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Photocatalysis and self-catalyzed photobleaching with covalently-linked chromophore-quencher conjugates built around BOPHY

Lookup NU author(s): Dr Dumitru Sirbu, Dr Owen Woodford, Professor Andrew Benniston, Emeritus Professor Anthony Harriman



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Royal Society of Chemistry, 2018.

For re-use rights please refer to the publisher's terms and conditions.


This journal is © The Royal Society of Chemistry and Owner Societies. Two Chromophore-Quencher Conjugates (CQCs) have been synthesized by covalent attachment of the anti-oxidant dibutylated-hydroxytoluene (BHT) to a pyrrole-BF2 chromophore (BOPHY) in an effort to protect the latter against photofading. In fluid solution, light-induced intramolecular charge transfer is favoured in polar solvents and helps to inhibit photo-bleaching of the chromophore. The rate of photo-fading, which scales with the number of BHT residues, is zero-order in polar solvents but shows a linear dependence on the number of absorbed photons. The zero-order rate constant shows an inverse correlation with the fluorescence quantum yield measured in the same solvent. Photo-bleaching in benzonitrile involves autocatalysis while reaction in cyclohexane shows an unexpected stoichiometry. NMR spectroscopy indicates initial damage takes place at the BHT unit and allows identification of a reactive hydroperoxide as being the primary product. In the presence of an adventitious substrate, this hydroperoxide is a photocatalyst for amide formation under mild conditions.

Publication metadata

Author(s): Sirbu D, Woodford OJ, Benniston AC, Harriman A

Publication type: Article

Publication status: Published

Journal: Photochemical and Photobiological Sciences

Year: 2018

Volume: 17

Issue: 6

Pages: 750-762

Print publication date: 01/06/2018

Online publication date: 25/04/2018

Acceptance date: 21/04/2018

Date deposited: 05/07/2018

ISSN (print): 1474-905X

ISSN (electronic): 1474-9092

Publisher: Royal Society of Chemistry


DOI: 10.1039/c8pp00162f


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