Theoretical Insights On Coordination And Separation Of Chiral Pesticide Profenofos By Uranyl Complexes Based On Amide Ligands

In the chemistry of organic actinides,it is an important direction to explore methods that can effectively utilize uranyl complexes.The object studied in this paper is a widely used chiral pesticide,R/S-Profenofos（R/S-PFFs）.The physical and chemical properties of its R/S configuration are very similar,but the biological toxicity to animals is very different.Therefore,designing novel uranyl complexes to identify and separate chiral profenofos pesticides plays an important role in environmental protection and food safety.In this paper,amide or thioamide groups were introduced into different ligands and then complexed with uranyl ion,and a new Uranyl-Ligand receptor was successfully constructed.Based on density functional theory（DFT）,the enantiomeric complexing ability and coordination selectivity of acceptors containing amide or thioamide groups to guest R/S-profenofos were systematically studied.The first part of this study systematically studied the relationship between[Uranyl-TMMT]²⁺and[Uranyl-TMMO]²⁺receptors and phosphoryl oxygen in R/S-PFFs by density functional theory（DFT）at the BP86//def2-SVP//RECP theoretical level.The coordination situation of Uranyl,including their surface electrostatic potential,geometric structure,Mayer bond level,electron density topological analysis,localized orbital indicator function map,and infrared spectrogram,and Uranyl are discussed by Gibbs free energy change before and after the reaction-Complexation and separation abilities of[Uranyl-TMMT]²⁺and[Uranyl-TMMO]²⁺receptors toward R/S-PFFs guests in different solvents.The calculation results show that the complexation and separation ability of the thioamide group-containing acceptor for R/S-PFFs guests is stronger than that of the amide-containing acceptor,and all acceptors have stronger selective separation ability for S-type PFFs.The receptors has the strongest separation ability for R/S-PFFs in water and the strongest binding ability to R/S-PFFs in toluene.The second part introduces two thioamide groups into PMMT ligands to compare TMMT ligand with one thioamide group,investigate whether the number of thioamide groups will affect the recognition and separation of Uranyl-Ligand receptor molecules and R/S-PFFs,and further reveal the enantioselective recognition mechanism of Uranyl-Ligand receptor molecules to R/S-PFFs.The results show that PMMT can form a stable asymmetric receptor with uranyl ions,and also has stronger complexation ability to S-type PFF.The thermodynamic properties further showed that under the standard condition（298.15K,1atm）,the complexation reaction between the receptor and the guest could occur spontaneously in water,ethanol,n-octanol,acetone and toluene.The enantioselectivity coefficients of[Uranyl-PMMT]²⁺in the above four organic solvents are more than 90%,especially in polar water,ethanol and acetone,the enantioselectivity coefficients of[Uranyl-PMMT]²⁺are more than 99%.Compared with TMMT with monothioamide group,the recognition and separation ability of PMMT receptor containing bisthioamide to R/S-PFFs was significantly weakened.