Calixarenes as enzyme models

Abstract
A review of the progress towards the use of calixarenes as enzyme models is presented. Double recognition of a substrate is illustrated with the crystal structure of (H3O+)[La(ONC5H5)2(H2O)6(p-sulfonatocalix[4]arene)]·6.5H2O, 1. The binding of zinc to calixarenes in a second-sphere fashion is shown with the crystal structure of Na2[Zn(H2O)4(ONC5H5)2][calix[4]arene]·8.5H2O, 4. The preparation and structures of aminomethylcalix[4]arenes are demonstrated with [p-(4-(2-pyridyl)piperidinomethyl)calix[4]arene], 5, and [p-(4-phenylpiperidinomethyl)calix[4]arene], 6.