Journal Article

IMPULSE-2026-00047

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png A doubly protonated fluorescent dye for acid-base measurement

Stock, S. A. ; Firouzihaji, R. ; Hantro, M. ; Kleybolte, M. E. ; Truglia, B. ; van Dyck, C. ; Vagin, S.MLZ* ; Lazzari, D. ; Tuszynski, J. ; Meldrum, A. (Corresponding author)

2025
Elsevier New York, NY [u.a.]

Please use a persistent id in citations: doi:10.1016/j.jphotochem.2025.116525

Abstract: Commonly employed pH-sensing dyes include coumarins, rhodamines, fluoresceins, and cyanines, each offering distinct spectral properties and tunability. The design of fluorescent acid-base sensors typically involves organic dye molecules with functional groups that can interact with OH− ions. Here, we demonstrate a distyrylbenzene-based fluorescent base-sensing dye (double-protonated carboxy-functionalized 1,4-bis(4-pyridyl-2-vinyl)benzene; c-P4VB⋅2HX, where X = Cl but can also be other anions) that provides a larger color change and a wider range of base concentrations due to the two-step deprotonation, compared to any previously-reported fluorescent base sensors. The c-P4VB⋅2HCl is orange luminescent in its doubly protonated state, which evolves through yellow, greenish, and finally electric blue in its unprotonated state, with fluorescence quantum efficiencies typically higher than 50 %. The c-P4VB⋅2HCl and its unprotonated form (c-P4VB) are highly soluble in moderately polar solvents like (short-chained) alcohols, dimethyl sulfoxide, and dimethyl formamide, and modestly soluble in water, due to the combination of pyridine groups and the caproic acid functional group. The reaction equilibria for the two deprotonation stages were investigated, the effect of the added OH– concentration and ambient temperature on the emission color and spectra were quantified, and biological imaging was finally demonstrated.

Keyword(s): Chemical Reactions and Advanced Materials (1st) ; Chemistry (2nd)

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Contributing Institute(s):

1. MLZ (MLZ)

Experiment(s):

1. No specific instrument

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; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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