Chemical Flexibility of Atomically Precise Metal Clusters.

Ligand-protected metal clusters possess hybrid properties that seamlessly combine an inorganic core with an organic ligand shell, imparting them exceptional chemical flexibility and unlocking remarkable application potential in diverse fields. Leveraging chemical flexibility to expand the library of available materials and stimulate the development of new functionalities is becoming an increasingly pressing requirement. This Review focuses on the origin of chemical flexibility from the structural analysis, including intra-cluster bonding, inter-cluster interactions, cluster-environments interactions, metal-to-ligand ratios, and thermodynamic effects. In the introduction, we briefly outline the development of metal clusters and explain the differences and commonalities of M(I)/M(I/0) coinage metal clusters. Additionally, we distinguish the bonding characteristics of metal atoms in the inorganic core, which give rise to their distinct chemical flexibility. Section 2 delves into the structural analysis, bonding categories, and thermodynamic theories related to metal clusters. In the following sections 3 to 7, we primarily elucidate the mechanisms that trigger chemical flexibility, the dynamic processes in transformation, the resultant alterations in structure, and the ensuing modifications in physical-chemical properties. Section 8 presents the notable applications that have emerged from utilizing metal clusters and their assemblies. Finally, in section 9, we discuss future challenges and opportunities within this area.

Encapsulation engineering of porous crystalline frameworks for delayed luminescence and circularly polarized luminescence.

Delayed luminescence (DF), including phosphorescence and thermally activated delayed fluorescence (TADF), and circularly polarized luminescence (CPL) exhibit common and broad application prospects in optoelectronic displays, biological imaging, and encryption. Thus, the combination of delayed luminescence and circularly polarized luminescence is attracting increasing attention. The encapsulation of guest emitters in various host matrices to form host-guest systems has been demonstrated to be an appealing strategy to further enhance and/or modulate their delayed luminescence and circularly polarized luminescence. Compared with conventional liquid crystals, polymers, and supramolecular matrices, porous crystalline frameworks (PCFs) including metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), zeolites and hydrogen-bonded organic frameworks (HOFs) can not only overcome shortcomings such as flexibility and disorder but also achieve the ordered encapsulation of guests and long-term stability of chiral structures, providing new promising host platforms for the development of DF and CPL. In this review, we provide a comprehensive and critical summary of the recent progress in host-guest photochemistry via the encapsulation engineering of guest emitters in PCFs, particularly focusing on delayed luminescence and circularly polarized luminescence. Initially, the general principle of phosphorescence, TADF and CPL, the combination of DF and CPL, and energy transfer processes between host and guests are introduced. Subsequently, we comprehensively discuss the critical factors affecting the encapsulation engineering of guest emitters in PCFs, such as pore structures, the confinement effect, charge and energy transfer between the host and guest, conformational dynamics, and aggregation model of guest emitters. Thereafter, we summarize the effective methods for the preparation of host-guest systems, especially single-crystal-to-single-crystal (SC-SC) transformation and epitaxial growth, which are distinct from conventional methods based on amorphous materials. Then, the recent advancements in host-guest systems based on PCFs for delayed luminescence and circularly polarized luminescence are highlighted. Finally, we present our personal insights into the challenges and future opportunities in this promising field.

Metal Clusters Confined in Chiral Zeolitic Imidazolate Framework for Circularly Polarized-Luminescence Inks.

Chiroptical activities arising in nanoclusters (NCs) are emerging as one of the most dynamic areas of modern science. However, devising an overarching strategy that is capable of concurrently enhancing the photoluminescence (PL) and circularly polarized luminescence (CPL) of metal NCs remains a formidable challenge. Herein, gold and silver nanoclusters (AuNCs, AgNCs) are endowed with CPL, for the first time, through a universal host-guest approach─centered around perturbing a chiral microenvironment within chiral hosts, simultaneously enhancing emissions. Remarkably, the photoluminescence quantum yield (PLQY) of AuNCs has undergone an increase of over 200 times upon confinement, escalating from 0.05% to 12%, and demonstrates a CPL response. Moreover, a three-dimensional (3D) model termed "NCs@CMOF" featuring CPL activity is created using metal cluster-based assembly inks through the process of 3D printing. This work introduces a potentially straightforward and versatile approach for achieving both PL enhancement and CPL activities in metal clusters.

