1. Department of Chemistry, Korea University, 5 Anamdong, Seongbuk‐gu, Seoul, 136‐701, Korea, Fax: (+82)‐2‐3290‐3121; phone: (+82) 2‐3290‐3136
2. Laboratoire Charles Friedel, UMR CNRS 7223, Chimie ParisTech ENSCP, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Fax: (+33)‐144‐071‐062