SOLVATOCHROMISM OF HOMODIMERIC STYRYL PYRIDINIUM SALTS

The solvatochromic properties of homodimeric styryl pyridinium salts are analyzed on the ground of Lippert-Mataga correlation, solvent scales of molar electronic transition energies E T (30) values, multilinear regression with the KamletTaft solvent scales and continuum McRae-Bayliss model. The protic and aprotic solvents refer to two isolated domains in the Lippert-Mataga and Reichardt plots, whereas fitting to Kamlet-Taft scales gives a linear regression valid for both types of solvents studied. Poor linearity is observed in case of McRae equation application. An intermolecular hydrogen bonding mechanism is advanced to explain the results obtained.