2,6-双(二硝基亚甲基)-1,3,4,5,7,8-六硝基十二氢二咪唑4,5-b:4',5'-e]吡嗪分子结构及性能的理论计算

设计了一种新型高能量密度化合物2,6-双(二硝基亚甲基)-1,3,4,5,7,8-六硝基十二氢二咪唑[4,5-b:4',5'-e]吡嗪(DNNIP)。首先在B3PW91/6-31G++(d,p)水平下对目标分子进行优化,通过键长和键级的比较分析,判断母环的五元环侧链处N—NO2键为分解引发键,其键解离能是96.40 k J/mol;然后,基于静电势改进的蒙特卡洛法推测出该化合物的理论密度为2.07 g/cm3,采用等键反应计算出生成热为1 907.33 k J/mol,并进一步计算出DNNIP的爆速为10.35 km/s,爆压为51.47 GPa,爆轰性能明显优于现有常见含能材料。DNNIP的撞击感度为12 cm,与CL-20接近;能级差为0.158 78 a.u.(4.32 e V),光热稳定性较高,并且通过态密度分析认为硝基是分子中相对敏感位置。

Computational Study on the Chemical Structure and Explosive Properties of 2,6-Bis(dinitromethylidene)-1,3,4,5,7,8-hexanitrododecahydrodiimidazo [4,5-b:4',5'-e]pyrazine

A novel high energetic density compound, 2,6-bis(dinitromethylidene)-1,3,4,5,7,8-hexanitrodo-decahydrodiimidazo[4,5-b:4',5'-e]pyrazine(DNNIP),was designed.The molecular structure was firstly optimized under B3PW91/6-31G++(d,p)level with Gaussian Software.After bond length and bond order analysis, it was found that decomposition would be initiated from the rupture of N—NO2 bond on imidazole ring with a bond dissociation enthalpy (BDE)of 96.4 kJ/mol.Its density was evaluated to be 2.07 g/cm3based on improved Monte Carlo method by electrostatic potential distribution, and formation heat was calculated as about 1907.33 kJ/mol from isodesmic reaction.From two parameters above,detonation velocity and pressure were calculated to be 10.35 km/s and 51.47 GPa,respectively,which were obviously better than those of common energetic materials.The evaluated impacting sensitivity of target compound having a significance in treatment is about 12 cm,which is close to that of CL-20.Energy gap between HOMO and LUMO [△E(LUMO-HOMO)]is 0.15878 a.u.(4.32 eV)indicating the stable molecular structure under general conditions.—NO2is supposed to be located at the sensitive sites within molecular structure according to the density of state(DOS) analysis.