Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9575315 | Chemical Physics | 2005 | 9 Pages |
Abstract
The photochemistry and photophysics of isoalloxazines (10-substituted 2,3,4,10-tetrahydro-benzo[g]pteridine-2,4-diones), and especially flavins (7,8-dimethyl substituted isoalloxazines), are of considerable interest due to the biological relevance of these compounds. In this paper we report data concerning the photophysics of riboflavin and iso-(6,7)-riboflavin (10-(2,3,4,5-tetrahydroxypentyl)-6,7-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione), and correlate the spectroscopic observations with theoretical calculations performed using time-dependent density functional theory. On the basis of these calculations the lowest excited singlet and triplet states are both assigned (Ï,Ï*) symmetry, and this result is used to explain the relatively low singlet oxygen quantum yields in comparison with alloxazines. Time-resolved emission studies have indicated 6,7-dimethylalloxazine a photodegradation product of iso-(6,7)-riboflavin.
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Authors
Ewa Sikorska, Igor Khmelinskii, Anna Komasa, Jacek Koput, Luis F.V. Ferreira, Jose R. Herance, Jose L. Bourdelande, Siân L. Williams, David R. Worrall, MaÅgorzata InsiÅska-Rak, Marek Sikorski,