1. Department of Chemistry, Guru Nanak Dev University, Amritsar 143005, India
2. School of Molecular and Cell Biology, University of the Witwatersrand, Private
Bag 3, Wits, 2050 Johannesburg, South Africa
3. School of Chemistry and Physics, University of KwaZulu Natal, P/Bag X54001, Westville, Durban 4000, South Africa
4. Department of Chemistry, Khalsa College, Amritsar 143005, India