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Updated: May 19, 2026

Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
Published on: August 19, 2013
Carbonyl-twisted 6-acyl-2-dialkylaminonaphthalenes as solvent acidity sensors
Amy M Green1, Hannah R Naughton, Zachariah B Nealy
1Department of Chemistry, College of William and Mary, Williamsburg, Virginia 23187-8795, United States.
Abstract:
Derivatives of 2-propionyl-6-dimethylaminonaphthalene (PRODAN) with twisted carbonyl groups were investigated as highly responsive sensors of H-bond donating ability. The PRODAN derivative bearing a pivaloyl group (4) was prepared. The torsion angle between the carbonyl and naphthalene is 26° in the crystal. It shows solvatochromism that is similar to five other PRODAN derivatives (1-3, 5, 6). Twisted-carbonyl derivatives 3, 4, and 6 show strong fluorescence quenching in protic solvents. The order of magnitude of the quenching is linearly related to the H-bond donating ability of the solvent (SA) but not to other solvent properties. Binary mixtures of protic solvents show specific interaction effects with respect to quenching and solvatochromism. Aggregation in water is an issue with the pivaloyl derivatives.
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