ISSN / EISSN : 0044-8249 / 1521-3757
Published by: Wiley (10.1002)
Total articles ≅ 112,661
Latest articles in this journal
Angewandte Chemie; doi:10.1002/ange.202107053
Developing transition metal single-atom catalysts (SACs) for oxygen reduction reaction (ORR) is of great importance. Zeolitic imidazolate frameworks (ZIFs) as a subgroup of metal–organic frameworks (MOFs) are distinguished as SAC precursors, due to their large porosity and N content. However, the activity of the formed metal sites is limited. Herein, we reported a decarboxylation-induced defects strategy to improve their intrinsic activity via increasing the defect density. Carboxylate/amide mixed-linker MOF (DMOF) was chosen to produce defective Co SACs ([email protected]) by gas-transport of Co species to DMOF upon heating. Comparing with ZIF-8 derived SAC ([email protected]), [email protected] with more defects yet one fifth Co content and similar specific double-layer capacitance shows better ORR activity and eight times higher turnover frequency (2.015 e s –1 site –1 ). Quantum calculation confirms the defects can weaken the adsorption free energy of OOH on Co sites and further boost the ORR process.
Angewandte Chemie; doi:10.1002/ange.202108902
Reducing CO 2 to long-chain carbon products is attractive considering such products are typically more valuable than shorter ones. However, the best electrocatalyst for making such products from CO 2 , copper, lacks selectivity. By studying alternate C2+ producing catalysts we can increase our mechanistic understanding, which is beneficial for improving catalyst performance. Therefore, we investigate CO reduction on silver, as density functional theory (DFT) results predict it to be good at forming ethanol. To address the current disagreement between DFT and experimental results (ethanol vs. no ethanol), we investigated CO reduction at higher surface coverage (by increasing pressure) to ascertain if desorption effects can explain the discrepancy. In terms of product trends, our results agree with the DFT-proposed acetaldehyde-like intermediate, yielding ethanol and propanol as C2+ products – making the CO 2 electrochemistry of silver very similar to copper at sufficiently high coverage.
Angewandte Chemie; doi:10.1002/ange.202107898
The asymmetric synthesis of enantiopure pyrrolidines is reported via a streamlined strategy relying on two sequential C–H functionalizations of simple hydrocarbons. The first step is a regio- and stereoselective catalytic nitrene C–H insertion. Then, a subsequent diastereoselective cyclization involving a 1,5-Hydrogen Atom Transfer (HAT) from a N -centered radical leads to the formation of pyrrolidines that can then be converted to their free NH- derivatives.
Angewandte Chemie; doi:10.1002/ange.202108144
All-solid-state battery with Li metal anode is a promising rechargeable battery technology with high energy density and improved safety. Currently, the application of Li metal anode is plagued by the failure at the interfaces between lithium metal and solid electrolyte (SE). However, little is known about the defects at Li–SE interfaces and their effects on Li cycling, impeding further improvement of Li metal anodes. Here, by performing large-scale atomistic modeling of Li metal interfaces with common SEs, we discover that lithium metal forms an interfacial defect layer of nanometer-thin disordered lithium at the Li–SE interfaces. This interfacial defect Li layer is highly detrimental, leading to interfacial failure such as pore formation and contact loss during Li stripping. By systematically studying and comparing incoherent, coherent, and semi-coherent Li–SE interfaces, we find that the interface with good lattice coherence has reduced Li defects at the interface and has suppressed interfacial failure during Li cycling. Our finding discovers the critical roles of atomistic lithium defects at interfaces for the interfacial failure of Li metal anode, and motivates future atomistic-level interfacial engineering for Li metal anode in solid-state batteries.
Angewandte Chemie; doi:10.1002/ange.202108987
Herein, we report a photocatalytic procedure that enables the acylation/arylation of unfunctionalized alkyl derivatives in flow. The method exploits the ability of the decatungstate anion to act as a hydrogen atom abstractor and produce nucleophilic carbon-centered radicals that are intercepted by a nickel catalyst to ultimately forge C(sp 3 )‒C(sp 2 ) bonds. Owing to the intensified conditions in flow, the reaction time can be reduced from 12-48 hours to only 5-15 minutes. Finally, kinetic measurements highlight how the intensified conditions do not change the reaction mechanism but reliably speed up the overall process.
