Photophysical Characterization of Pyrylium Salts

Sophia Jaeger, Thomas Guarr

Pyrylium salts are cationic species distinguished by a trivalent oxygen within a six membered conjugated ring.  Pyryliums can be utilitzed as precursors for heterocyclic benzene analogs, photocatalysts, fluorescent cellular probes, organic light emitting diodes, and in photodynamic therapies.  Their photophysical characteristics lend them to these applications.  To better understand the impact of structure on the photophysical properites of pyryliums, ten unique pyrylium salts were synthesized from four synthetic pathways.  The resulting pyryliums were then characterized using NMR and mass spectrometry.  Once their structures were confirmed, their photophysical characteristics were examined via UV-Visible spectroscopy and fluorescence spectroscopy.  In comparing the structure and unique spectrum of each pyrylium the impact of substituents on the central pyrylium ring on the fluorescent wavelenegth and lifetime were examined.

Sophia was a pleasure to work with this summer!  She just graduated from Michigan Tech University and is returning in the fall for her MS.  She impressed us with her knowledge but mostly with her infectious “chemistry is fun” attitude!  Her project was kind of narrow, but her contributions to the lab this summer were outsized and her hard work provided a lot of valuable info.  Thanks for spending the summer with us!