We report an entirely new application of the experimental electron density (EED) in the study of magnetic anisotropy of single‐molecule magnets (SMMs). Among those SMMs based on one single transition metal, tetrahedral Co(II)‐complexes are prominent, and their large zero‐field splitting arises exclusively from coupling between the dx2‐y2 and dxy orbitals. Using very low temperature single‐crystal synchrotron X‐ray diffraction data, we obtained an accurate electron density (ED) for a prototypical...
Thu Jul 30, 2020 13:11
Highly porous Ti(IV)‐based materials containing photosensitizers have attract ed significant attention because of their high photocatalytic activity. Herein, we present novel Titanium‐porphyrinic gels (TPGs) and Titanium‐porphyrinic aerogels (TPAs), in which a porphyrinic ligand, tetrakis(4‐carboxyphenyl)porphyrin, is coordinated to Ti‐oxo clusters. These hierarchically porous TPAs, with micro‐, meso‐, and macropores and reactant‐concentration‐dependent Brunauer‐Emmett‐Teller surface areas of 407–738...
Thu Jul 30, 2020 13:11
Encapsulation of a trinuclear FeIII 2FeII complex within channels of a unique MOF is leading to the generation of iron nanoclusters stabilized on the carbon layer. To inhibit the aggregation of iron atoms toward nanoclusters, a “heteroatom modulator approach” is developed by atomic replacement of FeII by ZnII/CoII. A stable iron dimer in an optimal metal–nitrogen moiety is synthesized as efficient oxygen evolution catalyst. Abstract Understanding the thermal aggregation behavior of metal...
Wed Jul 29, 2020 22:00
A synergistic activation of amides and hydrocarbons, both thermodynamically stable, was achieved to enable direct C(sp3)−H acylation through nickel/photoredox catalysis. Comprehensive mechanistic studies indicate an unusual mechanism where the C−H activation occurs prior to the oxidative addition to form NiI‐alkyl species which is critical for reaction efficiencies. Abstract The utilizations of omnipresent, thermodynamically stable amides and aliphatic C(sp3)−H bonds for various functionalizations...
Wed Jul 29, 2020 21:39
Core–shell ferrite nanoparticles for CO2 methanation : The magnetic properties of CoFe2O4 and CoFe2O4–Fe3O4 nanoparticles were controlled by the exchange‐spring magnetic approach. These nanoparticles showed excellent performance as air‐stable heating agents in CO2 methanation, resulting in CH4 yields above 95 %. Abstract Magnetically induced catalysis can be promoted taking advantage of optimal heating properties from the magnetic nanoparticles to be employed. However, when unprotected,...
Wed Jul 29, 2020 21:39
Cooperative catalysis : The highly enantioselective 1,4‐addition of α,β‐unsaturated carboxylic acids with cycloalkanones has been catalytically accomplished for the first time. Ketones and carboxylic acids are activated as chiral enamines and mixed anhydrides, respectively. The subsequent catalytic oxylactonization of 1,4‐adducts gives the corresponding spirolactones with high diastereoselectivity. Abstract An enantioselective 1,4‐addition of α,β‐unsaturated carboxylic acids with cycloalkanones...
Wed Jul 29, 2020 21:39
Hat‐trick : An alignment medium compatible with multiple solvents ([D6]DMSO, CD3OD, D2O) is fabricated by molecular self‐assembly. The facile fabrication of the three‐in‐one system combined with its negligible background signals and without strict purity requirements enables efficient and accurate RDC measurements of organic molecules with different polarities and solubilities. Abstract Residual dipolar coupling (RDC), a robust anisotropic NMR parameter for structural elucidation of organic...
Wed Jul 29, 2020 21:38
The NIIC‐20 (NIIC stands for Nikolaev Institute of Inorganic Chemistry) is a family of five isostructural metal‐organic frameworks (MOFs) based on dodecanuclear wheel‐shaped carboxylate building blocks {Zn 12 (RCOO) 12 (glycol) 6 } (glycol is deprotonated diatomic alcohol: ethylene glycol, 1,2‐propanediol, 1,2‐butanediol, 1,2‐pentanediol or glycerol), quantitatively crystallized from readily available starting chemicals. The crystal structures contain large mesoporous cages of 25 Å connected...
