PreprintArticleVersion 1Preserved in Portico This version is not peer-reviewed
Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study
Version 1
: Received: 17 April 2024 / Approved: 18 April 2024 / Online: 19 April 2024 (10:55:26 CEST)
How to cite:
Netto-Ferreira, J.C.; Bertoti, A.R. Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study. Preprints2024, 2024041296. https://doi.org/10.20944/preprints202404.1296.v1
Netto-Ferreira, J.C.; Bertoti, A.R. Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study. Preprints 2024, 2024041296. https://doi.org/10.20944/preprints202404.1296.v1
Netto-Ferreira, J.C.; Bertoti, A.R. Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study. Preprints2024, 2024041296. https://doi.org/10.20944/preprints202404.1296.v1
APA Style
Netto-Ferreira, J.C., & Bertoti, A.R. (2024). Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study. Preprints. https://doi.org/10.20944/preprints202404.1296.v1
Chicago/Turabian Style
Netto-Ferreira, J.C. and Ada Ruth Bertoti. 2024 "Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study" Preprints. https://doi.org/10.20944/preprints202404.1296.v1
Abstract
The triplet excited state reactivity towards phenolic hydrogen of the -diketones benzil and 2,2´-furil in the ionic liquid 1-n-butyl-3-methyl imidazolium hexafluorophosphate [bmim.PF6] was investigated employing the nanosecond laser flash photolysis technique. Irradiation (lmax=355 nm) of benzil yields its triplet excited state with lmax at 480 nm and tT=9.6 μs. Under the same conditions, 2,2’-furil shows a triplet-triplet absorption spectrum with bands at 380, 410, 450, and 650 nm and tT=1.4 μs. Quenching rate constants (kq) of the reaction between benzil triplet and substituted phenols ranged from 1.4x107 L mol-1 s-1 (para-chlorophenol) to 1.8x108 L mol-1 s-1 (para-methoxyphenol). A new transient was formed in all cases, assigned to the benzil ketyl. Similar results were obtained for the quenching of 2,2’-furil triplet by phenols, for which kq ranged from 1.9x108 L mol-1 s-1 (para-chlorophenol) to 2.2x108 L mol-1 s-1 (para-methoxyphenol). The 2,2’-furil ketyl radical was also observed in all cases (lmax=380 nm). The quenching rate constants are almost independent of the substituent and diffusion-controlled (kq ~ 108 L mol-1 s-1). The proposed mechanism for the phenolic hydrogen abstraction by benzil and 2,2´-furil triplet may involve a proton-coupled electron transfer reaction, ultimately leading to the radical pair ketyl/aryloxyl.
Chemistry and Materials Science, Physical Chemistry
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
