powder by calcination at 453.15 K in atmosphere. Interestingly, defects introduced into Bi 2 O 3- x simultaneously induced a localized surface plasmon resonance (LSPR) in the wavelength range of 600-1400 nm and enhanced the adsorption for CO 2 molecules, which enabled efficient photocatalysis of CO 2 -to-CO (~100% selectivity) even under low-intensity near-IR light irradiation. Signif...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Li Y, Wen M, Wang Y, Tian G, Wang C, Zhao J Tags: Angew Chem Int Ed Engl Source Type: research

Targeting RNA G-quadruplex in SARS-CoV-2: A Promising Therapeutic Target for COVID-19?
Abstract COVID-19 pandemic caused by SARS-CoV-2 has become a global threat. Understanding the underlying mechanisms and developing innovative treatments are extremely urgent. G-quadruplexes (G4s) are important non-canonical nucleic acids structures with distinct biofunctions. Here, we studied four putative G4-forming sequences (PQSs) in SARS-CoV-2 genome. One of them (namely RG-1), which locates in the coding sequence (CDS) region of SARS-CoV-2 nucleocapsid phosphoprotein (N), has been verified to form stable RNA G4 structure in live cells. G4-specific compounds, such as PDP, can stabilize RG-1 G4 and significantl...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Qu X, Zhao C, Qin G, Niu J, Wang Z, Wang C, Ren J Tags: Angew Chem Int Ed Engl Source Type: research

Surface Interrogation of Electrodeposited MnOx and CaMnO3 Perovskites by Scanning Electrochemical Microscopy: Probing Active Sites and Kinetics for the Oxygen Evolution Reaction.
Abstract Here we report the surface interrogation scanning electrochemical microscopy (SI-SECM) of two electrodeposited manganese-based electrocatalysts, amorphous MnOx and perovskite CaMnO3, to investigate the manganese oxidation state relating to the oxygen evolution reaction (OER) under neutral conditions. The results indicate the amounts of Mn(III) and Mn(IV) species in MnOx and CaMnO3 depend on potential. A Mn(V) species was identified in both structures during the OER. Time-delay titration of Mn(V) further revealed that MnOx produced two types of active sites with different OER reactions rates, k'fast(MnOx) ...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Jin Z, Bard AJ Tags: Angew Chem Int Ed Engl Source Type: research

Liquid-free all-solid-state Zn batteries and encapsulation-free flexible batteries enabled by in-situ constructed polymer electrolyte.
Abstract Zn batteries are usually considered as safe aqueous system promising for flexible batteries. On the other hand, any liquids, including water, being encapsulated in a deformable battery may result in potential troubles. Developing completely liquid-free all-solid-state Zn batteries needs high-quality solid-state electrolytes (SSEs). Here, we demonstrate the in-situ polymerized amorphous solid poly(1,3-dioxolane) electrolytes, which shows high Zn ion conductivity of 19.6 mS ×cm -1 at room temperature, low interfacial impedance, highly reversible Zn plating/stripping over 1800 h cycles, uniform & d...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Ma L, Chen S, Li X, Chen A, Dong B, Zhi C Tags: Angew Chem Int Ed Engl Source Type: research

Structural basis for α-helix mimicry and inhibition of protein-protein interactions with oligourea foldamers.
Structural basis for α-helix mimicry and inhibition of protein-protein interactions with oligourea foldamers. Angew Chem Int Ed Engl. 2020 Sep 16;: Authors: Guichard G, Cussol L, Mauran L, Buratto J, Belorusova AY, Neuville M, Osz J, Fribourg S, Fremaux J, Dolain C, Goudreau S, Rochel N Abstract Efficient optimization of a peptide lead into a drug candidate frequently needs further transformation to augment properties such as bioavailability. Among the different options, foldamers, sequence-based oligomers with precise folded conformation, have emerged as a promising technology. Here, we introdu...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Guichard G, Cussol L, Mauran L, Buratto J, Belorusova AY, Neuville M, Osz J, Fribourg S, Fremaux J, Dolain C, Goudreau S, Rochel N Tags: Angew Chem Int Ed Engl Source Type: research

