Fluorenylporphyrins functionalized by electrochromic ruthenium units as redox-triggered fluorescence switches

Zhang, Xu; Abid, Seifallah; Shi, Limiao; Williams, J.A. Gareth; Fox, Mark A.; Miomandre, Fabien; Tourbillon, Clarisse; Audibert, Jean-Frédéric; Mongin, Olivier; Paul, Frédéric; Paul-Roth, Christine O.

Abstract

Two dyads containing tris- and tetrakis-meso-fluorenyl-substituted porphyrin and ethynylruthenium units, 1 and 2, were investigated by emission spectro-electrochemical (SEC) methods for their potential use as fluorescence switches. The ruthenium group as a potential electron donor and the porphyrin as a potential electron acceptor are connected by a phenylene bridge in 1 and by a fluorenylene bridge in 2. The new fluorenyl-linked dyad 2 was probed by UV-visible, near-infrared (NIR) and infrared (IR) absorption SEC methods, and the properties interpreted with the aid of hybrid-DFT computations, for comparison with reported data for 1. The porphyrin-based fluorescence of 1 decreased in intensity upon oxidation to 1+ and decreased further on oxidising 1+ to 12+. A much weaker change in the fluorescence intensity of 2 was observed upon oxidation to 2+ but the intensity decreased upon subsequent oxidation of 2+ to 22+. These findings contrast with data reported for some other porphyrins appended with redox-active ruthenium or iron units, where fluorescence intensities increase upon oxidation of the peripheral metal centers, but they match data reported more recently for closely related arrays. A rationale for these apparently contrasting observations is proposed.

Citation

Zhang, X., Abid, S., Shi, L., Williams, J. G., Fox, M. A., Miomandre, F., …Paul-Roth, C. O. (2019). Fluorenylporphyrins functionalized by electrochromic ruthenium units as redox-triggered fluorescence switches. Dalton Transactions, 48(31), 11897-11911. https://doi.org/10.1039/c9dt02087j

• Journal Article Type: Article
• Acceptance Date: Jul 9, 2019
• Online Publication Date: Jul 10, 2019
• Publication Date: Aug 21, 2019
• Deposit Date: Aug 7, 2019
• Publicly Available Date: Jul 10, 2020
• Journal: Dalton Transactions
• Print ISSN: 1477-9226
• Electronic ISSN: 1477-9234
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 48
• Issue: 31
• Pages: 11897-11911
• DOI: https://doi.org/10.1039/c9dt02087j
• Public URL: https://durham-repository.worktribe.com/output/1325856