1. Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, 22060, Pakistan
2. Department of Chemistry, Faculty of Sciences, University of Douala, P.O Box 24157 Douala, Cameroon
3. Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan
4. Department of Fundamental Science, Higher Technical Teacher Training College, The University of Bamenda, P.O. Box 39 Bambili, Cameroon
5. Chemistry Department, Higher Teacher Training College, University of Yaoundé I, Yaoundé 47, Cameroon