Research

We are heavily engaged in developing new organic reaction methodologies powered by light energy. In particular, we are interested in functionalizing and manipulating strong chemicals bonds (C-H, C-Cl, etc.) for the development of products that may be difficult or impossible to synthesize by other methods. Current efforts include aryl chloride functionalizations and heterocyclic ring cleavage reactions among others. We support our synthetic efforts with detailed mechanistic investigations which, in turn, further inform new reaction development.

Pyrylium dyes are easily synthesized in one or two steps from commercially available materials. These dyes have traditionally been used as single electron photo-oxidants and the oxidizing power may be readily tuned via substitution changes around the ring. As a result, libraries of pyrylium dyes with varying oxidizing potential have previously been constructed. In the MacKenzie lab, our interests lie in using pyrylium dyes not as photo-oxidants, but instead as photo-reductants. The pyranyl radical, generated upon single electron reduction of the pyrylium, absorbs in the visible region of the electromagnetic spectrum and may therefore be promoted to an excited state upon absorption of a photon of light. We intend to use this excited radical intermediate as a reductant. The reducing power of this system may be tuned by substituent electronics (as for the oxidizing system) and we intend to develop a library of pyrylium dyes as photo-reductants. Application of these dyes in new reaction development is a further goal of this project.