Synthesis and redox properties of sterically crowded triarylphosphine bearing two phenothiazine moieties

The sterically crowded triarylphosphine bearing two phenothiazine moieties as redox sites was synthesized. The cyclic voltammogram of the phosphine exhibits three-step reversible oxidation, and the comparison with that of the triarylphosphine bearing one phenothiazine moiety suggests delocalization of positive charges during redox process.