Elevated levels of ammonium nitrogen (NH4+-N) in wastewater represent a significant threat to aquatic ecosystems. This study presents a circular-economy strategy for recovering NH4+-N through crystallization of ferrous ammonium phosphate (FAP, FeNH4PO4 center dot H2O), followed by its conversion into battery-grade FePO4. Mechanistically, FAP formation requires anaerobic conditions to preserve Fe2+ and prevent its oxidation to Fe3+. Under optimized conditions (pH 9, 60 degrees C, and a high NH4+-N loading of 18.7 g.L-1), PO43- tetrahedra bridge Fe-centered polyhedra, achieving 95.1% NH4+-N removal and 86.7% FAP purity with negligible ammonia volatilization. In contrast, aerobic synthesis leads to Fe2+ oxidation and yields Fe-3(PO4)(2)center dot 8H(2)O as a byproduct. Thermal decomposition kinetics revealed that anaerobic FAP exhibits favorable processability (activation energy Ea = 114.67 kJ center dot mol(-1)) via a two-step dehydration-deammoniation mechanism. The decomposition pathway is atmosphere-dependent: under N-2, Fe2P2O7 forms, whereas under O-2, high-purity FePO4 (92%) is produced directly at lower temperatures. The resulting LiFePO4/C cathode delivered a specific capacity of 107.7 mAh.g(-1) with 68.7% capacity retention. Interestingly, humic acid present in wastewater enhances FAP crystallization by providing nucleation sites and enriching local concentrations of Fe2+ and NH4+, and it further improves the cycling stability of the final cathode through formation of a more robust electrode-electrolyte interface. This closed-loop process structurally integrates nitrogen recovery with the synthesis of energy materials, shifting wastewater treatment from contaminant removal toward resource valorization in line with circular economy principles.

Viruses achieve remarkable complexity through the self-assembly of protein subunits, yet mimicking such processes synthetically has remained a grand challenge. While a 144-component metal-organic cage has been obtained, the maximum component count for known supramolecular assemblies of weak noncovalent forces is only 20. Here, we report a 62-component supramolecular cage assembled via a bioinspired strategy. By combining anion coordination with amide-π interactions, we construct a 62-component discrete dodecahedral cage structurally analogous to the dengue virus. This synthetic architecture, comprising three distinct molecular species held together via 60 H-bonds and 30 sets of amide-π interactions, demonstrates excellent stability in solution and exhibits multiple solid structural polymorphs. A reversible sol-gel transition is achieved by a mixture of the dodecahedra in acetylacetone (acac), which is driven by the host-guest-mediated higher-order assembly. These findings establish a previously unidentified paradigm for constructing multicomponent supramolecular cages, opening avenues for developing bioinspired molecular nanocontainers and providing a foundation for diverse nanotechnological applications.

Salicylaldehyde (SA) is a ubiquitous industrial compound exhibiting persistent toxicity to aquatic lives. The selective sensing of SA presents an urgent need. Here, we report a highly selective fluorescent sensor for SA based on a cyclopentadienyl-capped zirconium-oxo cluster (Zr-9) with ultra-low Eu(III) doping. The Zr-9 cluster, structurally analogous to cubic ZrO2, hosts the Eu(III) dopant at just 0.1580 wt%, achieving a high quantum yield of 45.12% (Zr-9@Eu-5). This represents a 645-fold enhancement over the undoped Zr-9, caused by efficient ligand-to-metal energy transfer. Zr-9@Eu-5 demonstrates exceptional stability in aqueous solutions and organic solvents. It detects SA with 99.88% quenching efficiency, a low detection limit of 0.6175 mu M, and high reusability (>72% intensity after 5 cycles). Theoretical calculations and spectral analyses reveal that the sensing mechanism involves competitive UV absorption by SA. This work presents cyclopentadienyl-capped zirconium-oxo clusters as a sustainable platform for ultra-low rare-earth doping, enabling sensitive monitoring of environmentally hazardous compounds.

