Overview:
This project investigates the changes in 13C NMR chemical shifts of mono-, di-, and trisaccharides in the solid state using density functional theory (DFT). The focus is on understanding how glycosidic linkages and crystal water molecules influence these chemical shifts.
Data Sources:
Experimental crystal structures of saccharides from the literature were optimized computationally. NMR data for known systems were used to establish a correlation between calculated shielding constants and experimental chemical shifts.
Tools and Technologies Used:
The chemical shifts were calculated using density functional theory (DFT) combined with the gauge-including projector augmented wave (GIPAW) method, implemented in the CASTEP program.
Key Findings:
Significant changes in 13C NMR chemical shifts (up to 14 ppm) occur at glycosidic linkage atoms when transitioning from monosaccharides to disaccharides. Crystal water molecules also affect nearby atoms, though the shifts (2-5 ppm) are smaller. No simple correlation between bond angles, distance to crystal water, and chemical shifts was found.
Learn More:
For a detailed exploration of this project please refer to the paper.