title: Effect of template ion-ligand complex stoichiometry on selectivity of ion-imprinted polymers.
abstract: In order to highlight the importance of the complex stoichiometry during ion imprinted polymer (IIP) synthesis, we investigated the effect of the complex structure on IIPs selectivity by adjusting the complex stoichiometry before polymerization. 2-(aminomethyl)pyridine monomer (amp) was chosen as a functionalized ligand for nickel(II) ions and a polymerizable vinylbenzyl derivative (Vbamp) was prepared. Complex formation was studied by varying the nickel/Vbamp ratio and recording absorption spectra of the complexes at the polymerization conditions. Using a least-squares minimization scheme, the complex species distribution was successfully established. From these results, it was possible to choose the metal/ligand stoichiometry in the complex (1:1; 1:2 or 1:3) by adjusting the initial metal/ligand ratio. IIPs were then prepared by inverse suspension copolymerization of Vbamp with ethyleneglycol dimethacrylate (EDMA). Highly porous particles with good nickel binding capacity and good Ni/Zn selectivity even at acidic conditions were obtained. Equilibrium uptake of Ni(II) at pH 7 ranged from 0.12 to 0.2 mmol g(-1) and relative selective coefficient was as high as 260 for the IIP prepared using the Ni(Vbamp)2 complex.
authors.affiliation: Lappeenranta University of Technology, Laboratory of Separation Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland. Electronic address: Katri.Laatikainen@lut.fi.
authors.forename: Katri
authors.initials: K
authors.lastname: Laatikainen
authors.affiliation: University of Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors.forename: Dutduan
authors.initials: D
authors.lastname: Udomsap
authors.affiliation: University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Siren
authors.affiliation: University of Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors.forename: Hugues
authors.initials: H
authors.lastname: Brisset
authors.affiliation: Lappeenranta University of Technology, Laboratory of Separation Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland.
authors.forename: Tuomo
authors.initials: T
authors.lastname: Sainio
authors.affiliation: University of Toulon, MAPIEM, EA 4323, 83957 La Garde, France. Electronic address: branger@univ-tln.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Branger
keywords: 2-(Aminomethyl)pyridine; Inverse suspension polymerization; Ion imprinted polymers; Nickel