Nucleoside Structure using Ab-Initio Computational Methods

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Chashmniam, Saeed | 2014

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 45960 (03)
University: Sharif University of Technology
Department: Chemistry
Advisor(s): Tafazzoli, Mohsen
Abstract:
The spin – spin coupling constants have been calculated by the Gaussian 2009 program in order to study the nucleosides conformation. To study the effect of solvent, the calculations were performed in four solvent including water, DMSO, chloroform and Carbon tetrachloride.
Also, the comparison is done on two computing methods including DFT (B3LYP) and HF using 6-311++g** and 6-311g basis set.One bonding (1JC-H), two bonding (2JN-H, 2JC-H) and three bonging coupling constants (3JC-H) have been calculated for unpaired adenosine, thymidine and uridine molecules.Formation of intra-molecular hydrogen bond and electron pair repulsion, respectively, makes the compounds stable and unstable. Because of the nucleosides are polar molecules, they are more stable in polar solvent than non-polar solvent.Also, dependence of the coupling constants on the torsion angle, the Karplus equation, is obtained
Keywords:
Spin-Spin Coupling ; Conformation ; Karplus Equation ; Ab Initio Calculation ; Nucleotides

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