fulltext.study @t Gmail

Formal intramolecular photoredox reactions of phenylbenzophenone, xanthone and fluorenone methanols in aqueous solution

Paper ID Volume ID Publish Year Pages File Format Full-Text
28211 44065 2009 10 PDF Available
Title
Formal intramolecular photoredox reactions of phenylbenzophenone, xanthone and fluorenone methanols in aqueous solution
Abstract

To further explore the structural and chromophoric effects on the formal intramolecular photoredox reaction discovered in our laboratory for aromatic ketones such as benzophenone and anthraquinones in aqueous solution, we have investigated whether this photochemistry can be applied to xanthones, fluorenones, and benzophenones that are “extended” by a conjugated phenyl ring where the oxidizable group is distal to the benzophenone. It was found that 2-(hydroxymethyl)xanthone (6) exhibited sufficient photoactivity that the intramolecular photoredox reaction was observable under neutral conditions whereas 2-(hydroxymethyl)fluorenone (7) displayed only very low but clean photoreactivity in acid. The last feature of this study focuses on the extension of the electronic transmission from the carbonyl functional group to the benzylic alcohol, by insertion of an additional phenyl group, to give a biphenyl (phenylene) structural feature. The addition of the phenyl group gives rise to bichromophoric molecules (8–10) rather than monochromophoric substrates studied in the past. We find that the location of the hydroxymethyl substituent on the attached phenyl ring plays a pivotal role in the overall photobehaviour: only the ortho-substituted compound gave evidence of an intramolecular photoredox reaction, while the meta- and para-substituted compounds primarily exhibited photobehaviour that can be interpreted as an “aborted” intramolecular redox process. Overall, the results show that photoredox or related reaction can occur for all of these systems but added complexities make them less useful compared to what was observed for the “parent” benzophenone system.

Keywords
Benzophenone; Xanthone; Fluorenone; Photoredox; Acid catalysis; Photoenolization; Excited state proton transfer; Carbon acidity
First Page Preview
Formal intramolecular photoredox reactions of phenylbenzophenone, xanthone and fluorenone methanols in aqueous solution
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 205, Issue 1, 10 June 2009, Pages 34–43
Authors
, ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us