1. Department of Chemistry, Faculty of Science, University of Kinshasa, P.O. 190, Kinshasa 63090201, Democratic Republic of the Congo
2. Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven B-3001, Belgium
3. Research Center for Theoretical Chemistry and Physics in Central Africa, Faculty of Science, University of Kinshasa, Kinshasa 63090201, DR Congo
4. Department of General Chemistry (ALGC), VUB, Brussels 1050, Belgium