Solvatochromism and halochromism of some furo/pyrazole cyanine dyes

Abstract

In this study, the electronic absorption spectra of some furo[2,3-b]pyrazole cyanine dyes was recorded and investigated in a number of 6 (six) pure solvents having different polarities [water (78.54), D.M.F (36.70), ethanol (24.3), chloroform (4.806), CC14 (2.238) and dioxane (2.209)], mixed solvents [DMF- H2O] and/or in a series of 8 (eight) aqueous universal buffer solutions having varied pH values [1.65, 2.32, 4.62, 5.85, 6.41, 7.82, 9.61 and 11.63 units] to evaluate their solvatochromic and/or halochromic properties, respectively. The study covers different types of cyanine dyes, it includes monomethine cyanine dyes (simple cyanine dyes), dimethine cyanine dyes and tetramethine cyanine dyes.