密度泛函理论研究咪唑类硝基衍生物的性能

Studies on Properties for Nitro Derivatives of Imidazole by Density Functional Theory

应用密度泛函理论在B3P86/6-311G**水平下较系统地研究13个咪唑类硝基衍生物的C—NO2、N—NO2键离解能(BDEs)、撞击感度(h50)、标准生成热(HOFs)、爆速、爆压等.根据键离解能确定化合物的最弱键,发现最弱键的BDE与电子能量E的比值BDEs/E与h50存在线性关系,计算出的h50值表明C取代硝基咪唑化合物比N取代硝基咪唑化合物稳定,随硝基数目的增加,化合物对撞击变得敏感.通过设计等键反应,计算得到13个咪唑类硝基衍生物的气相标准生成热.采用Monte Carlo方法计算其密度,运用Kamlet-Jacobs方程预测标题化合物的爆轰参数(爆速和爆压).基于安全性和爆轰性能筛选出5个既高能又钝感的含能化合物候选物.

The C-NO2 or N-NO2 bond dissociation energies （BDEs）,impact sensitivity （hso）,heats of formation（HOFs） and detonation performance of nitroimidazole derivatives were investigated by using density functional theory （DFT） at B3P86/6-311G ＊ ＊level.The trigger linkage in process of detonation has been identified on basis of bond dissociation energies.There is a linear relationship between h50 and the ratio of the weakest bond BDE to the total energy E.The results show that C-nitro substituted imdazole is more stable than the corresponding N-substituted one and compound is more sensitive towards impact stimuli with the increasing number of nitro groups on imidazole ring.Heats of formation for 13 nitroimidazole compounds at 298 K were calculated using isodesmic work reactions.The average molar volume and theoretical density were computed using the Monte-Carlo method based on 0.001 e bohr-3 density space.Furthermore,the detonation velocity （D） and pressure （P） of the derivatives were estimated by the Kamlet-Jacbos equation.Considering both impact sensitivity and detonation performance,5 compounds are good candidates of insensitive high energetic materials.