Thermodynamic characterization of the squaramide-carboxylate interaction in squaramide receptors

The thermodynamic characterization of squaramides is described. This fundamental information shows that the association in chloroform or DMSO is mainly exothermic. In contrast, in MeOH the equilibrium is endothermic and is entropically driven. The data shows the influence of a squaramide ring alone, modified or combined with tetraalkylammonium groups as the binding subunit for molecular recognition. (C) 2001 Elsevier Science Ltd. All rights reserved.