Abstract
A novel series of the title compound 4-(5-arylazo-2-hydroxystyryl)-1-methylpyridinium iodide
6
has been synthesized via condensation reactions of the arylazosalicylaldehyde derivatives
4a
–
i
with 1-methyl-picolinium iodide
5
. The structures of the new arylazo compounds were characterized by
1
H NMR, IR, mass spectroscopy, as well as spectral and elemental analyses. The electronic absorption spectra of arylazomerocyanine compounds
6
were measured in different buffer solutions and solvents. The pK′s and pK*′s in both the ground and excited states, respectively, were determined for the series and their correlations with the Hammett equation were examined. The results indicated that the title arylazomerocyanine dyes
6
exist in the azo form
6A
in both ground and excited states. The substituent and solvent effects (solvatochromism) of the title compound arylazomerocyanine dyes were determined using the Kamlet-Taft equation and subsequently discussed.