1. Department of Chemistry, University of North Bengal, Darjeeling 734013, West Bengal, India
2. Department of Chemistry, Siliguri College, Siliguri, Darjeeling 734001, West Bengal, India
3. Department of Chemistry, University of Gour Banga, Mokdumpur, Malda 732103, India
4. Alipurduar University, Alipurduar 736123, West Bengal, India
5. Department of Chemistry, Malda College, Malda 732101, India