THE EFFECT OF DIMETHYLSULFOXIDE ON THE FLUORESCENCE PROPERTIES OF SOME 4-HYDROXYQUINOLINES
Open Access
- 30 August 2021
- journal article
- Published by Yerevan State University in Proceedings of the YSU B: Chemical and Biological Sciences
- Vol. 55 (2 (255)), 112-117
- https://doi.org/10.46991/pysu:b/2021.55.2.112
Abstract
Fluorescence properties of 4-hydroxy-2-methylquinoline (1) and 2-(5-mercapto-1,3,4-oxadiazol-2-yl)-6-methylquinoline-4-ol (2) were studied in dimethylsulfoxide (DMSO) aqueous solutions. The fluorescence properties of 1 and 2 exhibit substantial dependence on the DMSO concentration. The fluorescence quantum yield $(\Phi_f)$ of 1 decreases upon adding DMSO due to the shift in the keto-enol (E) tautomeric equilibrium toward E form․ On the contrary 2 demonstrates a tendency of increase of $\Phi_f$ upon adding DMSO due to intermolecular charge transfer from DMSO to the aromatic ring of quinoline, which increases the electron density on the ring and hence the fluorescence efficiency.