Oxidative formation of phosphinyl radicals from a trigonal pyramidal terminal phosphide Rh(i) complex, with an unusually long Rh-P bond.

A rhodium complex containing a tetrapodal triolefin ligand (tropP) and a phosphanyl ligand (PPh) has been prepared and characterised. The special structural confinements of the tetradentate ligand impose an unusually long Rh-PPh bond. Chemical oxidation of the complex with FcOTf affords [Rh(OTf)(tropP)] and plausibly phosphanyl radicals, which react instantly with a spin trap reagent forming a nitroxide-based persistent radical, undergo HAT with silanes or dimerise to the corresponding diphosphine (PPh). Chemical oxidation with a peroxide leads to complex [Rh(POPh)(tropP)] which is photolabile and loses the PhPO moiety upon irradiation with UV/Vis light in CHCl.