1. School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
2. Department of Chemistry, Medi-Caps University, A. B. Road, Pigdamber, Rau, Indore 453331, Madhya Pradesh, India
3. Department of Chemistry, Maseno University, P.O. Box 333-40105, Maseno, Kenya
4. School of Pure and Applied Sciences, Mount Kenya University, P.O. Box 342-01000, Thika, Kenya
5. Department of Chemistry, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa