Ionized aminohydroxycarbene and its isomers: relative stability and unimolecular reactivity

Ab initio molecular orbital calculations at the G2(MP2,SVP) level have been employed to explore a large part of the [H3,C,N,O]+ potential energy surface. Ionized aminohydroxycarbene, NH2–C+–OH, 1, is found to correspond to the global minimum of the surface. The other stable species are also unconventional structures: ion–neutral complexes OC⋯NH3+, 2, and CO⋯NH3+, 2′, and the distonic ion, H3N+CO, 3. The more classical structures [HCONH2]+, 4, and [HC(OH)NH]+, 5 are higher in energy. The heat of formation of the five radical cations have been determined using their atomization energies. The various isomerization reactions connecting 1–5 as well as their dissociation by H or CO losses have been theoretically investigated and compared with the available experimental data.