Immobilized Eosin Y on Modified Silica Nanoparticles and their Applications in Organic Synthesis

The development of novel photocatalytic systems is crucial for advancing sustainable chemical processes in organic synthesis. In this study, we report the preparation, characterization, and application of a heterogeneous photocatalyst based on Eosin Y (EY) covalently immobilized on silica nanoparticles (SNPs). The SNPs-EY photocatalyst was thoroughly characterized using various techniques, including SEM, TEM, X-ray diffraction, UV-vis diffuse reflectance spectroscopy, solid-state fluorescence spectroscopy, XPS, FT-IR, TGA, and DLS. These analyses confirmed the successful immobilization of EY on SNPs and demonstrated the uniformity and favourable photophysical properties of the resulting hybrid material. The photocatalytic performance of SNPs-EY was evaluated in a series of model reactions, including aza-Henry reaction (cross-dehydrogenative coupling), reduction of nitrocompounds, and photooxidation of dimethylanthracene. The reaction results demonstrated that SNPs-EY is an effective and recyclable photocatalyst, offering yields comparable to or higher than those of homogeneous systems, while providing the advantages of easy separation and reuse. This study highlights the potential of SNPs-EY as a versatile photocatalyst for various organic transformations, promoting the advancement of green and sustainable chemistry.