1. Department of Chemistry, University of Calcutta, 92 A.P.C.
Road, Kolkata 700 009, India
2. Department of Chemistry, Panchakot Mahavidyalaya, Sarbari, Purulia,
Pin 723121, India
3. Departament
de Química, Universitat de les Illes Balears, Crta. de Valldemossa
km 7.5, 07122 Palma
(Baleares), Spain
4. Department of Chemistry, Bengal Engineering and Science University, Howrah 711 103, India
5. Institut fuer Physikalische und Theoretische
Chemie, Technische Universitaet Graz, 8010 Graz, Austria