1. Institute of Functional Material Chemistry
2. Faculty of Chemistry
3. Northeast Normal University
4. Changchun 130024
5. P. R. China
6. Key Laboratory of Molecular Epigenetics of the Ministry of Education
7. Institute of Cytology and Genetics
8. Changchun
9. Department of Chemistry
10. Durham University
11. Durham
12. UK
13. Department of Physics
14. Durham DH1 3LE