Boosting 2000-Fold Hypergolic Ignition Rate of Carborane by Substitutes Migration in Metal Clusters.

Hypergolic propellants rely on fuel and oxidizer that spontaneously ignite upon contact, which fulfill a wide variety of mission roles in launch vehicles and spacecraft. Energy-rich carboranes are promising hypergolic fuels, but triggering their energy release is quite difficult because of their ultrastable aromatic cage structure. To steer the development of carborane-based high-performance hypergolic material, carboranylthiolated compounds integrated with atomically precise copper clusters are presented, yielding two distinct isomers, Cu and Cu, both possessing similar ligands and core structures.

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.

Asymmetrical Interactions between Ni Single Atomic Sites and Ni Clusters in a 3D Porous Organic Framework for Enhanced CO Photoreduction.

3D porous organic frameworks, which possess the advantages of high surface area and abundant exposed active sites, are considered ideal platforms to accommodate single atoms (SAs) and metal nanoclusters (NCs) in high-performance catalysts; however, very little research has been conducted in this field. In the present work, a 3D porous organic framework containing Ni SAs and Ni NCs is prepared through the metal-assisted one-pot polycondensation of tetraaldehyde and hexaaminotriptycene. The single metal sites and metal clusters confined in the 3D space created a favorable micro-environment that facilitated the activation of chemically inert CO molecules, thus promoting the overall photoconversion efficiency and selectivity of CO reduction.

Single-atom tailored atomically-precise nanoclusters for enhanced electrochemical reduction of CO-to-CO activity.

The development of facile tailoring approach to adjust the intrinsic activity and stability of atomically-precise metal nanoclusters catalysts is of great interest but remians challenging. Herein, the well-defined Au nanoclusters modified by single-atom sites are rationally synthesized via a co-eletropolymerization strategy, in which uniformly dispersed metal nanocluster and single-atom co-entrenched on the poly-carbazole matrix. Systematic characterization and theoretical modeling reveal that functionalizing single-atoms enable altering the electronic structures of Au clusters, which amplifies their electrocatalytic reduction of CO to CO activity by ~18.

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.

Mechanism of the Impact-Sensitivity Reduction of Energetic CL-20/TNT Cocrystals: A Nonequilibrium Molecular Dynamics Study.

High-energy low-sensitivity explosives are research objectives in the field of energetic materials, and the formation of cocrystals is an important method to improve the safety of explosives. However, the sensitivity reduction mechanism of cocrystal explosives is still unclear. In this study, CL-20/TNT, CL-20 and TNT crystals were taken as research objects.

Constructing Highly Reliable and Adaptive Primary Explosive Composites for Micro-Initiator Assisting by a Hybrid Template of Metal-Organic Frameworks and Cross-Linked Polymers.

Primary explosive, as a reliable initiator for secondary explosives, is the central component of micro-initiators for modern aerospace systems and military operations. However, they are typically prepared as powders, posing potential safety risks because of the inevitable particles scattering issues in the actual working environments. Here, the fabrication of a highly adaptive bulk material of copper azide (CA)-based safe primary explosive for micro-initiators is demonstrated.

Cooperative Catalysis between Dual Copper Centers in a Metal-Organic Framework for Efficient Detoxification of Chemical Warfare Agent Simulants.

Chemical warfare agents (CWAs) are among the most lethal chemicals known to humans. Thus, developing multifunctional catalysts for highly efficient detoxification of various CWAs is of great importance. In this work, we developed a robust copper tetrazolate metal-organic framework (MOF) catalyst containing a dicopper unit similar to the coordination geometry of the active sites of natural phosphatase and tyrosinase enzymes.

Phosphate anion-induced silver-chalcogenide cluster-based metal organic frameworks as dual-functional catalysts for detoxifying chemical warfare agent simulants.

Two porphyrinic silver-chalcogenide cluster-based MOFs were achieved using a phosphate anionic template strategy, and the highly photoactive organic building modules combined with Lewis acidic silver clusters allow both SCC-MOFs to be used as versatile catalysts for the simultaneous degradation of sulfur mustard and nerve agent simulants.

Aminal-Linked Porphyrinic Covalent Organic Framework for Rapid Photocatalytic Decontamination of Mustard-Gas Simulant.

