Design and synthesis of disubstituted and trisubstituted thiazoles as multifunctional fluorophores with large Stokes shifts

Abstract

A series of fluorophores based on a thiazole core have been synthesized and shown to be very sensitive to both structural changes and the microenvironment. Simple modifications of the substituents’ electronic nature, spatial effects and location in the molecule allow the tuning of the photophysical properties of the investigated compounds and their susceptibility to the environment via the exhibition of long-wavelength emission, large Stokes shifts and good quantum yields. Additionally, the thiazole-2-acrylonitrile fluorophores demonstrate a multifunctional character with significant fluorescence properties (i.e., quantum yields and a large Stokes shift in both the liquid and solid states). The influences of different factors, including the solvent polarity, on the fluorescence properties of the synthesized compounds are discussed in detail. Quantum mechanical methods are employed to understand the underlying transitions and explain the experimental results. This work provides further information for the design of new sensors that have large Stokes shifts.