1. Department of Chemistry & Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
2. Department of Chemistry, King Fahd University of Petroleum & Minerals, PO Box 468 Dhahran, 31261, Saudi Arabia
3. African Institute of Biomedical Science & Technology, Dominion House, 211 Herbert Chitepo Street, Harare, Zimbabwe
4. Department of Chemistry & Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa.