Chracterization And Correlation Of Intermolecular Weak Interactions In DES-Containing Systems

In the micro world,there is a certain interaction between adjacent molecules or molecular polymers,called intermolecular weak interactions.Compared to the chemical bonds formed between atoms in a molecule,the energy of weak intermolecular interaction is 1 to 2 orders of magnitude smaller,but the large number of molecules in the macroscopic system and the accumulation of intermolecular weak interactions,will affect the physical-chemical properties and structure of the macroscopic system.So the impact can not be ignored.Therefore,research on weak interactions is very important.The most common deep eutectic solvent is mixed by choline chloride as the hydrogen bond acceptor,the researches using this type of solvent to absorb sulfur dioxide have relatively good experimental data.In this paper,quantum computations are used to study the changes in configuration and energy after deep eutectic solvents absorb SO₂.The quantitative relationship between the interaction energy and the various intermolecular weak interactions in deep eutectic solvents is also studied,mainly from the following aspects:?1?Energy calculated by CCSD?T?/CBS used as a criterion,select systems of THIO-SO₂ and SO₂-Cl^-,calculate the binding energy under a variety of different basis groups and methods,then compare and choose the one with minimum error which is m062x/6-311++?d,p?.?2?Determine choline chloride as the hydrogen bond acceptor?HBA?,malonate,urea,thiourea,ethylene glycol,and glycerol as the hydrogen bond donor?HBD?to form deep eutectic solvents to absorb SO₂.Explore the mechanism of SO₂ absorption by deep eutectic solvents,as well as the characteristics of the structure and energy changes from deep eutectic solvents.?3?Calculate the interaction energy and the bond critical point density of the disomic complexes:HBD-Cl^-,HBD-SO₂,and HBD-BBD,it was found that they have a strong linear correlation relationships between them.Calculate the interaction energy and the bond critical point density of the triad complexes:2HBD-Cl^-,2HBD-SO₂,and HBD-SO₂-Cl^-,it was found that The linear correlation between them become weaker,indicating that when the number of monomers in the system increases,the linear correlation relationship of the interaction energy and total the critical point density of the weak interaction bond will become weaker.?4?Taking the cluster systems of ChCl-2THIO absorbing SO₂ by two different mechanisms as examples,the interaction energy,charge transfer,and critical point density of bonds between each monomer and SO₂ in the deep eutectic solvent are calculated separately.Studies have shown that when SO₂ is absorbed by deep eutectic solvents,there is a multibody effect between the interaction energy of each component and SO₂,and the intermolecular weak interaction is only related to the distance.Therefore,the more monomers in the system,the worse the correlation between interaction energy and weak interactions.