Oxidation of a phosphinidene oxide: formation of a dioxaphosphirane oxide with oxygen scrambling

Abstract

The oxidation of a prototypical phosphinidene oxide FPO has been studied in O₂-doped Ar and N₂ matrices at 10 K. Upon 266 nm laser irradiation, FPO combines with O₂ and yields the cyclic peroxide, dioxaphosphirane oxide FP(O)(O₂). Unexpected oxygen scrambling occurs during the oxygenation as evidenced by the observation of a 1 : 2 mixture of FP(¹⁶O)(¹⁸O¹⁸O) and FP(¹⁸O)(¹⁶O¹⁸O) when ¹⁸O₂ was used. Quantum chemical calculations suggest that the scrambling happens via the intermediacy of the low-lying triplet FPO₃ by passing minimum energy crossing points (MECPs). In addition, inorganic dioxophosphorane FP(O)₂ has been also identified among the oxidation products of FPO.