a
College of Chemistry, Chongqing normal university, Chongqing, PR China
E-mail: Jianzhou888888@163.com
;
Fax: +86-775/2622315
;
Tel: +86-775/2622315
b
College of Chemistry and Material, Yulin Normal University, Yulin 537000, PR China
c
Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Chemistry and Chemical Engineering of Guangxi Normal University, Guilin 541004, P.R. China