【作者】 张建英；

【导师】 贡雪东；

【作者基本信息】 南京理工大学 ， 材料科学与工程， 2013， 博士

【摘要】 笼状化合物如六硝基六氮杂异伍兹烷CL-20和八硝基立方烷ONC因其卓越的性能吸引了大量关注,也引起了研究者探求新型笼状化合物的兴趣。本论文运用当代理论和计算化学方法,主要是量子化学和分子力学方法,对系列新型高氮笼状化合物的结构和性能,从气相分子到晶体,从几何构型到电子结构,从热力学性质到爆轰性能,进行了较为系统的计算和模拟。以寻求高能量密度化合物(HEDC)和高能量密度材料(HEDM),为实验合成提供参考。论文主要包括如下内容：1.通过设计CL-20衍生物、硝基立方烷与TATB杂合物、N12笼碳取代衍生物以及2,4,6,8,10,12,13-七氮杂四环[5.5.1.03,11.05,9]十三烷衍生物,采用密度泛函理论方法和分子力学方法对其结构进行优化,分析了气态和固态的各种结构信息,总结了结构参数与性能的关系。发现随着化合物中硝基数增多,前线轨道能级差和零点能逐渐减小,C-N02和C-C键变长,C-H键变短。固态笼状化合物属于分子型晶体,均具有较大的带隙,对态密度的分析表明N-NO2键可能是笼状化合物的热解引发键。2.进行了主要特征区的振动分析,对计算频率采用校正因子0.96进行校正,得到了各化合物的IR光谱,并对其主要特征振动带进行了归属分析。3.根据统计热力学原理和校正后的频率,用自编程序计算了化合物在200-800K温度范围的热力学函数,包括气体和晶体的标准恒压摩尔热容、标准摩尔熵和标准摩尔焓以及晶体的标准摩尔吉布斯自由能。所有化合物的热力学函数均随温度升高和硝基数的增加而增大。4.设计反应预测了系列笼状化合物的生成热,探讨了分子结构与生成热的内在联系,总结了不同取代基对生成热的影响规律。硝基对生成热的影响是排斥和超共轭协同作用的结果。当分子中取代基数目较少时,硝基的超共轭作用可以稳定分子结构；当取代基数目较多时,笼状骨架上拥挤的硝基基团之间的排斥作用占主导地位,此时化合物的总能量增加,对应的生成热也增加。5.设计反应计算了系列笼状化合物的张力能,研究了不同取代基对笼状化合物张力的影响。对于笼结构相同取代基不同的化合物,环上氮原子上连接吸电子基团会增大分子张力,而供电子基团则减小分子张力。6.采用Kamlet-Jacobs和Stine方法预测了笼状化合物的爆速、爆压和爆热等爆轰性能。结果表明前者的计算结果更接近实验值,而且氮杂环笼状化合物均具有较好的爆轰性能。密度、爆速和爆压值均随着硝基数目的增多而增大。7.计算了笼状化合物中各可能断裂键的键离解能。发现除C(N)-NO2键外,笼状骨架上的C-C或C-N键也有可能是热解引发键；所有键的键离解能均大于150kJ·mol-1,有的甚至接近200或300kJ·mol-1,因此所有笼状化合物均具有较高的热稳定性。更多还原

【Abstract】 Cage compounds such as hexanitrohexaazaisowurtzitane (CL-20) and octanitrocubane (ONC) have drawn a great deal of attention due to their excellent properties and attracted many research interests for new cage compounds.In this thesis, computational methods, especially density functional theory (DFT) of quantum chemistry and molecular mechanics (MM) have been employed to study a series of new designed cage compounds systematically from gas phase to crystalline. Contents include:1. A series of cage structures were designed including the derivatives of CL-20, N12, and2,4,6,8,10,12,13-heptaazatetracyclo [5.5.1.03,11.05,9] tridecane, and the hybrid derivatives of TATB and nitrocubane. Investigations on the structures and properties were carried out.The effects of substituents (nitro groups) on the total energy(Eo), zero point energy(ZPE), and bond length were studied. With the increasing number of nitro groups, E0and ZPE decrease, C-NO2and C-C bonds were lengthened, and C-H bond was shortened. A large gap usually found for nonmetallic compounds exists between the conduction (unoccupied crystal orbitals) and valence (occupied crystal orbitals) bands. This indicates that the compounds were stable. Analysis of density of state (DOS) and partial density of state (PDOS) showed that the N-NO2bond acts as an active center and may be the initial breaking bond in the thermal pyrolysis steps.2. The simulated IR spectra were obtained based on the scaled harmonic vibrational frequencies by0.96. The characteristic bands were analyzed and discussed.3. On the basis of the statistical thermodynamics principle, thermodynamic properties of the cage compounds in gas and solid state including standard molar heat capacity, standard molar entropy, and standard molar thermal enthalpy were evaluated. All of them increase with the increasing of temperature and the number of nitro groups.4. The heats of formation (HOFs) of the cage compounds were evaluated via designed reactions and the relationships between the structure and HOFs were discussed. The effect of nitro groups on the HOF is the results of both repulsion and superconjugation from nitro groups. When the number of nitro groups is small, the superconjugation effect of nitro groups can stabilize the cage skeleton. However, when there are more than three nitro groups on the skeleton, the repulsion energy strengthens and leads to the increase in the total energy and HOF.5. Strain energies (SEs) were estimated via the designed isodesmic reactions and the effects of substituents on the cage were discussed. Results indicate that the compounds linked with the electron-donating group have larger SEs than that with electron-withdrawing group.6. The detonation parameters were calculated using Kamlet-Jacobs equations and Stine equation. Results indicate that the data obtained from the former are more reliable and the cage compounds have good detonation performance. It is noticed that density p, detonation velocity D, and detonation pressure P increase with the increasing number of nitro groups.7. Bond dissociation energies (BDEs) were calculated. Results indicate that beside the N-NO2bond C-C and C-N bonds in the cage may also be the trigger bonds due to the cage strain. BDEs of all cage compounds are larger than150kJ·mol-1, with most of them being larger than200or even300kJ·mol-1, indicating that all the compounds designed in this thesis have good thermal stabilities.更多还原