Synthesis and ion-binding affinities of calix[4]arenes immobilized on cross-linked polystyrene

Calix[4]arene and its diphosphorylated derivative have been immobilized onto cross-linked polystyrene beads through an etherification reaction. The supported calixarene complexes 96.7% Cs(I) from a 10(-4) N solution in 1 M NaOH. Poly(hydroxystyrene) complexes 35.6% Cs(I) from the same solution. Immobilization of the calixarene onto a polymer support thus does not affect its inherently high affinity for cesium ions. Substituting two of the three remaining hydroxyl groups on the calixarene with diethoxyphosphoryl moieties allows for quantitative complexation of Fe(III) and Pb(II) from 0.01 M nitric acid solutions. The unsubstituted calixarene complexes 6.00% Fe(III) and 7.36% Pb(II) while diethoxy-phosphoryl-substituted poly(hydroxystyrene) complexes 10.0% Fe(III) and 3.76%, Pb(II). The calixarene therefore acts as a platform on which ligands can be immobilized in close enough proximity to permit cooperative binding of metal ions.