Angewandte Chemie最新文献

Helicobacter pylori infection represents a major global health challenge, characterized by high prevalence, significant association with gastric cancer, and rising antibiotic resistance. Carbohydrate-based vaccines targeting the O-antigen of lipopolysaccharide (LPS) present a promising alternative to conventional antimicrobial therapies. To explore the immunogenicity of LPS O-antigen from clinical isolate H. pylori SS1, we report an integrated chemoenzymatic strategy for the first synthesis of its octadecasaccharide O-antigen and related fragments for antigenicity evaluation. Our strategy features modular chemical synthesis of a decasaccharide precursor containing a high-carbon sugar (D,D-Hep) residue, a unique oligomeric β1,2-linked ribofuranosyl tetrasaccharide motif and a switchable glucosamine (GlcNH₂) residue through stereoconvergent [6 + 4] assembly, followed by protecting-group-controlled enzymatic elongation to precisely install hybrid Lewis antigen moiety (Le^y-Le^x) in a site-specific fucosylation manner to afford the target octadecasaccharide bearing five challenging 1,2-cis-glycosidic linkages. Chemical stereoselective construction of 1,2-cis-glucosidic and 1,2-cis-fucosidic linkages was accomplished by reagent-controlled glycosylation and 4-O-acyl remote participation, respectively. Enzymatic site-specific installation of the remaining three 1,2-cis-fucosidic linkages was achieved using two robust fucosyltransferases and a strategically designed GlcNH₂ residue. Glycan microarray-based screening of the synthetic O-antigen and its subunits with H. pylori-infected patient sera identified an undecasaccharide as a simpler and key epitope for vaccine development.

Cyclative C(sp³)–H functionalization of unactivated C─H bonds with heteroatoms is a straightforward way to construct saturated aza- and oxo-heterocycles, which continues to display ever-increasing prevalence in drug design. Building upon our recently reported copper catalysis that used simple N-methoxyamides as radical precursors, we report a method to access diverse aza- and oxo-heterocycles, including cyclic sulfonamides, cyclic ethers, and lactones of different ring sizes. By placing a heteroatom in the N-methoxyamide substrate, the carbon radical formed at the γ-position from the intramolecular H-abstraction by the amidyl radical could be trapped with the pendant heteroatom, leading to a redox-neutral Cu-catalyzed cyclative γ-C(sp³)–H functionalization. The syntheses of a wide range of saturated aza- and oxo-heterocycles demonstrate the versatility of this method.

Capturing radioactive molecular iodine (I₂) from nuclear waste under industrial conditions remains a considerable challenge. Herein, we developed for the first time a pore space multiple-layer functionalization (PSMLF) strategy, which enables directionally distribute functional sites across the multi-layer regions of large pore space, thereby enhancing the I₂ adsorption ability by optimizing pore space utilization. Utilizing this approach, the optimized adsorbent PAF-1-NTM achieves a record-high I₂ uptake of 88.58 wt% under simulated industrial conditions (150 °C and 150 ppmv I₂), a 108-fold improvement over its parent material, PAF-1. This performance significantly surpasses that of industrial Ag@MOR and all previously benchmarked adsorbents under the same conditions. Furthermore, adsorption kinetic of PAF-1-NTM (k₁ = 0.025 min⁻¹) are significantly higher than those of all other porous adsorbents reported to date. These results thus establish PAF-1-NTM as a new benchmark for high-temperature I₂ adsorbents. Mechanism investigation reveals a new insight that the I₂ adsorption capacity is positively correlated with the pore space utilization rate. Our work not only develops a promising adsorbent for industrial radioactive I₂ capture but also establishes a general design principle for creating high-temperature I₂ adsorbents suitable for practical applications.

Silicon/carbon (Si/C) composite anodes are among the most promising candidates for high-energy-density lithium-ion batteries but suffer from severe volume fluctuation and interfacial degradation during cycling. Herein, we report a water-processable covalent-and-supramolecular polymeric binders (CSPBs) that synergistically dissipate mechanical stress and promote Li⁺ transport to stabilize the Si/C anode interface. The CSPBs integrate poly(acrylic acid) (PAA), amine-terminated eight-arm poly(ethylene glycol) (8arm-PEG-NH₂), and benzo-21-crown-7/secondary ammonium host–guest complexes through amidation during electrode fabrication. The covalent linkages impart strong structural integrity, while the reversible supramolecular interactions act as sacrificial bonds to dissipate stress arising from Si volume expansion. Additionally, oxygen-rich PEG chains form continuous Li⁺ conduction pathways, enabling efficient ion transport. As a result, the CSPB-2-based Si/C anode delivers a high specific capacity of 582.0 mAh g⁻¹ after 265 cycles at 1C, with superior rate capability than the electrodes based on PAA or solely covalently cross-linked binders (CCBs). Kinetic analysis reveals an enhanced Li⁺ diffusion coefficient, confirming the improved ionic conductivity of the binder system. This work demonstrates a new strategy for integrating covalent anchoring and dynamic supramolecular adaptability within a sustainable, water-processable polymeric binder system, paving the way for the design of durable and high-performance silicon-based anodes.

