A1 Journal article (refereed)
Fluorescence enhancement of quinolines by protonation (2020)

Tervola, Essi; Truong, Khai-Nghi; Ward, Jas S.; Priimagi, Arri; Rissanen, Kari (2020). Fluorescence enhancement of quinolines by protonation. RSC Advances, 10, 29385-29393. DOI: 10.1039/d0ra04691d

JYU authors or editors

Publication details

All authors or editors: Tervola, Essi; Truong, Khai-Nghi; Ward, Jas S.; Priimagi, Arri; Rissanen, Kari

Journal or series: RSC Advances

eISSN: 2046-2069

Publication year: 2020

Volume: 10

Pages range: 29385-29393

Publisher: Royal Society of Chemistry (RSC)

Publication country: United Kingdom

Publication language: English

DOI: http://doi.org/10.1039/d0ra04691d

Open Access: Publication published in an open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/71433


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.

Keywords: fluorescence; aromatic compounds

Free keywords: fluorescence enhancement; protonation

Contributing organizations

Related projects

Haloniumsupramolecular Chemistry: New Molecular Machines and Nanoreactors
Rissanen, Kari
Academy of Finland

Ministry reporting: Yes

Last updated on 2020-18-08 at 14:28