1. Department of Chemical Sciences, University of Johannesburg, Doornfontein, P.O. BOX 17011, 2028 Johannesburg, South Africa
2. School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban, 4000, South Africa
3. Department of Chemical Sciences, Olabisi Onabanjo University, PMB 2002, Ago-Iwoye, Nigeria
4. Department of Biochemistry, Faculty of Natural and Applied Sciences, Nile University of Nigeria, Abuja, Nigeria