Difluorophosphoryl Nitrene F 2 P(O)N: Matrix Isolation and Unexpected Rearrangement to F 2 PNO

Triplet difluorophosphoryl nitrene F 2 P(O)N (X 3 A′′) was generated on ArF excimer laser irradiation ( λ =193 nm) of F 2 P(O)N 3 in solid argon matrix at 16 K, and characterized by its matrix IR, UV/Vis, and EPR spectra, in combination with DFT and CBS‐QB3 calculations. On visible light irradiation (λ>420 nm) at 16 K F 2 P(O)N reacts with molecular nitrogen and some of the azide is regenerated. UV irradiation ( λ =255 nm) of F 2 P(O)N (X 3 A′′) induced a Curtius‐type rearrangement, but instead of a 1,3‐fluorine shift, nitrogen migration to give F 2 PON is proposed to be the first step of the photoisomerization of F 2 P(O)N into F 2 PNO (difluoronitrosophosphine). Formation of novel F 2 PNO was confirmed with 15 N‐ and 18 O‐enriched isotopomers by IR spectroscopy and DFT calculations. Theoretical calculations predict a rather long PN bond of 1.922 Å [B3LYP/6‐311+G(3df)] and low bond‐dissociation energy of 76.3 kJ mol −1 (CBS‐QB3) for F 2 PNO.