An Isolable Heteroleptic Diarylphosphinyl Radical

Diarylphosphinyl radicals [Ar2P]• have
been known as transient species for over 50 years, but their isolation
in the condensed form has not been realized until now. In this work,
we report the synthesis and structural and spectroscopic characterizations
of the first isolable heteroleptic diarylphosphinyl radical 3 supported by a sterically congested hydrindacene substituent.
Electron paramagnetic resonance spectroscopy and density functional
theory calculations reveal that the spin density mainly resides at
the phosphorus center. The reactivity of 3 toward C2Cl6 and nBu3SnH was
investigated, affording diarylchlorophosphine and diarylphosphine,
respectively, revealing its phosphorus-centered radical nature.