Carborane-Cluster-Wrapped Copper Cluster with Cyclodextrin-like Cavities for Chiral Recognition.

Chiral atomically precise metal clusters, known for their remarkable chiroptical properties, hold great potential for applications in chirality recognition. However, advancements in this field have been constrained by the limited exploration of host-guest chemistry, involving metal clusters. This study reports the synthesis of a chiral Cu16(C2B10H10S2)8 (denoted as Cu16@CB8, where C2B10H12S2H2 = 9,12-(HS)2-1,2-closo-carborane) cluster by an achiral carboranylthiolate ligand. The chiral R-/S-Cu16@CB8 cluster features chiral cavities reminiscent of cyclodextrins, which are surrounded by carborane clusters, yet they crystallize in a racemate. These cyclodextrin-like cavities demonstrated the specific recognition of amino acids, as indicated by the responsive output of circular dichroism and circularly polarized luminescence signals of Cu16 moieties of the Cu16@CB8 cluster. Notably, a quantitative chiroptical analysis of amino acids in a short time and a concomitant deracemization of Cu16@CB8 were achieved. Density functional tight-binding molecular dynamics simulation and noncovalent interaction analysis further unraveled the great importance of the cavities and binding sites for chiral recognition. Dipeptide, tripeptide, and polypeptide containing the corresponding amino acids (Cys, Arg, or His residues) display the same chiral recognition, showing the generality of this approach. The functional synergy of dual clusters, comprising carborane and metal clusters, is for the first time demonstrated in the Cu16@CB8 cluster, resulting in the valuable quantification of the enantiomeric excess (ee) value of amino acids. This work opens a new avenue for chirality sensors based on chiral metal clusters with unique chiroptical properties and inspires the development of carborane clusters in host-guest chemistry.

Thiacalix[4]arene Etching of an Anisotropic Cu70H22 Intermediate for Accessing Robust Modularly Assembled Copper Nanoclusters.

Atom-precise metal nanoclusters (NCs) with large bulk (nuclearity >60) are important species for insight into the embryonic phase of metal nanoparticles and their top-down etching synthesis. Herein, we report a metastable rod-shaped 70-nuclei copper-hydride NC, [Cl@Cu70H22(PhC≡C)29(CF3COO)16]2+ (Cu70), with Cl- as the template, in which the Cl@Cu59 kernel adopts a distinctive metal packing mode along the bipolar direction, and the protective ligand shell exhibits corresponding site differentiation. In terms of metal nuclearity, Cu70 is the largest alkynyl-stabilized Cu-hydride cluster to date. As a typical highly active intermediate, Cu70 could undergo a transformation into a series of robust modularly assembled Cu clusters (B-type Cu8, A-A-type Cu22, A-B-type Cu23, and A-B-A-type Cu38) upon etching by p-tert-butylthiacalix[4]arene (H4TC4A), which could not be achieved by "one-pot" synthetic methods. Notably, the patterns of A and B blocks in the Cu NCs could be effectively modulated by employing appropriate counterions and blockers, and the modular assembly mechanism was illustrated through comprehensive solution chemistry analysis using HR-ESI-MS. Furthermore, catalytic investigations reveal that Cu38 could serve as a highly efficient catalyst for the cycloaddition of propargylic amines with CO2 under mild conditions. This work not only enriched the family of high-nuclear copper-hydride NCs but also provided new insights into the growth mechanism of metal NCs.

High-Efficiency Circularly Polarized Light-Emitting Diodes Based on Chiral Metal Nanoclusters.

