Authors: HASALETTİN DELİGÖZ, ÖZLEM ÖZEN KARAKUŞ
Abstract: Eight new mono-azo substituted chromogenic calixarenes (1-8) were synthesized by diazo-coupling reactions in which 25,26,27-tribenzoyloxy-28-hydroxy-5,11,17-tri-(tert-butyl)calixarene and diazonium salts (2-, 3-, and 4-nitroaniline; 4-phenyl azoaniline; 3- and 4-chloroaniline; or 2- and 4-methylaniline) formed the corresponding mono-azo substituted derivatives in high yields. The mono-azo substituted calixarenes were characterized by UV-Vis, FT-IR, and ^1H-NMR spectroscopic techniques. Elemental analysis was also carried out. In addition, the effects of varying pH levels and solvents upon the absorption ability of azocalixarenes substituted with electron-donating and electron-withdrawing groups at their o-, m-, and p- positions were studied. The results proved that the absorption maxima of the prepared compounds showed large bathochromic effects in comparison with analog compounds containing aromatic amine residue. Furthermore, concentration effects on the visible absorption maxima of the azocalixarene compounds studied were also reported.
Keywords: Calixarene, azocalixarenes, mono-azo substituted, diazo-coupling reaction, solvent effect, substituent effect, absorption properties
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