Ion-exchange study of poly[(2,4-dihydroxy benzophenone) propylene] resin and its polychelates: Synthesis, characterization

The polymeric ligand poly[(2,4-dihydroxy benzophenone) propylene] H(DHBP-PD) forms 1:2 metal-ligand complexes with Cu(II), Ni(II), Co(II) and Zn(II). The polymeric ligand and its polychelates were characterized on the basis of elemental analyses, magnetic susceptibilities, IR-spectroscopy, UV-visiblespectra, NMR, thermogravimetric analyses. The molecular weight of resin was determined using number average molecular weight (Mmacrn) by Vapor Pressure Osmometry (VPO) method. The stereochemistry, in case of the Cu(II) polychelate, is square-planar, tetrahedral for Zn(II) and octahedral for Ni(II) and Co(II). The stereochemistry in each chelate is proposed on the basis of magnetic susceptibilities and electronic spectra. IR spectra shows that the bidentate ligand coordinates through the oxygen atom of the carbonyl group and the oxygen atom of the phenolic group with replacement of hydrogen by metal ions. All the chelates are paramagnetic in nature except the Zn(II) chelate which is diamagnetic. The ion-exchange study of the prepared resin was checked by batch equilibration method at varying electrolyte concentration, pH and time with selected metal ions such as Cu(II), Ni(II), Fe(III) and UO22+(VI).