A new macrocyclic anion receptor utilizing amide, amine, and 9-anthracenyl hydrogens

We have developed a new macrocyclic anion receptor 2 utilizing two amide hydrogens, two amine hydrogens and 9-anthracenyl hydrogen to bind anions. As the binding cavity formed from these hydrogens is preorganized and its size is different from that of the previously reported receptor 1 due to its cyclization, the affinity of the receptor 2 for the anion is somewhat different from that of the receptor 1. The receptor 2 binds anions through hydrogen bonds with a selectivity of H2PO4->CH3CO2->F->C6H5CO2->Cl->Br->I- while the receptor 1 binds anions with a selectivity of CH3CO2->H2PO4->C6H5CO2->HSO4->ClO4->NO3-.