Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5400527 | Journal of Luminescence | 2014 | 8 Pages |
Abstract
Fluorescence steady-state and decay measurements of the azaaromatic derivative norharmane were obtained in solvents with different polarities: dichloromethane (DCM) and acetonitrile (ACN), at different temperatures, in the absence and the presence of a donor/acceptor hydrogen bond such as acetic acid. 2D NOESY experiments confirmed that this compound forms a hydrogen-bonding cyclic complex with acetic acid in the ground state. This complex induced a phototautomeric equilibrium, which produced new emission bands at 400 and 500Â nm. This tautomeric process was established only in the first excited state via a concerted proton-electron transfer. Indeed, the cyclic complex formed in the ground state evolved to a like-cation upon cooling from room temperature to 225Â K, and a new emission band at 450Â nm is observed. The fluorescence decay times confirmed these results.
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Authors
Dolores Reyman, Teresa Montoro, Montserrat H. Viñas, Cristina DÃaz-Oliva, Gloria Tardajos,