Novel fluorophores based on imidazopyrazine derivatives: Synthesis and photophysical characterization focusing on solvatochromism and sensitivity towards nitroaromatic compounds

Novel imidazopyrazine-based dyes of the D-A type, possessing (hetero)aryl electron-donating groups in the imidazole moiety, have been synthesized. Their photophysical properties have been investigated using absorption and emission spectral analyses, both in solution and in solid-state. All dyes exhibit strong emission solvatochromism (Delta lambda(em) = 146-201 nm) and possess quantum yields up to 0.28, depending on their molecular structure and solvent polarity. Meanwhile, fluorescence studies have shown that emission of all fluorophores is sensitive towards different nitroaromatic compounds, either in solutions or in a vapor phase. Thus, these compounds can be regarded as promising multifunctional chemosensors.