The Selectivity Prediction And The Mechanism Study Of Phosphine Ligand-controlled Pd、Co Catalyzed Reactions

The combined development model of "artificial intelligence + large chemical industry" represents the future development direction of the chemical industry.However,the field of fine chemical homogeneous catalysis has not yet had enough data to satisfy the "big data" method and the "machine learning" method.At the same time,multiple regression analysis methods have been widely used to establish catalytic reaction models.Phosphine ligands are widely used in homogeneous catalytic reactions.Experimental studies have found that the regioselectivity of catalytic reactions can be directly controlled by changing the structure of phosphine ligands.Therefore,quantifying the spatial and electronic effects of phosphine ligands is of great significance for in-depth understanding of the properties of phosphine ligands.Studies have found that the lowest electrostatic potential parameters of molecules can be effectively used to quantify the steric and electronic effects of phosphine ligands.But at present,this parameter has not been widely used to explain and predict the reactivity of molecules.This thesis is divided into five chapters.The first chapter introduces the current status of phosphine ligands regulating homogeneous catalytic reactions and the current research status of using mathematical models to predict the selectivity of phosphine ligands regulating catalytic reactions.The second chapter introduces the theoretical principles and calculation methods of various parameters used in this thesis.In the third chapter,through computational chemistry research methods,a number of physical parameter values that can represent the spatial and electronic properties of phosphine ligands are obtained,and the correlation between the lowest electrostatic potential parameters and the infrared vibration parameters is discussed.In Chapter4,according to the calculated physical parameters such as the lowest electrostatic potential parameters,a mathematical model is established by regression analysis,and the regioselectivity of the classical Suzuki reaction catalyzed by Pd is predicted.In Chapter 5,the density functional theory method is used to perform a detailed mechanism study on the selectivity of Co-catalyzed reaction controlled by phosphine ligands,and an attempt is made to use mathematical models to explain and predict the selectivity of Co-catalyzed reactions regulated by phosphine ligands.The main research contents of the thesis are as follows:Firstly,in order to obtain the spatial and electronic properties of the phosphine ligands,and find the relationship between the lowest electrostatic potential parameter and the infrared vibration parameters: In this paper,the following six physical parameters of 38 phosphine ligands were calculated.Using the stepwise regression technique,the calculated infrared vibration parameters and the lowest electrostatic potential parameters were regressed and analyzed,and it was found that when grouping according to the number of aryl groups,there is a strong correlation between the lowest electrostatic potential parameters and the infrared vibration parameters(the fitting goodness was higher than 0.9).Among them,the infrared symmetrical bending vibration of the three P-C bonds contributed the most to the correlation between the two parameters.Secondly,in order to predict the selectivity of Pd-catalyzed Suzuki reaction mediated by phosphines,the 27 phosphine ligands in the training set were classified as described in the previous chapter.Correlation analysis and multiple regression analysis between the regioselectivity of the classified phosphine ligand set and the physical parameters of the phosphine ligands obtained a mathematical model with high predictive ability and certain chemical significance.The final model was used to predict the regioselectivity of the reaction,and a result consistent with the experiment was obtained.Thirdly,the phosphine ligand-regulated Co-catalyzed C-H functionalization reaction of eneyne and benzaldehyde was carried out to study the reaction mechanism and predict the selectivity: When the cis-1,2-bis(diphenylphosphino)ethylene(dppen)participated as the ligand,the reaction mechanism mainly included oxidative cyclization,C-H metathesis and reduction elimination steps.The C-H metathesis was the rate-determining step.The parameters described in Chapter 2 were also used to predict the selectivity of this reaction.