1. Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
2. Department
of Chemistry, Jadavpur University, Jadavpur, Kolkata 7000032, India
3. Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy