From mono-rings to bridged bi-rings to caged bi-rings: a promising design strategy for all-nitrogen high-energy-density materials N10 and N12†
Abstract
The research of all-nitrogen compounds has always been a hot topic in nitrogen chemistry and high-energy-density material communities. This research mainly focuses on acyclic and monocyclic all-nitrogen derivatives, while the bicyclic systems of all-nitrogen materials have been rarely investigated. In this study, four bicyclic all-nitrogen derivatives, viz bridged N10 and N12, and caged N10 and N12, are presented. Caged-N10 and caged-N12 exhibit much higher density (d: 1.84 and 1.89 g cm−3) and higher heats of formation (Hf: 15.19 and 16.41 kJ g−1) than bridged-N10 and bridged-N12 (d: 1.71 and 1.72 g cm−3; Hf: 7.64 and 10.24 kJ g−1), respectively. All these materials exhibit remarkable detonation performance (D: 9.87–12.29 km s−1; P: 39.41–72.26 GPa) and excellent specific impulses (Isp: 325.00–434.60 s), which is superior to the state-of-art CL-20 (D: 9.40 km s−1; P: 44.60 GPa; Isp: 272.61 s), endowing these materials with great potential as promising explosives and propellants. In addition, molecular electrostatic potentials, frontier molecular orbitals, and noncovalent interactions were studied to investigate their structure–property relationship.