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−, HSO 4 - and H 2 PO 4 - . The binding of Cl−, Br−, HSO 4 - and H 2 PO 4 - 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).