1. Department
of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
2. Department
of Chemistry, Nanoscience Center, University of Jyvaskyla, P.O. Box. 35, FI-40014 Jyvaskyla, Finland
3. Discovery
Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan Qld 4111 Australia
4. Institut
für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, D-1146, Potsdam, Germany