Ab initio analysis on the interaction of CO2 binding to peracetated D-glucopyranose.

CO2-philes can be utilized as additives, surfactants, and a potential phase-change physical solvent or absorbent for CO2, so the design and synthesis of CO2-philes typically non-fluorous compounds is important to develop more application areas of CO2. Researchers have recently reported that peracetated D-glucopyranose has high solubility in CO2. In order to study the interaction properties between sugar acetates with CO2, 1,2-di-O-acetyl-α-D-glucopyranose and 1,2-di-O-acetyl-β-D-glucopyranose were decided as substrates after initial chemical stimulations with peracetated D-glucopyranose, and the complex model was one CO2 molecule combined with one sugar substrate (1:1). Ab initio calculations of these two systems were accomplished including geometry optimizations with HF/3-21G, B3LYP/6-31+G**, and single point energies calibration with MP2/aug-cc-pVDZ. The results indicated that hydrogen atoms can interact with CO2 by C-H··O hydrogen bond, but the dominant ones are the interactions of oxygen atoms in substrates with a CO2 molecule. It was also found that the binding energies increased when more oxygen atoms of substrate interacted with CO2, but were not affected by their chemical environment. The interaction of sugar substrate with CO2 is distance related, and should be an electrostatic interaction not only Lewis acid-Lewis base and hydrogen bond interactions. Therefore, it can be expected that one CO2-phile could interact with more CO2 molecules if more acetate-like groups or oxygen atoms were introduced into the molecular structure based on all these results, and this can be a guideline for design CO2-philes.