Angewandte Chemie; doi:10.1002/ange.202108999
„I chose my current career path because I loved teaching! My interest in teaching came first, and I grew to enjoy research later. … The most exciting thing about my research is that it brings together so many different fields …“ Find out more about Zachary Hudson in his Introducing … Profile.
Angewandte Chemie; doi:10.1002/ange.202107996
Oxidative-cyanation of aldehydes provides a promising strategy for the cyanide-free synthesis of organic nitriles. Design of robust and cost-effective catalysts is the key for this route. Herein, we designed a series of Se,S,N- tri -doped carbon nanosheets with a hierarchical porous structure (denoted as Se,S,N-CNs- x , x represents the pyrolysis temperature). It was found that the obtained Se,S,N-CNs- 1000 was very selective and efficient for oxidative-cyanation of various aldehydes including those containing other oxidizable groups into the corresponding nitriles using ammonia as the nitrogen resource below 100 o C. Detailed investigations revealed that the excellent performance of Se,S,N-CNs- 1000 originated mainly from the graphitic-N species with lower electron density and synergistic effect between the Se, S, N, and C in the catalyst. Besides, the hierarchically porous structure could also promote the reaction. Notably, the unique feature of this metal-free catalyst is that it tolerated other oxidizable groups, and showed no activity on further reaction of the products, thereby resulting in high selectivity. As far as we know, this is the first work for the synthesis of nitriles via oxidative-cyanation of aldehydes over heterogeneous metal-free catalysts.
Angewandte Chemie; doi:10.1002/ange.202107588
In solid tumours, tumour invasion and metastasis account for 90% of cancer-related deaths. Cell migration is steered by the lamellipodia formed at the leading edge. These lamellipodia can drive the cell body forward via its mechanical deformation regulated by cofilin. Inhibiting cofilin activity can cause significant defects in directional lamellipodia formation and the locomotory capacity of cell invasion, thus contributing to antimetastatic treatment. Here, a near infrared light (NIR)-controlled nanoscale proton supplier was designed with upconversion nanoparticles (UCNPs) with a core coated in MIL-88B for interior photoacids loading; this photoacids loading can boost H+ transients in cells, which converts the cofilin to an inactive form. Strikingly, inactive cofilin loses the ability to mediate lamellipodia deformation for cell migration. Additionally, the iron, which serves as a catalytic active centre in MIL-88B, initiates an enhanced Fenton reaction due to the increased H+ in the tumour, ultimately achieving intensive chemodynamic therapy (CDT). This work provides new insight into H+ transients in cells, which not only regulates cofilin protonation for antimetastatic treatment but also improves chemodynamic therapy.
Angewandte Chemie; doi:10.1002/ange.202107510
Electrocatalytic hydrogen production under acidic conditions is of great importance for industrialization in comparison to that in alkaline media, which, unfortunately, still remains great challenges due to the lack of earth-abundant, cost-effective and highly active anodic electrocatalysts that can be used durably under strongly acidic conditions. Here we report an unexpected finding that manganese oxide, a kind of common non-noble catalysts easily soluble in acidic solutions, can be applied as a highly efficient and extremely durable anodic electrocatalyst for hydrogen production from an acidic aqueous solution of alcohols. Particularly in a glycerol solution, a potential of as low as 1.36 V (vs. RHE) is needed at 10 mA cm -2 , which is 270 mV lower than that of oxygen evolution reaction (OER), to oxidize glycerol into value-added chemicals such as formic acid, without oxygen production. To our surprise, the manganese oxide exhibits extremely high stability for electrocatalytic hydrogen production in coupling with glycerol oxidation for longer than 865 hours compared to shorter than 10 h for OER. Moreover, the effect of the addition of glycerol on the electrochemical durability has been probed via in situ Raman spectroscopic analysis and density functional theory (DFT) calculation. This work opens an unprecedented window that acidity-unstable metal oxide electrocatalysts can be used robustly in acidic media under the presence of certain substances for electrochemical purposes, such as hydrogen production.
Angewandte Chemie; doi:10.1002/ange.202106250