Covalent organic frameworks (COFs) are appealing photocatalysts for toxic chemical degradation. Great efforts have been devoted to regulate the photocatalytic performance of COFs by tuning their organic building blocks, but the relationship between COF linkage and photochemical properties has rarely been explored. Herein, we report the synthesis and characterisation of a novel aminal-linked porphyrinic COF, namely Por-Aminal-COF.

Programming a Metal-Organic Framework toward Excellent Hypergolicity.

Exploring novel hypergolic fuels for modern space propulsion is highly desired. However, the analysis and understanding of the structure and hypergolic performance at the molecular level are still insufficient. To understand the factors that dictate hypergolicity, we conducted a comparative study on a series of metal-organic frameworks (MOFs) characterized by the same topology but with varied ligand structures.

Hydrazone connected stable luminescent covalent-organic polymer for ultrafast detection of nitro-explosives.

Developing promising luminescent probes for the selective sensing of nitro-explosives remains a challenging issue. Porous luminescent covalent-organic polymers are one of the excellent sensing probes for trace hazardous materials. Herein, fluorescent monomers 1,1,2,2-tetrakis(4-formyl-(1,1'-biphenyl))ethane (TFBE) and 1,3,5-benzenetricarboxylic acid trihydrazide (BTCH) were selected to build a novel hydrazone connected stable luminescent covalent-organic polymer (H-COP) of high stability by typical Schiff-base reaction.

Electropolymerization of Metal Clusters Establishing a Versatile Platform for Enhanced Catalysis Performance.

Atomically precise metal clusters are attractive as highly efficient catalysts, but suffer from continuous efficiency deactivation in the catalytic process. Here, we report the development of an efficient strategy that enhances catalytic performance by electropolymerization (EP) of metal clusters into hybrid materials. Based on carbazole ligand protection, three polymerized metal-cluster hybrid materials, namely Poly-Cu cba, Poly-Cu Au cbz and Poly-Cu Ag cbz, were prepared.

Assembling Silver Cluster-Based Organic Frameworks for Higher-Performance Hypergolic Properties.

Increasing research efforts have been focused on developing next-generation propellants. In this work, we demonstrated that assembling zero-dimensional (0D) silver clusters with energetic ligands into 3D metal organic frameworks (MOFs) not only inherited the short ignition delay (ID) time of the alkynyl-silver cluster but also significantly increased the output energy. Among them, the open cationic framework of ZZU-363 incorporating counter NO ions achieved a considerably reduced energy barrier and eventually the shortest ID time (26 ms), together with the highest volumetric energy density (40.

Silver Cluster-Porphyrin-Assembled Materials as Advanced Bioprotective Materials for Combating Superbacteria.

Superbugs are bacteria that have grown resistant to most antibiotics, seriously threating the health of people. Silver (Ag) nanoparticles are known to exert a wide-spectrum antimicrobial property, yet remains challenging against superbugs. Here, Ag clusters are assembled using porphyrin-based linkers and a novel framework structure (Ag -AgTPyP) is produced, in which nine-nuclearity Ag clusters are uniformly separated by Ag-centered porphyrin units (AgTPyP) in two dimensions, demonstrating open permeant porosity.

Integrating Single Atoms with Different Microenvironments into One Porous Organic Polymer for Efficient Photocatalytic CO Reduction.

The precise identification of single-atom catalysts (SACs) activity and boosting their efficiency toward CO conversion is imperative yet quite challenging. Herein, for the first time a series of porous organic polymers is designed and prepared simultaneously, containing well-defined M-N and M-N O single-atom sites. Such a strategy not only offers multiactive sites to promote the catalytic efficiency but also provides a more direct chance to identify the metal center activity.

Ozone Decomposition by a Manganese-Organic Framework over the Entire Humidity Range.

Ground-level ozone (O) is one of the main airborne pollutants detrimental to human health and ecosystems. However, the designed synthesis of high-performance O elimination catalysts suitable for broadly variable air compositions, especially a variable water vapor content, remains daunting. Herein, we report a new manganese-based metal organic framework, [Mn(μ-OH)(TTPE)(HO)]·2HO (HTTPE = 1,1,2,2-tetrakis(4-(2-tetrazol-5-yl)phenyl) ethane), denoted as ZZU-281.

-Carborane-Based and Atomically Precise Metal Clusters as Hypergolic Materials.

