Solid polysiloxane ligands containing glycine- or iminodiacetate-groups: synthesis and application to binding and separation of metal ions†

Abstract

Porous solid siloxane polymers carrying glycinate or iminodiacetate ligand groups on the pore surface have been synthesised and evaluated for their binding capacities for cobalt(II), nickel(II) and copper(II). Copper(II) appears to form four-co-ordinate 2∶1 and 1∶1 complexes, respectively, with the two ligands. The other metals form both 1∶1 and 2∶1 complexes with both ligands. When used as chromatographic stationary phases, the solid ligands allow clean separation of the three metals by pH-controlled elution. Cobalt(II) and nickel(II) can also be cleanly separated by displacement–elution with copper(II).