Effect of multiple oxadiazole rings with nitro and nitramino functionalities on energetic properties: computational analysis of the structure–property relationship

Abstract

The oxadiazole ring is an essential nitrogen-containing heterocycle and a valuable building block that is used in developing numerous functionalized energetic compounds. To understand the effect of multiple oxadiazole rings on energetic performance and sensitivities, we investigated oxadiazole rings connected with C–C and NN bond-possessing –NO₂ and –NHNO₂ groups. The results show that skeletal energy can be increased by the incorporation of oxadiazoles. All the studied compounds have positive heat of formation (> 410 kJ mol⁻¹) that are larger than those of 3,4-dinitrofurazan (O1, 219 kJ mol⁻¹) and N,N′-1,2,5-oxadiazole-3,4-diyldinitramide (O7, 254 kJ mol⁻¹). Even though various molecular combinations offer unlimited structural diversity options and energetic properties, the linear addition of oxadiazole rings efficiently reduces sensitivity but with decreased oxygen balance and detonation performance. To achieve a balance between sensitivity and detonation performance, incorporating oxadiazole rings in the molecular framework may be considered as an efficient scaffold and can significantly assist in the progress of developing new energetic compounds.