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, ineso-phenyldipyrromethane (5). However, AdD 4 forms complexes with F- characterized by 1:1 and 1:2 stoichiometry (AdD:F = 1:2). (C) 2007 Elsevier Ltd. All rights reserved.