Molecular Design And Properties Of Serveral Fused Ring-based Energetic Materials

Fused ring-based energetic compounds usually possess high positive heat of formation and high detonation performance due to their large number of C-N,N-N,N=N bonds in the structure and thus,makes it to be one of the hottest topic in the field of energetic materials.In this thesis,three kinds of fused-ring based energetic compounds were designed based on[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine,4,8-dihydrodifurazano[3,4-b,e]pyrazine and pyrazolo[3,4-d][1,2,3]triazole.The physicochemical properties of the designed compounds were fully investigated at B3LYP/6-311G（d,p）level of density functional theory.The mainly conclusions were summarized as follows:（1）48 types of energetic compounds based on[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine were designed and investigated by density functional theory.The results show that all the designed compounds have high positive heats of formation and-N=N-bridge/-N₃ groups can improve heats of formation evidently.However,the-N=N-bridge and-C（NO₂）₃ energetic groups are the most effective combination in improving the detonation properties while the combination of-C=C-/-CN groups will enhance the thermal stability of the designed compound.Considering the detonation properties and thermal stabilities,7 compounds（A8,B8,C8,D7,D8,E8,F8）were screened as candidates for high energy density materials and their electronic structures were simulated.（2）48types of energetic compounds based on4,8-dihydrodifurazano[3,4-b,e]pyrazine were designed and investigated by density functional theory.The results show that the-C（NO₂）₃ group with high oxygen content can improve the oxygen balance.The tetrazole ring and the-N₃ substituent are the most effective combination to increase the heat of formation while the tetrazole ring and the-C（NO₂）₃ substituent are the most effective combination to increase the detonation properties of the designed compounds.Meanwhile,the bond dissociation energy analysis showed that the-CN group will improve the thermal stability of the designed compounds.Considering the detonation properties and thermal stabilities,6 compounds（A8,B8,C8,D8,E8,F8）were finally screened as candidates for high energy density materials,and their electronic structures are simulated.（3）48 types of energetic compounds based on pyrazolo[3,4-d][1,2,3]triazole were designed and investigated by density functional theory.The results show that the-N=N-bridge/-N₃ energetic group are the most effective group to improve the heats of formation of the designed compounds.The-N=N-bridge/-C（NO₂）₃ substituent are the most effective combination to improve the detonation properties while the-C-C-bridge/-N_3/-NHNH₂ groups are the most effective combinations to increase their their thermal stabilities.Take the detonation properties and thermal stabilities into consideration,10 compounds（C3,C5,C7,D3,D5,D7,E3,E7,F3,F7）were finally screened as candidates for high energy density materials and their electronic structures were investigated to give better understanding of their physicochemical properties.