Theoretical Studies on the Chemical Structure of Carboxymethyl Chitosan

Abstract:

The density functional theory (DFT) calculations explored the structural optimization and the frequency of N-carboxymethyl chitosan (N-CMCS) and O-carboxymethyl chitosan (O-CMCS). For the isomers, the calculations comparatively were performed. The charge distribution and frontier molecular orbit were analyzed by using the natural bond orbital (NBO) method. The results showed: the two rotational isomers a and b can stably exist, with the stability order a>b; N-carboxymethyl chitosan reaction active sites are concentrated in -OH and -NHCH2COOH, while O-carboxymethyl chitosan reaction active sites are concentrated in -NH2 and -CH2COOH; The water-soluble mechanism of carboxymethyl chitosan was investigated deeply, on the one hand, the presence of carboxymethyl of carboxymethyl chitosan had a tendency to ionize H+, on the other hand the carboxymethyl increased the distance and weakened the hydrogen bonds between molecules, even though Einstein shift H-bond is formed in the carboxymethyl chitosan molecules.

• Periodical: Advanced Materials Research (Volumes 160-162)
• Pages: 1822-1827
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.160-162.1822
• Online since: November 2010
• Authors: Xi Lu, Juan Qin Xue, Yu Jie Wang, Wei Bo Mao, Ming Wu, Jing Xian Li
• Keywords: Carboxymethyl Chitosan, Density Function Theory (DFT), Frontier Molecular Orbital, H-Bonding, Reactivity

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