Science China Chemistry最新文献

Nitrate pollution and carbon emissions, driven by anthropogenic nitrogen cycle imbalance and fossil fuel overuse, pose serious threats to environmental and human health. Electrocatalytic C-N coupling of CO₂ with nitrogen-containing species offers a sustainable route for urea synthesis, contributing to nitrogen recycling and carbon neutrality. However, developing electro-catalysts with high activity, selectivity, and stability remains challenging. Recent advances in rationally designed copper (Cu)-based catalysts have deepened the understanding of C-N coupling mechanisms and structure-performance relationships. This review highlights recent progress in Cu-based electrocatalysts for urea synthesis (mainly for CO₂ and nitrate coupling), focusing on three key strategies: electronic structure modulation, defect engineering, and multi-site synergy. The reaction pathways are first summarized, followed by discussions on catalyst design principles aimed at optimizing intermediate adsorption, lowering C-N coupling barriers, and facilitating proton-coupled electron transfer. In-situ characterizations are employed to elucidate the mechanistic roles of these strategies. Finally, the key challenges and future directions for the application of Cu-based catalysts are outlined.

The electrochemical nitrate (NO ⁻₃ ) reduction reaction (NO ⁻₃ RR) provides a promising strategy for ammonia (NH₃) synthesis and NO ⁻₃ wastewater treatment. However, the reaction still suffers from sluggish kinetics and unsatisfactory NH₃ selectivity owing to the complex multi-step reaction process with eight-electron transfer and multiple intermediates. Here we report a hierarchical nanoporous CuCoNiPdRuAl catalyst with a high-entropy CuCoNiPdRu surface as an efficient electrocatalyst for NO ⁻₃ RR. By virtue of the high-entropy surface offering multiple catalytic sites and nanoporous architecture that facilitate mass transport, the np-CuCoNiPdRuAl exhibits a high NH₃ Faradic efficiency of 97.4% and an impressive NH₃ yield rate of 30.47 mg h⁻¹ mg ⁻¹_cat . Experimental and theoretical studies indicate that the high-entropy CuCoNiPdRu surface creates multiple catalytic sites, which not only enable the acceleration of every step of the NO ⁻₃ RR via a tandem reaction mechanism but also provide a facile channel for ultrafast *H spillover for enhanceing the hydrogenation of intermediates, ultimately leading to enhanced NO ⁻₃ RR performance. This work offers an opportunity to design highly active and selective NO ⁻₃ RR electrocatalysts with potential for practical application.

Purely organic scintillators typically suffer from limited X-ray absorption due to the absence of high atomic number elements, which significantly restricts their radioluminescence (RL) performance and makes dynamic X-ray imaging challenging. To overcome this limitation, halogen atoms were introduced into maleimide-based fluorescent molecules, resulting in a new type of purely organic glassy scintillator with enhanced X-ray absorption and excellent film-forming properties. Compared with the non-halogenated 1-butyl-3,4-diphenyl-1H-pyrrole-2,5-dione (PAM), the brominated derivative 3,4-bis(4-bromophenyl)-1-butyl-1H-pyrrole-2,5-dione (PAM-4Br) exhibits strengthened supramolecular interactions that facilitate the formation of a uniform amorphous glass with high optical transparency (>92% at 550–800 nm). Moreover, PAM-4Br glass demonstrates significantly improved scintillation efficiency through the heavy atom effect of bromine, achieving an RL intensity 110% that of Bi₄Ge₃O₁₂, an ultrafast response time of 6 ns and a low detection limit of 120 nGy s⁻¹. The resulting high-transparency glassy scintillator screen not only achieves a modulation transfer function (MTF) of 0.28 at 30.0 lp mm⁻¹ under static X-ray imaging, but also successfully enables real-time high-definition dynamic X-ray imaging. It provides a molecular design strategy for high-performance organic glassy scintillators, opening new avenues for advanced X-ray imaging.

Achieving ultrahigh-affinity molecular recognition in aqueous media remains a key challenge in supramolecular chemistry. We report the synthesis of (+)-CA-C[4]B, a water-soluble chiral macrocycle derived from enantiopure BINOL, featuring eight carboxylate groups on its rims to enhance cavity depth and binding affinity. In aqueous media, (+)-CA-C[4]B exhibits ultrahigh 1:1 host-guest binding affinities up to 10¹³ M⁻¹ and 1:2 binding affinities up to 10¹⁶ M⁻². Notably, it supports dual-mode 1:2 binding: face-to-face for planar aromatic guests and head-to-head for spherical guests like adamantane. Combined with its high recognition affinities, superior fluorescence (quantum yield 43%) and circularly polarized luminescence (|g_lum| = 2.6 × 10⁻³), (+)-CA-C[4]B offers transformative potential for chiral supramolecular materials.

