Preparation of catalyst for polymer electrolyte fuel cell using the Marimo-like carbon

3.3 Further functionalization by click chemistry To confirm the further possible functionalization using existing methylene groups, thiol-ene reaction was applied, as illustrated in Scheme 2. Figure 5 display the new observed peaks by addition of thioglycolic acid. This indicates that carboxyl groups could be added to PCL main chains using carboxythiol compound. The conversion was calculated to be ca. 50% by the 1H-NMR chart. Moreover, other thiol compounds such as mercaptoehanol or aminoethanethiol would be applicable for introducing hydroxyl groups and primary amino groups, respectively. It is probable that such functionalization would be influenced to the properties such as solubility and so on. Because polarity and bulkiness of the modified PCL would change by addition of the other moieties. Their properties depend on the kinds of thiol compounds added. Both efficiency of further functionalization and chemical properties of corresponded polymers will be discussed in next papers. Typical functional groups would be useful for further chemical reactions, functional group transformation, or chemical conjugation. Consequently, this study could prove the utility of the Petasis reagent for direct methylenation even in polymeric materials. In future, we will report the applications of methylenated polyesters.