C3v symmetric receptors show high selectivity and high affinity for phosphate.

The binding of phosphate to tripodal metalloreceptors 1 and 2 is reported. Receptors 1 and 2 are C3v symmetric, designed to complement three sides of a tetrahedron. The receptors derive from tripodal ligands that are preorganized through binding to a central Cu(II) atom. These metalloreceptors demonstrate high selectivity and affinity for the molecular recognition of phosphate in aqueous media at neutral pH. The binding of phosphate and other anions to the cavities of receptors 1 and 2 was monitored by UV/vis titration techniques. Binding algorithms were used to determine the affinity of phosphate to 1 and 2 with association values (Ka) of 2.5 x 104 and 1.5 x 104 M-1, respectively.