Thermosolvatochromism of phenol blue in polar and nonpolar solvents

The solvatochromic properties of phenol blue [N-(4-dimethylaminophenyl)-1,4-benzoquinoneimine] is investigated in polar and nonpolar solvents using variable-temperature (super 1)H NMR and electronic absorption spectroscopy. In addition, evidence for solvent dependence of the dipole difference mu(sub e)-mu(sub g) between the ground and excited electronic states is presented.