Adamantane-dipyrromethanes: novel anion receptors

New adamantane-dipyrromethanes (AdD 1-4) were synthesized and their anion binding properties investigated. AdD 1-3 form 2:1 complexes with F− (AdD:F = 2:1) characterized by high association constants, and 1:1 complexes with Cl−, Br−, HSO4- and H2PO4-. The binding of Cl−, Br−, HSO4-and H2PO4- by AdD 1-3 is 2-3 times stronger than for the reference compound, meso-phenyldipyrromethane (5). However, AdD 4 forms complexes with F− characterized by 1:1 and 1:2 stoichiometry (AdD:F = 1:2).