1. Key Laboratory of Magnetic Molecules and Magnetic Information Materials, Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, 1 Gongyuan Street, Linfen 041004, P. R. China
2. Department of Pharmacy, Changzhi Medical College, 161 East Jiefang Street, Changzhi, Shanxi 046000, P. R. China
3. School of Chemistry & Chemical Engineering, Shaanxi Normal University, 620 West Chang’an Street, Xi’ an, Shaanxi 710062, P. R. China