An imidazoacridine-based TADF material as an effective organic photosensitizer for visible-light-promoted [2 + 2] cycloaddition. Issue 8 (4th February 2022)

• Record Type: Journal Article
• Authors: Sauvé, Ethan R.; Mayder, Don M.; Kamal, Saeid; Oderinde, Martins S.; Hudson, Zachary M.
• Is Part Of: Chemical science. Volume 13:Issue 8(2022)
• Page Start: 2296
• Page End: 2302
• Publication Date: 2022-02-04
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1sc05098b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : This work describes the performance of imidazoacridine-based TADF materials for visible-light mediated triplet–triplet EnT photocatalysis. Abstract : Energy transfer (EnT) is a fundamental activation process in visible-light-promoted photocycloaddition reactions. This work describes the performance of imidazoacridine-based TADF materials for visible-light mediated triplet–triplet EnT photocatalysis. The TADF material ACR-IMAC has been discovered as an inexpensive, high-performance organic alternative to the commonly used metal-based photosensitizers for visible-light EnT photocatalysis. The efficiency of ACR-IMAC as a photosensitizer is comparable with Ir-based photosensitizers in both intra- and intermolecular [2 + 2] cycloadditions. ACR-IMAC mediated both dearomative and non-dearomative [2 + 2] cycloadditions in good yields, with high regio- and diastereocontrol. Cyclobutane-containing bi- tri- and tetracylic scaffolds were successfully prepared, with broad tolerance toward functional groups relevant to drug discovery campaigns. Fluorescence quenching experiments, time-correlated single-photon counting, and transient absorption spectroscopy were also conducted to provide insight into the reaction and evidence for an EnT mechanism.