Design of Schiff base complexes of Co(II) for the preparation of iodide-selective polymeric membrane electrodes

The response characteristics of some iodide-selective solvent polymeric membrane electrodes based on with N,N'-bis(salicylaldehyde-n-octyl) diimine cobalt(II) (Co(II)SAODI) which is a more lipophilic substitute for a previously reported iodide-carrier are described. The electrode doped with Co(II)SAODI into a plasticized poly(vinyl chloride) membrane exhibits an anti-Hofmeister selectivity pattern with high selectivity toward iodide, long lifetime and small interference from H(+). Quartz crystal microgravimetric measurements and ac impedance experiments show that the excellent selectivity for iodide is related to the unique interaction between the carriers and iodide and steric effect associated with the structure of the Schiff base ligands.