Flash vacuum pyrolysis of methoxysulfinyl azide: Stepwise decomposition via methoxysulfinyl nitrene

Abstract Methoxysulfinyl azide, CH 3 OS(O)N 3 , which is unstable at room temperature, has been synthesized and characterized as neat substance for the first time. Its decomposition in the gas phase has been studied by combining flash vacuum pyrolysis (FVP) and matrix isolation IR spectroscopy. The novel dipolar nitrene intermediate, CH 3 OS(O)N, in the singlet ground state with two distinct conformations ( syn and anti ) has been identified among the FVP products at 600 K. At higher FVP temperature (800 K) the nitrene undergoes further fragmentation into HNSO and H 2 CO. The stepwise decomposition mechanism of CH 3 OS(O)N 3 is supported by the quantum chemical calculations.