1. Institut für Organische Chemie Albert‐Ludwigs‐Universität Albertstraße 21 79104 Freiburg Germany
2. Molecular Sciences Institute School of Chemistry University of the Witwatersrand PO Wits 2050 Johannesburg South Africa
3. Department of Chemistry and Polymer Science Stellenbosch University Private Bag X1, Matieland 7602 Stellenbosch Western Cape South Africa