Anion Nature Influence on Spectral and Some Physico-Chemical Properties of 6,7-Dihydroxy-4-methyl-2-phenylchromenylium Salts

The influence of the nature of anions (Cl-, Br-, I-, ClO4-, and PF6-) on the physico-chemical properties (solubility, solvatochromism, and spectral characteristics) of 6,7-dihydroxy-4-methyl-2-phenylchromenylium salts was studied. The main spectrophotometric characteristics were determined. It was noted that the molar absorption coefficient increases on passing to polar solvents. The highest molar absorption coefficient was observed for the hexafluorophosphate anion, which has weak coordinating power that favors more efficient solvation of the organic cation.