1. Department of Chemistry, Faculty of Science, University of Kuwait, P. O. Box 5969, 13060 Safat, Kuwait
2. Department of Chemistry, Girls College for Arts, Science and Education, Ain Shams University, P. O. Box 11757 Heliopolis, Cairo, A. R., Egypt
3. Department of Chemistry, Faculty of Science, Cairo University, Giza, A.R. Egypt