Year-end Sale % OFF 
Abstract
Rose Bengal was used to sensitise the photoreduction of water in aqueous ethanol solution (5 % EtOH v/v; pH 4.4)via both a reductive and an oxidative quenching mechanism, using EDTA and methyl viologen, respectively, as quenchers of its triplet state. In the presence of EDTA (which acts as both tiplet quencher and sacrificial electron donor) the photoreduction of water sensitised by Rose Bengal was inefficient for a number of reasons, including a low triplet quenching rate constant (8 × 103 dm3 mol–1 s–1) and a rapid disproportionation reaction involving the protonated semi-reduced dye radicals. In the presence of methyl viologen (triplet quencher) and EDTA (sacrificial electron donor) the photoreduction of water sensitised by Rose Bengal was inefficient due to a low cage-escape yield (ϕ≈ 5 × 10–2) following the primary electron-transfer step, a fast back reaction (k 1 × 108 dm3 mol–1 s–1) and formation of a complex between the dye and methyl viologen (K= 6400 ± 300 dm3 mol–1). The complexed form of Rose Bengal appeared able to photosensitise, inefficiently, the photoreduction of methyl viologen in the presence of EDTA, without exhibiting problems of dye fade.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of the Chemical Society, Faraday Transactions 2
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
