UV–visible spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in eight binary solvent mixtures

Solvent effects on the recently synthesized hydrophilic and negatively solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye [E<INF>T</INF>(8) dye] in binary solvent mixtures of dimethyl sulfoxide and acetonitrile with water, methanol, propan-2-ol and 2-methylpropan-2-ol were studied by UV–visible spectroscopy and compared with analogous measurements of the standard E<INF>T</INF>(30) betaine dye [2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate]. A preferential solvation model was applied to the data obtained. The applicability of the E<INF>T</INF>(8) betaine dye for the determination of E<INF>T</INF>(30) values for aqueous media is discussed. Copyright © 2003 John Wiley & Sons, Ltd.