To improve the low density and oxygen balance of the pure azido compounds, experimental research has been devoted to developing the modified azido compounds, such as azido nitramines, azido nitrate esters, and azido nitro compounds. Using the experimental methods to obtain a compound with suitable performance needs more resources than using theoretical tests, which makes the theoretical investigations meaningful. In this work, three azido compounds (I, II, and III) and their 27 modified derivatives were designed and studied using the density functional theory method. Results show that –NNO2, –NO2, and –ONO2 all can improve the thermodynamic and energetic properties and the increment increases with the increasing number of substituent groups. The contribution to the thermodynamic properties is –ONO2 > –NO2 > –NNO2 and that to the energetic properties is –NNO2 > –ONO2 > –NO2. The azido nitramines possess the best energetic properties and azido nitrate esters have the best thermodynamic properties. These substituents slightly decrease the thermal stability and the azido nitrate esters possess the lowest thermal stability. Systematical inspection of the substituent effect can direct experimental researchers to synthesize modified azido compounds purposefully and selectively.
