Azocalixarenes.: 1:: synthesis, characterization and investigation of the absorption spectra of substituted azocalix[4]arenes

A series of novel azocalix[4]arene dyes (1-12) were prepared by linking o-, m-, p-chloroaniline, o-, m-, p-nitroaniline, o-, m-, p-toluidine, m-, p-anisidine and aniline to calix[4]arene through a diazo-coupling reaction. These compounds were characterized by UV-vis, FT-IR and H-1-NMR spectroscopic techniques and 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[4]arene. Concentration effects on the visible absorption maxima of the dyes are also reported. (C) 2003 Elsevier Ltd. All rights reserved.