Five macrocyclic ligands incorporating O2N2 or O2N3 donor sets have been appended to 2% crosslinked polystyrene, and the metal-ion-binding properties of the resulting functionalized polymers towards CoII , NiII, CuII and ZnII have been investigated. Loading studies were undertaken in ethyl acetate/methanol (9 : 1), and, under similar conditions, the degree of loading was found to be metal-dependent. In addition, in some cases metal uptake was found to exceed that required for 1:1 complexation of metal to cyclic ligand . In the above solvent mixture, metal-exchange reactions were found to be relatively facile. However, attempts to leach metal ions from the loaded polymers with either acid or ammonia in aqueous media were less successful due to poor swelling of the polymer beads in such media. Matrix effects associated with the polystyrene backbone appear to be the cause of the significant modification in metal-ion-binding properties of the immobilized macrocycles relative to those of their detached analogues.
Utilizing an Amino Acid Scaffold to Construct Heteroditopic Receptors Capable of Interacting with Salts under Interfacial Conditions
