Structure-activity relationship analysis and molecular structure construction of fused tricyclic energetic molecules containing flexible ring

A simple, mild and efficient method was proposed to construct fused tricyclic skeletons based on Mannich reaction. This work not only develops a new method to construct the tricyclic skeletons effectively, but also provides a new insight into the fused tricyclic skeletons containing flexible ring, which will greatly contribute to the research and development of the tricyclic energetic compounds. The relationship of structure-activity was studied by weak interactions calculation, single crystal structures analysis, electrostatic potentials calculation. The experimental and theoretical investigations suggest that the fused tricyclic skeleton containing flexible ring possesses better thermal stability and can be derivatized more easily compared with the similar aromatic fused tricyclic skeleton. Besides, the energetic derivates based on the fused tricyclic skeleton containing flexible ring possess good comprehensive properties: 2 (D ​= ​7726 ​m ​s⁻¹, p ​= ​22.7 ​GPa) and 4 (D ​= ​8151 ​m ​s⁻¹, p ​= ​26.3 ​GPa). All these results suggest that the fused tricyclic skeleton containing flexible ring is an ideal candidate to construct energetic compounds.