Hydrogen‐Bonded Complex of the Parent Phosphinidene

Abstract

The diatomic molecule PH is very reactive, and it serves as the parent compound for phosphinidenes featuring a monovalent phosphorus atom. Herein, we report the characterization and reactivity of a rare hydrogen‐bonded complex of PH. Specifically, the molecular complex between PH and HCl has been generated by photolysis of chlorophosphine (H2PCl) at 254 nm in a solid Ar‐matrix at 10 K. The IR spectrum of the complex HP•••HCl and quantum chemical calculations at the UCCSD(T)‐F12a/haTZ level consistently prove that the phosphorus atom acts as a hydrogen bond acceptor with a binding energy (D0) of –0.6 kcal mol−1. In line with the observed absorption at 341 nm for the binary complex, the triplet phosphinidene PH undergoes prototype H−Cl bond insertion by reformation of H2PCl upon photoexcitation at 365 nm. However, this hydrogen‐bonded complex is unstable in the presence of N2 and HCl, as both molecules prefers stronger interactions with HCl than PH in the observed complexes HP•••HCl•••N2 and HP•••2HCl.