Circularly polarized light-emitting diodes (CP-LEDs) are critical for next-generation optical technologies, ranging from holography to quantum information processing. Currently deployed chiral luminescent materials, with their intricate synthesis and processing and limited efficiency, are the main bottleneck for CP-LEDs. Chiral metal nanoclusters (MNCs) are potential CP-LED materials, given their ease of synthesis and processability as well as diverse structures and excited states. However, their films are usually plagued by inferior electronic quality and aggregation-caused photoluminescence quenching, necessitating their incorporation into host materials; without such a scheme, MNC-based LEDs exhibit external quantum efficiencies (EQEs) < 10%. Herein, we achieve an efficiency leap for both CP-LEDs and cluster-based LEDs by using novel chiral MNCs with aggregation-induced emission enhancement. CP-LEDs using enantiopure MNC films attain EQEs of up to 23.5%. Furthermore, by incorporating host materials, the devices yield record EQEs of up to 36.5% for both CP-LEDs and cluster-based LEDs, along with electroluminescence dissymmetry factors (|gEL|) of around 1.0 × 10-3. These findings open a new avenue for advancing chiral light sources for next-generation optoelectronics.

Engineering High-Performance Hypergolic Propellant by Synergistic Contribution of Metal-Organic Framework Shell and Aluminum Core.

Hypergolicity is a highly desired characteristic for hybrid rocket engine-based fuels because it eliminates the need for a separate ignition system. Introducing hypergolic additives into conventional fuels through physical mixing is a feasible approach, but achieving highly reliable hypergolic ignition and energy release remains a major challenge. Here, the construction of core-shell Al@metal organic framework (MOF) heterostructures is reported as high-performance solid hypergolic propellants. Upon contact with the liquid oxidizer the uniformly distributed hypergolic MOF (Ag-MOF) shell can induce the ignition of hypergolic-inert fuel Al, resulting in Al combustion. Such a synthetic strategy is demonstrated to be favorable in hotspot generation and heat transfer relative to a simple physical mixture of Al/Ag-MOF, thus producing shorter ignition delay times and more efficient combustion. Thermal reactivity study indicated that the functionalization of the Ag-MOF shell changes the energy release process of the inner Al, which is accompanied by a thermite reaction. The synergistic effect of implantation of hypergolic MOF and high energy Al contributes to high specific impulses of 230-270 s over a wide range of oxidizer-to-fuel ratios.

Readiness for return to work and its influencing factors among head and neck cancer patients: a cross-sectional study.

PURPOSE: This study aims to investigate the Readiness for Return-to-Work (RRTW) of patients with head and neck tumours and to analyse the relationships among self-efficacy, disease uncertainty, psychosocial adaptation, and RRTW in head and neck cancer (HNC) patients. METHODS: A cross-sectional study was conducted with 259 HNC patients with a discharge length of ≥1 month at a tertiary hospital in Liaoning Province. The research tools included a self-designed general information questionnaire, the Readiness for Return-to-Work (RRTW) Scale, the General Self-Efficacy Scale (GSES), the Mishel Uncertainty in Illness Scale (MUIS), and the Self-Reporting Psychosocial Adjustment to Illness Scale (PAIS-SR). Descriptive statistical analysis, the rank sum test, Spearman correlation analysis, and ordered multiple and dichotomous logistic regression analyses were used. RESULTS: The overall RRTW among HNC patients was low (41.9%). HNC patients who did not return to work were mainly in the precontemplation stage (38.1%) and contemplation stage (29.9%). HNC patients who returned to work were mainly in the active maintenance stage (64.2%). Children's status (OR = 0.218, 95% CI 0.068-0.703), self-efficacy (OR = 1.213, 95% CI 1.012-1.454), unpredictability (OR = 0.845, 95% CI 0.720-0.990), occupational environment (OR = 0.787, 95% CI 0.625-0.990), and family environment (OR = 0.798, 95% CI 0.643-0.990) influence the RRTW of HNC patients who have not returned to work. Educational level (OR = 62.196, 95% CI 63.307-68.567), children's status (OR = 0.058, 95% CI 1.004-2.547), self-efficacy (OR = 1.544, 95% CI 3.010-8.715), unpredictability (OR = 0.445, 95% CI 1.271-2.280), and psychological status (OR = 0.340, 95% CI 1.141-2.401) influence the RRTW of HNC patients who have returned to work. CONCLUSION: Children's status, education level, self-efficacy, illness uncertainty, and psychosocial adjustment are crucial to RRTW. This study provides a theoretical basis for formulating intervention measures aimed at improving the RRTW of patients.

