Meng Fanle, Ye Zihong, Zhu Hongwei, Sun Lianghe, Lu Ming, Xu Yuangang
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094, China.
Qian Xuesen College, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094, China.
Dalton Trans. 2025 Jan 21;54(4):1307-1319. doi: 10.1039/d4dt02727b.
As a new type of polynitrogen species that is stable at room temperature, the pentazolate anion (-N) has attracted much attention in the field of high-energy density materials, but its energy and stability are unbalanced. Cocrystallisation can balance their properties to some extent by forming new chemical compositions from existing -N compounds through non-covalent interactions. This article reviews the research progress of -N cocrystals in recent years, including synthetic methods, cocrystals of metal-N compounds, and cocrystals of nonmetallic pentazolate salts. The cocrystals of metal-N compounds mainly include metal-N solvates, cocrystals composed of metal-N compounds and amines/MSM, and metal-containing composite salts. The cocrystals of nonmetallic pentazolate salts include cocrystals composed of -N salts and solvents, cocrystals composed of -N salts and -heterocyclic molecules, and non-metallic composite salts. The fascinating crystal structures (in some cases topological structures), stable forms, and physicochemical properties of representative cocrystals were highlighted. In addition, the future directions that need to be focused on in this field were pointed out, including the development of more preparation methods, especially those suitable for scaling up; higher precision calculation or testing of enthalpy of formation; improvement of their thermal stabilities; creation of cocrystals of -N salts and high-density, high-oxygen balance, high-energy oxidizers; and exploration of the formation mechanism.
作为一种在室温下稳定的新型多氮物种，五唑阴离子（-N）在高能量密度材料领域引起了广泛关注，但其能量和稳定性并不平衡。共结晶可以通过非共价相互作用，由现有的-N化合物形成新的化学组成，从而在一定程度上平衡它们的性质。本文综述了近年来-N共晶体的研究进展，包括合成方法、金属-N化合物共晶体以及非金属五唑盐共晶体。金属-N化合物共晶体主要包括金属-N溶剂化物、由金属-N化合物与胺类/含能材料组成的共晶体以及含金属复合盐。非金属五唑盐共晶体包括由-N盐与溶剂组成的共晶体、由-N盐与-杂环分子组成的共晶体以及非金属复合盐。文中突出介绍了代表性共晶体迷人的晶体结构（某些情况下为拓扑结构）、稳定形态及物理化学性质。此外，还指出了该领域未来需要关注的方向，包括开发更多制备方法，尤其是适合放大生产的方法；对生成焓进行更高精度的计算或测试；提高它们的热稳定性；制备-N盐与高密度、高氧平衡、高能量氧化剂的共晶体；以及探索形成机理。
