A bistriazolotetrazine zwitterionic architecture: mitigating the pervasive energy-stability antagonism in bistable energetic matrices

Abstract

The pursuit of high-energy density materials has been long stymied by the fundamental trade-off between energy output and mechanical sensitivity, a challenge that has persisted for centuries. Herein, we present a dizwitterionic design strategy that enables the synthesis of TYX-2, a planar bistriazolotetrazine-based material exhibiting an unprecedented synergy of high energy and low sensitivity. The molecular model of TYX-2 was elucidated through single-crystal X-ray diffraction analysis of its dimethylamine adduct (TYX-2²⁻·2(Me₂NH₂⁺)), which was successfully obtained via crystallization from an aqueous dimethylamine solution. With a measured density of 2.04 g cm⁻³ and detonation velocity of 9.915 km s⁻¹, neutral TYX-2 attains energetic performance comparable to that of the benchmark caged explosive CL-20 while demonstrating radically improved safety characteristics. Its mechanical sensitivity, measured at 180 N (friction) and 22.5 J (impact), represents a 3.7-fold and 5.6-fold reduction relative to CL-20, respectively. When integrated into PNMMO-based solid propellants as a replacement for conventional explosives (such as AP, RDX, HMX and CL-20), neutral TYX-2 significantly enhances specific impulse while mitigating safety risks inherent to current formulations. This work achieves decoupling of energy and sensitivity in energetic materials, offering transformative potential for both military and civilian propulsion technologies.