Amine-Boranes as Transfer Hydrogenation and Hydrogenation Reagents: A Mechanistic Perspective.
Abstract Transfer hydrogenation (TH) has historically been dominated by Meerwein-Ponndorf-Verley (MPV) reactions. However, with growing interest in amine-boranes, not least ammonia-borane (H 3 N·BH 3 ), as potential hydrogen storage materials, these compounds have also started to emerge as an alternative reagent in TH reactions. In this review we discuss recent literature into TH chemistry using H 3 N·BH 3 and their analogues (amine-boranes and metal amidoboranes) as sacrificial hydrogen donors. By analyzing the mechanisms operating three distinct pathways were considered: ( i ) classical TH, ( ii ) ...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Lau S, Gasperini D, Webster RL Tags: Angew Chem Int Ed Engl Source Type: research

Isolable Silicon-Based Polycations with Lewis Superacidity.
Abstract Molecular silicon polycations of the types R 2 Si 2+ and RSi 3+ (R = H, organic groups) are elusive Lewis superacids and currently unknown in the condensed phase. Here, we report the synthesis of a series of isolable terpyridine-stabilized R 2 Si 2+ and RSi 3+ complexes, [R 2 Si(terpy)] 2+ (R = Ph 1 2+ ; R 2 = C 12 H 8 2 2+ , (CH 2 ) 3 3 2+ ) and [RSi(terpy)] 3+ (R = Ph 4 3+ , cyclohexyl 5 3+ , m-xylyl 6 3+ ), in form of their triflate salts. The stabilization of the latter is achieved through higher coordination and to the expense of reduced fluoride ion affinities, but a significant level of Lewis super...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Driess M, Hermannsdorfer A Tags: Angew Chem Int Ed Engl Source Type: research

A New Synthetic Methodology of Site-Specific Functionalized Polypeptides: Metal-Free, Highly Active and Selective at Room Temperature.
Abstract Functionalized polypeptides have attracted tremendous interest in recent years and found many stimulating applications due to their tunable physicochemical characteristics including hydrophilicity and stimuli-responsive behavior. The development of new strategies to produce these polymers without metallic contaminants is crucial for their applications in high-value and sensitive domains, such as biomedical, microelectronic, food packaging and personal beauty care fields. Herein, a highly efficient strategy to access well-defined site-specific functionalized polypeptides is developed by combining Michael r...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Zhao W, Lv Y, Li J, Feng Z, Ni Y, Hadjichristidis N Tags: Angew Chem Int Ed Engl Source Type: research

The Metaphosphite (PO2-) Anion as a Ligand.
r S Abstract The utilization of monomeric, lower phosphorous oxides and oxoanions, such as metaphosphite (PO 2 - ), which is the heavier homologue of the common nitrite anion but previously only observed in the gas phase and by matrix isolation, requires new synthetic strategies. Here, a series of rhenium(I-III) complexes with PO 2 -  as ligand is reported. Synthetic access was enabled by selective oxygenation of a terminal phosphide complex. Spectroscopic and computational examination revealed slightly stronger  σ -donor and comparable  π -acceptor properties of PO 2 -  compared to ho...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Abbenseth J, Wätjen F, Finger M, Schneider S Tags: Angew Chem Int Ed Engl Source Type: research

Hydromagnesiation of 1,3-enynes by magnesium hydride for synthesis of tri- and tetra-substituted allenes.
Abstract A protocol for regio-controlled hydromagnesiation of 1,3-enynes was developed using magnesium hydride that is generated in situ by solvothermal treatment of sodium hydride (NaH) and magnesium iodide (MgI 2 ) in THF. The resulting allenylmagnesium species could be converted into tri- and tetra-substituted allenes by subsequent treatment with various carbon- and silicon-based electrophiles with the aid of CuCN as a catalyst. PMID: 32936502 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Wang B, Li Y, Pang JH, Watanabe K, Takita R, Chiba S Tags: Angew Chem Int Ed Engl Source Type: research

