Confinement of the pentanitrogen cation inside carbon nanotubes

In recent years, the field of polynitrogen chemistry has seen a sparking activity, with new outstanding theoretical and experimental results. Polynitrogen clusters are excellent candidates for high-energy density materials, but their intrinsic instability poses great challenges for the synthesis and the subsequent storage. In this work, we explore by means of quantum chemical calculations the confinement of the pentanitrogen cation, N +5, inside carbon nanotubes of different diameters. The interaction of the two fragments is such that a charge transfer from the nanotube to the nitrogen cation occurs and leads to the subsequent decomposition of N +5, thus resulting in an overall unstable system. Nonetheless, preliminary results on the confinement of the neutral N 8 chain (as the product of an N +5 + N −3 addition) are presented, where it is shown that the encapsulation decreases the overall energy of the complex system. Two stable N 8 isomers are discussed and a first investigation on possible decomposition pathways is carried out.