Intramolecular hydrogen bond and vibrational spectroscopic study of cellulose oligosaccharide using density functional theory

The structural geometry, intramolecular hydrogen bond (H-bond) and IR spectra of cellulose oligosaccharide with degree of polymerization up to 5 are studied by density-functional theory (DFT) at CAM-B3LYP/6-311G(d,p) level in this study. Bader’s QTAIM is used to elucidate long-range forces of non-bonding atom such as intramolecular H-Bond and van der Waal’s interaction. The electrostatic potential map is used to depict the reactive sites of the oligosaccharides. A comparative approach was used validate the IR spectra of the cellulose oligomer. The simulated IR spectra of cellulose oligomers have good agreement with the experimental IR spectra of cellulose. This research has significant importance on characterization of oligomeric cellulose for specific purposes such as mechanistic study of proton transport and ion adsorption that close related to H-Bond.