Super-resolution spatial proximity detection with proximity-PAINT.
ann R Abstract Visualizing the functional interactions of biomolecules such as proteins and nucleic acids is key to understanding cellular life on the molecular scale. Spatial proximity is often used as a proxy for the direct interaction of biomolecules. However, current techniques to visualize spatial proximity are either limited by spatial resolution, dynamic range, or lack of single-molecule sensitivity. Here, we introduce Proximity-PAINT (pPAINT), a variation of the super-resolution microscopy technique DNA-PAINT. pPAINT uses a split-docking-site configuration to detect spatial proximity with high sensitivity,...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Schueder F, Lara-Gutiérrez J, Haas D, Beckwith KS, Yin P, Ellenberg J, Jungmann R Tags: Angew Chem Int Ed Engl Source Type: research

Self-Assembly of Photoresponsive Molecular Amphiphiles in Aqueous Media.
Abstract Amphiphilic molecules, comprising hydrophobic and hydrophilic moieties and the intrinsic propensity to self-assemble in aqueous environment, sustain a fascinating spectrum of structures and functions ranging from biological membranes to ordinary soap. Facing the challenge to design responsive, adaptive, and out-of-equilibrium systems in water, the incorporation of photoresponsive motifs in amphiphilic molecular structures offers ample opportunity to design supramolecular systems that enables functional responses in water in a non-invasive way using light. Here, we discuss the design of photoresponsive mol...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Chen S, Costil R, Leung FK, Feringa BL Tags: Angew Chem Int Ed Engl Source Type: research

Clathrate XI K58Zn122Sb207: A new branch on the clathrate family tree.
Abstract The compositional screening of K-Zn-Sb ternary system aided by machine learning, rapid exploratory synthesis using KH salt-like precursor and in-situ powder X-ray diffraction yielded a novel clathrate type XI K 58 Zn 122 Sb 207 . This clathrate consists of a 3D Zn-Sb framework hosting K + ions inside polyhedral cages, some of which are reminiscent of known clathrate types while others are unique to this structure type. The complex non-centrosymmetric structure in the tetragonal space group I-4 2 m was solved by means of single crystal X-ray diffraction as a 6-component twin due to pseudocubic symmetry and...
Source: Angewandte Chemie - September 16, 2020 Category: Chemistry Authors: Cox T, Gvozdetskyi V, Bertolami M, Lee S, Shipley K, Lebedev OI, Zaikina JV Tags: Angew Chem Int Ed Engl Source Type: research

Synthetic Biology Driven Biosynthesis of Unnatural Tropolone Sesquiterpenoids.
Abstract Tropolone sesquiterpenoids (TS) are an intriguing family of biologically active fungal meroterpenoids that arise through a unique intermolecular hetero Diels-Alder (hDA) reaction between humulene and tropolones. Here, we report on the combinatorial biosynthesis of a series of unprecedented analogs of pycnidione 1 and xenovulene A 2 . In a systematic synthetic biology driven approach, we recombined genes from three TS biosynthetic gene clusters (pycnidione  1, xenovulene A  2 and eupenifeldin 3 ) in the fungal host Aspergillus oryzae NSAR1. Rational design of the reconstituted pathways granted co...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Schotte C, Li L, Wibberg D, Kalinowski J, Cox RJ Tags: Angew Chem Int Ed Engl Source Type: research

