由N_3H和N^+_5合成高能量密度化合物N_8H^+的理论研究

Theoretical studies on synthesis of the high energy compound N_8H^+ from N_3H and N^+_5

富氮高能量密度化合物在实验室中能否被合成很大程度上依赖于其动力学稳定性。采用密度泛函方法(DFT-B3LYP/6-311+G(3df)),利用实验室已合成的N3H和N+5作为反应物,设计合成高能量密度化合物N8H+的反应路径。结果显示,共有两种可能的合成路径和三种N8H+异构体。通过计算合成、分解和异构反应的势垒发现,路径1较路径2更容易进行(势垒分别为16.6和30.7 kcal·mol-1),生成的异构体N8H+-A极易转化成异构体N8H+-B结构(势垒为2.4 kcal·mol-1)。B结构较低的分解势垒(13.9 kcal·mol-1)说明,利用N3H和N+5为反应物生成N8H+是不理想的。

The existence of high energetic density material depends more on its kinetic stability. A DFT （B3LYP/ 6 -311 ＋ G（3df）） study on the NsH ＋ synthesis from experimental available reactants N3H and N5＋ reveals two possible reaction channels with three isomers. The calculated barriers towards synthesis, decomposition and isom- erization reveal that channel one is more feasible than channel two because of the lower barrier （ 16.6 and 30.7 kcal ·mol^-1, respectively）. The isomer N8H ^＋- A formed in channel one converts to the isomer N8H ^＋- B easily with a barrier height of only 2.4 kcal · mol^ - 1. The low dissociation barrier （ 13.9 kcal· mol ^- 1 ） of isomer B indicates that the synthesis of N8H^ ＋ from N3 H and N5 ^＋ is impossible.