1. a School of Chemistry , University of Hyderabad , Hyderabad, 500 046, India E-mail:
2. b Department of Chemistry , Jackson State University , Jackson, Mississippi, 39217-0510, USA E-mail:
3. c Department of Knowledge-Based Information Engineering , Toyohashi University of Technology, Tempaku-cho , Toyohashi, 441, Aichi-ken, Japan E-mail: