Anion‐receptor molecules: Macrocyclic and macrobicyclic effects on anion binding by polyammonium receptor molecules

Abstract

AbstractThe stability constants for anion binding by the acyclic hexaamine 1, its macrocyclic analogue 2, and the bicyclic compound 3 in their protonated forms are reported. Compound 3 forms stable and selective complexes with halide ions, the stability sequence being I− > Br− > Cl−. Compound 2 forms more stable complexes with sulfate, oxalate, and malonate dianions than its acyclic analogue 1 and shows a better selectivity pattern. Compound 3 forms stronger complexes with oxalate2− than 2 and shows a remarkably high binding selectivity between oxalate2− and malonate2−. The comparison of the ability of 1–3 to complex anions demonstrates the macrocyclic and macrobicyclic effects on anion binding stability and selectivity.