ABSTRACT The development of durable high‐performance cathodes is paramount to promote the potential application of potassium‐ion batteries in grid‐scale energy storage. Prussian blue analogues, such as iron hexacyanoferrate (FeHCF), offer superior cyclic stability, but their electrochemical activity is limited by poor K + diffusion depth, leading to a sharp decay in reversible capacity with increasing particle size and thus hindering their practical application. Herein, we demonstrate that the rational introduction of vacancies into the FeHCF framework is pivotal for enhancing potassium‐storage kinetics. This approach mitigates the detrimental particle size effect, enabling 500 nm FeHCF particles to retain 72% of the capacity of 50 nm particles. Building upon this, we further propose a local lattice reconstruction strategy to reinforce the framework, promoting reversible capacity and capacity retention. The as‐prepared FeHCF with a particle size of 500 nm delivers a high reversible capacity of 90 mAh g −1 at 50 mA g −1 and outstanding cycling stability (82.6% retention after 800 cycles), alongside remarkable rate performance. This work demonstrates the beneficial role of vacancies in optimizing K + storage kinetics in PBAs, providing support for the development of high‐performance potassium‐ion battery cathodes.

ABSTRACT Biological assemblies such as proteins adapt their helical morphology and function in response to external stimuli, yet controlled polymorphic transitions in synthetic chiral supramolecular analogues remain poorly understood. Herein, we demonstrate a strategy to achieve controlled chiral supramolecular polymorphism in water by coupling molecular design with external stimuli. An unsymmetrical oligo(phenyleneethynylene) derivative 1 bearing a pyridine unit, a hydrogen‐bonding amide group, and chiral hydrophilic side chains self‐assembles into three distinct chiral supramolecular polymorphs in water that are stable at different temperature regimes. At room temperature (RT), 1 self‐assembles into short cylinders ( AggI ), which undergo a polymorphic transition to transient double helical fibers upon heating around the LCST ( AggII , ≈ 325 K) and ultimately to irregular planar aggregates ( AggIII ) above the LCST. Remarkably, the polymorphic transitions are linked to the temperature‐dependent conformation and degree of dehydration of the glycol chains. Although AggII exists only within a narrow temperature window in pristine water, it can be stabilized and isolated at RT through chemical stimuli such as co‐solvents or metal salts that modulate the LCST. Our results establish LCST‐coupled chirality as a powerful strategy to regulate thermoresponsive supramolecular polymorphism and offer potential strategies for the design of adaptive materials.

ABSTRACT The practical application of Fe‐N‐C catalysts in proton exchange membrane fuel cells is fundamentally constrained by the inherent activity‐stability trade‐off. Here, we propose a “repair‐and‐upgrade” engineering strategy that not only repairs pyrolysis‐induced defects through carbon and nitrogen supplementation but also evolves conventional FeN 4 moieties into stabilized FeN 5 configurations via an in situ constructed carbon bilayer. The axial nitrogen modulates the electronic structure of Fe center to enhance catalytic activity, while the adaptive interlayer spacing of the N‐linked carbon bilayer compensates for fluctuations in the axial Fe─N bond length during catalysis, therefore anchoring the Fe active sites. When integrated into membrane electrode assemblies, the catalyst delivers a high peak power density of 1221 mW cm −2 and exhibits exceptional durability, retaining over 85% of its initial power density after 10,000 cycles in H 2 ‐O 2 and showing negligible decay over 45 h at 0.6 V in H 2 ‐air tests. This work presents a novel design strategy for stable single‐atom catalysts, centered on creating an adaptive local environment that ensures exceptional electrocatalytic stability.

