Jian‐Ke Sun

The development of advanced adsorbents for the selective and efficient recovery of gold from complex aqueous matrices is of paramount importance for sustainable resource recycling. Here, we report a phosphorus‐functionalized, quaternized ammonium cages (Phos‐QA‐Cage‐Cl) featuring multiple integrated binding sites, which delivers exceptional Au(III) uptake of up to 2331 mg g ^{− 1} . The intrinsically cationic skeleton and Au‐affinitive phosphorus sites synergistically capture AuCl ₄ ⁻ through combined electrostatic and coordination interactions. Thermal activation generates persistent radicals within the cage, which further enhance Au uptake by reducing Au(III) to nanoparticles, followed by halide‐promoted ripening of the nascent Au species. DFT calculations reveal the cooperative roles of noncovalent interactions, coordination bonding and radical‐assisted redox chemistry in driving efficient Au(III) capture. As a result, the cage exhibits rapid adsorption kinetics, high selectivity, and good recyclability in complex aqueous matrices. Leveraging its solution processability, a mixed‐matrix membrane based on polyvinylidene fluoride is fabricated, enabling efficient filtration and recovery of Au(III) (up to 95%) from dilute solutions, with a high permeate flux (87 L m ^{− 1} h ^{− 1} bar ^{− 1} ). This work introduces a new class of functionalized porous cages for precious metal recovery and highlights the potential of integrating molecular design with solution processibility for environmental applications.

The development of advanced adsorbents for the selective and efficient recovery of gold from complex aqueous matrices is of paramount importance for sustainable resource recycling. Here, we report a phosphorus‐functionalized, quaternized ammonium cages (Phos‐QA‐Cage‐Cl) featuring multiple integrated binding sites, which delivers exceptional Au(III) uptake of up to 2331 mg g ^{− 1} . The intrinsically cationic skeleton and Au‐affinitive phosphorus sites synergistically capture AuCl ₄ ⁻ through combined electrostatic and coordination interactions. Thermal activation generates persistent radicals within the cage, which further enhance Au uptake by reducing Au(III) to nanoparticles, followed by halide‐promoted ripening of the nascent Au species. DFT calculations reveal the cooperative roles of noncovalent interactions, coordination bonding and radical‐assisted redox chemistry in driving efficient Au(III) capture. As a result, the cage exhibits rapid adsorption kinetics, high selectivity, and good recyclability in complex aqueous matrices. Leveraging its solution processability, a mixed‐matrix membrane based on polyvinylidene fluoride is fabricated, enabling efficient filtration and recovery of Au(III) (up to 95%) from dilute solutions, with a high permeate flux (87 L m ^{− 1} h ^{− 1} bar ^{− 1} ). This work introduces a new class of functionalized porous cages for precious metal recovery and highlights the potential of integrating molecular design with solution processibility for environmental applications.

Coinage metal nanoclusters with near‐infrared‐II (NIR‐II, λ _PL > 1000 nm) photoluminescence hold great promise for biological applications. Here, we report the first icosahedral M ₁₃ cluster exhibiting NIR‐II phosphorescence, achieved through an unprecedented metallomacrocyclic ligand coordination combined with an alloying strategy, denoted as M ₁₃ @M ₆ clusters. The metallomacrocyclic ligands strongly regulate the photophysical properties of the M ₁₃ core, governing its lowest triplet excited state (T ₁ ) and enabling a markedly red‐shifted emission. They also provide a distinctive “core surface→metallomacrocycle→inner core” pathway for stepwise silver doping. Combined theoretical calculations and emission spectra reveal that doping‐induced charge transfer between the M ₁₃ core and M ₆ metallomacrocycles drives the photoluminescence shift from the NIR‐I to the NIR‐II region. Furthermore, functionalization of the metallomacrocyclic ligands with bulky pyrene groups enhances NIR‐II emission by an order of magnitude. Catalytic studies demonstrate that site‐specific tuning of metal composition within M ₁₃ @M ₆ clusters enables nanometer‐scale modulation of catalytic activity, highlighting the versatility of metallomacrocyclic ligands for regulating both luminescence and catalytic properties. This work not only extends coinage metal cluster protection from conventional organic ligands to metallomacrocycles but also provides a systematic framework for NIR‐II emission modulation through inner‐core and metallomacrocycle doping, ligand engineering at the coordination interface, and outer‐sphere functionalization.

