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![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Triarylamine-Substituted Benzimidazoliums as Electron Donor-Acceptor Dyad-Type Photocatalysts for Reductive Organic
Ryo Miyajima1, Yuuki Ooe1, Tomoaki Miura1
1Department of Chemistry, Faculty of Science, Niigata University, 8050 Ikarashi-2, Nishi-ku, Niigata 950-2181, Japan.
Abstract:
Triarylamine-substituted benzimidazoliums (BI+-PhNAr2), new electron donor-acceptor dyad molecules, were synthesized. Their photocatalytic properties for reductive organic transformations were explored using absorption and fluorescence spectroscopy, redox potential determinations, density functional theory calculations, transient absorption spectroscopy, and reduction reactions of selected substrates. The results show that irradiation of BI+-PhNAr2 promotes photoinduced intramolecular electron transfer to form a long-lived (∼300 μs) charge shifted state (BI•-PhN•+Ar2). In the pathway for photocatalysis of reduction reactions of substrates, BI•-PhN•+Ar2 is subsequently transformed to the neutral benzimidazolyl radical (BI•-PhNAr2) by single-electron transfer from the donor 1,3-dimethyl-2-phenylbenzimidazoline (BIH-Ph) serving as a cooperative agent. Among the benzimidazoliums explored, the bromo-substituted analogue BI+-PhN(C6H4Br-p)2 in conjunction with BIH-Ph demonstrates the most consistent catalytic performance.
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