Changes induced by solvent polarity in electronic absorption spectra of some azo disperse dyes

The electronic absorption spectra of some azo disperse dyes in various solvents of different polarities have been studied at room temperature The solvent effects on the wavenumbers of the absorption band maxima ((V) over tilde)(max)) were discussed using the following solvent parameters refractive index n dielectric constant epsilon and empirical Kamlet-Taft solvent parameters Pi* (dipolarity/polarizability) alpha (hydrogen bond donating capacity) and beta (hydrogen bond accepting ability) The solute-solvent interactions were determined on the basis of multilinear solvation energy relationships concept The fitting coefficients obtained from this analysis allowed us to estimate the contribution of each type of interactions to the total spectral shifts in solution The established dependences between (V) over tilde (max) and the solvent parameters emphasize that the visible band of the studied molecules is affected by both non-specific and specific solute-solvent interactions 0 2010 Elsevier BV All rights reserved