1. Key Laboratory of Magnetic Molecules and Magnetic Information Materials MOE, School of Chemistry & Material Science, Shanxi Normal University, Taiyuan, 030006, P. R. China
2. Department of Chemistry, Changzhi University, Changzhi, 046011, P. R. China
3. College of Chemistry & Chemical Engineering, Xinjiang Normal University, Urumqi 830054, P. R. China
4. College of Chemistry, Taiyuan University of Technology, Taiyuan, 030024, P. R. China