Zwitterionic Dipnictanes as Photoresponsive Radical Precursors

<jats:p> Heavier dipnictanes possess weak chemical bonds, making them attractive precursors to open-shell reactivity. Here, we demonstrate that photoexcitation provides a general strategy to unlock the radical reactivity of otherwise persistent dipnictanes. Zwitterionic distibanes and dibismuthanes containing highly charged [Pn <jats:sub>2</jats:sub> ] <jats:sup>4+</jats:sup> cores were synthesised by oxidation of low-valent pnictinidenes. Despite their elongated Pn–Pn bonds, electronic-structure analyses reveal persistent and covalent σ interactions. Photoexcitation selectively populates Pn–Pn σ* orbitals, enabling access to transient Pn-centred radical species that undergo small molecule activation and radical trapping. Zwitterionic distibane additionally catalyses atom-transfer radical addition reactions under 370 nm irradiation, providing a proof of concept for light-enabled radical catalysis based on photoresponsive Sb–Sb bonds. </jats:p>