Liquid-liquid extraction and transport of biologically important metal ions Li+, K+, Ca2+ and Mg2+ across an artificial liquid membrane system

Abstract

Redox switched anthraquinone derived podands 1-(anthra­quinonyloxy), 3 methoxy methane (T1) and 1,5 bis-(2-(2-hydroxyethoxy)ethoxy)anthracene-9-10-dione (T2) have been synthesized by condensation of 1-chloroanthraquinone, 1,5-dichloro-anthraquinone with methoxy methanol and diethylene glycol in THF under N2 atmosphere characterized by m.p., TLC and IR, NMR, Mass analysis. Extraction and transport of metal ions in oxidized and reduced state is Ca2+>K+>Li+, Li+>K+>Ca2+. The results of the transport study reveal that ionophore T1 and T2 are selective for Ca2+; this selectivity can be used for fabrication of ion selective electrodes and sensors. Double-armed ionophore T2 is a good extractant and is transporter for metal ions compared to single-armed podands. Extraction and transport ability enhanced in reduced state.

Keywords

• alkali-alkaline earth metal ions
• liquid membrane system
• redox switched podands