Acknowledgement 

_________________________________________________________________________ 

I would like to express deep gratitude towards my supervisor Dr. Bhaskar 

Chakraborty, Associate Professor in Chemistry and Head of department, Sikkim 

Government College, Gangtok who has been an integral part in shaping these four 

years in research into a unique and rewarding experience for me. Throughout the 

research work I have received expert criticism, valuable comment and above all his 

best loving care. His creativity has had a significant impact on my research, and his 

passion for his work has in turn provided me with a wealth of opportunities and for 

which I am truly grateful. I am also equally grateful to Dr. Pranab Ghosh, Associate 

Professor in Chemistry, University of North Bengal for guiding me with his advices. 

I have also had the good fortune to interact with faculty members at both Department 

of Chemistry, University of North Bengal and Indian Association for the Cultivation 

of Science, Jadavpur over the course of my PhD career. Heartfelt thanks goes to Prof. 

B. Basu and  Dr. A.K Nanda, Department of Chemistry, University of North Bengal 

for their constructive ideas and for providing NMR spectra of some of the vital 

compounds related to my present work. I would also take this opportunity to thank 

Prof. B. C. Ranu and Prof. A. Dey of Indian Association for the Cultivation of 

Science, Jadavpur for their valuable suggestion relating to the research work. Thanks 

are also due to Dr. M. P. Kharel, Principal, Sikkim Government College, Tadong, Dr. 

S. K. Pradhan, former Principal, Sikkim Government College, Dr. C. B. Sunwar, 

former Principal, Sikkim Government College for their enthusiastic support, constant 

co-operation and for providing research facilities. I am equally grateful to scientist 

in-charge, SAIF, CDRI, Lucknow for providing IR, NMR, MS Spectral data.  

I express my personal appreciation of the assistance given by Dr.Manjit Singh 

Chhetri, Dr.  Saurav Kafley, Shri Govinda Prasad Luitel, Chiran Devi Sharma, 

Neelam Rai and Esmita Chhetri, Department of Chemistry, Sikkim Government 

College in this work. I am equally thankful to Dr. Amalesh Samanta of  Jadavpur 

University, Kolkata for helping in finding out the biological aspects of the entire 

work. Without their support my review work would not have been completed. I would 

like to express my thanks to Mr. Denlock Lepcha, Mr.Bijay Prakash Rai, Mr. Royal  



 
 

 

 

Karthak, Mr. Arun Thapa, staff members of Chemistry Department, Sikkim 

Government College for his continuous support. I would like to express my heartfelt 

thanks to Mrs. Malini Chakraborty for her continuous encouragement. Finally, I 

would like to express my deep gratitude towards my parents, family members and 

specially to my dear wife Yasoda. Their affection ever encouraged me for the entire 

work. Lastly, all the people who rendered valuable help and support in direct and 

indirect ways in bringing this research work to completion are sincerely 

acknowledged. 

 

 

            ( Date : 21.06.2016) 

[PRAWIN KUMAR SHARMA] 

Department of Chemistry, 

Sikkim Government College , 

Gangtok ,Sikkim- 737102