Oxidative addition of a mechanically entrapped C(sp)-C(sp) bond to a rhodium(I) pincer complex.
Abstract By use of a macrocyclic phosphinite pincer ligand and bulky substrate substituents, we demonstrate how the mechanical bond can be leveraged to promote the oxidative addition of an interlocked 1,3-diyne to a rhodium(I) center. The resulting rhodium(III) bis(alkynyl) product can be trapped out by reaction with carbon monoxide or intercepted through irreversible reaction with dihydrogen, resulting in selective hydrogenolysis of the C-C σ-bond. PMID: 32929831 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Leforestier B, Gyton MR, Chaplin AB Tags: Angew Chem Int Ed Engl Source Type: research

Structural evidence for a [4Fe-5S] intermediate in the non-redox desulfuration of thiouracil.
We report here the crystal structure of TudS, refined at 1.5 Å resolution, which harbors a [4Fe-4S] cluster, bound by three cysteines only. Incubation of TudS crystals with 4-thiouracil trapped the cluster with a hydrosulfide ligand bound to the fourth non-protein-bonded iron, as established by the sulfur anomalous signal. This indicates that a [4Fe-5S] state of the cluster is a catalytic intermediate in the desulfuration reaction. Structural data and site-directed mutagenesis indicate that a water molecule is located next to the hydrosulfide ligand and to two catalytically important residues, Ser101 and Glu45. This ...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Zhou J, Pecqueur L, Aučynaitė A, Fuchs J, Rutkienė R, Vaitekūnas J, Meškys R, Boll M, Fontecave M, Urbonavičius J, Golinelli-Pimpaneau B Tags: Angew Chem Int Ed Engl Source Type: research

Expedient Synthetic Identification of a Novel P-stereogenic Ligand Motif for the Palladium-Catalyzed Preparation of Isotactic Polar Polypropylenes.
Abstract The iso -specific statistical copolymerization of unprotected polar monomers with propylene still stands a as grand challenge in the field of polymer chemistry. Current research in the field is hampered as to date only a single natural product derived dimenthylphosphine-motif is known to allow for the preparation of moderately isotactic polypropylene copolymers. To overcome this structural limitation, we developed time-efficient synthetic protocols that minimize the tediousness associated with P-donor ligand development. The strength of these protocols was exemplified by the preparation of twenty-five new...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Seidel FW, Tomizawa I, Nozaki K Tags: Angew Chem Int Ed Engl Source Type: research

C-H Methylation of Iminoamido Heterocycles with Sulfur Ylides.
Abstract The direct methylation of N -heterocycles is an important transformation for the advancement of pharmaceuticals, agrochemicals, functional materials, and other chemical entities. Herein, the unprecedented C(sp 2 )-H methylation of iminoamido heterocycles as nucleoside base analogues is described. Notably, trimethylsulfoxonium salt was employed as a methylating agent under aqueous conditions. A wide substrate scope and excellent level of functional group tolerance were attained. Moreover, this method can be readily applied to the site-selective methylation of azauracil nucleosides. The feasibility of gram-...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Ghosh P, Kwon NY, Kim S, Han S, Lee SH, An W, Mishra NK, Han SB, Kim IS Tags: Angew Chem Int Ed Engl Source Type: research

Fluorescent Self-Threaded Peptide Probes For Biological Imaging.
Abstract A generalizable synthetic method creates a new class of covalently connected,  self-threaded  fluorescent molecular probes with figure-eight topology, an encapsulated deep-red fluorophore, and two peripheral peptide loops. The globular molecular shape and rigidified peptide loops enhance imaging performance by promoting water solubility, eliminating probe self-aggregation, and increasing probe stability. Moreover, the peptide loops determine the affinity and selectivity for targets within complex biological samples such as cell culture, tissue histology slices, or living subjects. For examp...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Zhai C, Schreiber C, Padilla-Coley S, Oliver A, Smith BD Tags: Angew Chem Int Ed Engl Source Type: research

