Hydrogen-bonding interactions of photoacids: correlation of optical solvatochromism with IR absorption spectra

The effect of specific hydrogen-bonding interactions on the electronic spectra and the infrared (IR) absorption spectra of several naphthol-type photoacids was investigated. A correlation between the pK(a)(*) of the photoacid and its optical solvatochromism was observed for R*O-(HB)-B-...-type hydrogen bonds using the Kamlet-Taft (K-T) analysis. In addition, a correlation between the spectral shift in the IR stretching frequency of the RO-(HB)-B-... bond and the optical Stokes shift in the fluorescence spectra of the photoacids was found. (C) 2003 Elsevier B.V. All rights reserved.