Assembly of Tetrazolylfuroxan Organic Salts: Multipurpose Green Energetic Materials with High Enthalpies of Formation and Excellent Detonation Performance

A series of highly energetic organic salts comprising a tetrazolylfuroxan anion, explosophoric azido or azo functionalities, and nitrogen-rich cations were synthesized by simple, efficient, and scalable chemical routes. These energetic materials were fully characterized by IR and multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Additionally, the structure of an energetic salt consisting of an azidotetrazolylfuroxan anion and a 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazolium cation was confirmed by single-crystal X-ray diffraction. The synthesized compounds exhibit good experimental densities (1.57–1.71 g cm⁻³), very high enthalpies of formation (818–1363 kJ mol⁻¹), and, as a result, excellent detonation performance (detonation velocities 7.54–8.26 kms⁻¹ and detonation pressures 23.4–29.3 GPa). Most of the synthesized energetic salts have moderate sensitivity toward impact and friction, which makes them promising candidates for a variety of energetic applications. At the same time, three compounds have impact sensitivity on the primary explosives level (1.5–2.7 J). These results along with high detonation parameters and high nitrogen contents (66.0–70.2 %) indicate that these three compounds may serve as potential environmentally friendly alternatives to lead-based primary explosives.     

Fully C/N‐Polynitro‐Functionalized 2,2′‐Biimidazole Derivatives as Nitrogen‐ and Oxygen‐Rich Energetic Salts

Through the use of a fully C/N‐functionalized imidazole‐based anion, it was possible to prepare nitrogen‐ and oxygen‐rich energetic salts. When N,N‐dinitramino imidazole was paired with nitrogen‐rich bases, versatile ionic derivatives were prepared and fully characterized by IR, and ¹H, and ¹³C NMR spectroscopy and elemental analysis. Both experimental and theoretical evaluations show promising properties for these energetic compounds, such as high density, positive heats of formation, good oxygen balance, and acceptable stabilities. The energetic salts exhibit promising energetic performance comparable to the benchmark explosive RDX (1,3,5‐trinitrotriazacyclohexane).     

基于机器学习的直接电离质谱爆炸物检测方法

直接电离质谱系统在现场快速检测中的应用日益广泛,主要用于爆炸物、毒品、食品添加剂等的检测。然而,直接电离质谱系统中质谱信号波动大且同一浓度样品峰强呈现对数正态分布,严重影响了检出限附近低浓度样品的检测准确性。该研究将乙酰水杨酸(115个样品)作为爆炸物模拟物,利用介质阻挡放电离子源与质谱系统,研究了基于机器学习的直接电离质谱数据预处理和分类算法,以提高低浓度样品的检测准确率。对两种浓度为1 ng/mL的常见爆炸物样本(三硝基甲苯和硝酸铵分别为110、90个)及空白对照样本(366个)开展了应用实验。结果表明,与传统提取离子流方法和高斯混合模型方法相比,采用随机森林算法可将F_score从0.74、0.89提升至0.96,显著提高了检测准确率,且单个样本数据分析时间远少于0.1 s,满足实时检测需求。     

比色法在爆炸物检测中的研究进展

爆炸物杀伤力大、隐蔽性强,被广泛应用于军事战争,也是恐怖分子施暴方式的首选。基于保护人民生命和财产安全的迫切需求,爆炸物检测技术受到世界公共安全领域的高度重视。相比于其它分析方法,比色法因操作简便、抗干扰性强,不依赖分析设备的优势成为最适用于现场快速检测爆炸物的方法之一。该文主要综述了比色法在爆炸物探测领域的研究进展,包括对比色探针和比色阵列研究进展的总结与前景分析,并重点讨论了比色人工嗅觉系统及其在爆炸物检测中的应用,展望了其未来的发展趋势和应用前景。     

Ammonia–(Dinitramido)boranes: High‐Energy‐Density Materials

Two ammonia–(dinitramido)boranes were synthesized by the reaction of dinitroamine with ammonia–borane. These compounds are the first reported examples of (dinitramido)boranes. Ammonia–mono(dinitramido)borane is a perfectly oxygen‐balanced high‐energy‐density material (HEDM) composed of an ammonia–BH₂ fuel group and a strongly oxidizing dinitramido ligand. Although it is thermally not stable enough for practical applications, its predicted specific impulse as a solid rocket propellant would be 333 s. Its predicted performance as an explosive matches that of pentaerythtritol tetranitrate (PETN) and significantly exceeds that of trinitrotoluene (TNT). Its structure was established by X‐ray crystallography and vibrational and multinuclear NMR spectroscopy. Additionally, the over‐oxidized ammoniabis(dinitramido)borane was detected by NMR spectroscopy.     

