A Thermally Resilient High-Performing Metal-Free Primary Explosive

Abstract

Lead Azide (LA), though discovered centuries ago, remains the most widely used primary explosive due to its reliable initiation performance. However, its toxicity and environmental persistence present serious health and ecological concerns. This has driven the pursuit of leadfree, environmentally benign, thermally stable, and intrinsically safe alternatives with high initiating capability. Herein, we report the design and synthesis of a novel organic metal free 3) with a tricyclic fused-ring scaffold, prepared via a simple route from commercially available reagents in high yield. Its planar structure having high nitrogen content and various noncovalent interactions impart high density, controlled sensitivity, and excellent priming ability, while being free from metals and perchlorates. Compound 3 exhibits exceptional thermal stability with a decomposition temperature of 216 ºC, the highest reported for any metal-free primary explosive. It also shows excellent environmental resistance, low cost, and scalability. Notably, in detonation test, compound 3 initiates 500 mg of RDX with a minimum primary charge (MPC) of 10 mg, equals to LA (10 mg), and outperforming ICM-103 (60 mg), and DDNP (70 mg). These features position compound 3 as a leading candidate for next-generation safer, thermally stable metal free primary explosives and a potential replacement of benchmark explosives such as DDNP and Lead Azide and all the recent reports.