Protonated sapphyrins. Highly effective phosphate receptors

A unique approach to phosphate ion chelation based on the use of protonated sapphyrins, macromolecules that are also known as expanded porphyrins, is described. The study investigated three sapphyrin derivatives. The results showed that the diprotonated forms of sapphyrin are capable of forming stable complexes with phosphate-derived monoions. They are also capable of forming a 1:1 chelate complex in the solid state with either mono- or dibasic phosphoric acid. These results indicate that protonated sapphyrins are highly effective phosphate receptors.