Coordination of transition-metals by chelating cation-exchange resins; Co(II), Ni(II), Zn(II) and Cu(II) coordinated by the 8-quinolinol group in spheron oxine 1000

Abstract

The interaction between the 8-quinolinol group of the chelating ion-exchange resin Spheron oxine 1000 and Cu(II), Co(II), Ni(II) and Zn(II) has been studied with the aid of electronic spectra and EPR. It is concluded that the 8-quinolinol group in Spheron oxine 1000 coordinates as a bidentate chelating ligand to Cu(II). The Cu(II) binds preferentially to two 8-quinolinol groups although coordination to only one 8-quinolinol group, most probably due to sterical reasons, has also been observed. The coordination polyhedron of the Cu(II) bound in a 1:2 ratio is square planar, resulting in a chromophore [MO 2N 2]. The coordination polyhedron of Cu(II) bound in a 1:1 ratio is completed by water molecules resulting in a chromophore [MO 5N]. No definite conclusions could be drawn about Co(II) and Ni(II), that seem to bind preferentially in a 1:2 ratio, for cases when an excess of the resin is present, although (small amounts of) 1:1 species cannot be excluded.