Coinage metal nanoclusters with near‐infrared‐II (NIR‐II, λ _PL > 1000 nm) photoluminescence hold great promise for biological applications. Here, we report the first icosahedral M ₁₃ cluster exhibiting NIR‐II phosphorescence, achieved through an unprecedented metallomacrocyclic ligand coordination combined with an alloying strategy, denoted as M ₁₃ @M ₆ clusters. The metallomacrocyclic ligands strongly regulate the photophysical properties of the M ₁₃ core, governing its lowest triplet excited state (T ₁ ) and enabling a markedly red‐shifted emission. They also provide a distinctive “core surface→metallomacrocycle→inner core” pathway for stepwise silver doping. Combined theoretical calculations and emission spectra reveal that doping‐induced charge transfer between the M ₁₃ core and M ₆ metallomacrocycles drives the photoluminescence shift from the NIR‐I to the NIR‐II region. Furthermore, functionalization of the metallomacrocyclic ligands with bulky pyrene groups enhances NIR‐II emission by an order of magnitude. Catalytic studies demonstrate that site‐specific tuning of metal composition within M ₁₃ @M ₆ clusters enables nanometer‐scale modulation of catalytic activity, highlighting the versatility of metallomacrocyclic ligands for regulating both luminescence and catalytic properties. This work not only extends coinage metal cluster protection from conventional organic ligands to metallomacrocycles but also provides a systematic framework for NIR‐II emission modulation through inner‐core and metallomacrocycle doping, ligand engineering at the coordination interface, and outer‐sphere functionalization.

In nature, functional complexity often arises from multiscale assembly across hierarchical levels. Inspired by this principle, porous organic cages (POCs), featuring well‐defined intrinsic cavities, solution processability, and high chemical tunability, have emerged as versatile molecular platforms for multiscale materials engineering. This concept highlights representative examples in which POCs act as modular, shape‐persistent building blocks within hierarchical assemblies, and elucidates how their confined cavities, solubility, and structural modularity enable the rational construction of sophisticated materials systems. At the molecular level, POCs function as enzyme‐mimetic hosts that encapsulate and stabilize metal clusters (MCs) within discrete cavities. Benefiting from their structural tunability, POCs can also serve as bulky building blocks for integration into extended frameworks (e.g., COFs, MOFs, and supramolecular frameworks), as well as for the construction of nested host‐in‐host architectures and well‐ordered multiscale crystalline materials. Such hierarchical assembly integrates structural advantages across length scales by preserving intrinsic porosity while introducing efficient mass and electron transport pathways, thereby enabling enhanced separation and catalytic performance. By translating bioinspired design principles into synthetic materials, these systems offer a programmable route towards multifunctional platforms.

