Study On Density Functional Theory,Application And Synthesis Of Novel Polyoxometalate-Based Ionic Liquids Salts

Heteropoly acid is a kind of classical inorganic metal cluster material,although it has excellent catalytic performance,but due to their deliquescence,high solubility in polar solvents and poor plasticity,it is seldom being used in the field of electrochemistry.These problems can be solved by using as heteropoly acid as anions to hybridize with ionic liquids which had high flexible structures.The prepared hybrid materials are not only poses excellent properties,but also exhibits their advantages.In this paper,a non-toxic,green and environment-friendly synthesis method is proposed to overcome the disadvantages of the traditional toxic and expensive synthetic process.We also synthesized and investigated three new types of heteropoly acid ionic liquid salt.Meanwhile their geometric configurations,charge distribution,binding energy and density of states have been analyzed by a series of density functional calculations,we verified and predicted their properties of these materials directly or indirectly,these works can offer valuable reference to the quantitative structure-activity relationship and other relevant theoretical research of heteropoly acids and hybrids.The main research achievements are as follows:1.The acidic ionic liquid 1-?2-hydroxy-3-sulfonate?propyl-3-propyl-imidazole ionic liquid salt[PIM-CHP]was synthesized by a new synthetic technology.The optimum synthetic conditions of[PIM-CHP]were determined by orthogonal experiments.which was the reaction temperature at85?,reaction time at 5 h and the acid replacement temperature is 95?.2.We use[PIM-CHP]as cationic component,and three substituted heteropoly acids as anionic components respectively to synthesis three novel organic-inorganic hybrid materials([PIM-CHP]₃·PW₁₁MoO_40,[PIM-CHP]₃·PW₉Mo₃O₄₀0 and[PIM-CHP]₃·PW₆Mo₆O₄₀).3.Various methods were used to characterize heteropoly acid and hybrid materials.The results showed that hybrid materials not only had higher conductivity and lower activation energy.But also they all had high plasticity due to their reversible phase transition behavior from quasi-solid state to liquid state.In addition,the mechanism of proton conductivity was determined by the measurement of proton conductivity.4.A density functional theory study method on three heteropoly acids and three hybrids is carried out by MaterialStudio software.The equilibrium molecular geometry of their steady structures are determined after 100 steps opitimizing calculation.According to their equilibrium molecular gemetry,we found that the lower number of replacement molybdenum atoms can't produce much influences on electronic structure and density of states,but an excessive replacement molybdenum atoms cause much influence on their bond length.Their electrophilic/nucleophilic activity centers of heteropoly acids and heteropoly anions were determined through calculation and comparison.The charge number of heteropoly anions was increased and their nucleophilicity was enhanced after hybridization.We also found their stability relation by fractional calculation.