Metal Ions on Crosslinked Polymer Ligands

Complexation of Metal Ions on Crosslinked Polymer Ligands 

Intra-polymer chelates show the following features, as mentioned in the previous section (i) the polymer ligand is markedly contracted because of intra-polymer chelation and (ii) the formation constants of a polymer chelate are much larger than those of a monomeric complex. It is also an important feature that the shape and stability of the polymer chelate depend on the metal ion species. 

when a crosslinked polymer is used as a polymer ligand, the crosslinked polymer ligand can be expected to form stable complexes with a specific metal ion because the polymer-ligand chain has been previously contracted and immobilized. The present section describes studies of the adsorption behavior of metal ions on crosslinked polymer ligands. 

Gregor et al66 reported the Cu-complex formation of poly(methacrylic acid) (PMA) resins crosslinked with 1% or 9% divinylbenzene. The formation constants of the Cu complexes with the resins were smaller than that of noncrosslinked PMA. The stepwise formation constants decreased from Ki to KA in the resin system, which was the opposite of the noncrosslinked PMA system. The rigidity of the polymer-ligand chain was considered to hinder chelate formation. Formation constants of the PMA resin were also reported by Gustafson era/.67. The formation constant of the noncrosslinked PMA decreased for various metal ions  

Poly(ethyleneimine)(PEI) bridged by alkylene dihalide has been used as a chelating resin for Cu and Co68. Dingman et al,69 studied the adsorption of metal ions on PEI resins crosslinked with toluene diisocyanate. The amount of metal ions adsorbed decreases with the degree of crosslinking. These crosslinked PEI resins 

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B. Complexation of Metal Ions on Crosslinked Polymer Ligands... 

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