Design and Facile Synthesis of Novel Asymmetric Bis(1,2,4-oxadiazoles) Featuring Methyl and Dinitromethyl Groups

This study designs and synthesizes a novel asymmetric bis-heterocyclic compound: 3-(5-methyl-1,2,4-oxadiazol-3-yl)-5-(dinitromethyl)-1,2,4-oxadiazole and its ionic salts. The molecule is based on a rigid 3,3′-bis(1,2,4-oxadiazole) skeleton, with its two 5-positions substituted by complementary electron-donating methyl and strong electron-withdrawing dinitromethyl energetic groups, thereby constructing a unique “push–pull” electronic system. Among them, compounds 5–7 exhibit high thermal stability (177–271 °C) and favorable detonation performance (7019–7769 m s–1; 20.2–23.8 GPa), coupled with low mechanical sensitivity [friction sensitivity (FS) ≥ 320 N; impact sensitivity (IS) ≥ 32 J]. Notably, compound 6 demonstrates superior overall performance (Tdec = 208 °C, D = 7769 m s–1, P = 23.81 GPa, FS > 360 N, IS > 40 J). The unique structural design provides a valuable candidate platform for the future development of novel energetic materials or functional molecules. This work offers an effective strategy for the synthesis of asymmetric bis(1,2,4-oxadiazole) derivatives.