Facile Dinitrogen and Dioxygen Cleavage by a Uranium(III) Complex: Cooperativity Between the Non-innocent Ligand and the Uranium Center.
This study establishes that the combination of uranium and a low-valent nonmetal is a promising strategy to achieve a full N2 and O2 cleavage under ambient conditions, which may aid the design of new system for small molecules activation. PMID: 32930496 [PubMed - as supplied by publisher] (Source: Angewandte Chemie)
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Wang P, Douair I, Zhao Y, Wang S, Zhu J, Maron L, Zhu C Tags: Angew Chem Int Ed Engl Source Type: research

Molecular Machine Learning: The Future of Synthetic Chemistry?
s F Abstract During the last decade, modern machine learning has found its way into synthetic chemistry. Some long-standing challenges, such as computer-aided synthesis planning (CASP), have been successfully addressed, while other issues have barely been touched. This Viewpoint poses the question of whether current trends can persist in the long term and identifies factors that may lead to an (un)productive development. Thereby, specific risks of molecular machine learning (MML) are discussed. Furthermore, possible sustainable developments are suggested, such as explainable artificial intelligence (exAI) for synt...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Pflüger PM, Glorius F Tags: Angew Chem Int Ed Engl Source Type: research

High-voltage Rechargeable Alkali-acid Zn-PbO2 Hybrid Battery.
Abstract Aqueous rechargeable batteries have attracted tremendous research attentions owning to their advantages of safety, low cost and sustainability, while the limited electrochemical stability window (1.23 V) of water leads to their failure in competition with organic based lithium ion batteries. In this work, we report an alkali-acid Zn-PbO 2 hybrid battery by coupling alkaline Zn anode with acidic PbO 2 cathode, which show capability to deliver an impressively high open-circuit voltage ( V oc ) of 3.09 V and an operate voltage of 2.95 V at 5 mA cm -2 , thanks to the contribution from expanding the voltage wi...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Xu Y, Cai P, Chen K, Ding Y, Chen L, Chen W, Wen Z Tags: Angew Chem Int Ed Engl Source Type: research

Exploiting the Potential of Meroterpenoid Cyclases to Expand the Chemical Space of Fungal Meroterpenoids.
Abstract Fungal meroterpenoids are a diverse group of hybrid natural products with impressive structural complexity and high potential as drug candidates. In this work, we evaluate the promiscuity of the early structure diversity-generating step in fungal meroterpenoid biosynthetic pathways: the multibond-forming polyene cyclizations catalyzed by the yet poorly understood family of fungal meroterpenoid cyclases. In total, 12 unnatural meroterpenoids were accessed chemoenzymatically using synthetic substrates. Their complex structures were determined by 2D NMR studies as well as crystalline-sponge-based X-ray diffr...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Abe I, Mitsuhashi T, Barra L, Powers Z, Kojasoy V, Cheng A, Yang F, Taniguchi Y, Kikuchi T, Fujita M, Tantillo DJ, Porco JA Tags: Angew Chem Int Ed Engl Source Type: research

Carbene-Catalyzed Enantioselective Aldol Reaction: Post-Aldol Stereochemistry Control and Formation of Quaternary Stereogenic Centers.
Abstract The dominated approaches for asymmetric aldol reactions have primarily focused on the aldol carbon-carbon bond forming events. Here we postulate and develop a new catalytic strategy that seeks to modulate the reaction thermodynamics and control the product enantioselectivities via post-aldol processes. Specifically, a NHC catalyst is used to activate a masked enolate substrate (vinyl carbonate) to promote the aldol reaction in a non-enantioselective manner. This aldol event is subsequently followed by a dynamic kinetic resolution process that is mediated by the same (chiral) NHC catalyst without introduci...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Yang X, Majhi PK, Chai H, Liu B, Sun J, Liu T, Liu Y, Zhou L, Xu J, Liu J, Wang D, Zhao Y, Jin Z, Chi YR Tags: Angew Chem Int Ed Engl Source Type: research