ABSTRACT The transition to sustainable agriculture requires technologies that simultaneously enhance crop yields and reduce environmental impacts. Solar‐driven nitrate valorization, when coupled with CO 2 capture from industrial flue gas, presents a promising dual strategy for producing high‐value fertilizers while mitigating carbon emissions. However, its practical implementation is hindered by two interrelated challenges: (i) the intermittent nature of solar irradiation and (ii) the competitive hydrogen evolution reaction (HER), which severely compromises Faradaic efficiency (FE) of desired nitrogenous products. Here, we address these challenges by designing a heterogeneous CuPd electrocatalyst featuring an amorphous/crystalline heterojunction. This catalyst suppresses HER across a broad potential window (−0.4 to −1.4 V), maintaining >80% FE(ammonia) for >100 h. The catalytic robustness enables stable solar‐powered electrolysis even under low irradiation (0.4 sun), achieving >70% FE(ammonia) and 6% solar‐to‐fuel conversion efficiency, while catholyte simultaneously captures CO 2 at a rate of 6–20 mg h −1 . Techno‐economic analysis demonstrates cost competitiveness against biological counterparts. When applied to plant cultivation, this artificial photosynthesis system boosts solar‐to‐biomass conversion efficiency by 3.5‐fold compared to natural photosynthesis. By unifying solar energy harvesting, waste nitrate reduction, and carbon sequestration, our work provides a scalable blueprint for a closed‐loop agrochemical ecosystem and advanced catalyst design for intermittent renewable‐powered electrosynthesis.

ABSTRACT Developing hydrogen‐bonded organic frameworks (HOFs) for highly efficient Xe/Kr separation is an attractive alternative for producing high‐purity noble gases. However, its practical application is hampered by insufficient binding sites and intrinsically slow adsorption kinetics. We herein report a microporous HOF (HOF‐TBPDM) featuring the unique two‐dimensional (2D) and size‐matched pore architecture, which enables the rapid diffusion of Xe and high‐efficiency Xe/Kr separation. Specifically, HOF‐TBPDM achieves a high Xe uptake and a record Xe/Kr IAST selectivity (26.9) at 298 K and 1 bar. Especially, the kinetic adsorption results confirm the 2D pores lead to the rapid Xe diffusion rate. Dynamic breakthrough experiments indicate that after one cycle of separation operation 4.8 mol kg −1 high‐purity Kr (>99.99%) and 1.0 mol kg −1 Xe (>99.9%) can be directly obtained. The dynamic selectivity calculated from desorption process is as high as 16.5, which exceeds all the reported porous organic materials. Gas‐loaded crystal data combined with molecular modeling clearly reveal that the size‐matched pores within HOF‐TBPDM induce a stronger polarization effect on Xe than Kr, leading to preferential binding of Xe molecules. Overall, this study demonstrates the effectiveness of 2D pore in HOFs for balancing thermodynamic adsorption and kinetic diffusion, providing a viable strategy for advanced Xe/Kr separation.

ABSTRACT Alkyne complexes are known for transition metals across the d‐block with exception of the radioelement technetium despite considerable synthetic efforts. DFT calculations suggest that this is not inherent to the transition metal but a consequence of the overall ligand sphere. The arsenic‐based tolane ligand 1,2‐bis(2‐(diisopropylarsaneyl)‐4‐(trifluoromethyl)phenyl)ethyne (L i Pr ) forces a coordination of the central alkyne moiety onto the metal through ligand design. The stable, crystalline Tc(III) and Tc(V) alkyne complexes mer ‐[Tc III Cl 3 (κ 4 ‐ As , CC , As ‐L i Pr )], mer ‐[Tc V NX 2 (κ 4 ‐ As , CC , As ‐L i Pr )] (X = Cl, Br) and cis,trans , mer ‐[Tc V N(CN)Cl(κ 4 ‐ As , CC , As ‐L i Pr )] alongside their rhenium homologs mer ‐[Re V Cl 3 (κ 4 ‐ As , CC , As ‐L i Pr )] and mer ‐[Re V NCl 2 (κ 4 ‐ As , CC , As ‐L i Pr )] have been prepared and fully characterized. According to spectroscopic and DFT analyses, the technetium complexes represent robust, classical 2e − alkyne complexes, while a different situation was found for mer ‐[Re V Cl 3 (κ 4 ‐ As , CC , As ‐L i Pr )] with a formally oxidized metal ion and reduced 4e − donor ligand. This has general implications for π‐ligand coordination in group 7 and potentially for neighboring elements. Successful translation to the medicinally relevant nuclear isomer 99m Tc proves the viability of alkyne donors as building blocks for stable chelation of technetium at the tracer level.