Enhancing the migration of photogenerated charges in semiconductor catalysts is an important way to enhance hydrogen (H2) production. We fabricated ZnIn2S4-CuNiP (Z-CuNiP) heterostructure by a simple ultrasonic blending method. These composites can be thought of as cheaper substitutes for expensive metal cocatalysts such as platinum or palladium. The incorporation of CuNiP was found to be highly efficacious in increasing the photocatalytic performance of ZnIn2S4 (ZIS) in visible light of relatively low intensity to reach a H2 production rate of 1.06 mmol·g-1·h-1. This is roughly four times that of pure ZIS. A key characteristic is the occurrence of a wide and close contact between ZIS and CuNiP that allows separation of photoinduced electron-hole pairs. Due to this, the efficiency of photocatalytic water splitting with respect to ZIS of the designed heterostructure increases significantly.

Conjugated polymers (CPs) are essential for advanced electronic applications due to their pi-conjugated backbones, which impart excellent electrical properties. For integration into flexible and stretchable electronics, balancing electrical conductivity with mechanical flexibility is critical. Recent advances show that conjugationbreak spacers (CBSs), ranging from alkyl chains to heteroatom-containing units, enable tuning of backbone rigidity and, consequently, modulation of packing/aggregation tendencies and mechanical performance. However, the molecular-level mechanisms dictating the interplay between rigid and flexible segments, particularly from an entropy-driven perspective, remain unclear. Here, we employ the Kremer-Grest model to systematically investigate how varying segment length and angle stiffness modulate conformational freedom, packing/orientational ordering, and toughness in stiffness-heterogeneous polymer thin films. Because the model intentionally omits chemistry-specific directional attractions (e.g., explicit pi-pi stacking), the "aggregation/order" discussed here refers to coarse-grained stiff-segment packing and alignment driven by excluded-volume constraints and bending energetics. Our results show that increasing rigid segment length and stiffness (Nrigid and krigid) enhances ordered packing, while flexible segments (CBS-like spacers) can promote aggregation through chain folding. Aggregation intensifies when flexible spacers constitute less than 60% of a chain, with Nrigid = 5 emerging as a critical threshold. Rigid segments increase strength but also promote brittleness, whereas flexible segments improve ductility but reduce interchain load transfer. Optimal mechanical performance is achieved with moderate spacer flexibility (kflex = 1.5 epsilon), combined with sufficiently long and stiff rigid segments (Nrigid >= 5, krigid = 64.0 epsilon). These insights, linked to practical parameters such as Kuhn length, provide guidance for designing CP-inspired architectures with an improved balance between ordered packing, strength, and ductility.

The photoelectrochemical water-splitting process for hydrogen production is limited by the large bandgap of semiconductor titanium dioxide (TiO2) and by interfacial recombination at particle interfaces. The technique used in this paper is that of electrochemical anodization to produce robust, ordered TiO2 nanotube arrays (TiO2 nanorod arrays denoted as TNTAs). Using the immersion-annealing method, Nd2O3 nanoparticles can be immobilized in situ, and Nd2O3/TNTAs composite photoanodes are fabricated. The heterointerface caused between the Nd2O3 nanoparticles and TiO2 results in the alignment of the Fermi levels and the formation of band bending and an internal electric field at the interface. It allows rapid photo-generated electron-hole (e(-)/h(+)) separation at the interface and, simultaneously, introduces novel localized electron states of Nd3+ within the TiO2 bandgap. This triggers hybridisation between the 3d orbitals of Ti and the 2p orbitals of O, thereby altering the band structure of TiO2. The best-performing Nd2O3/TNTAs photoelectrode outperforms pure TNTAs, with a photocurrent density of 1.59 mA & centerdot;cm(-2) at 1.23 V vs. RHE. It produces 162.6 mu mol & centerdot;cm(-2) of hydrogen in a 3 h photocatalytic hydrogen production experiment, which is about 12.2 times that of pure TNTAs. This approach highlights the unique benefits and creative opportunities of applying rare-earth elements to address the critical issues of photocatalysts, such as significant band gaps and rapid recombination.

