1. Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. Box 15000, Halifax, NS B3H 4R2, Canada.
2. Department of Chemistry, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan.
3. Department of Chemistry, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada.