Study of inclusion complex formation between a homologous series of n-alkyltrimethylammonium bromides and β-cyclodextrin, using conductometric technique

The behaviour of the inclusion complex based on a homologous series of n-alkyltrimethylammonium bromides and beta-cyclodextrin (beta-CD) were studied using conductometric technique. Association constants have been determined for S(CD) and S(CD)(2) complexes. It has been found that DETAB and DOTAB form only the 1:1 complexes, while TTAB forms 1:1 1:2 TTAB/CD complexes. The results are explained in terms of the difference in chain length of surfactants and dimensions of the beta-CD cavity. The experiments were carried out at different temperatures. The association constant values are used for evaluation of thermodynamic parameters of complexation, such as DeltaGdegrees, DeltaHdegrees and DeltaSdegrees. (C) 2004 Elsevier B.V. All rights reserved.