Difluorophosphoryl Nitrene F₂P(O)N: Matrix Isolation and Unexpected Rearrangement to F₂PNO

Abstract

Triplet difluorophosphoryl nitrene F(2)P(O)N (X(3)A'') was generated on ArF excimer laser irradiation (lambda=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 (lambda>420 nm) at 16 K F(2)P(O)N reacts with molecular nitrogen and some of the azide is regenerated. UV irradiation (lambda=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 P-N bond of 1.922 A [B3LYP/6-311+G(3df)] and low bond-dissociation energy of 76.3 kJ mol(-1) (CBS-QB3) for F(2)PNO.

Elusive Fluoro Sulfinyl Nitrite, FS(O)NO, Produced by Photolysis of Matrix‐isolated FS(O)2N

“…The EPR spectrum is attributed to fluoro sulfonyl nitrene, FS(O) 2 N, and confirms the triplet nature of its ground state. The observed ZFS compares well with that of the closely related fluoro phosphoryl nitrene, F 2 P(O)N 14. The EPR spectrum of F 2 P(O)N14 is also shown in Figure 1 for comparison.…”

“…The observed ZFS compares well with that of the closely related fluoro phosphoryl nitrene, F 2 P(O)N 14. The EPR spectrum of F 2 P(O)N14 is also shown in Figure 1 for comparison. In contrast, the previously measured benzene sulfonyl nitrenes, p ‐fluorobenzenesulfonyl nitrene (| D / hc | = 1.555 cm –1 , | E / hc | < 0.005 cm –1 , single crystal)21 and p ‐methylbenzenesulfonyl nitrene (| D / hc | = 1.471 cm –1 , | E / hc | = 0 cm –1 , EPA glass)20 revealed significantly smaller D values.…”

“… The |Δ m s | = 1 EPR transitions of FS(O) 2 N obtained after 193 nm irradiation of argon matrix isolated FS(O) 2 N 3 at 5 K, and simulated spectrum ( g = 2.003, v = 9.60635 GHz, | D / hc | = 1.620 cm –1 , and | E / hc | = 0.0055 cm –1 ). For comparison EPR spectra of F 2 P(O)N (| D / hc | = 1.60 cm –1 , and | E / hc | = 0.0054 cm –1 )14 and FC(O)N (| D / hc | = 1.623 cm –1 , and | E / hc | = 0.031 cm –1 )24 in solid argon are shown. …”

“…On the other hand, more reactive intermediates featuring sterically inconspicuous ligands can be explored by matrix‐isolation in an inert cryogenic host. Our approach to the synthesis of elusive sulfinyl nitrites was thus stimulated by an unusual Curtius‐type photo‐rearrangement of difluoro phosphoryl nitrene, F 2 P(O)N, which yields the nitroso phosphonous difluoride [Equation (2)] 14…”

Carbenes and Nitrenes: Recent Developments in Fundamental Chemistry

“…(9)]. [42] FPO and F 3 PO were also formed, but the radical F 2 PO was not observed. Calculations indicated ab arrier of about 40 kcal mol À1 for the unobserved Curtius-type rearrangement to FP(O)=NÀF, but arearrangement to F 2 PÀN=Owas observed photochemically.…”