Theoretical studies of a series of azaoxaisowurtzitane cage compounds with high explosive performance and low sensitivity

Ten novel azaoxaisowurtzitane cage compounds were designed by introducing the oxygen atoms into the azaisowurtzitane cage to replace the N-NO₂ groups. Then, their heats of formation (HOFs), energetic properties, strain energies, thermal stability, and impact sensitivity were studied by using density functional theory. The introduction of the oxygen atom in the cage is not helpful for increasing the HOFs, densities, and energetic properties of parent compound CL-20. But all the title compounds exhibit remarkable detonation properties superior to or very close to HMX. All the azaoxaisowurtzitane cage compounds exhibit higher thermal stability than parent compound CL-20. The introduction of the oxygen atom in the cage effectively decreases the sensitivity of parent compound CL-20. Considered the detonation performance, thermal stability, and impact sensitivity, six compounds can be regarded as the potential candidates of HEDC because these azaoxaisowurtzitane cage compounds not only exhibit excellent energetic properties comparable with CL-20, but also have higher thermal stability and lower sensitivity than CL-20.