Health information-seeking experience in people with head and neck neoplasms undergoing treatment: a qualitative study.

PURPOSE: To describe the health information-seeking experience and its influencing factors of people with head and neck neoplasms undergoing treatment. METHODS: This was a descriptive phenomenology study. Participants were recruited by purposive sampling. The semistructured interviews and all observation results were recorded. The data were analysed using Colaizzi's method. RESULTS: Fourteen participants were selected. We identified four themes that illustrate factors that influence the health information-seeking behaviour of participants: patients' awareness of health information needs, patients' competence, doctor-patient communication, and online advertising interference. We also determined the value of different types of information and patients' information needs and sources. CONCLUSION: These findings can help professionals understand patients' behaviours and think about how to deliver practical information support in a network environment to guide patients in continuous information seeking while taking specific factors into account.

Association between residential proximity to major roadways and chronic multimorbidity among Chinese older adults: a nationwide cross-sectional study.

BACKGROUND: Multiple negative health outcomes were linked to residential proximity to major roadways. Nevertheless, there is limited knowledge regarding the association between residential proximity to major roadways and chronic multimorbidity. METHODS: We used data from the 2018 wave of the Chinese Longitudinal Healthy Longevity Survey, which included 12,214 individuals aged ≥ 60. We derived the residential proximity to major roadways from self-reported data, defining chronic multimorbidity as the presence of two or more concurrent chronic diseases. A binary logistic regression model was utilized to investigate the association between residential proximity to major roadways and chronic multimorbidity. The model accounted for some demographic features, socioeconomic conditions, social participation, and health conditions. Subsequently, we conducted subgroup analyses to examine potential interaction effects. RESULTS: Residential proximity to major roadways was associated with chronic multimorbidity, even after adjusting for confounding factors. Compared with those living > 300 m from major roadways, the OR for those living 201-300 m, 101-200 m, 50-100 m, and < 50 m were increased. When subgroup analyses were conducted using a cutoff point of 200 m, the risk of chronic multimorbidity associated with residential proximity to major roadways was stronger in participants with education levels > 6 years (P = 0.017). CONCLUSION: Our findings provide important implications for improving residential area siting, transportation policies, and environmental regulations to reduce the risk of chronic multimorbidity caused by traffic-related exposure.

Inter-relationships of obesity-related eating behavior with depression and anxiety among adults during the COVID-19 pandemic: A network analysis.

The COVID-19 pandemic has significantly impacted individuals' mental health, resulting in a higher incidence of depression, anxiety, and changes in eating behaviors. The objective of this study is to examine the inter-relationships among obesity-related eating behavior, depression, and anxiety in adults during the COVID-19 pandemic, utilizing a network analysis method. We conducted a cross-sectional survey among a representative sample of 9091 adults between July 10 and September 15, 2021. Participants completed self-report measures to assess obesity-related eating behavior and symptoms of depression and anxiety. Network analysis was employed to investigate the inter-relationships among these variables. The network analysis revealed that item 2 (i.e., Do not feel satisfied unless I eat until full) exhibited the highest node strength within the network, followed by item 5 (i.e., Like oily foods). In addition, positive correlations were found between the severity of depression and anxiety and most of the obesity-related eating behavior items. These findings offer valuable insights into the interplay between obesity-related eating behavior, depression, and anxiety during the COVID-19 pandemic, underscoring the significance of considering these factors in comprehending and addressing mental health and well-being in adults. Further research is warranted to explore potential interventions and treatment approaches that specifically target the identified relationships.

