Synthesis and colour spectrophotometric measurements of some novel merocyanine dyes

Novel merocyanine dyes cyanine dyes derived from benzo[2,3-b; 2′, 3′ - b′ ]bis pyrazolo[4,5-b]-l,4-(oxa-, thia-, and pyra)-zine-6,12-dione ring system were prepared. The prepared cyanines involve acyclic merocyanine and cyclic merocyanine types. Colour spectrophotometric measurements for all the synthesized merocyanine dyes were investigated in 95% ethanol solution. Colour spectrophotometric measurements for some selected synthesized merocyanines were examined in pure solvents having different polarities and/or in aqueous universal buffer solutions. General chemical–physical characterization was carried out through elemental analysis, IR and 1H NMR spectral data.