ConspectusIn biological systems, multivalent interactions orchestrate the hierarchical assembly of biomolecules into compartmentalized architectures, enabling spatial segregation and cooperative regulation of multiactive sites, thereby promoting complex reaction networks. Mimicking these assembly principles to develop biomimetic confined environments has emerged as a promising strategy for engineering highly efficient catalysts. Organic molecular cages (OMCs) possess discrete nanocavities and open windows, in which spatial confinement enables enzyme-mimetic encapsulation and stabilization of active sites; however, most research has focused on single-site catalysis. Ionic organic cages (IOCs), a charged subclass of the OMCs, incorporate charged skeletons balanced by counterions. This ionic architecture imparts pronounced biomimetic functionality, expanding their behaviors through electrostatic tunability and functional adaptability. These attributes include (1) broad solubility, particularly in aqueous media, facilitating complexation with biological sites and efficient catalysis under mild or physiological conditions; (2) tunable electrostatic microenvironments, where high-density and uniformly distributed charges of the skeleton modulate both the cavity environment and the electronic structure of encapsulated metal clusters; and (3) intrinsic multivalency, which drives hierarchical assembly and integration of multiple catalytic sites through a combination of electrostatic, covalent, and coordination interactions, recapitulating the biological compartment architecture. Ultimately, the synergy between structural mimicry and functional integration establishes IOCs as versatile biomimetic platforms.This Account highlights recent advances in IOCs as multifunctional biomimetic catalytic platforms. We first outline synthetic strategies, including direct self-assembly from charged building blocks enabled by covalent bonding, and postsynthetic modifications, including neutralization, nucleophilic substitution, and oxidation, to introduce tunable charges. These strategies allow fine control over charge density and distribution throughout the cage skeleton. We then introduce an "inside-out" framework to dissect the three defining elements of IOCs─discrete nanocavities, charged skeletons, and exchangeable functional counterions─and discuss their crucial role in endowing the IOCs with both structural and functional biomimetic characteristics. Following an "electrostatic mediation and stepwise assembly" design principle, we elucidate how multivalent interactions arising from charged skeletons and functional counterions direct hierarchical assembly, enabling the coexistence and interplay of diverse active sites (e.g., metal clusters, radicals, enzymes, and metal complexes). Special emphasis is placed on the cooperative mechanisms among multiple active sites, including compartmentalization, electron communication, and spatiotemporal regulation, which collectively underpin efficient tandem catalysis. By emulating the spatial segregation and dynamic regulation of biological systems, IOCs represent an emerging platform for designing complex catalysts that unite precision, versatility, and adaptability, offering a promising path toward artificial systems with life-like catalytic sophistication.

Ammonia (NH ₃ ) is essential for agriculture and industry, yet the Haber–Bosch process is energy‐intensive and carbon‐emissive. Electrochemical nitrate reduction reaction (NO ₃ RR) offers a sustainable alternative by coupling NH ₃ synthesis with water remediation. However, challenges such as weak NO ₃ ⁻ adsorption, competing hydrogen evolution, and suboptimal catalyst microenvironments hinder performance. Here, we report a family of electrocatalysts, Pd⊂QA‐Cage ^{x +} ( x = 24, 12, 6), constructed by encapsulating Pd clusters within quaternized organic cages. These discrete hosts enable uniform metal cluster confinement and precise control over the interfacial microenvironment. Increasing cage charge density enriches interfacial NO ₃ ⁻ concentration, upshifts Pd d ‐band center, and enhances *NO ₃ activation. Simultaneously, potential‐driven electron transfer from the counterion (Cl ⁻ ) to –NH ₂ ⁺ – generates stable radicals in the cage skeleton, which mediate water activation to form hydrogen radicals (H•) that spill over to Pd sites, accelerating intermediate hydrogenation. The optimized Pd⊂QA‐Cage ²⁴⁺ delivers a Faradaic efficiency of 95.44% and an NH ₃ yield of 25.70 mg h ^{− 1} mg _cat ^{− 1} in neutral electrolytes, outperforming its lower‐charge analogs. Moreover, it enables > 99.4% nitrate removal from eutrophic seawater, reducing NO ₃ ⁻ concentrations below potable water standards. This work introduces ionic cages as programmable interfacial modifiers, offering a supramolecular strategy to regulate electrochemical microenvironments and boost electrocatalytic NO ₃ RR performance.

