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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

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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.


Abstract

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

URL: https://doi.org/10.1039/c8pp00162f

DOI: 10.1039/c8pp00162f


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Funding

Funder referenceFunder name
EPSRC

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