1. Department of Chemistry
2. College of Science
3. King Saud University
4. Riyadh 11451
5. Saudi Arabia
6. Faculty of Science
7. Cairo University
8. Giza 12613
9. Egypt
10. H. E. J. Research Institute of Chemistry
11. International Center for Chemical and Biological Sciences
12. University of Karachi
13. Karachi-75270
14. Pakistan
15. Institut für Organische Chemie
16. Universität Stuttgart
17. Stuttgart 70569
18. Germany