1. Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education Department of Chemistry Northeast Normal University Changchun Jilin 130024 P. R. China
2. Center for Advanced Analytical Science c/o School of Chemistry and Chemical Engineering Guangzhou University Guangzhou Guangdong 510006 P. R. China
3. Northeast Normal University Library Changchun 130024 P. R. China
4. Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory of UV-Emitting Materials and Technology Ministry of Education Northeast Normal University Changchun 130024 P. R. China