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Molecular conformation of molecule is influenced by several non-covalent interactions such as H-bonding, stacking interaction, exerted by surrounding molecules. The Weak interactions persuade the very decisive role in stabilizing geometrical arrangement of molecules. The present study deals with this particular approach. In order to develop new flexible models for studying aromatic interaction, 3-cyano-4,6-dimethyl,2-oxo-nicotinonitrile, and 4-methylsulfanyl-1H-pyrazolo[3,4-d]pyrimidine based flexible models have been synthesized. We have synthesized polymethylene and methyl benzene linked dimers of these heterocyclic bases. Due to presence of flexible nature in molecules, they arrange them in such a way that conformational polymorphism observed via stabilization of packing through non covalent interaction in different orientation. In solution state, degree of freedom of a molecule is free and most stable conformation can be predicted by NMR and CD - spectra, whereas in solid state, molecular conformation is studied by x-ray crystallographic techniques.

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Rashmi Dubey, Ph.D. (Organic Chemistry). Five years experience in the filed of organic synthesis and applications. Presently affiliated with Dep. of Applied Chemistry, Sejong University, Seoul (Republic of Korea) as a postdoctoral research scientist.

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