1. Department of Chemistry, National Dong Hwa University, Hualien 974301, Taiwan R.O.C
2. Chemistry Division, Department of Sciences and Humanities, VFSTR (Deemed to be University), Vadlamudi, Guntur 522213, A.P., India
3. School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban 4000, South Africa