基于面-面π-π堆积的低感高能晶体构筑策略研究

Low sensitive and high energetic materials (LSHEMs) are highly desired in the fields of weapons, and serve as one of the main aims of the development of energetic materials (EMs). Evidently, it is a key to construct low sensitive and high energetic crystals (LSHECs) to achieve LSHEMs. However, the evolution of LSHEMs is now seriously restricted with a limited yield, due to a bias on the energy-safety contradiction of EMs and a deficient ability to design energetic crystals. The present project will propose a strategy for constructing LSHECs, based on a fundamental understanding that the energy-safety contradiction of EMs can largely be alleviated on the crystal level, and a breakthrough point that the face-to-face π-π stacking favors the most low impact sensitivity. To experimentally verify the strategy, we will design, synthesize and prepare some new LSHECs with a concept of crystal engineering. The related details include a strategy for building molecular structures that can be face-to-face π-π stacked in crystal, and another one that can balance an energetic crystal as a LSHEC. It will proceed with a comprehensive consideration of increasing molecular stability, packing density, reaction heat and gas production of unit mass. Furthermore, three kinds of energetic crystals will be covered in the strategy, including single component crystals composed of neutral molecules, co-crystals and ionic salts. It is expected that the implement of the project will facilitate to richen the understanding of the relationships among components, structures and properties of EMs, and promote the establishment of a perfect theory system of LSHEMs construction and the practical applications of energetic crystal engineering.

低感高能材料（LSHEM）在武器领域有着重大应用需求，是含能材料（EM）发展的一个重要方向；而构筑低感高能晶体（LSHEC）是获得LSHEM的关键。但是，由于传统EM能量与安全性间矛盾认知上的束缚和含能晶体设计能力的不足，LSHEC制备的理性化程度极低，现有的LSHEC寥寥无几，严重制约了其的发展。本项目将基于EM能量-安全性间矛盾在晶体层次可以大大缓解的基本认知，以最有利于低撞击感度的面-面π-π晶体堆积结构为切入点，探索LSHEC的构筑策略；并以晶体工程的基本理念设计合成制备新型LSHEC，检验此策略。具体内容包括构造形成面-面π-π堆积的分子结构的策略和综合考虑提高分子稳定性、堆积密度、反应热与单位质量产气量的平衡策略。本项目提出的LSHEC构筑策略，将涵盖单组份晶体、共晶和离子盐，必将有利于丰富EM组成、结构与性能间关系的认知，推进构建完善的LSHEM理论体系与EM晶体工程应用。

低感高能材料（LSHEM）在武器领域有着重大应用需求，而构筑低感高能晶体（LSHEC）是获得LSHEM的关键。本项目以最有利于低撞击感度的面-面π-π晶体堆积结构为切入点，发展了LSHEC的构筑策略并实现了其在创制新型LSHEC中的应用。通过对401个面-面π−π堆积晶体结构中的分子进行分析，发现在结构上，除了分子平面性要求外，在分子对称性并无其它要求；组成上，对于含氢原子的分子，应具有强HB供体和强HB受体，而无氢分子，层间分子间相互作用明显增强。提出了基于共轭体系中引入氨基的构筑高密度晶体策略和基于强HB的构筑面-面π−π堆积策略。成功设计并合成了一种新型的面-面π−π堆积的化合物4-硝基-7-叠氮-吡唑并四嗪-2-氧，满足LSHEC的要求。本项目的研究结果将有利于丰富EM组成、结构与性能间关系的认知，推进构建完善的LSHEM理论体系与EM晶体工程应用。