Silacrown Ethers-Clay Intercalation Materials: Application in Potentiometric Sensors for Detection of Alkali-Ions

Abstract

Abstract Dimethylsila-14-crown-5 (DMS14C5) and dimethylsila-17-crown-6 (DMS17C6) macrocyclic polyethers have been intercalated into montmorillonite layered silicates containing Li+, Na+ or K+ cations as exchangeable cations. XRD and FTIR spectroscopy offer information on the disposition of the macrocycle in the interlayer and accommodation of cations within the cavity of the polyoxyethylene ligand. 13C and 23Na solid-state NMR spectroscopy provides information about the replacement of water molecules from the hydration shell of interlayer cations by the macrocyclic ligand and confirms differences in the interactions depending on the nature of the ligand. The resulting montmorillonite intercalation materials were tested as active phase of PVC electrodes for the development of potentiometric sensors, in a preliminary attempt to evaluate their electrochemical response towards alkali-metal ions in solution.