Ab initio and density functional theory study of the mechanism of synthesis of the N5+ cation

The synthesis pathway of the N5+ cation from N2F+ and HN3 has been investigated by ab initio and density functional theory (DFT) methods. Reactants, products, transition state (TS), and related ion–molecule complexes have been fully optimized up to the B3LYP/6-311++G∗∗ level of theory. Relative energies are further calculated using MP4 and CCSD(T) methods. The optimized TS has a four-membered ring structure with C1 symmetry. At the CCSD(T)/6-311++G∗∗//B3LYP/6-311++G∗∗ level of theory, the energetic barrier height is predicted to be 12.5 kcal/mol, and the whole synthesis reaction is exothermic by 79.4 kcal/mol.