1 College of Material Science and Engineering, Shanghai University, Shanghai, 2000444, China.
2 Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China tel.: +86 21 6613 2663; fax: +86 21 66134080. wclu@shu.edu.cn.
3 College of Life Sciences, Shanghai University, Shanghai, 2000444, China tel.: +86 21 6613 7038; fax: +86 21 66134080. nbyzm@yahoo.com.cn.
4 Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China tel.: +86 21 6613 2663; fax: +86 21 66134080.