Synthesis and Studies on New Dimethine and Tetramethine Cyanine Dyes
Authors: H.A. Shindy, A.K. Khalafalla, M.M. Goma, A.H. Eed
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New dimethine cyanine dyes and tetramethine cyanine dyes having the nucleus of furo[(3,2-d; ( , -d)-bis pyrazole] were prepared. The electronic visible absorption spectra of all the synthesized cyanine dyes were investigated in 95 % ethanol solution to evaluate their spectral sensitization properties. Solvatochromism for some selected dyes were examined in pure solvents having different polarities [Water (78.54), Dimethylformamide (36.70), Ethanol (24.3), Chloroform (4.806), Carbontetrachloride (2.238) and Dioxane (2.209)] to evaluate their solvatochromic properties. Halochromism (acid-base properties) of some chosen dyes were measured in aqueous universal buffer solutions having varied pH values (1.75, 2.45, 4.65, 5.80, 7.88, 8.75, 10.58 and 12.60 units) to evaluate their halochromic characterization. Structural determination were carried out through elemental analysis, visible spectra, mass spectrometer, IR and 1H NMR spectral data.