5-(3-Thienyl)-10,15,20-triethyl-21H,23H-porphine was prepared by the ring closure of pyrrole and a 3:1 mixture of propionaldehyde and 3- thiophenecarbaldehyde. Oxidative polymerization of the porphyrin with typical oxidants such as FeCl3 gave a polythiophene derivative bearing porphyrins directly bound to the β-position of the main chain. The very bulky β-substituents allowed the polymerization to proceed regioselectively even at room temperature, resulting in the formation of the β-substituted polythiophene with an HT-HT content of more than 90%. The porphyrin substituents aligned cofacially along the main chain, which served as the catalytic site for the four-electron reduction of O2 to H2O (O2 + 4e- + 4H+ = 2H2O) when cobalt ions were introduced into the porphyrins. A novel platinum-free catalyst for the reduction of O2 for fuel cell cathodes, 1/CB (M = CoII), was thus prepared by the electropolymerization of the porphyrin at the surface of carbon black (CB), which reduced O2 with four electrons at more poritive potentials than the standard two-electron reduction potential of O2 to H2O2.
|出版ステータス||Published - 2006 12 1|
|イベント||55th Society of Polymer Science Japan Symposium on Macromolecules - Toyama, Japan|
継続期間: 2006 9 20 → 2006 9 22
|Other||55th Society of Polymer Science Japan Symposium on Macromolecules|
|Period||06/9/20 → 06/9/22|
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