1. Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Chemistry and Materials Science of Shanxi Normal University, Taiyuan 030032, China
2. Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Taiyuan 030032, P. R. China
3. School of Chemistry, Taiyuan University of Technology, Taiyuan 030024, P. R. China