Azocalixarenes. 3: Synthesis and investigation of the absorption spectra of hetarylazo disperse dyes derived from calix[4]arene

Abstract

Synthesis of some novel hetarylazocalix[4]arene dyes was achieved by diazotisation of six heterocyclic amines using nitrosyl sulphuric acid, coupling with calix[4]arene. The absorption spectra of the dyes are discussed, both the effect of varying pH and solvent upon the absorption ability of azocalixarenes. The hetarylazocalix[4]arene readily undergo acidic dissociation into the common anion in DMF and DMSO. Absorption maxima of the dyes showed large bathochromic effects in comparison with analogues dyes containing carbocyclic amine residue. The colour of the dyes is discussed with respect to the nature of the heterocyclic ring and substituents there in. Concentration effects on the visible absorption maxima of the dyes are also reported. © 2004 Elsevier Ltd. All rights reserved.