Synthesis Of Mo / W-based Polyoxometalates-Based Compounds And Electrochemical Sensing Of Dopamine

Objective:The excellent redox properties of polyoxometalates,a new polyoxometalates-based crystalline compound is proposed to be synthesized,and electrochemical detection methods are used to study its catalytic activity on small biomolecules to dopamine obtain crystalline compounds that can detect small biomolecules dopamine.Provide a new way to detect small biological molecules.Methods:Organic ligands?1,2,3-trz and bix?,metal ions?Cu?and polyoxometalates were used as basic materials,and the self-assembly principle was used as the theoretical basis.The hydrothermal synthesis method was used to synthesize the obtained crystalline compounds.X-ray single crystal diffraction,X-ray powder diffraction,X-ray photoelectron spectroscopy,Raman spectroscopy,scanning electron microscopy,elemental analysis and infrared spectroscopy were used to analyze the structure;Using the glassy carbon electrode as the working electrode,platinum wire as the pair electrode and Ag/Ag Cl as the reference electrode,the activity of the new crystal materials for the detection of dopamine molecules was evaluated by several electrochemical analysis methods,including cyclic voltammetry,differential pulse voltammetry and alternating current impedance.Results:Four new polyoxometalates-based crystal compounds were synthesized.Their molecular formulas are:[H₃?Cu?bix?₂?][PW₁₂O₄₀]·2H₂O?1?;[H₄?Cu?bix?₂?][Si W₁₂O₄₀]·2H₂O?2?;[Cu₃?trz?₂?Mo O₄?₂]·H₂O?Cu TRZMo O₄??3?;[Cu₃?trz?₄Cl₂]?Cu TRZCl??4?.The electrochemical evaluation of small molecules of dopamine was performed to evaluate the performance of the above four complexes.It was found that compound 1,2and 3 had activity to detect dopamine molecules.Among them,compound 1 and 2 have the same structure except that the polyacid cores are different,and the detection limits of compounds 1 and 2 for dopamine can reach 0.5?mol·L^-1 and 0.8?mol·L^-1,respectively.Among the compound 3 and 4,only the compound 3 has the activity of detecting dopamine.In order to further enhance the catalytic activity of the compound 3,a compound 3/polypyrrole hybrid material was prepared.Catalytic activity,the enhancement of this activity is of great importance in relationship with the mass ratio between the two components.Finally,we explored a composite material with the best effect,with a detection limit of 80 nmol·L^-1.Conclusion:In summary,four kinds of novel polyoxometalates-based crystalline compounds were synthesized by hydrothermal synthesis in this experiment,which showed excellent electrocatalytic activity in the detection of biological small molecule dopamine,expanded the family of polyoxometalates-based crystal compounds and its application in electrochemical sensing.The synergistic effect of different properties between polyacid based nanomaterials and polypyrrole improves the electrochemical activity of dopamine detection,which provides important reference for later research on to non-enzyme electrochemical sensors.