Cai Jinxiong, Fei Teng, Li Rui, Xiong Jin, Zhang Jinya, Yin Ping, Pang Siping
School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China.
Jingzhou Municipal Ecological Environment Information and Testing and Evaluation Center, Jingzhou 434000, China.
ACS Appl Mater Interfaces. 2022 Nov 30;14(47):52951-52959. doi: 10.1021/acsami.2c16164. Epub 2022 Nov 15.
Recently, the construction of novel fused-ring frameworks has become one of the most significant innovative approaches to access high-energy and thermostable energetic molecules. In this work, an ether bridge was utilized as a building block to construct energetic fused-ring skeletons for the first time. Two new [5,7,5]-tricyclic N-heterocycle-based backbones, ditriazole-1,3,6-oxadiazepine and pyrazole-triazole-1,3,6-oxadiazepine, were synthesized via a straightforward one-step synthetic route and the energetic performances of their derivatives were further evaluated. Containing an additional oxygen atom, high-density pyrazole-triazole backbone, and high crystal packing coefficient, the asymmetric molecule 2,10,11-trinitro-5,7-pyrazolo[1,5-][1,2,4]triazolo[5,1-][1,3,6]oxadiazepine () features a high crystal density of 1.825 g cm, much superior to those of the symmetrical analogues 2,10-dinitro-5,7-bis([1,2,4]triazolo)[1,5-:5',1'-][1,3,6]oxadiazepine (, = 1.758 g cm) and ( = 1.634 g cm). Meanwhile, the compounds and exhibit better thermal stability than the parent molecule ( = 251 °C), and their decomposition temperatures reach up to 303 and 294 °C, respectively. The remarkable overall performance of and strongly suggests them as appropriate candidates for heat-resistant explosives. Our study may give new insights into the close correlation of the structural properties of energetic fused-ring frameworks, and the universality of the asymmetric heterocycles combination strategy for designing advanced high-energy density materials (HEDMs) was emphasized again.
近年来，构建新型稠环骨架已成为获取高能且热稳定含能分子的最重要创新方法之一。在本工作中，首次将醚桥用作构建单元来构建含能稠环骨架。通过简单的一步合成路线合成了两种基于[5,7,5]-三环氮杂环的新骨架，即二唑并-1,3,6-二氮杂卓和吡唑-三唑-1,3,6-二氮杂卓，并进一步评估了它们衍生物的能量性能。不对称分子2,10,11-三硝基-5,7-吡唑并[1,5-][1,2,4]三唑并[5,1-][1,3,6]二氮杂卓（）含有一个额外的氧原子、高密度的吡唑-三唑骨架以及高晶体堆积系数，其晶体密度高达1.825 g/cm³，远优于对称类似物2,10-二硝基-5,7-双（[1,2,4]三唑并）[1,5-:5',1'-][1,3,6]二氮杂卓（， = 1.758 g/cm³）和（ = 1.634 g/cm³）。同时，化合物和表现出比母体分子（ = 251 °C）更好的热稳定性，它们的分解温度分别高达303和294 °C。和的卓越整体性能强烈表明它们是耐热炸药的合适候选物。我们的研究可能为含能稠环骨架的结构性质之间的紧密关联提供新的见解，并且再次强调了不对称杂环组合策略在设计先进高能量密度材料（HEDMs）中的普遍性。
