How boron is adsorbed by d-glucamine: A density functional theory study

In this study, we carried out a molecular scale analysis of boron adsorption by density functional theory (DFT) computations.All 30 species of boron-bonding d-glucamine were considered in an adsorption site model. Moreover, a total of 24 bis-d-glucamine adsorption sites, including five-membered and six-membered chelate rings were calculated. The values of ΔH and ΔG in the boron adsorption reaction were obtained by the PW6B95-D3ATM/ma-def2-TZVP//PBE0/6-31 + G(d,p) level of theory with the SMD solvation energy. Moreover, the 11B NMR chemical shift was also computed to compare the experimental results.Our computational results concluded that the adsorption of boron was achieved through two d-glucamine groups. The boron-adsorbed species has five-membered and/or six-membered chelate rings. The predicted 11B NMR chemical shift of the species matched with the experimental value. We conclude that the adsorption of boron by the bis-d-glucamine site is an endothermic reaction despite adsorption, which means the driving force of the reaction is entropy. These results suggested that there is a possibility for improvement in boron adsorption from the design of the adsorption functional group.Graphical abstract

Source: Computational and Theoretical Chemistry - January 29, 2019 Category: Chemistry Source Type: research