1. Department of Chemistry, Center for Molecular Catalysis (CMC), College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
2. Department of Chemistry, Kyungpook National University, Taegu, 702-701, Korea
3. Department of Chemistry, College of Natural Sciences, Pusan Women's University, Pusan 616-736, Korea
4. Department of Chemistry, College of Natural Sciences, Pusan National University, Pusan 609-735, Korea