Selective Preparation of Phosphorus Mononitride (P≡N) from Phosphinoazide and Reversible Oxidation to Phosphinonitrene

Abstract

AbstractThe interstellar candidate phosphorus mononitride PN, a metastable species, was generated through high‐vacuum flash pyrolysis of (o‐phenyldioxyl)phosphinoazide in cryogenic matrices. Although the PN stretching band was not directly detected because of its low infrared intensity and possible overlaps with other strong bands, o‐benzoquinone, carbon monoxide, and cyclopentadienone as additional fragmentation products were clearly identified. Moreover, an elusive o‐benzoquinone‐PN complex formed when (o‐phenyldioxyl)phosphinoazide was exposed to UV irradiation at λ=254 nm. Its recombination to (o‐phenyldioxyl)‐λ5‐phosphinonitrile was observed upon irradiation with the light at λ=523 nm, which demonstrates for the first time the reactivity of PN towards an organic molecule. Energy profile computations at the B3LYP/def2‐TZVP density functional theory level reveal a concerted mechanism. To provide further evidence, UV/Vis spectra of the precursor and the irradiation products were recorded and agree well with time‐dependent DFT computations.