Dr. K. S. Viswanathan
Professor , Chemical Sciences

Matrix Isolation Infrared Spectroscopy:   Our interest is in the study the infrared spectroscopy of molecules trapped in a solid inert gas matrix. The small linewidths of the infrared features observed in this technique allows for the study of molecular conformations and weak intermolecular adducts, such as hydrogen bonded and van der Waals complexes, which have been the focus of our research. We have been studying the conformations of organic phosphates, acetals and ketals, to understand the role of anomeric interactions in conformational preferences. These studies have thrown light on some of the chemical engineering problems encountered in the solvent extraction of metals using organic phosphates as extractants. We have also studied various hydrogen bonded systems, involving H-Ï€ interactions, such as acetylene-chloroform and acetylene-methanol. One of the unique features of the matrix isolation technique, is its ability to trap local minima and which therefore allowed us to study such structures. In some cases, we were also able to observe complexes whose stabilities were clearly enhanced by interactions with the matrix, and which therefore highlighted the role of the matrix in such studies.

Fluorescence spectroscopy of lanthanides:   Our group is also interested in developing techniques for trace level detection of lanthanides and actinides and towards this end we have studied ligand sensitized fluorescence using various ligands. Recently, we have incorporated these ideas towards developing novel room temperature ionic liquids that could serve this purpose. The fluorescence enhancement observed using these methods have led to sub nanomolar detection of some of the lanthanides.

• "Effect of matrix on IR frequencies of acetylene and acetylene-methanol complex: Infrared matrix isolation and ab initio study", Jovan Jose K. V., Shridhar R. Gadre, K. Sundararajan, K. S. Viswanathan, J. Chem. Phys. 127, 104501 (2007)
  
• "Novel room temperature ionic liquid for fluorescence enhancement of Eu3+ and Tb3+", V. Shyamala Devi, S. Maji, K. S. Viswanathan, J. Luminescence, 131, 739 (2011).
  
• "Hydrogen bonded complexes of acetylene and boric acid: A matrix isolation infrared and ab initio studies", K. Sundararajan, N. Ramanathan, Bishnu Prasad Kar, K. S. Viswanathan, J. Mol. Struc.991, 35 (2011).
  
• "Matrix Isolation FTIR Studies of Non-Planar Trans-Stilbene", Bishnu Prasad Kar, N. Ramanathan, K. Sundararajan, K. S. Viswanathan, J. Mol. Struct. 994, 364 (2011)
  
• "Conformations of trimethyl phosphite: Matrix isolation and ab initio studies" N. Ramanathan, Bishnu Prasad Kar, K. Sundararajan, K. S. Viswanathan, J. Phys. Chem. 2011 (DOI: 10.1021/jp205368k)