Azocalixarenes. 2: Synthesis, characterization and investigation of the absorption spectra of azocalix[6]arenes containing chromogenic groups

Abstract

Twelve new azocalix[6]arenes (1-12) have been synthesized by linking o-, m-, p-chloroaniline, o-, m-, p-nitroaniline, o-, m-, p-toluidine, m-, p-anisidine and aniline to calix[6]arene through a diazo-coupling reaction. The prepared compounds were characterized based on UV-vis, FT-IR and 1H-NMR spectroscopic techniques as well as elemental analysis. The effect of varying pH and solvent upon the absorption ability of azocalixarenes substituted with electron-donating and electron-withdrawing groups at their o-, m-, p-position was examined. Observed results were compared with those found for unsubstituted azocalix[6]arenes. Concentration effects on the visible absorption maxima of the dyes are also reported. © 2004 Elsevier Ltd. All rights reserved.