Syntheses of cyanide-bridged metal clusters have traditionally relied on toxic and environmentally hazardous cyanide ions (CN−). Herein, we report a body-centered tetrahedral cluster [CuI(CN)4CuII4L4](BF4)5(DMF)2(1) (L = tris(2-naphthimidazolylmethyl)amine, DMF = N,N-dimethylformamide) synthesized using the green reagent 7,7,8,8-tetracyanoquinodimethane (TCNQ) as cyanide source. TCNQ not only serves as a cyanide source but also acts as a reducing agent, converting CuII to CuI during the synthesis of 1, as clearly demonstrated by gas chromatography-mass spectrometry (GC-MS) analysis. The body-centered tetrahedral [CuI(CN)4CuII4L4]5+ core is chiral and spontaneously resolves upon crystallization, yielding enantiomorphic crystals of 1 in the chiral space groups P3121 or P3221. These chiral tetrahedral clusters further assemble into a three-dimensional (3D) supramolecular architecture composed of fused DNA-like double helices, mediated by BF 4 − anions and DMF molecules through hydrogen bonding and amide-π interactions, respectively. Compound 1 exhibits excitation-dependent dual emission both in the crystalline state and in solution. Aggregation-induced luminescence was further observed for the solution of 1 in MeOH.

Spherical surfactant micelles, widely used as templates for synthesizing porous inorganic materials, suffer from undeterminable atomic-level structures. Developing structurally precise spherical micelle-like architectures is therefore highly beneficial for understanding template syntheses yet remains challenging. Here, we demonstrate a series of micelle-like π-stacked architectures self-assembled from tripodal synthons ([ML(SO4)], [ML(SCN)]+, or [H3L(HPO4)]+, where M = Co2+ or Zn2+ and L = tris(2-benzimidazolylmethyl)amine). These structures form through anion-coordination-regulated π-π stacking. While a honeycomb architecture of oppositely aligned neutral [CoL(SO4)] forms without the directing of anions, various cationic micelle-like π-stacked architectures of [ML(SCN)]+ and [H3L(HPO4)]+ are successfully constructed via anion coordination-regulated π-π stacking. Within these assemblies, the π-stacked tripodal synthons and the H-bonded anion networks mutually template each other, reminiscent of how surfactant micelles template porous inorganic materials. Remarkably, this approach yields two new Frank-Kasper (FK) C15 phases, representing the first FK C15 complexes formed by small-molecule assembly. These results establish a universal strategy leveraging the interplay between π-π stacking and anion coordination to access complex supramolecular FK structures, potentially enabling new synthetic approaches for porous inorganic materials such as zeolites and porous silicon.

The spontaneous emergence of chirality from racemic or achiral small molecules and nanoclusters remains a fascinating yet poorly predictable phenomenon. Herein, we report a rational design strategy for achieving spontaneous chiral resolution, as demonstrated through the controlled synthesis of a series of trinuclear silver clusters based on C 3-symmetric tris(2-benzimidazolylmethyl)amine and its derivatives. Our results show that complexes formed by trinuclear clusters bearing sterically demanding ligands and trifluoromethanesulfonate (OTf-) favor spontaneous chiral resolution, forming homochiral structures due to helical scaffolds from bidirectional intermolecular π⋯π interactions. In contrast, trinuclear silver clusters bearing ligands with less steric hindrance paired with OTf- lead to social self-sorting, resulting in racemic crystals. On the other hand, only social self-sorting was observed for the pairing of the trinuclear silver clusters with methanesulfonate (OMs-). Remarkably, the homochiral structures can be reversibly converted to racemic forms via anion exchange, enabling controllable switching between chiral and centrosymmetric polymorphs. The resulting chiral crystals exhibit optical activity and second-harmonic generation (SHG) responses, underscoring their potential for nonlinear optical applications. This work demonstrates that chiral self-sorting can be directed by systematically tuning intermolecular π⋯π interactions, offering key insights for the rational design of spontaneous resolution systems.

