1. Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 P. R. China
2. Group of Chemistry and Chemical Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Chengdu Organic Chemicals Co., Ltd. Chinese Academy of Sciences Chengdu 610041 P. R. China
4. Department of Chemistry and Chemical Engineering Beijing University of Technology Beijing 100022 P. R. China