Authors: Jaren Meikle, Samuel Archer
Mentors: Jacob Dean
Insitution: Southern Utah University
Dipyrroles are bicyclic, heterocyclic compounds ubiquitous in nature. Dipyrroles form subunits in commonly-occurring photoactive biological subunits such as bilins, and are thus remarkable in their ability to absorb visible light despite their chemical simplicity. In this work, the photochemistry of a model dipyrrole serving as an analogue to the core subunit found in bilins was investigated and found to show a proclivity to undergo pH-dependent reactions. When the acidic and basic variants were irradiated with blue light and the time-resolved UV-vis spectra were recorded, we found stark differences in reactivity between the two variants. The protonated variant is highly photostable and resistant to photoxidation with photonic energy being channeled into rapid internal conversion. The basic variant, however, undergoes consistent oxygen-dependent photooxidation, forming hydroxy and methoxy adducts. Our research is currently focused on elucidating the structure of these photoproducts, identifying the mechanism of photooxidation, as well as modeling the kinetics of the reaction.