ABSTRACT We report a Pd‐catalyzed carboamination of conjugated enynes for the direct synthesis of functionalized allenic amines. The reaction proceeds through a selective 1,4‐coupling of anilines and aryl triflates with enynes, utilizing a free alcohol as a native directing group. The obtained allenes undergo versatile transformations, including cyclization to dihydropyrans, hydroamination, and tandem carboamination sequences. Notably, the use of primary anilines enables a second carboamination to generate multifunctionalized 3‐pyrroline heterocycles through dual C‐N bond formation with two distinct aryl triflates. The transformation represents a novel approach to allene synthesis and heterocycle construction through sequential carboamination events.

ABSTRACT Helical ladder polymers possess rigid, helically fused backbones that confer distinctive chiroptical properties, yet their integration into polymer brush architectures remains highly challenging. Here, we report the first synthesis of bottlebrush polymers with a helically fused ladder backbone, achieved through acid‐catalyzed intramolecular cyclization followed by controlled ATRP grafting‐from polymerization. By integrating a single‐handed ladder scaffold with flexible, water‐soluble PNIPAM side chains, the resulting architecture markedly enhances the processability and structural tunability of helical ladder polymers. Moreover, the traditional helical ladder, long regarded as completely rigid and static, has been found to exhibit dynamic transition properties. This change was caused by conformational triggering of the thermally driven binaphthyl dihedral angles, which was quantitatively confirmed by the thermodynamic dynamics and molecular dynamics simulations, demonstrating the hierarchy of the transition from axial chirality to helical chirality. Overall, this work establishes a promising synthetic method for helical ladder bottlebrush polymers and demonstrates their potential as versatile platforms for designing dynamic chiral materials.

ABSTRACT Seeking recyclable, more sustainable alternatives to nylon 6 has drawn much attention, but achieving its variants with both crystallinity and enhanced recyclability still remains a challenge. Here, by utilizing bio‐derivable mono‐substituted racemic lactam monomers, we reveal surprisingly large effects of methyl substitution positions on the nylon‐6 backbone on crystallizability, thermomechanical performance, and recyclability of the resulting atactic nylon‐6 variants. While γ‐methyl substitution gives an amorphous nylon, all other four methyl‐substitution positions (α, β, δ, and ε) afford, unexpectedly, crystalline nylons with melting temperatures ranging from 145°C to 200°C and tunable mechanical performance from being stiff and strong (α, ε) to ductile (β, δ). Investigations reveal that the crystallinity of atactic nylons arises independently of stereoregularity, which is driven by the amide backbone with robust hydrogen‐bonding interactions and countered by the chain flexibility regulated by the substitution position. These nylons can be chemically recycled back to their parent monomers with high isolated yields up to 92%, enabling a circular, tacticity‐independent crystalline nylon platform.

ABSTRACT Incorporating redox active ligands into coordination cages offers a direct way to reach architectures whose structure or composition can be modulated in response to changes in the oxidation state. An exTTF‐based ditopic ligand L affords a M 2 L 4 cage in presence of a palladium(II) salt (M). The resulting M 2 L 4 cavity exhibits selective binding properties for medium length α,ω‐dinitrile alkanes. Modifying the coordination geometry of the ligand by oxidation to its L ox state redirects the self‐assembly process toward a M 2 L ox 2 structure. The oxidized ligand can also be combined with a dibenzothiophene linker (L′) to afford a heteroleptic M 2 L ox L′ 2 structure whose vacant coordination sites enable subsequent dimerization into an unprecedented M 4 L 4 L′ 4 architecture. Key intermediates and products were structurally authenticated by single‐crystal x‐ray diffraction. Notably, these processes are reversible. Reduction converts the M 2 L ox L′ 2 assembly back to the homoleptic M 2 L 4 cage. This sequence illustrates how changes of oxidation state can reshape nuclearity and composition in metal organic assemblies.