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Updated: Mar 7, 2026

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
Oxidative formation of phosphinyl radicals from a trigonal pyramidal terminal phosphide Rh(i) complex, with an
Urs Fischbach1, M Trincado2, Hansjörg Grützmacher2
1Cilag AG, 8200 Schaffhausen, Switzerland.
Abstract:
A rhodium complex containing a tetrapodal triolefin ligand (trop3P) and a phosphanyl ligand (PPh2-) has been prepared and characterised. The special structural confinements of the tetradentate ligand impose an unusually long Rh-PPh2 bond. Chemical oxidation of the complex with FcOTf affords [Rh(OTf)(trop3P)] 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 (PPh2)2. Chemical oxidation with a peroxide leads to complex [Rh(POPh2)(trop3P)] which is photolabile and loses the Ph2PO moiety upon irradiation with UV/Vis light in CH2Cl2.
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