Complexation of metal ions with Langmuir-Blodgett films of novel calixarene azo-derivative

The complexation properties of Langmuir-Blodgett (LB) films of an amphiphilic calix(4)resorcinarene substituted by four arylazo groups with some heavy metal ions were studied using UV-vis spectral measurements. It was shown that soaking samples in metal salt solutions leads to irreversible decrease of absorbance at 460 nm. Efficiency of complexation is found to depend on both metal cations and anions. Effects of film thickness, solution concentration and time of exposure have also been studied. It was also shown that the addition of a small amount of aromatic compounds such as aniline, leads to a further decrease in the absorbance of the films. The presence of metal salts in the film was directly confirmed by XPS. The mechanism of ion complexation is discussed. (C) 1998 Elsevier Science S.A. All rights reserved.