The Synthesis And The Study In Catalytic Activity Of POMs-MOFs Compounds

Objective According to the principle of molecular self-assembly,we have designed and synthesized new polyoxometalates-based compounds,and studied synthesis rules of compound 1～4;we have explored the relationship between the microscopic structure and macroscopic properties by regarding the synthesis of Aspirin as reaction model.Methods All compounds have been synthesized on basis of hydrothermal technique methods and structurally characterized by single crystal X-ray diffractions,elemental analyses,XRPD and IR.Meanwhile,by adopting double wavelength UV method,we studied effects of different time and temperature on the yield of Aspirin and the conversion of Salicylic acid.Results The four polyoxometalates-based compounds have been synthesized.Na[Ag₄（pyttz）₂][H₂PMo₁₂O₄₀]（1）;[Ag₆tz₆][H₃PMO₁₂O₄₀]₂·6H₂₀（2）;[K₁₀tZ₆][H₅PMO₁₂O₄₀]·2H₂₀（3）;[Cu9（2-pytz）₆（H₂O）₆（OH）₆(P₂W₁₈O₆₂]·3H₂0（4）;Compounds 1～4 were used as catalyst to synthesis Aspirin,and the yield of Aspirin and the conversion of Salicylic acid were used as indexes to measure the activity of these compounds,and then the catalytic activity of compound 1-4 were evaluated,and the results showed that compound 1～4 have good catalytic activity.Conclusion We have synthesized 4 POMs-MOFs compounds by choosing Htz,H2pyttz and Hpytz as organic ligands,bridging POMs base unit with bonds between the ligands and intermolecular forces in the presence of Ag⁺ and Cu²⁺.The results of catalytic synthesis of Aspirin show that the catalytic activity of compounds were influenced by compositions and structures heavily,compound 3 and 4 showed better catalytic activity,the yield of Aspirin reached 92.9%and 90.7%respectively;compound 3 and 4 showed general catalytic activity,the yield of Aspirin reached 86.8%and 83.7%respectively.This may be related to the types of composition POMs and the structure of compounds.