Angewandte Chemie最新文献

Birefringent and nonlinear optical (NLO) crystals are crucial for advanced optical applications, yet achieving large birefringence (Δn), noncentrosymmetric (NCS) structures, and broad transparency from solar-blind ultraviolet (SUV) to near-infrared (NIR) regions remains challenging. Here, we report a 4HPX family of twelve 4-hydroxypyridinium halides, constructed from 4-hydroxypyridinium cations [4HPH]⁺ and halide anions [X]⁻ (X = F (I, II), Cl (III, VII, X), Br (IV, VIII, XI), I (V, VI, IX, XII)). Solution acidity dictates the structural transformations of this family, from centrosymmetric (I–IX) to NCS (X–XII) phases, where C─O bond lengths act as definitive structural fingerprints. Their optical bandgaps exceed those of all known halogen polyanion-based crystals due to the large HOMO–LUMO gaps of both [4HPH]⁺ and [X]⁻ and can be systematically tuned via hydrogen-bond strength. The large hyperpolarizability and polarizability anisotropy of [4HPH]⁺ endow this family with exceptional Δn and suitable second–harmonic generation (SHG) responses. Notably, II [C₅H₆NO]⁺(HF₂)⁻ exhibits the largest Δn (0.293) within the 4HPX family and among reported water–free SUV crystals. Meanwhile, I–V (0.222–0.293) also outperform commercial birefringent materials. NLO crystals X–XII show SHG responses. This work provides valuable insights into the rational design of next-generation birefringent and NLO crystals.

Fluorinated four-membered rings represent valuable structural motifs in bioactive molecules and pharmaceuticals; however, the asymmetric synthesis of such fluorinated frameworks bearing chiral quaternary carbon centers has not yet been achieved. Herein, we report a Rh-catalyzed enantioselective defluoroarylation of gem-difluorinated cyclobutenes with aryl boronates, enabling the asymmetric construction of fluorinated cyclobutenes bearing chiral quaternary carbon centers with high enantioselectivity via an addition/β-fluoride elimination process. In situ treatment with an additional distinct aryl boronate enables one-pot bis-defluoroarylation to give unsymmetrical diarylated cyclobutenes.

Integrating molecular self-assembly with additive manufacturing has opened new avenues for the direct production of thermosetting polymers with intricate geometries and tailored microstructures. The wide range of available chemical compositions enables diverse applications for the materials, including nanostructured porous materials, solid polymer electrolytes, and inorganic composites. Here, we introduce a novel concept by developing photocurable polymeric inks with precisely controlled nanostructures suitable for direct ink writing (DIW). In particular, amphiphilic block copolymers (BCPs) synthesized via reversible addition–fragmentation chain-transfer (RAFT) polymerization is combined with a crosslinker that also acts as a selective solvent, yielding inks with stable and well-ordered nanostructures. Upon photocuring of these inks, the nanostructures were largely preserved, and reinitiation of the RAFT end-groups during network formation covalently anchored the nanodomains to the matrix, thereby improving nanoscale morphology retention and enhancing mechanical performance. These inks exhibit shear-thinning behavior with rapid structural recovery after extrusion, enabling high-fidelity DIW. Our strategy offers a powerful route to precisely fabricating hierarchical thermosetting materials under ambient conditions, requiring no complex processing steps and specialized equipment. This work significantly broadens possibilities for designing advanced thermosetting materials with customizable architecture and enhanced functionalities.

Integrating molecular self-assembly with additive manufacturing has opened new avenues for the direct production of thermosetting polymers with intricate geometries and tailored microstructures. The wide range of available chemical compositions enables diverse applications for the materials, including nanostructured porous materials, solid polymer electrolytes, and inorganic composites. Here, we introduce a novel concept by developing photocurable polymeric inks with precisely controlled nanostructures suitable for direct ink writing (DIW). In particular, amphiphilic block copolymers (BCPs) synthesized via reversible addition–fragmentation chain-transfer (RAFT) polymerization is combined with a crosslinker that also acts as a selective solvent, yielding inks with stable and well-ordered nanostructures. Upon photocuring of these inks, the nanostructures were largely preserved, and reinitiation of the RAFT end-groups during network formation covalently anchored the nanodomains to the matrix, thereby improving nanoscale morphology retention and enhancing mechanical performance. These inks exhibit shear-thinning behavior with rapid structural recovery after extrusion, enabling high-fidelity DIW. Our strategy offers a powerful route to precisely fabricating hierarchical thermosetting materials under ambient conditions, requiring no complex processing steps and specialized equipment. This work significantly broadens possibilities for designing advanced thermosetting materials with customizable architecture and enhanced functionalities.

Innovative strategies for efficient photocatalytic urea production are desirable due to the wide applications of urea and derivatives in agriculture and pharmaceuticals, which remain highly challenging. Here, we introduce a simple but efficient radical addition approach to address this challenge by fully utilizing the in situ, synchronously generated aminyl radical (·NH₂) and hydroperoxyl radical (HO₂·) via the coupling of photocatalytic NH₃ oxidation and O₂ reduction. The two radicals reassembled and cooperatively reacted with NH₂COOH to form urea with markedly lower kinetic barrier than the industrial process. This approach not only achieved record-high urea production and conversion rates (42.6 mmol g_cat⁻¹ h⁻¹ and 70%, respectively) but also enabled the direct, single-step synthesis of unsymmetrical urea derivatives with good yields.

Photosynthetische Mikroorganismen können zur lichtgetriebenen H₂-Entwicklung genutzt werden. Eine Einschränkung ist jedoch die damit verbundene Bildung von molekularem Sauerstoff als Nebenprodukt der Photosynthese, der die Aktivität des Biokatalysators für die H₂-Produktion, d. h. die Hydrogenase, inhibiert. Wir stellen eine elektrochemische Strategie vor, die eine effiziente Entfernung von O₂ aus immobilisierten mikrobiellen Zellen und deren Umgebung ermöglicht.