Ammonia (NH ₃ ) is essential for agriculture and industry, yet the Haber–Bosch process is energy‐intensive and carbon‐emissive. Electrochemical nitrate reduction reaction (NO ₃ RR) offers a sustainable alternative by coupling NH ₃ synthesis with water remediation. However, challenges such as weak NO ₃ ⁻ adsorption, competing hydrogen evolution, and suboptimal catalyst microenvironments hinder performance. Here, we report a family of electrocatalysts, Pd⊂QA‐Cage ^{x +} ( x = 24, 12, 6), constructed by encapsulating Pd clusters within quaternized organic cages. These discrete hosts enable uniform metal cluster confinement and precise control over the interfacial microenvironment. Increasing cage charge density enriches interfacial NO ₃ ⁻ concentration, upshifts Pd d ‐band center, and enhances *NO ₃ activation. Simultaneously, potential‐driven electron transfer from the counterion (Cl ⁻ ) to –NH ₂ ⁺ – generates stable radicals in the cage skeleton, which mediate water activation to form hydrogen radicals (H•) that spill over to Pd sites, accelerating intermediate hydrogenation. The optimized Pd⊂QA‐Cage ²⁴⁺ delivers a Faradaic efficiency of 95.44% and an NH ₃ yield of 25.70 mg h ^{− 1} mg _cat ^{− 1} in neutral electrolytes, outperforming its lower‐charge analogs. Moreover, it enables > 99.4% nitrate removal from eutrophic seawater, reducing NO ₃ ⁻ concentrations below potable water standards. This work introduces ionic cages as programmable interfacial modifiers, offering a supramolecular strategy to regulate electrochemical microenvironments and boost electrocatalytic NO ₃ RR performance.

The escalating global energy crisis has intensified the demand for advanced materials that enable efficient energy storage and conversion. Porous organic cages (POCs), together with their metal cluster (MC) composites, have recently emerged as a versatile and powerful class of functional materials for energy‐related applications. POCs combine discrete, shape‐persistent molecular architectures with intrinsic porosity, structural modularity, and solution processability, while MCs impart well‐defined electronic, catalytic, and redox‐active properties. The integration of these two components creates hybrids that synergistically unite molecular precision with functional complexity. This Review presents a comprehensive overview of the synthetic strategies used to construct POCs and POC‐MC composites, with particular emphasis on rational design principles that link synthetic choices to targeted energy applications. We highlight recent advances in tailoring cage structures, cavity environments, and host‐guest interactions to regulate the dispersion, stability, and reactivity of MCs. The resulting materials have demonstrated broad utility across diverse energy technologies, including thermocatalysis, photocatalysis, electrocatalysis, energy harvesting, rechargeable battery systems such as lithium‐ion, perovskite solar, and aqueous zinc batteries, as well as proton‐conducting materials. Finally, we critically assess the key achievements, unresolved challenges, and future opportunities in translating POC‐based materials from fundamental studies toward practical energy storage and conversion technologies.

The construction of complex artificial hierarchical compartmentalized hosts that enable interhost electron communication to modulate─or even amplify─material properties remain a significant challenge. Herein, we report a supramolecular host-in-host assembly formed by electrostatic interactions between deprotonated hydroxyl-functionalized organic cages and bipyridinium bearing poly(ionic liquid)s (PILs). In this architecture, anionic cages are encapsulated within a polymeric network, creating a hierarchical structure that integrates discrete molecular hosts within an extended network. Benefiting from well-organized arrangement and cooperative functionality of dual-host components, UV light-triggered interhost electron transfer─from electron-rich O^- sites in the cages to electron-deficient pyridinium N⁺ centers in the PILs─is realized. This electronic interplay markedly enhances the material's physicochemical properties, yielding a ∼500-fold increase in conductivity and a high near-infrared (NIR) photothermal conversion (808 nm) efficiency of ∼82.2%. Incorporation of Pd clusters into the cage cavities further highlights the role of interhost electron communication in modulating the local catalytic environment─reshaping the electronic structure of Pd and the charge distribution around hydroxyl-lined cage windows to promote substrate orientation, adsorption and transport. Coupled with the nanofurnace effect of the nested architecture, these features collectively lead to markedly enhanced catalytic activity and selectivity in hydrogenation reactions.