Angewandte Chemie最新文献

Understanding C─C coupling pathways is essential for achieving selective CO₂ conversion into multi-carbon products. However, controlling intermediates dimerization remains highly challenging due to both the complexity of the catalytic systems and the limited mechanistic knowledge into the C─C coupling process. In this work, a model dual-site catalyst with precisely configured Fe-O-Cu sites is designed by covalently grafting iron-phthalocyanine (FePc) onto copper nanowires via oxygen bridges (FeN₄-O-Cu NW), which enables probing of atomic-level mechanistic insights into the C─C coupling pathways during electrochemical CO₂ reduction reaction (CO₂RR). Remarkably, the FeN₄-O-Cu NW exhibits a 23.6-fold enhancement in the ethanol-to-ethylene Faradaic efficiency ratio as compared to O-Cu NW, achieving > 80% C₂₊ Faradaic efficiency at an industrially relevant current density of 1 A cm⁻². ¹³CO₂/¹²CO co-feed experiments together with a collection of operando/in-situ characterizations reveal that the enhanced ethanol selectivity over FeN₄-O-Cu NW arises from asymmetric C─C coupling between *CO and *CHO intermediates, where *CO is generated at the low-spin single-Fe-atom site, while *CHO is produced at the oxygen-bridged Cu site. Density functional theory (DFT) calculations further unveil that the oxygen-bridged Fe-O-Cu site can not only stabilize the in situ generated low-spin Fe(II) active site for enhancing CO₂ activation and lowering *CO desorption energy but also construct an oxygen-bridged Cu active site to stabilize the *OCHO intermediate, significantly lowering the *OCHO-to-*CHO conversion energy barrier, orchestrating an efficient asymmetric *CO─*CHO coupling path and boosting the CO₂-to-ethanol conversion.

Photocatalytic semi-hydrogenation of acetylene (C₂H₂) to ethylene (C₂H₄) is seriously limited by the inefficient generation and directional transfer of active hydrogen species. Here, we report a proton-coupled electron transfer (PCET) mechanism for photocatalytic acetylene semi-hydrogenation by establishing a hydroxyl network over hydroxyl-modified carbon nitride (C₃N₄-OH)/Ni(OH)₂ composite. Such a hydroxyl network not only enhances photogenerated charge separation but also establishes a strong hydrogen-bonding microenvironment for adsorbing interfacial water and facilitating hydrogen transfer dynamics. Femtosecond transient absorption (fs-TA) spectroscopy, in situ photochemical infrared spectroscopy, kinetic isotope effect (KIE), and active hydrogen (H*)-trapping reveal that the fast proton transfer via a PCET mechanism, rather than a conventional hydrogen atom transfer (HAT) pathway. Eventually, the C₃N₄-Ni(OH)₂ achieves an exceptionally high C₂H₄ production rate of 15.7 mmol g_cat⁻¹ h⁻¹ with a C₂H₄ selectivity of 98.2% under simulated solar irradiation. For purifying a crude C₂H₄ stream containing 0.5 vol% C₂H₂, the C₂H₂ conversion remains ∼98% over a long-term continuous-flow operation. This work elucidates the pivotal role of surface hydroxyl networks in governing hydrogen kinetics and paves a new avenue for the design of high-performance photocatalysts.

We report light-triggered charge separation in two discrete supramolecular architectures that self-assemble in a single step from donor (D) and acceptor (A) functionalized bridging ligands and Pd(II) cations. The “shape complementary assembly” (SCA) strategy allows for exclusive formation of the cis-[Pd₂D₂A₂]⁴⁺ cage isomer. Compared to previously reported statistical DA assemblies, lacking stoichiometry and stereo control, the number of possible electron transfer routes was reduced. This enables a better understanding and tunability of the excited state dynamics. Cage assembly was investigated by NMR, MS, and single crystal X-ray diffraction analysis. Steady-state absorption and electrochemical properties indicate that donor and acceptor moieties remain largely independent in the electronic ground state. Femtosecond pump-probe spectroscopy in the visible and infrared was applied to compare the fate of photoexcited states for pure ligands, donor- and acceptor-only assemblies, and the donor–acceptor heteroleptic cages. For the latter, ultrafast intracage ligand-to-ligand charge separation is followed by two back electron transfer pathways, occurring on timescales of hundreds of picoseconds and around one nanosecond, assignable to D/A ligands facing each other in cis- or trans-position. Our work shows that non-statistical modular self-assembly can be used for the precise positioning of photoredox-active components in defined distances on the nanoscale.

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.

