Lookup NU author(s): Dr Dumitru Sirbu,
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.
Author(s): Sirbu D, Woodford OJ, Benniston AC, Harriman A
Publication type: Article
Publication status: Published
Journal: Photochemical and Photobiological Sciences
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
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