P(v) dications: carbon-based Lewis acid initiators for hydrodefluorination.

The P(iii) dication [(terpy)PPh]2+ is oxidized by reaction with o-chloranil or 9,10-phenanthrenequinone to give the P(v) dications [(terpy)(C6Cl4O2)PPh]2+ and [(terpy)(C14H8O2)PPh]2+, respectively. These species are coordinatively saturated at phosphorus and yet display the ability to effect Lewis acid initiation of hydrodefluorination of fluoroalkanes. Experimental and computational data support the notion that the P(v) dications are Lewis acidic at the para-carbon of the central ring of the terpy ligand.