1. a Department of Chemistry , University College of Science, University of Calcutta , 92, A.P.C. Road, 700 009, Kolkata, India
2. b Panihati Mahavidyalaya , Sodepur, Barasat Road, 700 010, Kolkata, India
3. c School of Chemistry, The University of Reading , PO BOX 224, Whiteknights, Reading RG6 6AD, UK
4. d The State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences , Fuzhou, Fujian, 350002, P.R., China