Liquid membrane transport of potassium fluoride by the organotin-based ditopic host Ph2FSnCH2SnFPh-CH2-[19]-crown-6.

The extraction of KF from aqueous media and transport through an organic membrane is extremely challenging owing to the high hydration energies of especially the F- anions. A novel organotin-based ditopic host containing the Ph2FSnCH2SnFPh-CH2-moiety (selective for fluoride anion complexation) covalently linked to 19-crown-6 (selective for potassium cation complexation) is reported. It transports KF up to 5.5- and 2.5-times faster than the dual-host mixture composed of the bidentate Lewis acid Ph2FSnCH2SnFPh2 and 18-crown-6 at low and high salt concentrations, respectively.