Development of Efficient One-Pot Methods for the Synthesis of Luminescent Dyes and Sol-Gel Hybrid Materials.

This paper presents a comparison of the simultaneous preparation of di--alkylated and ether-ester derivatives of fluorescein using different methods (conventional or microwave heating). Shortening of the reaction time and increased efficiency were observed when using a microwave reactor. Moreover, described here for the first time is the application of a fast, simple, and eco-friendly ball-assisted method to exclusively obtain ether-ester derivatives. We also demonstrate that fluorescein can be effectively functionalized by -alkylation carried out under microwave or ball-milling conditions, saving time and energy and affording the desired products with good yields and minimal byproduct formation. All the synthesized products as well as pH-dependent (prototropic) forms trapped in the SiO matrix were examined using UV-Vis and fluorescence spectroscopy.