Acceptance level of advance care planning and its associated factors among the public: A nationwide survey.

BACKGROUND: Advance care planning (ACP) can contribute to individuals making decisions about their healthcare preferences in advance of serious illness. Up to now, the acceptance level and associated factors of ACP among the public in China remain unclear. This study aims to investigate the acceptance level of ACP in China and identify factors associated with it based on the socioecological model. METHODS: A total of 19,738 participants were included in this survey. We employed a random forest regression analysis to select factors derived from the socioecological model. Multivariate generalized linear model analysis was then conducted to explore the factors that were associated with the acceptance level of ACP. RESULTS: On a scale ranging from 0 to 100, the median score for acceptance level of ACP was 64.00 (IQR: 48.00-83.00) points. The results of the multivariate generalized linear model analysis revealed that participants who scored higher on measures of openness and neuroticism personality traits, as well as those who had greater perceptions of social support, higher levels of health literacy, better neighborly relationships, family health, and family social status, were more likely to accept ACP. Conversely, participants who reported higher levels of subjective well-being and greater family communication levels demonstrated a lower likelihood of accepting ACP. CONCLUSIONS: This study identified multiple factors associated with the acceptance level of ACP. The findings offer valuable insights that can inform the design and implementation of targeted interventions aimed at facilitating a good death and may have significant implications for the formulation of end-of-life care policies and practices in other countries facing similar challenges.

Platonic and Archimedean solids in discrete metal-containing clusters.

Metal-containing clusters have attracted increasing attention over the past 2-3 decades. This intense interest can be attributed to the fact that these discrete metal aggregates, whose atomically precise structures are resolved by single-crystal X-ray diffraction (SCXRD), often possess intriguing geometrical features (high symmetry, aesthetically pleasing shapes and architectures) and fascinating physical properties, providing invaluable opportunities for the intersection of different disciplines including chemistry, physics, mathematical geometry and materials science. In this review, we attempt to reinterpret and connect these fascinating clusters from the perspective of Platonic and Archimedean solid characteristics, focusing on highly symmetrical and complex metal-containing (metal = Al, Ti, V, Mo, W, U, Mn, Fe, Co, Ni, Pd, Pt, Cu, Ag, Au, lanthanoids (Ln), and actinoids) high-nuclearity clusters, including metal-oxo/hydroxide/chalcogenide clusters and metal clusters (with metal-metal binding) protected by surface organic ligands, such as thiolate, phosphine, alkynyl, carbonyl and nitrogen/oxygen donor ligands. Furthermore, we present the symmetrical beauty of metal cluster structures and the geometrical similarity of different types of clusters and provide a large number of examples to show how to accurately describe the metal clusters from the perspective of highly symmetrical polyhedra. Finally, knowledge and further insights into the design and synthesis of unknown metal clusters are put forward by summarizing these "star" molecules.

The effect of loneliness on interpersonal sensitivity among nursing undergraduates: a chain mediation role of problematic internet use and bedtime procrastination.

BACKGROUND: Loneliness was associated with interpersonal sensitivity, but the factors contributing to this relationship in nursing students remain unclear. This study investigated the relationship between loneliness and interpersonal sensitivity among nursing undergraduates, with a specific focus on the mediating roles played by problematic internet use and bedtime procrastination. METHOD: This study was conducted as a cross-sectional survey at a university in China between November and December 2022. Data were collected using a self-administered online questionnaire that included demographic characteristics, the Three-Item Loneliness Scale (T-ILS), the Chinese Version of Short Form of Interpersonal Sensitivity Measure (IPSM-CS), the 6-item short form of the Problematic Internet Use Questionnaire (PIUQ-SF-6), and the Bedtime Procrastination Scale (BPS). Pearson correlation analysis was employed to explore the relationships among loneliness, interpersonal sensitivity, problematic internet use, and bedtime procrastination. Structural equation modeling (SEM) was conducted using AMOS software to examine the mediating role of problematic internet use and bedtime procrastination between loneliness and interpersonal sensitivity. RESULTS: Loneliness was positively related to interpersonal sensitivity among nursing undergraduates (ß = 0.44, P < 0.001). There was a significant chain mediation role of problematic internet use and bedtime procrastination in the relationship between loneliness and interpersonal sensitivity. CONCLUSIONS: The study contributed to deepening the understanding of the relationship between loneliness and interpersonal sensitivity and provided valuable insights into the improvement of interpersonal sensitivity in nursing undergraduates.

