1. Catalysis and Peptide Research Unit, School of Health Sciences; University of KwaZulu-Natal; Durban 4001 South Africa
2. School of Chemistry and Physics; University of KwaZulu-Natal; Durban 4001 South Africa
3. CIBER-BBN, Networking Centre on Bioengineering; Biomaterials and Nanomedicine; Barcelona Science Park 08028 Barcelona Spain
4. Department of Chemistry, College of Science; King Saud University; P.O. Box 2455 Riyadh 11451 Saudi Arabia
5. Department of Organic Chemistry; University of Barcelona; 08028 Barcelona Spain