Heterogeneous photoredox catalysis using fluorescein polymer brush functionalized glass beads

Abstract

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.

Thermoresponsive polymer brush photocatalytic substrates for wastewater remediation

“…The synthesis of dual responsive polymer brush photocatalytic materials was performed following our previously published surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization approach (see ESI†). 64,65 The RAFT chain transfer agent (CTA) 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl] pentanoic acid (CDTPA) was immobilized on soda lime silica (SiO x ) glass beads ( D z = 76.3 μm) to afford SI-RAFT of a thermoresponsive copolymer comprised of 10 mol% fluorescein o -acrylate (FlA) in N -isopropylacrylamide (NIPAAm) (see Fig. 2a).…”

“…The synthesis of dual responsive polymer brush photocatalytic materials was performed following our previously published surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization approach (see ESI †). 64,65 The Fig. 2 (a) Illustration of the dual-responsive poly(fluorescein o-acrylate-co-N-isopropylacrylamide) heterogeneous catalysts and (b) comparing the experimental molecular weights from the free polymer formed in solution to increasing the thickness of poly(FlA-co-NIPAAm) on silicon wafers.…”

Reusable polymer brush-based photocatalysts for PET-RAFT polymerization

“…1a) were synthesized following our previously published procedure. 76 Successful surface functionalization was verified via X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA, see ESI Fig. S4 †).…”

Photocontrolled RAFT polymerization: past, present, and future

“…9b). 245,246 The catalytic performance was comparable to that of their small molecule counterparts and was preserved after repeated recoveries. Moreover, after its conjugation to silica NPs, the stability of EY against photodegradation was enhanced.…”