1. Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China, http://www‐chem.ust.hk/Faculty%20staff/leung/content.htm
2. School of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, China
3. Department of Chemistry, The Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Kowloon, Hong Kong, China
4. School of Biological and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, China