Negative solvatochromism of a series of pyridinium phenolate betaine dyes with increasing steric hindrance

Patrice Jacques (1) , Bernadette Graff (1) , Vincent Diemer (2) , Emel Ay (2) , Hélène Chaumeil (2) , Christiane Carré (3) , Jean-Pierre Malval (4)

1 LPIM - Laboratoire de Photochimie et d'Ingénierie Macromoléculaires
2 COB - Laboratoire de Chimie organique et bioorganique
3 FOTON - Fonctions Optiques pour les Technologies de l'informatiON
4 IS2M - Institut de Science des Matériaux de Mulhouse

The negative solvatochromism of a series of pyridinium phenolates betaine dyes is investigated using three approaches: (a) empirical, based on the empirical solvent polarity parameter ET(30); (b) semi-empirical, based on the p⁄, a, b set of parameters used in Kamlet-Taft's Solvatochromic Comparison Method (SCM); and (c) physical, by means of the Onsager reaction-field model of solvents. Comparison of the obtained correlations underscored the roles of both the two tert-butyl groups ortho to the oxygen atom and the interplanar angle between the phenyl rings on the very blue shifts observed as the polarity increases.

Domaines: Optique / photonique

Patrice Jacques, Bernadette Graff, Vincent Diemer, Emel Ay, Hélène Chaumeil, et al.. Negative solvatochromism of a series of pyridinium phenolate betaine dyes with increasing steric hindrance. Chemical Physics Letters, 2012, 531, pp.242-246. ⟨10.1016/j.cplett.2012.02.018⟩. ⟨hal-00727616⟩