Molecular recognition of the imidazole residue by a dicopper(II) complex with a bisdien macrocycle bearing two pendant arms

The dicopper(II) macrocyclic complex 4 tightly binds the imidazolate ion in aqueous solution at pH 9 and recognises molecules containing an imidazole fragment, e.g.L-histidine, in the presence of any other amino acid.