Wed Jul 29, 2020 21:32
Two for one : Inverting the reactivity of the functional groups in ambiphilic molecules provides a new way to perform late‐stage enantiodivergence. Thus, starting from a common chiral substrate both enantiomers of the final product can be obtained. This concept is exemplified by the synthesis of substituted five‐ and six‐membered oxacycles. Abstract Inverting the reactivity of the functional groups in ambiphilic molecules provides a new synthetic strategy to perform late‐stage enantiodivergence....
Wed Jul 29, 2020 21:31
Radiation‐cleavage chemistry that can achieve tumor‐selective prodrug activation without causing unwanted side effects is of high value for clinical use yet has not been established. Here, we describe 3,5‐dihydroxybenzyl carbamate (DHBC) as a masking group that can be selectively and efficiently removed by external radiation in vitro and in vivo . DHBC reacts mainly with hydroxyl radical among reactive oxygen species produced by radiation to afford hydroxylation on para/ortho positions, followed...
Wed Jul 29, 2020 21:31
Organic and hybrid systems have emerged to challenge the classical inorganic structures through their enormous chemical diversity and modularity. Recent advances in the design of synthetic architectures and promising strategies toward (solar) fuel synthesis are discussed, highlighting progress on materials from dyes and catalysts to polymers and covalent organic frameworks. Abstract From the understanding of biological processes and metalloenzymes to the development of inorganic catalysts,...
Wed Jul 29, 2020 21:26
19 F and 13 C in RNA—a perfect match . An aromatic 19F–13C isotope labeling protocol is introduced for uridines and cytidines in RNA up to 60 nucleotides. The favorable TROSY properties of this spin pair will be useful to probe large RNAs by NMR spectroscopy. Abstract We present the access to [5‐19F, 5‐13C]‐uridine and ‐cytidine phosphoramidites for the production of site‐specifically modified RNAs up to 65 nucleotides (nts). The amidites were used to introduce [5‐19F,...
Wed Jul 29, 2020 21:25
Images : The reaction of [124/131]I2 with AuI‐N‐heterocyclic carbene precursors affords a strategy to label AuIII anticancer agents and study their biodistribution in vivo by positron emission tomography. Abstract AuIII complexes with N‐heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII‐NHC complexes by direct oxidation with radioactive...
Wed Jul 29, 2020 21:23
The mainstream approach to antiviral drugs against COVID‐19 is to focus on key stages of the SARS‐CoV‐2 life cycle. The vast majority of candidates under investigation are repurposed from agents of other indications. Understanding of protein‐inhibitor interactions at molecular scale will provide crucial insights for drug discovery to stop this pandemic. In this article, we summarize and analyze the most recent structural data on several viral targets with the presence of promising inhibitors for...
Wed Jul 29, 2020 17:06
The ability to pursue heterogeneous catalysis or nanocatalysis at a single‐electron level has been largely unsuccessful. The emergence of atomically precise metal nanoclusters with unique electronic structures provides access to currently inaccessible issues. Here we investigate the catalytic behaviours by performing the incoming and outgoing of a free valence electron of Au 6s1 on the Au25(SR)18 nanoclusters. Our studies reveal the distinct performances: Au25(SR)18– from donating an electron to...
Wed Jul 29, 2020 17:06
The first copper‐catalyzed asymmetric cyanation and etherification of enamides have been established, where a carbon‐centered radical adjacent to a nitrogen atom (CRAN) is enantioselectively trapped by a chiral copper (II) species. Moreover, the asymmetric cyanation of vinyl esters was disclosed as well. These reactions featuring very mild reaction conditions and high functional group tolerance give a series of chiral α‐cyano amides, α‐cyano esters and α‐hemiaminals in good yields with excellent...
Wed Jul 29, 2020 17:06
Establishing the atomic‐scale structure of metal‐oxide surfaces during electrochemical reactions is a key step to modelling this important class of electrocatalysts. Here, we demonstrate that the characteristic (√2×√2)R45° surface reconstruction formed on (001)‐oriented magnetite single crystals is maintained after immersion in 0.1 M NaOH at 0.20 V vs. Ag/AgCl and investigate its dependence on the electrode potential. We follow the evolution of the surface using in situ and operando surface X‐ray...
