1. Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 P. R. China
2. Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province Shantou University Shantou Guangdong 515063 PR China
3. Department of Chemistry Engineering Research Center of Advanced Rare Earth Materials (Ministry of Education) Tsinghua University Beijing 100084 P. R. China