Network analysis of the urban-rural differences in depressive symptoms among older adults with multiple chronic conditions: Evidence from a national survey.

BACKGROUND: Evidence on the differences in depressive symptoms among older adults with multiple chronic conditions (MCCs) in urban and rural areas is limited. METHODS: Measures of depressive symptoms (Center for Epidemiologic Studies Depression Scale-10) and demographic factors (age, gender, and urban-rural distribution) were used. RESULTS: A total of 4021 older adults with MCCs were included in this study. Significant differences were observed in both network global strength (Urban: 3.989 vs. Rural: 3.703, S = 0.286, p = 0.003) and network structure (M = 0.139, p = 0.002) between urban and rural residents. CONCLUSIONS: The study highlights the need for region-specific approaches to understanding and addressing depression and holds the potential to enhance understanding of the psychological health status of older adults with MCCs in urban and rural settings.

Microwave-Assisted Rapid Synthesis of MOF-Based Single-Atom Ni Catalyst for CO2 Electroreduction at Ampere-Level Current.

Carbon-based single-atom catalysts (SACs) have attracted tremendous interest in heterogeneous catalysis. However, the common electric heating techniques to produce carbon-based SACs usually suffer from prolonged heating time and tedious operations. Herein, a general and facile microwave-assisted rapid pyrolysis method is developed to afford carbon-based SACs within 3 min without inert gas protection. The obtained carbon-based SACs present high porosity and comparable carbonization degree to those obtained by electric heating techniques. Specifically, the single-atom Ni implanted N-doped carbon (Ni1 -N-C) derived from a Ni-doped metal-organic framework (Ni-ZIF-8) exhibits remarkable CO Faradaic efficiency (96 %) with a substantial CO partial current density (jCO ) up to 1.06 A/cm2 in CO2 electroreduction, far superior to the counterpart obtained by traditional pyrolysis with electric heating. Mechanism investigations reveal that the resulting Ni1 -N-C presents abundant defective sites and mesoporous structure, greatly facilitating CO2 adsorption and mass transfer. This work establishes a versatile approach to rapid and large-scale synthesis of SACs as well as other carbon-based materials for efficient catalysis.

Tandem Nitrate-to-Ammonia Conversion on Atomically Precise Silver Nanocluster/MXene Electrocatalyst.

Electrocatalytic reduction of nitrate (NO3 RR) to synthesize ammonia (NH3 ) provides a competitive manner for carbon neutrality and decentralized NH3 synthesis. Atomically precise nanoclusters, as an advantageous platform for investigating the NO3 RR mechanisms and actual active sites, remain largely underexplored due to the poor stability. Herein, we report a (NH4 )9 [Ag9 (mba)9 ] nanoclusters (Ag9 NCs) loaded on Ti3 C2 MXene (Ag9 /MXene) for highly efficient NO3 RR performance towards ambient NH3 synthesis with improved stability in neutral medium. The composite structure of MXene and Ag9 NCs enables a tandem catalysis process for nitrate reduction, significantly increasing the selectivity and FE of NH3 . Besides, compared with individual Ag9 NCs, Ag9 /MXene has better stability with the current density performed no decay after 108 hours of reaction. This work provides a strategy for improving the catalytic activity and stability of atomically precise metal NCs, expanding the mechanism research and application of metal NCs.

