1. Institute of Chemistry Martin-Luther University Halle-Wittenberg Kurt-Mothes Str. 2 D-06120 Halle/Saale Germany
2. Department of Chemistry Faculty of Science Cairo University P.O. 12613 Giza Egypt
3. Shaanxi International Research Center for Soft Matter State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi An Shi Xi'an 710049 P. R. China
4. Wanhua Chemical Group Co Ltd. Yantai 265505 P. R. China