Title
Effects of substituents on absorption and fluorescence properties of trimethylsilylethynyl- and tert-butylethynyl-pyrenes
Year
2020
Journal
Journal of Photochemistry and Photobiology A: Chemistry
Abstract
Effects of substituents introduced at 1-position of trimethylsilylethynyl- and tert-butylethynyl-pyrenes on absorption and fluorescence properties were investigated. Fluorescence intensities of 1.0 × 10–5 M CH2Cl2 solutions of these pyrene derivatives were significantly larger than that of pyrene. Absorption of a silyl derivative having a formyl group shifted to longer wavelengths as the solvent polarity increased, whereas that of the carbon analog shifted to shorter wavelengths. On the other hand, in the solvent dependence of fluorescence, both fluorescence of them shifted to longer wavelengths as the polarity of the solvent increased. Fluorescence spectra of pyrene derivatives synthesized in this study at saturated concentrations in CH2Cl2 exhibited excimer emissions in the longer wavelength regions compared to that of unsubstituted pyrene. Fluorescence quantum yields of silicon analogs were higher than that of the corresponding carbon analogs in both solution and solid states. From the results of molecular orbital calculations, it was clarified that the effects of the substituents at the 1-position on the pyrene ring on the absorption and fluorescence properties can be explained by the properties of the molecular orbitals corresponding to the respective electron transitions.
Instrument
FP-8500
Keywords
Fluorescence, Chemical stability, Quantum yield, Materials