Azaheterocyclic push-pull chromophores: synthesis, photophysical properties and applications as fluorescent sensors

Abstract

The recently obtained data on functionalization of pyrimidine [1–9] and pyrazine [10–12] derivatives by Suzuki or transition metal-free cross-coupling reactions will be presented. Due to the significant π-deficient character of azaheterocyclic moiety, they can be used as electron-withdrawing group in push-pull structures in which intramolecular charge transfer process occurs (figure). The photophysical properties for such fluorophores have been investigated using absorption and emission spectral analyses, both in solution and in solid-state. Some dyes exhibit strong emission solvatochromism (up to 200 nm) and possess high quantum yields, depending on their molecular structure and solvent polarity. Meanwhile, fluorescence studies have shown that emission of this fluorophores is sensitive towards various nitroaromatic compounds, either in solutions or in a vapor phase. Thus, these compounds can be regarded as promising multifunctional chemosensors.