1. Department of Chemistry, University College of Science, University of Calcutta, 92, A.P.C. Road, Kolkata, West Bengal 700009, India
2. Department of Electronic Science, University of Calcutta, 92, A.P.C. Road, Kolkata, West Bengal 700009, India
3. School of Chemistry, The University of Reading, P.O. Box 224, Whiteknights, Reading RG6 6AD, United Kingdom
4. Departament de Química, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, Palma, Baleares 07122, Spain