Afterglow imaging uses delayed luminescence to suppress tissue autofluorescence and improve signal-to-background ratios for in vivo diagnostics and therapy. However, because afterglow induction typically requires external light, conventional photoactivated approaches remain suboptimal. Here, we report two hybrid molecular sonoafterglow luminophores that pair tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)₃) as a sonosensitizer with a phenoxy-adamantylidene afterglow substrate: cRuPA and ncRuPA, which are connected via a conjugated alkyne and a nonconjugated amide linker, respectively. After ultrasound treatment, only ncRuPA produces a strong sonoafterglow. In cRuPA, rapid electron transfer across the conjugated alkyne cleaves the dioxetane intermediate before emission can occur, whereas the nonconjugated amide in ncRuPA blocks this transfer, stabilizing the dioxetane and enabling sustained luminescence. ncRuPA is further developed into an activatable probe (ncRuPA_APN) that selectively turns on its sonoafterglow in response to the cancer biomarker aminopeptidase N. ncRuPA_APN enables sensitive tumor imaging and mediates efficient sonodynamic therapy via ultrasound-triggered singlet oxygen production. These Ru-based sonoafterglow probes represent the first hybrid sonoafterglow molecules and open new molecular-design routes toward cancer theranostics.

Atomically dispersed FeNC materials have emerged as the promising catalysts for replacing precious Pt-based catalysts in the oxygen reduction reaction (ORR). However, their widespread application remains limited by sluggish kinetics and the long-term stability of the isolated Fe single-atom sites. Herein, we report a highly active and durable catalyst (FeSnNC) featuring d-block iron and p-block-metal tin dual-atom pair sites. In situ infrared spectroscopy and X-ray absorption spectroscopy, together with ab initio molecular dynamics and density functional theory calculations reveal that the Fe─Sn dual-atom pair sites enable the bridge absorption of O₂ and facilitate direct O─O bond cleavage. The redirection of *OH desorption to the Sn site alleviates Fe-site degradation, while Sn incorporation can also reinforce the Fe─N bond, jointly enhancing ORR activity and durability. Under alkaline conditions, the catalyst delivers a half-wave potential of 0.91 V and a kinetic current density of 69 mA cm⁻² at 0.85 V, with negligible performance loss after 10,000 cycles. When applied in a zinc–air battery, FeSnNC exhibits a peak power density of 262 mW cm⁻² and a cycling lifetime exceeding 1,100 hours at 10 mA cm⁻². This work demonstrates the great potential of d–p metal atomic pair sites in ORR catalysis and provides new insights into the rational design of atomically precise metal catalysts.

Photoelectrochemical seawater electrolysis for the chloride oxidation reaction (ClOR) suffers from low selectivity against competing reactions and high onset potentials, which severely limits its efficiency for disinfectant production and marine-based chemical synthesis. Herein, we engineer an amorphous CoWO_x layer on BiVO₄ photoanodes that enables highly selective active chlorine (AC) production directly from natural seawater. The CoWO_x/BiVO₄ photoanode delivers a remarkable photocurrent density of 4.78 mA cm⁻² at 1.2 V_RHE under AM 1.5G illumination, with a record-low onset potential of 0.38 V_RHE. Notably, it maintains > 95% Faradaic efficiency and selectivity for AC production across a wide potential range of 0.9–1.8 V_RHE, and retains 86.9% selectivity at 0.6 V_RHE, overcoming the challenge of achieving efficient ClOR at low potentials. The incorporation of W suppresses the dissolution of Bi and V, while a dynamic Co²⁺/Co³⁺ equilibrium ensures operational stability over 150 h. In situ characterization and density functional theory (DFT) calculations reveal that CoWO_x accelerates Cl⁻ oxidation to •Cl intermediates and steers the reaction pathways toward selective AC formation by thermodynamically favoring key chlorine adsorption configurations. Scaled-up 25 cm² photoanodes achieves an AC production rate of 838 µmol h⁻¹. The resulting disinfectant exhibits broad-spectrum bactericidal efficacy, including 99.99% inactivation of E. coli and S. aureus within 24 h. This work establishes a scalable photoelectrode design for the direct, energy-efficient and selective production of valuable active chlorine from seawater.

Site-specific antibody conjugation through glycoengineering offers a promising route to generate homogeneous glycosite-specific antibody‒drug conjugates (gsADCs) with improved therapeutic indices. Dozens of gsADCs are advancing from preclinical studies to clinical trials. However, current methods involve either multiple enzymes or lengthy preparation of substrates. Herein, we report a novel and synthetically streamlined platform utilizing LacNAc-derived 4,6-acetal glycosyl donors for glycosite-specific transglycosylation mediated by a single enzyme. These glycosyl donors can be synthesized in as few as two steps, representing a major advancement in synthetic accessibility compared to previously reported glycosyl donors, which often require more than 15 steps. Computational analysis showed that the acetal ring restricts conformation, directing donor 7 to a π–π-stabilized groove of the enzyme. Donor 7, along with a positive control, was evaluated in the context of gsADCs, consistently demonstrating potent and selective cytotoxicity toward HER2-positive cancer cells, while sparing HER2-negative cells. Furthermore, donor 7 was successfully adapted to generate glycosite-specific degrader-antibody conjugates (gsDACs), highlighting its broad utility. Additional studies revealed that donor 7 produces antibodies with markedly enhanced resistance to Endo S2 mediated hydrolysis. Together, these findings establish a practical and broadly applicable platform for glycosite-specific antibody conjugation, paving the way for next-generation antibody-based therapeutics.