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

- The synthesis and properties of methoxysulfinyl azide are described.
- The flash vacuum pyrolysis of methoxysulfinyl azide is reported.
- The key intermediate methoxysulfinyl nitrene in two conformations is observed.
- A stepwise decomposition mechanism of the azide is supported by quantum chemical calculations.

Methoxysulfinyl azide, CH3OS(O)N3, 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, CH3OS(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 H2CO. The stepwise decomposition mechanism of CH3OS(O)N3 is supported by the quantum chemical calculations.

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