| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 177201 | Dyes and Pigments | 2011 | 7 Pages |
Highly conjugated azo-aromatic systems have been prepared in high to moderate yields by linking mono- and bis-azo aromatic fragments to 4-(Rn-azulen-1-yl)-2,6-dimethyl-pyridine. The synthesized π-extended systems have been studied by NMR spectroscopy, UV–Vis and electrochemistry. Systematic increase of the conjugation along the azobenzene skeleton has affected the spectral properties of the azophenyl substituted 4-(azulen-1-yl)-pyridine. The synthesized compounds exhibit a bathochromic shift of the visible absorption maxima with the increase of the conjugating skeleton and introduction of an electron-withdrawing group. The electrochemical behavior revealed a high stability toward oxidation owing to the higher polarization induced by the azulenylpyridine moiety.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The synthesis and physico-chemical properties of highly conjugated azo-aromatic systems prepared by linking mono- and bis-azo aromatic fragments to 4-(Rn-azulen-1-yl)-2,6-dimethyl-pyridine is reported. ► Systematic increase of the conjugation along the azobenzene skeleton affected the spectral properties of the azophenyl substituted 4-(azulene-1-yl)-pyridine, namely a bathochromic shift of the visible absorption maxima. ► The solvatochromic behavior of both mono- and bis-azo diazene showed that by changing the solvent polarity, the λmax value is less influenced, the influence of the solvent on the electronic molecular system being reduced due the presence of two moieties which can act as push–pull systems. ► Owing to higher polarization, the azulenylpyridine diazene exhibit high oxidation potential.