We present di-tert-butyl peroxide (DTBP)-catalyzed long-wavelength light-induced Group 13, 14, and 15 elementalizations of alkenes and alkynes, through in situ production of tert-butyl radicals, followed by a hydrogen-atom-transfer process generating silyl, germyl, stannyl, alkyl, boryl, and phosphoryl radicals. This mild and photosensitizer-free methodology employing blue (450 nm)/green (530 nm)/orange (600 nm) LEDs affords high chemoselectivity and broad functional group tolerance compared to conventional use of shorter-wavelength light. Synthetic, spectroscopic, and computational data are consistent with a vibration-mediated photolysis mechanism of DTBP involving electronic excitation from vibrationally excited ground states (S₀μ_n) to the excited state (S₀μ_n→S_n transitions), driven by ultraweak absorption of long-wavelength visible light.

Direct ethanol fuel cells (DEFCs) are recognized as a promising energy conversion technology due to their high energy density and the renewable, eco-friendly nature of ethanol. However, their commercialization is hindered by the lack of anode catalysts that simultaneously offer high activity, stability, and selectivity toward the C1 pathway in the ethanol oxidation reaction (EOR). Herein, we report a rationally designed Pd₂Ga₁-ZrO₂@NC electrocatalyst, in which Pd₂Ga₁ alloy nanoparticles are anchored on a nitrogen-doped carbon-encapsulated ZrO₂ nanoframework. In alkaline media, this catalyst exhibits exceptional EOR performance, achieving a remarkable mass activity of 27.3 A mg_Pd⁻¹, 3.6 and 21.8 times higher than those of Pd-ZrO₂@NC and commercial Pd/C, respectively. Furthermore, it demonstrates a high C1 pathway selectivity of 58.7% at 0.8 V_RHE and retains 48.9% of its initial activity after 2000 accelerated durability test cycles, significantly outperforming state-of-the-art benchmarks. Combined experimental and DFT studies reveal the crucial function of Ga as an electron donor, which reverses the electron transfer around Pd from outward (in Pd-ZrO₂@NC) to inward (in Pd₂Ga₁-ZrO₂@NC), creating an electron-rich Pd state. This electronic restructuring thereby lowers the *CO oxidation barrier, strengthens *OH adsorption, and enhances metal-support interaction, collectively boosting both the C1 pathway selectivity and the overall EOR performance. This work provides valuable insights for the design of high-performance alloy-oxide composite electrocatalysts.

We present di-tert-butyl peroxide (DTBP)-catalyzed long-wavelength light-induced Group 13, 14, and 15 elementalizations of alkenes and alkynes, through in situ production of tert-butyl radicals, followed by a hydrogen-atom-transfer process generating silyl, germyl, stannyl, alkyl, boryl, and phosphoryl radicals. This mild and photosensitizer-free methodology employing blue (450 nm)/green (530 nm)/orange (600 nm) LEDs affords high chemoselectivity and broad functional group tolerance compared to conventional use of shorter-wavelength light. Synthetic, spectroscopic, and computational data are consistent with a vibration-mediated photolysis mechanism of DTBP involving electronic excitation from vibrationally excited ground states (S₀μ_n) to the excited state (S₀μ_n→S_n transitions), driven by ultraweak absorption of long-wavelength visible light.

The inverted perovskite solar cell (PSC), featuring self-assembled monolayers (SAMs) as the hole transport layer, has achieved a power conversion efficiency (PCE) exceeding 27%. However, the non-uniformity of SAMs and intrinsic defects within the perovskite film continue to constrain further enhancements in device performance. Herein, we developed a strategy for the synchronous modification of SAMs and perovskite by incorporating an ionic liquid of 1-butyl-3-methylimidazole-hexafluorophosphate (BM) to enhance the uniformity of SAMs and passivate defects in perovskite. Specifically, BM was incorporated into the perovskite precursor solution to effectively occupy halide vacancies and passivate the uncoordinated Pb²⁺. Meanwhile, owing to its ionic properties and the interaction between its functional groups and SAM, BM can effectively regulate the colloidal properties and reduce surface roughness, achieving a more uniform SAM layer. By employing this dual modification strategy, BM significantly modulates the crystallization kinetics, thereby facilitating the formation of highly crystalline perovskite films characterized by substantially enlarged grain sizes and a markedly reduced defect density. Consequently, the device incorporating dual modification of BM achieved a champion PCE of 26.59%, demonstrating exceptional operational stability with no observable PCE degradation after continuous power output at maximum power point (MPP) for 1000 h.

Die Austauschreaktion von Ameisensäure an Meersalz-Aerosolen, bei der HCl freigesetzt wird, fordert die herkömmliche Säure-Base-Chemie heraus. Unsere Gasphasenversuche zeigen, dass diese Reaktion an reinen NaCl-Clusterionen in Abwesenheit von Wasser stattfindet. Oberflächendefekte der NaCl-Clusterionen ermöglichen diese Reaktion durch verstärkte elektrostatische Wechselwirkungen der Salzionen mit dem Formiat, die den Unterschied in der Gasphasen-Acidität zwischen HCl und Ameisensäure mehr als ausgleichen.

In the Research Article (e202519101), Tengfei Yan, Ofer Reany, Junqiu Liu, and co-workers present a reversible, light-controlled ON/OFF chloride channel based on azobenzene-functionalized semiaza-bambus[6]urils. These biomimetic systems achieve stimulus-responsive chloride transport through photoisomerization, demonstrating unprecedented controllability in both liposomal membranes and living cells. The (E)-isomer selectively enables chloride flux, induces significant mitochondrial and lysosomal disruption, and promotes apoptosis in cancer cells, while the (Z)-isomer remains inactive.