Transient Absorption Spectra of Some Naphthalimide Derivatives

In this presentation transient absorption (TA) and steady state, as well as time-resolved fluorescence spectroscopy were used to investigate the mechanisms of fluorescence quenching in order to obtain new sensors for water detection in solutions of methanol, dimethylformamide and dioxane. The new synthesized naphthalimide compounds present a good fluorescence, high quantum yield, stability and sensitivity. We chose to approach the investigation of these naphthalimide derivatives for the theoretical information, and also some applications resulting from this study, as sensors. For fundamental study, the dynamic and static quenching theories as well as the combined dynamic and static method were applied. The emission lifetime in excited state, and the quantum yield were estimated. In the presence or absence of water, ground state bleaching bands (GSB) are present after 230 nm in the TA maps. An absorption band in excited state (ESA) occurs at shorter wavelengths after 210 nm, and at longer wavelength, after 430 nm negative bands appeared, which can be assigned to the stimulated emissions (SE).

The obtained results suggest that these naphthalimide-based derivatives can act as potential sensors detecting low amounts of water.