Corroles are aromatic compounds with structures similar to those of porphyrins. Similar to porphyrins, corroles demonstrate exceptional photophysical properties in regards to their absorbance of light and fluorescence. Corroles exist in two separate tautomeric states causing them to exhibit noticeably different photophysical and electrochemical behaviors in different solvents. A proper understanding of corroles interaction with solvents and how they affect corroles light absorbing emitting capabilities are necessary to develop potential uses of corrole in artificial photosynthetic devices, petroleum explorations, cancer diagnosis, and tumor treatment. We investigated the photophysical, electrochemical, and spectroelectrochemical properties of free-base triphenyl corrole (H3TPCor). We have characterized corroles ability to absorb light in a series of 10 solvents and in a multitude of concentrations (aggregation effect). We have also characterized the excited state emission of H3TPCor and the role of solvent in the lifetime of the same excited state. UV-Visible data show a trend indicating that the transition from one tautomer to another is dominated by the H-bonding donating ability of the solvent molecules with the core of H3TPCor. We have also found that both tautomers can co-exist in some of the solvents, and we have built a model to estimate the amount of each tautomer and what solvent property better correlate with this trend. One tautomer shows four oxidation potentials in the electrochemistry experiments, while the other shows three oxidation potentials. Both tautomers have only one reduction potential. UV-Visible spectra of reduced H3TPCor species all followed the same trend. The results indicate that the reduced species prefers this form irrespective of the solvent used. When oxidized, H3TPCor spectrum resembles the profile of the most stable tautomer.

Photophysical, electrochemical, and spectroelectrochemical characterization and solvent effect on the tautomerism of free-base corrole

2019 Spring National Meeting

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