PEO (polyethylene oxide)-based electrolytes, which is characteristic of the advantages such as good film-forming properties, ease of mechanical processing, and non-reactivity with lithium metal, have been extensively studied. However, there still exist some certain issues related to energy and lifespan of all-solid-state lithium-ion batteries (ASSLIBs). The Cd-In cage [Cd2In3L2Cl5(H2O)(9)]Cl-2 (L = 2,2 ',2 ''-(nitrilotris(methylene))tris(1H-benzo[d]imidazole-5-carboxylic acid) in this research can greatly disperse into PEO without significant agglomeration. The intrinsic cavities from the Cd-In cages form channels for lithium ion transport but inhibiting the transport of the corresponding counter anions, thereby protecting the electrode interface by reducing the interfacial reaction. For LFP||PEO-LiTFSI/Cage||Li cell at a fixed current density of 1.0 C, the specific capacity maintained a consistent level of 136 mA h/g over a span of 100 cycles. This value was higher than those of cells prepared with pristine PEO electrolyte.

A ZnII-based coordination polymer {[Zn(BBP)(1,4-NDC)]& sdot;solvent}n (Zn1) (BBP = 2,6-bis(2-benzimidazolyl)pyridine and 1,4-H2NDC = 1,4-naphthalic acid) was successfully synthesized. Zn1 is robust to various solvents and exceptional stable against both acidic and basic media. Fluorescence assays revealed that Zn1 can serve as a luminescent sensor for detection of furfural in methanol, exhibiting remarkable sensitivity and selectivity with the detection limit reaching to 0.0572 mg/L. Moreover, the fabrication of a mixed matrix film with Zn1 and polymethyl methacrylate (PMMA) allowed indirect and rapid assessment of furfural amounts in methanol, implying its practical application on the detection of furfural in transformer oil.

Calcite is a promising material choice for adsorbing phosphates because of its abundance and environmentally benign nature. However, the slow adsorption kinetics and hence low adsorption capacity within a short time frame hinders its practical application. In this work, we solve these problems by presenting a low Mg2+-doped calcite adsorbent, Mg-10. With a 3.75 wt% of Mg2+ doping, Mg-10 exhibits a remarkable adsorption capacity of 157.7 mg P/g. It also demonstrates a substantial boost in the adsorption kinetics, achieving a sixfold increase in adsorption capacity within 24 h compared to the undoped calcite. Meanwhile, Mg-10 not only offers improved adsorption selectivity but also maintains a stable effluent pH, underscoring its environmental compatibility. By conducting soil column experiments, we find that Mg-10 quickly captures the excess phosphates during the mimicking fertilization process, and slowly releases the nutrient afterwards, which can increase the feralization efficiency. These results provide alternative strategies for managing phosphate pollution originated from fertilization, and underscores the potential of Mg-10 in sustainable agriculture and environmental remediation.

Singlet fission (SF) is a process in which the absorption of a single photon results in the generation of a pair of triplet excited states, showing potential for enhancing solar conversion efficiency. The thermodynamic driving force behind SF is determined by the energy difference between the first singlet excited state and the first triplet excited state, denoted as ΔE1 = E(S1) - 2E(T1). In general, an excessively large ΔE1 value (i.e., excessive exoergicity) can facilitate alternative relaxation pathways for excitons, thereby diminishing SF efficiency. Consequently, when designing high-efficiency SF chromophores, optimization of ΔE1 becomes crucial. Herein, we introduce a helically locked tethering strategy to optimize ΔE1 for low-efficiency SF chromophores. Specifically, different dihedral angles are induced by tethering tethers of different lengths (Cn = -(CH2)n-, n = 1-6) to tetraazaacenes, allowing us to systematically monitor the variational characteristic as a function of the dihedral angle. Tethered products show strong chirality with a high energy barrier to twist back and forth. A tunable ΔE1 has been realized by adjusting the tether length, allowing us to identify the optimal ΔE1 of 0.29, 0.26, and 0.11 eV at tether lengths of n = 3 or 2. Our results suggest that this strategy could be applied to existing low-efficiency SF databases that are not typically considered for future application in the SF field, thereby creating novel high-efficiency and stable SF chromophores. This strategy not only makes full use of the existing resources but also greatly expands the SF arsenal.

