Polynitro-Functionalized Dipyrazolo-1,3,5-triazinanes: Energetic Polycyclization toward High Density and Excellent Molecular Stability

A new fused N-heterocyclic framework, dipyrazolo1,3,5-triazinane, was synthesized and the physiochemical properties of its derivatives were investigated to evaluate the integrated energetic performance. In contrast to 1,3,5-trinitro1,3,5-triazinane (RDX) featuring a distorted chair confirmation, polynitro-functionalized dipyrazolo-1,3,5-triazinanes have nearly planar backbones, thereby enhancing the density and thermal stability. Among these new energetic tricyclic compounds, 5a and 12 show favorable crystal densities of 1.937 g cm(-3) and 1.990 g cm(-3) at 150 K, respectively, which rank highest in triazinane-based energetic compounds. Additionally, this synthetic approach was carried out to form seven-membered and eight-membered rings, giving rise to tetranitro dipyrazolo-1,3,5-triazepane (5b) and tetranitro dipyrazolo1,3,5-triazocane (5c), respectively.