1. Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
2. Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
3. Department of Chemistry and Chemical Biology, Inorganic Chemistry, TU Dortmund, Dortmund, Germany
4. Department of Chemistry, Higher Teachers’ Training College, University of Yaoundé I, Yaoundé, Cameroon