Prospects of fused polycyclic nitroazines as thermally insensitive energetic materials

Novel chemical structures originally proposed as new thermally insensitive explosives were certain zero- to low-hydrogen-content, polynitro, polycyclic heteroaromatic compounds based on nitrogenous heterocycles. The proposed compounds were expected to be high-density materials with explosive yields in the RDX-to-HMX range, but with high melting points, good shock sensitivity, and significantly better thermal stabilities. Originally proposed candidates incorporated 3,6-dinitropyridazine as a structural feature. Based on the experimental results and on conclusions drawn from a careful consideration of principles of reactivity of this general class of compound—polynitroazines—important lessons were learned that are applicable to future choices of practical new energetic materials targets. A conclusion is drawn that the intractability of certain polynitroazine target compounds unavoidably arises from an extraordinary susceptibility to ubiquitous environmental contaminants such as water. The recognition of this structure–property relationship should have an important payoff toward future choices of target compounds.