[1] Univ Johannesburg, Dept Chem Sci, Johannesburg, South Africa
[2] Univ Johannesburg, Analyt Facil, POB 524, ZA-2006 Auckland Pk, South Africa
[3] Univ Johannesburg, Dept Sci & Innovat, Natl Res Fdn South African Res Chair Initiat DSI, ZA-2028 Doornfontein, South Africa
[4] Univ Johannesburg, Ctr Synth & Catalysis, POB 524, ZA-2006 Auckland Pk, South Africa
[5] Univ South Africa, Coll Sci & Engn & Technol, Dept Chem, Florida Sci Campus, Johannesburg, South Africa