Heterogeneous photoredox catalysis using fluorescein polymer brush functionalized glass beads

Photocatalysis is a valuable and versatile method to perform a variety of chemical transformations under ambient temperatures and pressures using mild visible light. This work showcases an example of fluorescein-functionalized polymers grafted to micro-scale glass beads as heterogeneous photoredox catalysts. X-ray photoelectron spectroscopy and thermogravimetric analysis were used to analyze the resulting functional glass beads. Model reactions that are demonstrated include a cyclic condensation and a radical dehalogenation that can both be performed to high yields. Successful recyclability of the fluorescein polymer brush beads is demonstrated with detailed characterization confirming that photocatalytic polymer brushes remain tethered to the surface. As such, this allows for purification and reuse of the heterogeneous photocatalyst beads after simple filtration.