1. Department of Chemistry, Korea University, 208 Seochang, Chochiwon, Chung-nam 339-700, South Korea
2. JSI Silicone Co., Rm#1511, Megacenter, SK Technopark, Jungwon, Seongnam 462-807, South Korea
3. Department of Chemistry, Ajou University, Suwon 443-749, South Korea
4. Center for Fuel Cell Research, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Sungbuk-gu, Seoul 136-791, South Korea