Investigation of the Photochemistry and Photophysics of Para-substituted Tertiary Thiocinnamamides
We report the synthesis and photochemical investigation of a new series of compounds, the tertiary, p-substituted thiocinnamamides. The synthesis centers on a one-pot conversion of the corresponding cinnamamide to the thiocinnamamide via Lawesson’s reagent. Results of semi-empirical calculations predict a frontier orbital structure for the thiocinnamamides that is similar to the analogous cinnamamides. One important difference is the inclusion of the sulfur non-bonding orbital as the highest occupied orbital of the thiocinnamamides. The oxygen non-bonded orbital of the cinnamamides is considerably lower in energy, and does not contribute significantly to the frontier orbital structure. The absorption and emission spectra were measured and are described. The quantum yields for E-Z photoisomerization at various wavelengths were measured and the quantum yields were not found to vary with wavelength. The photostationary states were measured and found to depend on the absorbance of the E and Z isomers at the irradiation wavelength as was expected. Analysis of photoproducts and triplet quenching studies suggest the importance of a triplet state in the photoreactivity of the tertiary thiocinnamamides.
Journal of Photochemistry and Photobiology A: Chemistry
DOI of Published Version
Elbert, Jeffery E. and Logue, Brian A., "Investigation of the Photochemistry and Photophysics of Para-substituted Tertiary Thiocinnamamides" (199). Chemistry and Biochemistry Faculty Publications. 47.