1. Department of Chemistry; National Institute of Technology Rourkela; Orissa 769008 India
2. Department of Life Science; National Institute of Technology Rourkela; Orissa 769008 India
3. Theoretical Chemistry Laboratory, Department of Chemistry; National Institute of Technology Rourkela; Orissa 769008 India
4. Department for X-Ray Diffraction; Institut für Anorganische Chemie, Universität Duisburg-Essen; D-45117 Essen Germany