An isomeric study of N5+, N5, and N5−: a Gaussian-3 investigation

An isomeric study for N5, N5+, and N5− has been carried out using the Gaussian-3 (G3) method. At the MP2(FU)/6-31G(d) level, six N5, five N5+, and four N5− isomers are identified. Of these 15 species, 12 of them have not been reported previously. The most stable N5 isomer is a weak N2⋯N3 complex with C2v symmetry, while the most stable N5− isomer is also a weak N2⋯N3− complex with the same symmetry. The most stable species for N5+ has an open-chain structure with C2v symmetry, which has been synthesized and characterized spectroscopically. Natural bond orbital (NBO) analysis suggests that the stability of this cation is enhanced by hyperconjugation.