1. State Key Laboratory of Rare Earth Materials Chemistry and Applications & PKU‐HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R.China, Fax: 86‐10‐62751708
2. College of Chemistry and Chemical Engineering, The Key Laboratory of Organic Synthesis of Jiangsu Province, Suzhou University, Street Shizi No. 1, Suzhou 215006, P. R.China, Fax: 86‐512‐65224783