Synthesis of class II dual mechanism bifunctional ion exchange/coordination resins and characterization of their substrate recognition properties

A new type of phosphorus-based Class II dual mechanism bifunctional polymers (DMBPs) has been developed as selective metal ion complexing agents. The newly developed resins include an exchange ligand to enhance the accessibility and a coordinative component to enhance the selectivity to metal ions. The resins were prepared via a new method in which a fully functionalized phosphonic acid resin was first halogenated with SOCI₂ and then converted to the phosphonate monoester by the subsequent quenching and hydrolysis processes. A series of bifunctional phosphonate resins containing a coordination ligand such as pyridine or tertiary amine groups on the ester linkage have been synthesized. The binding constants of these new resins to Cu⁺² and Co⁺² ions in pH 5 solutions were determined by Langmuir isotherm plots. The results indicate that the binding ability is increased due to the presence of the coordination ligand pyridine, and the pyridine group forms a more stable complex to Cu⁺² than to Co⁺².

The synthesis of a polymer supported dye resin was investigated. The dye group was synthesized via a condensation reaction between poly(p-formylstyrene) and o-chlorophenol in the presence of concentrated sulfonic acid as a catalyst. The intermediate polymer containing a triphenylmethane group was obtained and its structure was confirmed via a model compound. Oxidation of the intermediate to final quinoid dye was studied. The recognition of aniline and its substituted derivatives in methanol by this dye resin was examined.