四氮杂戊搭烯类含能化合物分子设计及性能预估

Molecule design and performance prediction of tetrazapentalene derivatives

以耐热含能材料为目标,四氮杂戊搭烯为基本结构单元,构建含苯环或吡啶环的四氮杂戊搭烯结构,引入硝基、氨基为含能基团,设计了12种四氮杂戊搭烯类耐热含能化合物。基于密度泛函理论(DFT),采用B3LYP方法结合6-311g(d,p)基组对四氮杂戊搭烯类耐热含能化合物进行几何优化,得到其稳定的几何构型。采用蒙特-卡洛法、原子化法和Kamlet-Jacobs方程对化合物的密度、生成焓和爆轰性能进行了计算和讨论。结果表明,12种化合物密度在1.80~1.94 g·cm^(-3)之间;生成焓介于646.5~745.3 kJ·mol^(-1);爆速分布范围为7480~8203 m·s^(-1),爆压分布范围为25.3~31.8 GPa。引发键的BDE值大小顺序为:C—N>N—N>C—NO_(2),C—NO_(2)键是上述化合物中的相对最弱键,其中,1,3,7,9-四氨基-2,4,8,10-四硝基-二苯并-1,3a,6,6a-四氮杂戊搭烯(B7)同时兼具较高的引发键键离解能和较大的能带宽度,热稳定性最好。1,3a,6,6a-构型四氮杂戊搭烯的生成焓、爆速和爆压整体高于1,3a,4,6a-构型的化合物,且感度更低,归因于其高度对称的分子结构。根据理论计算结果,3,9-二氨基-2,4,8,10-四硝基-二吡啶并-1,3a,6,6a-四氮杂戊搭烯(B9)的爆轰性能最优,感度较低,热稳定性较好,其密度为1.94 g·cm^(-3),爆速与爆压分别为8203 m·s^(-1)和31.8 GPa,特性落高(H)值为90 cm。

Taking heat-resistant energetic material as target,twelve tetrazapentalene derivatives containing benzene ring or pyridine ring with nitro or amino energetic groups were constructed.Their structures were optimized by B3 LYP method at 6-311 g(d,p)basis set based on density functional theory.The density,enthalpy of formation and detonation performance were calculated by Monte-Carlo,atomization method and Kamlet-Jacobs equations,respectively.The results show that the density,enthalpy of formation,detonation velocity,detonation pressure of the twelve compounds are in the range of 1.80~1.94 g·cm^(-3),646.5~745.3 kJ·mol^(-1),7480~8203 m·s^(-1)and 25.3~31.8 GPa,respectively.The BDE value of the trigger bond is found in the order of C—N>N—N>C—NO_(2),and C—NO_(2)is the relatively weakest bond in the above compounds.Therein,1,3,7,9-tetramine-2,4,8,10-tetranitro-dibenzo-1,3 a,6,6 a-tetrazapentalene(B7)possesses the best thermal stability with high bond dissociation energy and wide band width.The enthalpy of formation,detonation velocity and pressure of tetrazapentalene compounds with 1,3 a,6,6 a-configuration are higher than those of compounds with 1,3 a,4,6 a-configuration due to their highly symmetrical structure.According to the theoretical calculation results,3,9-diamine-2,4,8,10-tetranitro-dipyridine-1,3 a,6,6 a-tetrazapentalene(B9)features the best detonation performance,low sensitivity and good thermal stability with the density,detonation velocity,detonation pressure and characteristic height(H)of 1.94 g·cm^(-3),8203 m·s^(-1),31.8 GPa and 90 cm,respectively.