6533b852fe1ef96bd12aabca
RESEARCH PRODUCT
Fluorescence enhancement of quinolines by protonation.
Essi TervolaJas S. WardKhai-nghi TruongArri PriimagiKari Rissanensubject
aromaattiset yhdisteet010405 organic chemistryHydrogen bondprotonationGeneral Chemical Engineering116 Chemical sciencesQuinolinefluoresenssifluorescence enhancementProtonationGeneral Chemistry010402 general chemistry01 natural sciencesMedicinal chemistryFluorescence3. Good health0104 chemical scienceschemistry.chemical_compoundBenzenesulfonic acidchemistryAcridineTrichloroacetic acidIsoquinolinedescription
A study of the fluorescence enhancement of isoquinoline, acridine (benzo[b]quinoline) and benzo[h]quinoline is reported with six organic acids of different pKa values. Protonation was found to be an effective tool in the fluorescence enhancement of quinolines. A significant increase in the fluorescence intensity is observed only when strong acids are used, resulting in an over 50-fold increase in fluorescence with trifluoroacetic or benzenesulfonic acid and isoquinoline in a 1.5 : 1 ratio. The benzenesulfonic acid was found to be the most effective in the protonation of the bases despite its higher pKa value compared to trifluoro- and trichloroacetic acid. The X-ray crystal structures of 14 salts reveal the charge-assisted hydrogen bond O⋯N distances to vary very little, from 2.560(2)-2.714(3) Å, with the exception of the isoquinolinium benzenesulfonate where the O⋯N distance of 2.862(7) Å is caused by additional intermolecular interactions in the solid-state. publishedVersion Peer reviewed
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2020-01-01 | RSC advances |