1. Department of Chemistry, Faculty of Sciences, Egerton University, P.O. Box 536, 20115 Egerton, Kenya
2. Institute of Environmental Research (INFU), Department of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
3. Department of Chemistry, Addis Ababa University, P.O. Box 33658, 1230 Addis Ababa, Ethiopia
4. Department of Microbial Drugs, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
5. Inorganic Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund, Otto−Hahn−Straße 6, 44227 Dortmund, Germany