Calixarene Metalloreceptors: Demonstration of Size and Shape Selectivity inside a Calixarene Cavity

Calix[4]arenes substituted with amido groups on the upper rim, can be used a starting materials for the synthesis of calixarene ligands. These ligands can be ortho-palladated to form calixarene metalloreceptors capable of coordinating a substrate inside the bowl-shaped cavity of the calixarene. The principles of size and shape selectivity can be demonstrated employing substituted aromatic amines as model substrates.