The plasma membrane exhibits diverse substructures, such as pseudopodia, membrane nanotubes, and migrasomes, that are essential for cellular communication and cargo transport. Imaging these fine structures remains challenging due to their nanoscale dimensions and limitations of existing fluorescent probes. Here, we report the development of two rhodamine-based probes, RSD1 and RSD2, incorporating anionic membrane-anchoring groups and pyrrolidine auxochromes to enable wash-free, serum-compatible, long-term plasma membrane imaging. RSD2, in particular, demonstrates superior fluorogenicity, brightness, and photoswitching properties, facilitating high-resolution imaging in both live and fixed cells. It selectively labels membrane substructures across diverse cell types and maintains membrane specificity in the presence of serum. RSD2 is compatible with advanced microscopy techniques including confocal microscopy, instant structured illumination microscopy (iSIM), and direct stochastic optical reconstruction microscopy (dSTORM), achieving up to 40 nm resolution. Using two-color dSTORM, we visualize silica nanoparticle trafficking via membrane nanotubes and gondola-like bulges in neuronal cells, marking the first such observation. RSD2 also enables imaging of migrasomes and retraction fibers, revealing dynamic membrane-mediated transport processes. This probe offers a robust and versatile platform for investigating membrane architecture and function, with broad applicability in cell biology, nanomedicine, and super-resolution imaging.

Copper(I)-based hybrid halides feature highly designable structures, systematic tunability, and excellent photoluminescence; however, developing design rules that can predictably modulate their emission across different structural types remains under explored. Here, we report an acid-programmed generating approach, in which reaction acidity simultaneously modulates ligand protonation and the nucleation barrier, thereby generating coordination, ionic, and all-in-one copper(I) chloride architectures by tuning reaction acidity and affording six new compounds with emissions spanning 520–625 nm. Among these, the AIO compound 3 A-1H[CuCl₂] (A = 4-(aminomethyl)pyridine, 4AMP) exhibits a record-high photoluminescence quantum yield (PLQY) of 99%, setting a new benchmark for AIO Cu(I)-based emitters. Temperature-dependent photoluminescence and time-resolved spectroscopy reveal that the ultrahigh PLQY originates from enhanced lattice rigidity and a triplet phosphorescence pathway. Solubility and thin film fabrication demonstrate excellent processability, while long-term stability stands in stark contrast to the notorious instability of conventional Cu(I) halides. Moreover, mixing compounds yields broad-range white-light emission, underscoring the potential of materials for tunable and high-efficiency solid-state lighting. This study establishes acid-driven structural integration as a general strategy for constructing functional copper(I) halide compounds, laying the foundation for stable, solution-processable, and high-performance optoelectronic materials.

Copper(I)-based hybrid halides feature highly designable structures, systematic tunability, and excellent photoluminescence; however, developing design rules that can predictably modulate their emission across different structural types remains under explored. Here, we report an acid-programmed generating approach, in which reaction acidity simultaneously modulates ligand protonation and the nucleation barrier, thereby generating coordination, ionic, and all-in-one copper(I) chloride architectures by tuning reaction acidity and affording six new compounds with emissions spanning 520–625 nm. Among these, the AIO compound 3 A-1H[CuCl₂] (A = 4-(aminomethyl)pyridine, 4AMP) exhibits a record-high photoluminescence quantum yield (PLQY) of 99%, setting a new benchmark for AIO Cu(I)-based emitters. Temperature-dependent photoluminescence and time-resolved spectroscopy reveal that the ultrahigh PLQY originates from enhanced lattice rigidity and a triplet phosphorescence pathway. Solubility and thin film fabrication demonstrate excellent processability, while long-term stability stands in stark contrast to the notorious instability of conventional Cu(I) halides. Moreover, mixing compounds yields broad-range white-light emission, underscoring the potential of materials for tunable and high-efficiency solid-state lighting. This study establishes acid-driven structural integration as a general strategy for constructing functional copper(I) halide compounds, laying the foundation for stable, solution-processable, and high-performance optoelectronic materials.

The plasma membrane exhibits diverse substructures, such as pseudopodia, membrane nanotubes, and migrasomes, that are essential for cellular communication and cargo transport. Imaging these fine structures remains challenging due to their nanoscale dimensions and limitations of existing fluorescent probes. Here, we report the development of two rhodamine-based probes, RSD1 and RSD2, incorporating anionic membrane-anchoring groups and pyrrolidine auxochromes to enable wash-free, serum-compatible, long-term plasma membrane imaging. RSD2, in particular, demonstrates superior fluorogenicity, brightness, and photoswitching properties, facilitating high-resolution imaging in both live and fixed cells. It selectively labels membrane substructures across diverse cell types and maintains membrane specificity in the presence of serum. RSD2 is compatible with advanced microscopy techniques including confocal microscopy, instant structured illumination microscopy (iSIM), and direct stochastic optical reconstruction microscopy (dSTORM), achieving up to 40 nm resolution. Using two-color dSTORM, we visualize silica nanoparticle trafficking via membrane nanotubes and gondola-like bulges in neuronal cells, marking the first such observation. RSD2 also enables imaging of migrasomes and retraction fibers, revealing dynamic membrane-mediated transport processes. This probe offers a robust and versatile platform for investigating membrane architecture and function, with broad applicability in cell biology, nanomedicine, and super-resolution imaging.

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.