PDI-Functionalized Glass Beads: Efficient, Metal-Free Heterogeneous Photocatalysts Suitable for Flow Photochemistry

Ali, Hamza; Ahmed, Ifty; Robertson, Karen; Lanterna, Anabel E.

Abstract

Perylene diimides (PDI) have an extraordinary ability to activate both energy and electron transfer processes upon light excitation; however, their extremely low solubility has hindered their wide use as photocatalysts. Here, we show that the combination of solid-supported PDIs with continuous flow photochemistry offers a promising strategy for process intensification and a scalable platform for heterogeneous photocatalysis. The photocatalyst immobilized onto glass beads is highly efficient, easy to separate, and extremely reusable, with a broad synthetic application range. Using the photo-oxidation of n-butyl sulfide as a benchmark reaction, we demonstrate that immobilized PDI are highly active, outperforming reported homogeneous photosensitizers, and capable of extensive reuse (turnover number (TON) >57,000 over 2 months). Transferring the process from batch to flow results in a 10-fold reduction in irradiation time and an increase in the space-time yield by a factor of 33 (40 vs 1338 mmol–1 h–1 L–1 batch vs flow). What is more, the same catalyst sample can be used for the preparation of a range of sulfoxides, the aza-Henry reaction between nitromethane and N–Ar tetrahydroisoquinolines, and the photo-oxidation of furfural with high catalytic activity. Overall, our work combines the remarkable photocatalytic properties of PDI with inert, easy-to-handle glass beads, producing hybrid materials that are reusable and can be adapted for performing heterogeneous photocatalysis in a range of scalable photochemical reactors.

Citation

Ali, H., Ahmed, I., Robertson, K., & Lanterna, A. E. (2024). PDI-Functionalized Glass Beads: Efficient, Metal-Free Heterogeneous Photocatalysts Suitable for Flow Photochemistry. Organic Process Research and Development, 28(9), 3698-3706. https://doi.org/10.1021/acs.oprd.4c00256

• Journal Article Type: Article
• Acceptance Date: Aug 29, 2024
• Online Publication Date: Sep 6, 2024
• Publication Date: Sep 20, 2024
• Deposit Date: Sep 7, 2024
• Publicly Available Date: Sep 13, 2024
• Journal: Organic Process Research and Development
• Print ISSN: 1083-6160
• Electronic ISSN: 1520-586X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 9
• Pages: 3698-3706
• DOI: https://doi.org/10.1021/acs.oprd.4c00256
• Public URL: https://nottingham-repository.worktribe.com/output/39177670
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.oprd.4c00256