Calixarenes, new selective molecular receptors

Calixarenes are easily amenable to chemical modifications, e.g. derivatization of the phenolic hydrogen atoms or substitution at the para-positions, which can be operated separately or combined. They thus assume the role of platforms supporting arrays of functional groups able to act as ligating sites and resulting in a great variety of receptors displaying specific complexing abilities. A selection of examples are presented with the aim of illustrating the different factors of their ionic recognition properties and their already existing applications in the field of chemical sensors. (C) 1997 Elsevier Science S.A.