Atomically precise -carboranealkynyl-protected clusters [Ag(CBH)(CHCN)]·2NO (CBA-Ag) and [CuAg(CBH)Cl]NO (CBA-CuAg) have been found to exhibit hypergolic activity, such that they are capable of spontaneous ignition and combustion upon contact with the white fuming nitric acid oxidizer. In particular, CBA-CuAg has a short ignition delay time of 15 ms, whereas the -carboranealkynyl ligand is hypergolically inert. Systematic investigation revealed that the metal cluster core catalyzed the hypergolic behavior of inert -carboranealkynyl ligand, and Cu doping further accelerated combustion catalysis.

Fabrication of silver chalcogenolate cluster hybrid membranes with enhanced structural stability and luminescence efficiency.

The present study reports the fabrication of a silver chalcogenolate cluster hybrid membrane (SCC membrane) through self-assembly of SCCs, and then covalent cross-linking of the modified SCC assembled materials. This strategy provides access to silver clusters with superior chemical stability and enhanced luminescence efficiency for practical applications.

Porphyrinic Silver Cluster Assembled Material for Simultaneous Capture and Photocatalysis of Mustard-Gas Simulant.

Silver cluster-assembled materials (SCAMs), by virtue of their tunable structure, accessible surface area and excellent stability, hold great promise as highly efficient catalysts. Herein, we report a new SCAM [Ag(SBu)(CFCOO)(TPyP)] (denoted as AgTPyP) composed of a Ag chalcogenolate cluster core stabilized by porphyrinic ligands. AgTPyP showed superior sulfur mustard simulant (2-chloroethyl ethyl sulfide, CEES) degradation efficiency and achieved a half lifetime () of 1.

A porous β-cyclodextrin-based terpolymer fluorescence sensor for trinitrophenol detection.

Permanent porosity plays a key role in fluorescent-based polymers with "on-off" emissive properties due to the role of guest adsorption at accessible fluorophore sites of the polymer framework. In particular, we report on the design of a porous fluorescent polymer (FL-PFP) composed of a covalently cross-linked ternary combination of β-cyclodextrin (β-CD), 4,4'-diisocyanato-3,3'-dimethyl biphenyl (DL) and tetrakis(4-hydoxyphenyl)ethene (TPE). The textural properties of FL-PFP were evaluated by the gas uptake properties using N and CO isotherms.

Fabrication of Copper Azide Film through Metal-Organic Framework for Micro-Initiator Applications.

The paradox between safety and detonation performance, along with the intrinsic fragility of primary explosives, is the main bottleneck precluding their application in a micro-initiation system. To tackle these issues, we fabricate a flexible copper azide film (CA-C film@PF) via employing the metal-organic framework (MOF) film produced by electrospinning technique as the precursor, followed by pyrolysis treatment, in situ azide reaction, and perfluorinated coating procedures. The synergetic effect of MOF and interweaved polymer fiber endow the resultant copper azide film with excellent electrostatic stability and remarkable detonation performance.

Nanoscale Homogeneous Energetic Copper Azides@Porous Carbon Hybrid with Reduced Sensitivity and High Ignition Ability.

Research on green primary explosives with lead-free and excellent ignition performance is of significance for practical applications. In this work, we have developed a novel, green, and facile strategy for synthesizing copper azide@porous carbon hybrids (CA@PC) based on ionic cross-linked hydrogel with low-cost cellulose derivatives as the starting material, in which the CA nanoparticles are uniformly distributed in the porous carbon skeletons. The detailed characterizations and control experiments demonstrated that such an outstanding performance originates from the excellent electric conductivity of nanoscale carbon cages.

A Heat-Resistant and Energetic Metal-Organic Framework Assembled by Chelating Ligand.

Heat-resistant explosives with high performance and insensitivity to external stimulus or thermal are indispensable in both the military and civilian worlds especially when utilized under harsh conditions. We designed and synthesized a new heat-resistant three-dimensional chelating energetic metal-organic framework (CEMOF-1) by employing 4-amino-4H-1,2,4-triazole-3,5-diol (ATDO) as a ligand. Because of its chelating 3D structural feature, good oxygen balance (-29.

Explosives in the Cage: Metal-Organic Frameworks for High-Energy Materials Sensing and Desensitization.

An overview of the current status of coordination polymers and metal-organic frameworks (MOFs) pertaining to the field of energetic materials is provided. The explosive applications of MOFs are discussed from two aspects: one for detection of explosives, and the other for explosive desensitization. By virtue of their adjustable pore/cage sizes, high surface area, tunable functional sites, and rich host-guest chemistry, MOFs have emerged as promising candidates for both explosive sensing and desensitization.