Wed Jul 29, 2020 17:05
A Pd‐catalyzed enantioselective intramolecular aminoazidation of unactivated alkenes using readily accessible 1‐azido‐1,2‐benziodoxol‐3(1H )‐one (ABX) as an azidating agent was established. This reaction affords a wide variety of structurally diverse 3‐N3‐substituted piperidines in good yields with excellent enantioselectivity, proceeds under mild reaction conditions, and features good functional‐group compatibility. Abstract The first Pd‐catalyzed enantioselective azidation of unactivated...
Wed Jul 29, 2020 14:57
Quantum chemical calculations show that the carbonyl⋅⋅⋅tellurazole chalcogen bond is at least as strong as conventional hydrogen bonds. This type of chalcogen bond was used in combination with hydrogen bonds to design a honeycomb‐like supramolecular organic framework showing two types of channels. Abstract In the last years, chalcogen bonding, the noncovalent interaction involving chalcogen centers, has emerged as interesting alternative to the ubiquitous hydrogen bonding in many research...
Wed Jul 29, 2020 14:57
Organic nitrate esters were synthesized through the use of a hypervalent‐iodine‐based nitrooxylating reagent. Its versatile reactivity under various reaction conditions is demonstrated in the synthesis of nitrooxylated β‐keto esters, 1,3‐diketones, malonates, and oxindoles under mild conditions. Abstract Herein, the synthesis and characterization of a hypervalent‐iodine‐based reagent that enables a direct and selective nitrooxylation of enolizable C−H bonds to access a broad array of organic...
Wed Jul 29, 2020 14:56
Blown away : Microcellular self‐blown non‐isocyanate polyurethanes foams were constructed from reactive formulations by guiding the chemo‐ and regioselective ring‐opening and decarboxylation of cyclic carbonates by amines and thiols. This novel concept is versatile, easily accessible, and scalable. Abstract Polyurethane (PU) foams are indisputably daily essential materials found in many applications, notably for comfort (for example, matrasses) or energy saving (for example, thermal insulation)....
Wed Jul 29, 2020 14:55
Cold‐wall chemical vapor deposition is a facile and scalable approach for large‐area growth of superclean graphene films. The gas‐phase reaction is efficiently suppressed because of the reduced temperature of the gas phase. The as‐received superclean graphene film exhibits improved optical and electrical properties. Abstract Chemical vapor deposition (CVD) has become a promising approach for the industrial production of graphene films with appealing controllability and uniformity. However,...
Wed Jul 29, 2020 14:54
A versatile and robust chiral discrimination strategy for small aromatic compounds is of significant importance in multidisciplinary fields. However, most current methods lack either the sufficient sensitivity for recognizing the chirality of the target molecules or their molecular specificity information. We have developed a versatile and chiral‐label‐free surface‐enhanced Raman scattering (SERS)‐based chiral discrimination sensing system for small aromatic molecules, where the molecular structural...
Wed Jul 29, 2020 12:59
The development of novel antibiotics is critical to combating the growing emergence of drug‐resistant pathogens. Malacidin A is a new member of the calcium‐dependent antibiotic (CDAs) family with activity against antibiotic‐resistant pathogens. Its mode of action is distinct from classical CDAs. However, the absolute structure of malacidin A has not been established. Herein, the total syntheses of malacidin A and its analogues are reported by a combination of Fmoc‐based Solid‐Phase Peptide Synthesis...
Wed Jul 29, 2020 12:30
To achieve efficient proton pumping in the light‐driven proton pump bacteriorhodopsin, the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark‐adapted state, and were found to be mostly well‐ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10% residual proton pumping activity, are less well ordered...
Wed Jul 29, 2020 11:00
Extracellular pH is an important biomarker in many diseases yet a routine method for imaging tissue pH has not been established in the clinic. Paramagnetic chemical exchange saturation transfer (paraCEST) agents are well‐suited for imaging tissue pH because the basis of CEST, chemical exchange, is inherently sensitive to pH. Several previous pH‐sensitive paraCEST agents were based upon with an exchanging Ln 3+ bound water molecule as the CEST antenna but this design often added additional line‐broadening...
Wed Jul 29, 2020 11:00
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