While biomaterials are endowed with sophisticated functions by the temporal dynamics and autonomy derived from non-equilibrium assemblies in biological systems, fabricating advanced materials counterparts with these features through kinetic control remains rare. Herein, we report a non-equilibrium hydrogel that exhibits autonomous time-dependent ultrabright fluorescence (quantum yield 0.90), achieved through the kinetically controlled incorporation of thermodynamic equilibrium host-guest complexes into a poly(2-hydroxyethyl methacrylate) (PHEMA) network. Transient complexes are programmed by coupling rapid assembly kinetics with the slow competitive binding of the polymer matrix. This kinetic mismatch converts a thermodynamic equilibrium supramolecular system into a non-equilibrium state, generating temporally dynamic fluorescence that cyclically shifts from yellow to green and self-reverts. The programmed temporal dynamics endow the hydrogel with high potential for information encryption applications.

Conventional electrolytic methods for separating chemically similar lanthanides (Ln) and actinides (An) are limited by thermodynamics and slow reaction kinetics, restricting their efficiency in rare-earth refining and nuclear fuel recycling. Herein, we report an electroextraction and oxidative back-extraction (EOB) strategy utilizing a LiCl-KCl-KAlCl₄ molten salt that overcomes these limitations by leveraging divergent interfacial reactivity. The EOB process achieves an exceptional separation factor for Ln/An (> 1000), while simultaneously increasing the separation rate by at least one order of magnitude. Through in-situ synchrotron radiation X-ray micro-computed tomography (SR-μCT) and X-ray diffraction (SR-XRD), we capture selective oxidation-induced destabilization of Ln-Al alloys while actinides retain phase stability-directly visualizing the electrochemical alloy transition mechanism. This research redefines the separation of f-block elements in molten salt systems and introduces a multimodal approach to investigating transient interfacial phenomena that are usually inaccessible to conventional metallurgical diagnostics under extreme conditions.

The Z/E configuration of alkenes profoundly influences their chemical and biological properties. Direct synthesis of thermodynamically less favorable (Z)-vinyl sulfonamides represents a significant challenge in organic synthesis. This study introduces a novel copper-catalyzed hydrosulfamoylation of alkynes, using SO₂, trimethylsilylhydride [(TMS)₃SiH], and electrophilic amines in a straightforward manner, which enables the stereoselective anti-Markovnikov synthesis of (Z)-vinyl sulfonamides by leveraging kinetic controls. This methodology effectively yields diverse (Z)-vinyl sulfonamides with excellent regioselectivity and stereoselectivity, compatible with aryl alkynes as well as primary and secondary amines. Density functional theory (DFT) calculations underscore the vinyl radical as a crucial intermediate, whose kinetic-based transformation dictates the stereoselectivity of the resulting products. This research not only presents a robust strategy for synthesizing (Z)-vinyl sulfonamides but also advances the understanding of the (Z)-isomerization mechanism.

Cellular forces critically regulate physiology and pathology—including cell shape, proliferation, migration, and immune responses. However, conventional mechanosensing techniques lack the spatial resolution and non-invasiveness needed to monitor these forces in living cells in real time. DNA nanotechnology overcomes these limitations through programmable design, piconewton force sensitivity, and inherent biocompatibility, enabling transformative platforms for next-generation mechanical sensors. This review synthesizes a decade of progress in DNA-based molecular force sensors, examining their structural designs, mechanotransduction mechanisms, and applications in force mapping, super-resolution imaging, and dynamic tracking at membrane receptors, extracellular microenvironments, and intercellular junctions. We further highlight how these advances will catalyze mechanopharmacology and clinical diagnostics via high-throughput mechanoreceptor screening and mechanoresponsive drug delivery systems.

Antisense oligonucleotides (ASOs) hold considerable promise for cancer gene therapy through targeted mRNA degradation. However, their biomedical application is hindered by inefficient delivery and limited visualization of biodistribution. Herein, we report a novel traceable afterglow nanoparticle platform for PLK1-targeted ASO delivery, representing the first reported integration of autofluorescence-free afterglow imaging with antisense therapeutics to enable non-invasive monitoring. Afterglow nanoparticle was assembled via nanoprecipitation of afterglow molecules (triple-anthracene derivatives) with surfactants, followed by polyethylenimine functionalization to enable ASO loading through electrostatic interactions, resulting in uniform nanoparticles with a favorable size distribution and high loading efficiency. In vitro evaluations revealed efficient cellular uptake, effective lysosomal escape and pronounced PLK1 silencing with substantial mRNA and protein downregulation, leading to marked induction of apoptosis in HeLa cells compared to free ASO. In vivo afterglow imaging demonstrated preferential tumor accumulation via the enhanced permeability and retention effect, with high signal-to-background ratios. In HeLa xenograft models, afterglow nanoparticle-mediated ASO delivery induced substantial tumor growth inhibition and widespread apoptosis, without detectable systemic toxicity as indicated by stable body weights and unremarkable organ histology. These findings highlight the potential of afterglow nanoparticles as a versatile platform for imaging-guided gene therapy, providing new avenues for enhanced precision in nucleic acid-based cancer treatments.