计算钝感炸药爆轰过程的一种新反应率模型

根据钝感炸药爆轰过程中含有激化过程和慢反应,建立了一种新的反应率模型。与其他反应率模型相比,这种反应率模型可以应用于较粗的网格。在每厘米50个网格条件下,炸药驱动铝飞片和钽飞片的自由面计算结果与实验结果很接近。同时,应用此反应率模型计算了钝感炸药驱动LiF过程,在每厘米50个网格的条件下,炸药与LiF间速度的计算值同实验值接近,且误差随网格尺寸变小而变小。这些表明,此反应率模型能够在较粗的网格条件下,比较准确地描述钝感炸药驱动飞片过程,有利于在工程实际中应用。     

从分子结构式估算凝聚炸药最高装药密度

本文应用对应态原理建立了一种从凝聚炸药的分子结构式估算其最高装药密度的经验方法。应用此法对101种环状化合物的密度进行了估算,计算值与实验值的平均偏差为1.08％。与类似工作相比,本文方法精度较高,使用方便。     

关于分形和炸药撞击感度的一点记注

通过对现有炸药冲击感度的标度方法进行了分析和讨论。从落锤试验分幅照相结果，初步建议用分形维数作为炸药冲击感度的标度，识为是有这种可能性。并讨论了这种方法的优点。     

Exceptional Blueshifted and Enhanced Aggregation‐Induced Emission of Conjugated Asymmetric Triazines and Their Applications in Superamplified Detection of Explosives

A novel conjugated asymmetric donor–acceptor (CADA) strategy for preventing the redshift in photoluminescence, as well as preserving the merits of donor–acceptor architectures, was proposed and demonstrated for two triazine derivatives, which showed highly efficient, narrow, and blueshifted ultraviolet light emission in solid films along with special aggregation‐induced emission behavior. A mechanism of aggregation‐induced locally excited‐state emission by suppressing the twisted intramolecular charge‐transfer emission for the spectacular optoelectronic phenomena of these CADA molecules was suggested on the basis of both experimental measurements and theoretical calculations. By taking advantage of this special CADA architecture, fluorescent probes based on aggregates of conjugated asymmetric triazines in THF/water for the detection of explosives show superamplified detection of picric acid with high quenching constants (>1.0×10⁷ M ^?1) and a low detection limit of 15 ppb.     

Design and Synthesis of Nitrogen-Rich Azo-Bridged Furoxanylazoles as High-Performance Energetic Materials

A series of novel energetic materials comprising of azo-bridged furoxanylazoles enriched with energetic functionalities was designed and synthesized. These high-energy materials were thoroughly characterized by IR and multinuclear NMR (¹H, ¹³C, ¹⁴N) spectroscopy, high-resolution mass spectrometry, elemental analysis, and differential scanning calorimetry (DSC). The molecular structures of representative amino and azo oxadiazole assemblies were additionally confirmed by single-crystal X-ray diffraction and X-ray powder diffraction. A comparison of contributions of explosophoric moieties into the density of energetic materials revealed that furoxan and 1,2,4-oxadiazole rings are the densest motifs while the substitution of the azide and amino fragments on the nitro and azo ones leads to an increase of the density. Azo bridged energetic materials have high nitrogen-oxygen contents (68.8–76.9 %) and high thermal stability. The synthesized compounds exhibit good experimental densities (1.62–1.88 g cm⁻³), very high enthalpies of formation (846–1720 kJ mol⁻¹), and, as a result, excellent detonation performance (detonation velocities 7.66–9.09 km s⁻¹ and detonation pressures 25.0–37.7 GPa). From the application perspective, the detonation parameters of azo oxadiazole assemblies exceed those of the benchmark explosive RDX, while a combination of high detonation performance and acceptable friction sensitivity of azo(1,2,4-triazolylfuroxan) make it a promising potential alternative to PETN.