1. Department of Chemistry, Ibn Tofail University, ESCTM, P.O. Box 133, 14000, Kenitra, Morocco
2. Department of Chemistry, University of North Texas, P.O. Box 305070, Denton, TX, 76203, USA
3. Department of Chemistry, Faculty of Science, FI-00014, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, Finland