Study on Photophysical Properties of Novel Fluorescent Phenanthroimidazole-Thiadiazole Hybrid Derivatives

Phenanthroimidazole-thiadiazole hybrid derivatives, which are new heterocyclic compounds with fluorescence properties, were synthesized by designing a two-step reaction mechanism and their photophysical properties were investigated. The synthesized derivatives were purified and their structures were elucidated by ATR-IR, 1 H-NMR, elemental analysis and HR-MS methods. In the next stage of the study, the absorption and emission spectra of the synthesized new phenanthroimidazole-thiadiazole hybrid derivatives were determined by UV–Vis and fluorescence spectroscopy. Stokes’ shifts, molar extinction coefficients (ε), singlet energy levels (Es), quantum yield (ϕ f ), lifetimes (τ), the radiative (k r ) and the nonradiative (k nr ) constant for new hybrid derivatives were measured in DMSO. In addition, aggregation measurements, which is an important parameter that changes the photophysical properties were performed and for these compounds, structure: photophysical properties were discussed.