The capture of radioactive iodine (129I or 131I) is of significant importance for the production of nuclear power and the treatment of nuclear waste. In recent years, crystallized porous materials have been extensively investigated to achieve highly effective adsorption of radioactive iodine. Herein, by using the hydrothermal method, a Ni cluster-based framework (1) was successfully constructed through a self-assembly process. Driven by the π–π stacking interactions between π-electron-rich benzimidazole groups, [Ni5S6] clusters stack in a lattice, forming a porous framework with proper channels, rendering compound 1 as an ideal adsorbent for iodine. Compound 1 delivered a capability of iodine adsorption (2.08 g g−1 and 560 mg g−1 for gaseous and solution iodine, respectively) with stable cyclability.

In general, flexible metal-organic frameworks (MOFs) change their structures via framework breathing in response to external stimuli (usually guest adsorption and desorption). Here, we show a dynamic coordination bond in a flexible MOF driving a thermo-induced diffuse phase transition occurring in a wide temperature range of 130–270 K (centered at ∼200 K), which enables the switching of magnetism and second-harmonic generation (SHG) responses. In specific, a solvent-free CoII-based flexible MOF Co2(TPY)2(BPTC) (1), bearing biphenyl-3,3′,5,5′-tetracarboxylic acid (H4BPTC) and 2,2′:6′,2″-terpyridine (TPY) ligands, exhibits a reversible thermo-responsive coordination-mode switching between five- and six-fold. This dynamic bond results in the reversible transformation between a distorted polar framework and a regular nonpolar framework, and therefore leads to the subtle change of the magnetic property and substantial change of the nonlinear optical property of 1.

Constructing artificial sophisticated architectures from simple small-molecular subunits by cooperative interactions remains one of the most formidable challenges. Herein, we report a complex supramolecular structure, {{[CoL(SCN)]20}{[CoL(SCN)]24}3(SO4)23(HSO4)46}$246(CH3CN) (1), that arises from the assembly of [CoL(SCN)]+ with SO42- and HSO4- (L = tris(2-benzimidazolylmethyl)amine) under solvothermal condition. The crystallization of compound 1 is driven by the cooperation of the ir-ir stacking interactions between [CoL(SCN)]+ cations and the hydrogen bonds between [CoL(SCN)]+ and SO42- and HSO4-. [CoL(SCN)]+ cations self-associate through intermolecular ir-ir stacking interactions to create two ir-stacked polyhedral 512-{[CoL(SCN)]20} dodecahedra and 51262-{[CoL(SCN)]24} tetrakaidekahedra. These two ir-stacked polyhedral subunits coexist in the same lattice in a 1:3 ratio and coordinate with SO42- and HSO4-, resulting in a complex Frank-Kasper (FK) A15 structure. This research demonstrates that small-molecular scaffolds can assemble into sophisticated architectures and creates exciting perspectives for constructing sophisticated clathrate structures from simple small molecules.

Hydrogen-bonded organic frameworks (HOFs) exhibit intriguing structural features with potential applications in various fields. However, constructing HOFs based on high-connectivity nodes is a challenging task. In this study, we report the synthesis of three new metal-hydrogen-bonded organic frameworks (M-HOFs), Hf4-P4/n, Hf4-Fddd-1, and Hf4-Fddd-2, based on a charge-neutral tetranuclear hafnium-oxo cluster [Hf4(μ2-OH)8L8] (L = 1H-benzimidazole-2-carboxylate) as the building unit. The rigid benzimidazole-carboxylate ligand maintains the cluster's symmetry while providing hydrogen-bonding sites. By modulating crystallization conditions, three distinct supramolecular packing modes are achieved: Hf4-P4/n forms an sql net via four pairs of hydrogen bonds and four groups of DMF-mediated van der Waals interactions between [Hf4(μ2-OH)8L8] units; Hf4-Fddd-1 adopts a rarely seen 8-connected tsi net through eight pairs of intercluster hydrogen bonds; Hf4-Fddd-2 exhibits a dia net with only four pairs of hydrogen bonds per cluster. Framework stability correlates with interaction strength and number. Notably, Hf4-P4/n and Hf4-Fddd-1 show superior solvent stability compared to Hf4-Fddd-2. Porosity analysis reveals that Hf4-Fddd-1 possesses interconnected channels, with a void fraction of 31.1% and a surface area of 277.7 m2/g. This work highlights metal-oxo clusters as potential building units for synthesizing complex HOFs with high-connectivity nodes.

