Amphoteric Ionization and Cocrystallization Synergistically Applied to Two Melamine-Based N-Oxides: Achieving Regulation for the Comprehensive Performance of Energetic Materials

The development of new energetic materials with good comprehensive performance often occurs at a glacial pace because of the contradiction between energy and safety. Herein, the synergy between amphoteric ionization and cocrystallization is found to be an effective strategy for regulating the comprehensive performance of energetic materials. The strategy was successfully applied to two amphoteric melamine-based N-oxides, namely 2,4,6-triamino-1,3,5-triazine 1,3-dioxide (TTDO) and 4,6-diamino-3-hydroxy-2-oxo-2,3-dihydro-1,3,5-triazine 1-oxide (DDTO). Pairing protonated and deprotonated TTDO and DDTO with different anions and cations allowed us to obtain many new energetic compounds with various properties. Among them, the perchlorate salts TTDO+PCL– and DDTO+PCL– composed of the oxidant component ClO4– and oxidant-deficient TTDO or DDTO exhibit satisfying detonation performance but poor safety as for many high-energetic compounds. Hence, a cocrystallization strategy of cocrystallizing energetic compounds with positive and negative oxygen balances (OBs) was successfully used for DDTO+PCL– and DDTO, resulting in the formation of the energetic cocrystal (DDTO+PCL–)·DDTO with outstanding comprehensive performance. (DDTO+PCL–)·DDTO overcomes the general detonation performance tradeoff disadvantage of cocrystals, and its safety, especially the thermal safety, is superior to that of DDTO+PCL–. The crystal structure cohesion and the reason for the increasing stability of the cocrystal (DDTO+PCL–)·DDTO were analyzed. Our study provides an inspiration for regulating the comprehensive performance of energetic materials.