Reversible Local Protonation-Deprotonation: Tuning Stimuli-Responsive Circularly Polarized Luminescence in Chiral Hybrid Zinc Halides for Anti-Counterfeiting and Encryption.

Precise control over the organic composition is crucial for tailoring the distinctive structures and properties of hybrid metal halides. However, this approach is seldom utilized to develop materials that exhibit stimuli-responsive circularly polarized luminescence (CPL). Herein, we present the synthesis and characterization of enantiomeric hybrid zinc bromides: biprotonated ((R/S)-C12H16N2)ZnBr4 ((R/S-LH2)ZnBr4) and monoprotonated ((R/S)-C12H15N2)2ZnBr4 ((R/S-LH1)2ZnBr4), derived from the chiral organic amine (R/S)-2,3,4,9-Tetrahydro-1H-carbazol-3-amine ((R/S)-C12H14N2). These compounds showcase luminescent properties; the zero-dimensional biprotonated form emits green light at 505 nm, while the monoprotonated form, with a pseudo-layered structure, displays red luminescence at 599 and 649 nm. Remarkably, the reversible local protonation-deprotonation behavior of the organic cations allows for exposure to polar solvents and heating to induce reversible structural and luminescent transformations between the two forms. Theoretical calculations reveal that the lower energy barrier associated with the deprotonation process within the pyrrole ring is responsible for the local protonation-deprotonation behavior observed. These enantiomorphic hybrid zinc bromides also exhibit switchable circular dichroism (CD) and CPL properties. Furthermore, their chloride counterparts were successfully obtained by adjusting the halogen ions. Importantly, the unique stimuli-responsive CPL characteristics position these hybrid zinc halides as promising candidates for applications information storage, anti-counterfeiting, and information encryption.

Introducing Carborane Clusters into Crystalline Frameworks via Thiol-Yne Click Chemistry for Energetic Materials.

Crystalline frameworks represent a cutting-edge frontier in material science, and recently, there has been a surge of interest in energetic crystalline frameworks. However, the well-established porosity often leads to diminished output energy, necessitating a novel approach for performance enhancement. Thiol-yne coupling, a versatile metal-free click reaction, has been underutilized in crystalline frameworks. As a proof of concept, we herein demonstrate the potential of this approach by introducing the energy-rich, size-matched, and reductive 1,2-dicarbadodecaborane-1-thiol (CB-SH) into an acetylene-functionalized framework, Zn(AIm)2, via thiol-yne click reaction. This innovative decoration strategy resulted in a remarkable 46.6 % increase in energy density, a six-fold reduction in ignition delay time (4 ms) with red fuming nitric acid as the oxidizer, and impressive enhancement of stability. Density functional theory calculations were employed to elucidate the mechanism by which CB-SH promotes hypergolic ignition. The thiol-yne click modification strategy presented here permits engineering of crystalline frameworks for the design of advanced energetic materials.

Unveiling Ionized Interfacial Water-Induced Localized H* Enrichment for Electrocatalytic Nitrate Reduction.

Electrocatalytic nitrate reduction reaction (NO3RR) is a process that requires the participation of eight electrons and nine protons. The regulation of active hydrogen (H*) supply and a deep understanding of related processes are necessary for improving the ammonia yield rate and Faradaic efficiency (FE). Herein, we synthesized a series of atomically precise copper-halide clusters Cu2X2(BINAP)2 (X = Cl, Br, I), among which the Cu2Cl2(BINAP)2 cluster shows the optimal ammonia FE of 94.0% and an ammonia yield rate of 373 µmol h-1 cm-2. In situ experiments and theoretical calculations reveal that halogen atoms, especially Cl in Cu2Cl2(BIANP)2, can significantly affect the distance of alkali metal-ionized water on the catalyst surface, which can promote the water dissociation to enhance the localized H* enrichment for the continues hydrogenation of nitrate to ammonia. This work explains the role of H* in the hydrogenation process of NO3RR and the importance of localized H* enrichment strategy for improving the FEs.