Methanesulfonyl Azide: Molecular Structure and Photolysis in Solid Noble Gas Matrices

The parent sulfonyl azide CH3SO2N3 has been characterized in a neat
form by IR (gas, matrix-isolation)
and Raman (solid) spectroscopy, and its structure has been established
by X-ray crystallography. In both gas phase and solid state, the azide
exhibits single conformation with the azido ligand being synperiplanar
to one of the two SO groups. In the crystal molecules of CH3SO2N3 are interconnected through three-dimensional
O···H–C–H···O hydrogen
bonds. Upon an ArF laser (193 nm) photolysis, the azide in solid noble
gas matrices splits off N2 and yields the sulfonyl nitrene
CH3SO2N in the triplet ground state. Subsequent
photolysis with UV light (266 nm) causes the transformation from the
nitrene to the pseudo-Curtius rearrangement product CH3NSO2. The identification of the photolysis intermediates
by matrix-isolation IR spectroscopy is supported by quantum chemical
calculations with DFT methods.