Frustrated Radical Pairs: Insights from EPR Spectroscopy.
Abstract Recent progress in frustrated Lewis pair (FLP) chemistry has revealed the importance of the main group elements which has opened new avenues in synthetic chemistry. Recently, new reactivities of frustrated Lewis pairs have been uncovered that disclose certain combinations of Lewis acid and Lewis base undergo single electron transfer (SET) processes. Here a single electron can be transferred from the Lewis basic donor to a Lewis acid acceptor to produce a reactive frustrated radical pair (FRP). This review aims to highlight the recent advancements in this emerging field covering the synthesis and reactivit...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Ayan D, Richards E, Melen R Tags: Angew Chem Int Ed Engl Source Type: research

Quantitative Protein Corona Composition and Dynamics on Carbon Nanotubes in Biological Environments.
Abstract When nanoparticles enter biological environments, proteins adsorb to form the "protein corona" which causes significant changes in biodistribution and toxicity. Herein, we measure protein corona formation on DNA-functionalized single-walled carbon nanotubes (ssDNA-SWCNTs), a nanoparticle ideal for sensing and delivery, in blood plasma and cerebrospinal fluid. We characterize corona composition by mass spectrometry, revealing high-abundance corona proteins involved in lipid binding, complement activation, and coagulation. We investigate roles of electrostatic and entropic interactions driving sel...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Pinals RL, Yang D, Rosenberg DJ, Chaudhary T, Crothers AR, Iavarone AT, Hammel M, Landry M Tags: Angew Chem Int Ed Engl Source Type: research

Molecular Zinc Hydride Cations [ZnH]+: Synthesis, Structure, and CO2 Hydrosilylation Catalysis.
Abstract Protonolysis of thermally unstable and insoluble [ZnH2]n with the conjugated Brønsted acid of the bidentate diamine TMEDA (N,N,N',N'-tetramethylethane-1,2-diamine) and TEEDA (N,N,N',N'-tetraethylethane-1,2-diamine) gave the zinc hydride cation [(L2)ZnH]+, isolable either as the mononuclear THF adduct [(L2)ZnH(thf)]+[BArF4]- (L2 = TMEDA; BArF4- = [B(3,5-(CF3)2-C6H3)4]-) or as the dimer [{(L2)Zn)}2(μ-H)2]2+[BArF4]-2 (L2 = TEEDA). In contrast to [ZnH2]n, the cationic zinc hydrides are thermally stable and soluble in THF. [(L2)ZnH]+ was also shown to form di- and trinuclear adducts of the elusive ne...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Okuda J, Ritter F, Spaniol TP, Douair I, Maron L Tags: Angew Chem Int Ed Engl Source Type: research

Generation of Glycosyl Radicals from Glycosyl Sulfoxides and Its Use in the Synthesis of C-linked Glycoconjugates.
Abstract We here report glycosyl sulfoxides appended with an aryl iodide moiety as readily available, air and moisture stable precursors to glycosyl radicals. These glycosyl sulfoxides could be converted to glycosyl radicals by way of a rapid and efficient intramolecular radical substitution event. The use of this type of precursors enabled the synthesis of various complex  C -linked glycoconjugates under mild conditions. This reaction could be performed in aqueous media and is amenable to the synthesis of glycopeptidomimetics and carbohydrate-DNA conjugates. PMID: 32935426 [PubMed - as supplied by publi...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Shang W, Su SN, Shi R, Mou ZD, Yu GQ, Zhang X, Niu D Tags: Angew Chem Int Ed Engl Source Type: research

Turning on Zn 4s Electrons in a N2-Zn-B2 Configuration to Stimulate Remarkable ORR Performance.
Abstract Zn based single atom catalyst has been recently explored with distinguished stability, of which the fully occupied Zn 2+ 3d 10 4s 2 electronic configuration is Fenton reaction inactive, but the catalytic activity is thus inferior. Herein, we report a new approach to manipulate the s-band by constructing a state-of-the-art B, N co-coordinated Zn-B/N-C catalyst. We confirm both experimentally and theoretically that the unique N2-Zn-B2 configuration is crucial, in which Zn + (3d 10 4s 1 ) can hold enough delocalized electrons to generate suitable binding strength for key reaction intermediates and promote th...
Source: Angewandte Chemie - September 15, 2020 Category: Chemistry Authors: Wang J, Li H, Liu S, Hu Y, Zhang J, Xia M, Hou Y, Tse J, Zhang J, Zhao Y Tags: Angew Chem Int Ed Engl Source Type: research

