Synthesis and photophysical characterization of 2’-aminochalcones

Chalcones have several biological activities and currently are very studied due to their high therapeutic potential. They can have antitumor, anti-inflammatory, antifungal and antibacterial properties.¹ These compounds occur in Nature as secondary metabolites of terrestrial plants and are precursors of flavonoids biosynthesis.² Generally, they are not luminescent, but derivatives with some particular patterns of substitution can present fair quantum yields.³

Excited State Intramolecular Proton Transfer (ESIPT) is a particular case of tautomerization, and molecules exhibit ESIPT fluorescence if their structures incorporate an intramolecular hydrogen bonding interaction between a hydrogen donor (-OH or -NH) and a hydrogen acceptor.⁴ The intramolecular hydrogen bonding plays a crucial role in the proton transfer process.⁵ If the dye is fluorescent, emission from both tautomers may be observed, leading to a dual emission.⁶

Here, we report the synthesis and photophysical characterizations of 2’-aminochalcones, substituted with electron donating or withdrawing groups, which could be used as markers to study the environment of cellular organelles.