Interactions Between Sodium Ion and Constituents of Chitosan: DFT Study

Abstract

Glucosamine and acetylglucosamine are the constituents of chitosan and chitin natural biopolymers. In the present study, the structure and properties of the D-glucosamine monomer (A), N-acetylglucosamine monomer (B), and ion-molecular adducts with Na + cation have been explored. The equilibrium geometrical structure, vibrational spectra of the species have been determined, using the DFT/B3LYP method with the 6-31G(d) basis set. Larger basis sets up to 6-311++G(d,p) were utilized to compute energies of reactions between Na + ion and A and B molecules. The exothermicity and spontaneous character of the adducts formation reactions have been confirmed.

Understanding of the Effect of the Adsorption of Atom and Cluster Silver on Chitosan: An In Silico Analysis

“…Therefore, the more stable structure is Q1, because it has 0.061 eV less than the Q4 and Q5 structures, where the Ag atom interacts with the amine group from chitosan. These results agree with reports in the literature where the interaction of metallic atoms such as Cu and Na are carried out by said amino functional group, as reported [41,42]. The re-optimized structures under the def2-TZVPP50 basis set of MCh-Ag and MCh-Ag-c are shown in Figure 5; both systems find the energy minimum on the anionic charge potential energy surface (Q = −1|e|) and multiplicity 1 and 2, respectively (Table A2), with an adsorption energy of −1.63 eV for MCh-Ag and −2.45 eV for MCh-Ag-c, indicating that the Ag chemically adsorbs the MCh in both systems (Table 1).…”