Oligosilanes as Silyl Radical Precursors through Oxidative Si-Si Bond Cleavage using Redox Catalysis.
r A Abstract Oligosilanes are of great interest in the fields of organic photonics and electronics. In this communication, a highly efficient visible-light-mediated hydrosilylation of electron-deficient alkenes through cleavage of a trimethylsilyl-polysilanyl Si-Si bond is explored. These reactions smoothly occur on readily available organo(tristrimethylsilyl)silanes and other oligosilanes in the presence of an Ir III -based photo-redox catalyst under visible light irradiation. Silyl radicals are generated through single electron oxidation of the oligosilane assisted by the solvent. The introduced method exhibits ...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Yu X, Lübbesmeyer M, Studer A Tags: Angew Chem Int Ed Engl Source Type: research

Cross-Coupling between Hydrazine and Aryl Halides with Hydroxide Base at Low Loadings of Palladium by Rate-Determining Deprotonation of Bound Hydrazine.
We report the Pd-catalyzed C-N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as low as 100 ppm of Pd and KOH. Mechanistic studies revealed two catalyst resting states: an arylpalladium(II) hydroxide and arylpalladium(II) chloride. These compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the select...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Wang JY, Choi K, Zuend SJ, Borate K, Shinde H, Goetz R, Hartwig JF Tags: Angew Chem Int Ed Engl Source Type: research

Dual Reactivity of 1,2,3,4-Tetrazole: Manganese-Catalyzed Click Reaction and Denitrogenative Annulation.
Abstract A general catalytic method using Mn-porphyrin-based catalytic system is discovered that enables two different reactions (click reaction and denitrogenative annulation) affording two different classes of nitrogen heterocycles, such as 1,5-disubstituted 1,2,3-triazoles (with a pyridyl motif) and 1,2,4-triazolo-pyridines. Mechanistic investigations suggest that while click reaction likely proceeds through an ionic mechanism, which is different from the traditional click reaction, denitrogenative annulation undergoes likely via an electrophilic metallonitrene intermediate rather than the metalloradical interm...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Chattopadhyay B, Khatua H, Das SK, Roy S Tags: Angew Chem Int Ed Engl Source Type: research

Hydrogen purification through dual-phase oxygen permeable membrane with excellent stability.
Abstract Using oxygen permeable membranes (OPMs) to upgrade low-purity hydrogen is a promising concept for high-purity H 2 production.  At high temperatures, water dissociates  into hydrogen and oxygen. The oxygen permeates through OPM and oxidizes hydrogen in a waste stream on the other side of membrane. Pure hydrogen can be obtained on the water splitting side after condensation. However, the existing Co- and Fe-based OPMs are chemically unstable due to the over-reduction of Co and Fe ions under reducing atmospheres. Herein, dual-phase membrane Ce 0.9 Pr 0.1 O 2- δ -Pr 0.1 Sr 0.9 M...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Jia J, He G, Zhang Y, Caro J, Jiang H Tags: Angew Chem Int Ed Engl Source Type: research

