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2021 Abstracts

Laser Mediated Photochemistry: Exploring the Isomerization and Decaying Behavior of Dipyrroles

Presenter: Taime Clark, College of Science and Engineering, Physical Science
Authors: Taime Clark
Faculty Advisor: Jacob Dean, College of Science and Engineering, Physical Science
Institution: Southern Utah University

Chemical compounds have a variety of properties and behaviors when excited by photons to accommodate the increase in energy; some isomerize to a different structure, some decay, and others may fluoresce, to name a few possible pathways. Some compounds that are particularly efficient at transferring this energy are light harvesting bilins found in cyanobacteria and some varieties of algae. In this project, we are focusing on the behavior of a specific bilin subunit, referred to simply as DPY, in dichloromethane and acidic methanol solvents. This subunit has the potential to be three different isomers; the ZZ isomer, which is the most stable structure, and the ZE and EE isomers, all of which have a different mechanism. We are interested in using a diode laser of a specific wavelength to go from the default ZZ isomer, to one of the others, and tracking this isomerization via UV-Vis absorbance spectroscopy. It was found in previous studies that it is in fact the EE isomer that forms by going through a concerted twist upon photon excitation. Next, we are most interested in building up this photoisomer product, and monitoring any decay, as well as the reversibility potential. To accomplish this, we will track the isomerization using UV-Vis spectroscopy, save the product solution and take its absorbance spectra to see if it has decayed or reverted on its own over time, then use a diode laser of a different wavelength and track the changes to see if we can remake the ZZ isomer. This will give insight to the possibility of making controllable chemical photoswitches. After the reversibility studies, we will also perform quantitative investigations into the quantum yield of the isomerization. This data will provide a lot of information in relation to structure functions and their possible uses in biological photo reception.