The molecular structures, infrared spectra, heats of formation （HOFs）, detonation proper- ties, chemical and thermal stabilities of several tetrahydro-[1,4]dioxino[2,3-d：5,6-d＇] diimida- zole derivatives with diff...The molecular structures, infrared spectra, heats of formation （HOFs）, detonation proper- ties, chemical and thermal stabilities of several tetrahydro-[1,4]dioxino[2,3-d：5,6-d＇] diimida- zole derivatives with different substituents were studied using DFT-B3LYP method. The properties of the compounds with different groups such as -NO2, -NH2, -N3, and -ONO2 were further compared. The -NO2 and -ONO2 groups are effective substituents for in- creasing the densities of the compounds, while the substitution of -N3 group can produce the largest HOF. The compound with -NO2 group has the same detonation properties as 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, while the compound with -ONO2 group has lower detonation properties than those of hexahydro-1,3,5-trinitro-l,3,5-triazine. The na- ture bond orbital analysis reveals that the relatively weak bonds in the molecules are the bonds between substituent groups and the molecular skeletons as well as C-O bonds in the dioxin rings. The electron withdrawing groups （-NO2, -N3, and -ONO2） have induc- rive effects on the linkages between the groups and molecular skeletons. In addition, re- searches show that the electronegativities of the groups are related with the stabilities of the compounds. Considering detonation performance and thermal stability, the 1,5-dinitro-2,6- bis（trinitromethyl）-3a,4a,7a,8a-tetrahydro-[1,4]dioxino-[2,3-d：5,6-d＇] diimidazole satisfies the requirements of high energy density materials.展开更多
文摘The molecular structures, infrared spectra, heats of formation （HOFs）, detonation proper- ties, chemical and thermal stabilities of several tetrahydro-[1,4]dioxino[2,3-d：5,6-d＇] diimida- zole derivatives with different substituents were studied using DFT-B3LYP method. The properties of the compounds with different groups such as -NO2, -NH2, -N3, and -ONO2 were further compared. The -NO2 and -ONO2 groups are effective substituents for in- creasing the densities of the compounds, while the substitution of -N3 group can produce the largest HOF. The compound with -NO2 group has the same detonation properties as 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, while the compound with -ONO2 group has lower detonation properties than those of hexahydro-1,3,5-trinitro-l,3,5-triazine. The na- ture bond orbital analysis reveals that the relatively weak bonds in the molecules are the bonds between substituent groups and the molecular skeletons as well as C-O bonds in the dioxin rings. The electron withdrawing groups （-NO2, -N3, and -ONO2） have induc- rive effects on the linkages between the groups and molecular skeletons. In addition, re- searches show that the electronegativities of the groups are related with the stabilities of the compounds. Considering detonation performance and thermal stability, the 1,5-dinitro-2,6- bis（trinitromethyl）-3a,4a,7a,8a-tetrahydro-[1,4]dioxino-[2,3-d：5,6-d＇] diimidazole satisfies the requirements of high energy density materials.
