Molecular Design Of Cycloalkanes And Pentaprimane Derivatives For High Energy Density Compounds

Nowadays, the main purpose of research about new energetic materials is to find compounds with better detonation performance and lower sensitivity. Cyclic compounds and cage compounds have attracted great attention in recent years due to their large strain force, large crystal density, and high energy, which make them superior explosives over the conventional ones. In the present work, density functional theory(DFT) has been employed to predict the detonation performance and the thermal stability of cycloalkanes derivatives and pentaprismane derivatives. By comparing their detonation performance and thermal stability with those of traditional explosives, the potential candidates of high energy density compounds(HEDCs) were selected. The study can be divided into two parts as follows:1. Cycloalkanes derivativesA series of novel cycloalkanes derivatives Cm(N–NO2)m(m=3-8) were theoretically designed by substitution of the hydrogen atoms with N-NO2 group. The density functional theory(DFT) has been employed to evaluate the heats of formation, crystal structure, detonation velocity, detonation pressure, and thermal stability of the desinged cycloalkanes derivatives. The isodesmic reaction was employed to predict the heats of formation(HOF). We found that the designed compounds have large positive heats of formations, which are proportional to the amount of N–NO2 groups. The crystal packing of these molecules was predicted by Dreiding force field. On the basis of the predicted crystal densities, the Kamlet-Jacobs equations were used to estimate their detonation performance. The thermal stabilities of these compounds were evaluated by calculating the bond dissociation energy and the impact sensitivity. All the bond dissociation energy values of the designed compounds are over the threshold of 80 kJ mol-1 for HEDCs. Considering both detonation performance and thermal stability, all the designed compounds except cyclohexane derivatives may be promising candidates for energetic materials.2. Pentaprismane derivativesA series of pentaprismane derivatives were theoretically designed by substitution of the hydrogen atoms with –NO2, –NO, –CN, –N3, –NH2, –NHNO2, and –ONO2 groups for novel and stable high-energy-density-compounds(HEDCs). The DFT-B3LYP/6-31G** method was employed to evaluate the heats of formation(HOF), crystal structure, detonation performance, and thermal stability. The isodesmic reaction was employed to predict the HOF. The results indicated that different substituent groups exert diverse influences on the HOF, and the –N3 and –CN groups greatly increase the HOF. The calculated detonation velocities and detonation pressures indicate that the –NO2, and –NHNO2 derivatives exhibit remarkable detonation performance compared with other derivatives. An analysis of the bond dissociation energies(BDE) reveals that the designed compounds meet the qualification of HEDCs. Considering the detonation performance and thermal stability, the designed compounds, especially –NO2 and –NHNO2 derivatives, are recommended as promising candidates of HEDCs...