Photochemical in-situ Exfoliation of Metal-Organic Frameworks for Enhanced Visible-Light-Driven CO2 Reduction.
Abstract Two novel two-dimensional metal-organic frameworks (2D MOF), 2D-M 2 TCPE (M = Co or Ni, TCPE = 1,​1,​2,​2-​tetra(4-​carboxylphenyl)​ethylene), which are composed of staggered (4,4)-grid layers based on paddlewheel-shaped dimers, serve as heterogeneous photocatalysts and achieve efficient reduction of CO 2 to CO. During the visible-light-driven catalysis, these structures undergo in-situ exfoliation to form nanosheets, which exhibit excellent stability and improved catalytic activity. The exfoliated 2D-M 2 TCPE nanosheets display a high CO evolution rate of 4174 μ mol g -1 h -1 and high sele...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Zheng HL, Huang SL, Luo MB, Wei Q, Chen EX, He L, Lin Q Tags: Angew Chem Int Ed Engl Source Type: research

Strong σ-hole activation on icosahedral carborane derivatives for a directional halide recognition.
Strong σ-hole activation on icosahedral carborane derivatives for a directional halide recognition. Angew Chem Int Ed Engl. 2020 Sep 14;: Authors: Jeon IR, Beau M, Lee S, Kim S, Han WS, Jeannin O, Fourmigué M, Aubert E, Espinosa E Abstract Crystal engineering based on σ -hole interactions is an emerging approach for realization of new materials with higher complexity. Neutral inorganic clusters derived from 1,2-dicarba- closo -dodecaborane, substituted with -SeMe, -TeMe, and -I moieties on both skeletal carbon vertices are experimentally demonstrated here as outstanding chalcogen- a...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Jeon IR, Beau M, Lee S, Kim S, Han WS, Jeannin O, Fourmigué M, Aubert E, Espinosa E Tags: Angew Chem Int Ed Engl Source Type: research

Carbon-Carbon Coupling on Inert Surfaces by Deposition of en Route Generated Aryl Radicals.
Abstract On-surface synthesis of exceptionally stable and p-conjugated carbon-carbon (C-C) bonded nanostructures requires metal surfaces. Albeit beneficial for characterization, metal surfaces are detrimental for electronic applications. To also facilitate C-C coupling on inert surfaces, we devised a radical deposition source (RDS) for the direct deposition of aryl radicals onto arbitrary substrates. Its core piece is a heated reactive drift tube through which halogenated precursors are deposited and en route converted into radicals. For the proof-of-concept we study 4,4''-diiodo- p -terphenyl (DITP) precursors on...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Galeotti G, Fritton M, Lackinger M Tags: Angew Chem Int Ed Engl Source Type: research

Formation of Nucleophilic Allylboranes from Molecular Hydrogen and Allenes Catalyzed by a Pyridonate Borane that Displays Frustrated Lewis Pair Reactivity.
Abstract Here we report the in situ generation of nucleophilic allylboranes from H 2 and allenes mediated by a pyridonate borane that displays frustrated Lewis Pair reactivity. Experimental and computational mechanistic investigations reveal that upon H 2 activation, the covalently bound pyridonate substituent becomes a datively bound pyridone ligand. Dissociation of the formed pyridone borane complex liberates Piers borane and enables a hydroboration of the allene. The allylboranes generated in this way are reactive towards nitriles. A catalytic protocol for the formation of allylboranes from H 2 and allenes and ...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Gellrich U, Hasenbeck M, Ahles S, Averdunk A, Becker J Tags: Angew Chem Int Ed Engl Source Type: research

Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses.
Abstract Sugar alcohols are of great importance to the food industry and are promising building blocks for bio-based polymers. Industrially, they are produced by heterogeneous hydrogenation of sugars with H 2 , usually with none to low stereoselectivities . Now, we present a homogeneous system based on commercially available components (DTBM-SEGPHOS and [RuCl 2 (benzene)] 2 ), which not just increases the overall yield (d.r. up to 31:1), but also allows a wide range of unprotected, densely functionalized ketoses to be diastereoselectively hydrogenated by choosing the appropriate ligand configuration. Furthermore, ...
Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Tindall DJ, Mader S, Kindler A, Rominger F, Hashmi ASK, Schaub T Tags: Angew Chem Int Ed Engl Source Type: research