Polarizability over dipolarity for the spectroscopic behavior of azobenzenes in room-temperature ionic liquids and organic solvents

The Catalán and Spange empirical solvent parameters scales were applied to the solvatochromismof azobenzene and para-monosubstitued derivatives in a series of solvents. The experimental solvent-dependentwavenumbers of the maximumadsorption band (νmax) were spectrophotometrically determined at 25 °C and compared to the values calculated by multiple linear regression analysis. The results show that polarizability (SP) is the dominant parameter over dipolarity (SdP), solvent acidity (SA) and solvent basicity (SB) in the solute-solvent interactions for the azobenzene derivatives in the investigated media.