1. State Key Lab of Superhard Materials College of Physics Jilin University Changchun 130012 P. R. China
2. College of Chemistry and Life Science Institute of Functional Molecules Chengdu Normal University Chengdu 611130 P. R. China
3. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China