Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1235821 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2012 | 7 Pages |
The absorption spectra of three azoquinolin-8-ol derivatives (o-, m-, p-cyano hydroxy azoquinolin dyes) were investigated in liquid and liquid crystalline solutions as a function of the solvent polarity. The spectral data of the dyes were compared in both ordinary liquid solvents and liquid crystalline media. Analysis of the spectral data was used to determine the azo and hydrazone forms in both the environments. The spectral shifts were correlated by Kamlet–Taft and Katritzky multi-parameter polarity scales. For the azoquinoline dyes, the azo form is almost entirely dominated in polar anisotropic hosts. In contrast, the compounds remain dominantly in hydrazone form in some polar solvents such as DMF. The polarized absorption spectra of the compounds in the anisotropic media were measured and their degree of anisotropies was determined.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Azo-hydrazone tautomeric behavior of some azoquinoline dyes was studied. ► The spectral shifts were correlated by multi-parameter polarity scales. ► The azo form is almost entirely dominated in polar anisotropic hosts.