Gaseous nitryl azide N4O2: A joint theoretical and experimental study

Abstract Gaseous nitryl azide N 4 O 2 is generated by the heterogeneous reaction of gaseous ClNO 2 with freshly prepared AgN 3 at −50 °C. The geometric and electronic structure of the molecule in the gas phase has been characterized by in situ photoelectron spectroscopy (PES) and quantum chemical calculations. The experimental first vertical ionization energy of N 4 O 2 is 11.39 eV, corresponding to the ionization of an electron on the highest occupied molecular orbital (HOMO) {4a″(π nb(N4–N5–N6) )} −1 . An apparent vibrational spacing of 1600 ± 60 cm −1 (ν as O1N2O3) on the second band at 12.52 eV (π nb(O1–N2–O3) ) further confirms the preference of energetically stable chain structure in the gas phase. To complement the experimental results, the potential-energy surface of this structurally novel transient molecule is discussed. Both calculations and spectroscopic results suggest that the molecule adopts a trans -planar chain structure, and a five-membered ring decomposition pathway is more favorable.