Thermally persistent fluorosulfonyl nitrene and unexpected formation of the fluorosulfonyl radical.

Thermally persistent triplet sulfonyl nitrene, FSO(2)N, was produced in the gas phase in high yields (up to 66%) by flash vacuum pyrolysis of FSO(2)N(3). Surprisingly, no rearrangement of FSO(2)N was observed, but the long-sought radical FSO(2) (22%) and traces of SO(2) (3%) were identified by IR ((15)N, (18)O, (34)S) spectroscopy. The photoinduced Curtius rearrangement of the nitrene to FNSO(2) was observed in solid noble gas matrices, and reactions of the nitrene with O(2), NO, and CO were studied.