1. Physical and Theoretical Chemistry LaboratoryFaculty of Science, University of Yaoundé I P.O. Box 812 Yaoundé Cameroon
2. Computational Chemistry LaboratoryHigh Teacher Training CollegeUniversity of Yaoundé I P. O. Box 47 Yaoundé Cameroon
3. Department of Organic ChemistryUniversity of Valencia Dr. Moliner 50, Burjassot Valencia 46100 Spain
4. Department of Chemistry and Chemical BiologyMcMaster University 1280 Main Street West, Hamilton Ontario L8 S 4 L8 Canada