No abstract

Calixarene molecules are very powerful ligand for ions and small molecules, and have been studied with several techniques as models for host-guest systems. In this approach, the formation of Langmuir monolayer properties of three kinds calix[4]arene derivative were characterized and one of them, p-tert-butylthiacalix [4]arene (TCA), was chosen as object to study its Langmuir monolayer affected by different subphase conditions. The purpose of this study is to investigate the molecular recognition ability of TCA for metal ions at the water-air interface. Changing the composition of aqueous subphase (containing various metal ion solutions respectively) produced strong variations on the monolayer parameters, indicating a different selectivity of the TCA ligand for the different metal cations. In particular, high selectivity for transition metal ions was found. Limiting area values are discussed in relation to the orientation of the cone-shaped molecules at the water-air interface.