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

Abstract

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.