Systematicly tuning the porosities of porous materials is crucial for targeted gas mixture separation, yet it remains a long-standing challenge. As a common strategy, altering the phenylene ring count in the organic building units has been exploited to adjust pore apertures in metal organic frameworks (MOFs) and covalent organic frameworks (COFs), resulting in only a stepwise pore size variation of approximately 2.8 Å. Unlike MOFs and COFs, the porosities for supramolecular assembly frameworks are highly dependent on the packings of the molecular building units in the lattice. The above strategy cannot be applied to supramolecular assembly frameworks and other strategies are required to adjust pore apertures in supramolecular frameworks, especially to achieve porous materials with the optimal pore size for D2/H2 separation (∼3 Å). Here, we successfully modulate the porosity of supramolecular frameworks of [CoII12CoIII8L12(μ3-OH)24(X)]11+ clusters (L = mono-deprotonated 1-iminoisoindole-3-amine, X = ClO4− or Cl−) by controlling the duration of self-assembly processes. By simply adjusting the reaction time, we obtain three [CoII12CoIII8L12(μ3-OH)24(X)]11+ supramolecular frameworks: [CoII12CoIII8(μ3-OH)24(ClO4)L12)]·(Cl)4·(HCO2)7 (1), [CoII12CoIII8L12(μ3-OH)24(Cl)]·(ClO4)4·(Cl)6·(HCO2)·(H2O)10 (2), and [CoII12CoIII8L12(μ3-OH)24(Cl)]·(Cl)11·(H2O)12 (3). The different stacking patterns of the [CoII12CoIII8L12(η3-OH)24(X)]11+ clusters in these frameworks lead to significantly varied stabilities and porosities. Compound 1 exhibits permanent porosity with interconnected channels and maintains stability under harsh conditions. In contrast, compound 2 is nearly nonporous, and compound 3 becomes unstable upon desolvation. The pores of compound 1 show higher affinity to D2 than H2, and the pore aperture diameter of compound 1 (∼3.06 Å) meets the optimal porosity for D2/H2 separation. Consequently, compound 1 demonstrates moderate D2/H2 separation at 77 K (retention time: ∼7 min/g for D2/H2/Ne (10/10/80 vol

Cascade reactions that form multiple chemical bonds in one synthetic step are important for the synthesis of complex molecules. Molecular catalysts for cascade reactions generally require two or more catalytic centers, yet anchoring distinct catalytic centers onto a single molecular catalyst remains extremely challenging. Here a metal-organic cage (MOC) [(ClO4)2@Zn20(L)8(HCO2)6(OH)6(H2O)8]2+ (Zn20-MOC) (H3L = tris(2-benzimidazolylmethyl)amine) carrying dual biomimetic active sites is reported, i.e. mononuclear {ZnII(L)(H2O)} and dinuclear {L2ZnII(CHO2)(OH)ZnIIL2}. The two active sites play different roles in the catalytic cascade trimerization of 1,2-diaminocyclohexane 1), which produces hexadecahydro-5a,11a-butanoquinoxalino[2,3-b]quinoxaline 2) with a yield of ≈71.32%. It is find that the mononuclear {ZnII(L)(H2O)} site catalyzes the dimerization reaction of 1, yielding an intermediate product 1,2,3,4,4a,6,7,8,9,10a-decahydrophenazine (inter. 4). Further reaction between 1 and inter. 4 to form the final product must be catalyzed by the dinuclear {L2ZnII(HCO2)(OH)ZnIIL2} site. This work not only provides a new approach to designing catalysts for cascade reactions, but also develops a unique synthetic strategy for the trimerization of 1,2-diaminocyclohexane, a process that has been unexplored until now.