Ion-thermal Synthesis, Structure And Properties Of Zn(?)/Eu(?)/Tb(?)-pyromellitic Acid Metal-organic Framework Compounds

Ionic liquids(ILs)have advatanges of low vapor pressure,wide liquidus range,high chemical and thermal stability.By using ionic liquids as reaction media,ionothermal reactions,a kind of green and safe synthesis method for metal-organic frameworks(MOFs),have attracted great attention.In this work,pyromellitic acid(H4BTeC)as ligand ionothermally reacted with Zn2+,Eu3+,and Tb3+ to give twelve MOFs.It was discussed the roles of two temperature-controlled Zn-MOFs as solid adsorbents in dye removal.It was also discussed about the applications of Eu-and Tb-MOFs as fluorescence probes in the detection of molecules or ions.In the first part,with Zn(NO3):.6H2O as metal source and H4BTeC as ligand,eight kinds of Zn-MOFs were synthesized through ionothermal processes:[RMI]2[Zn2(BTeC)(H2BTeC)](RMI= EMI(Zn1),PMI(Zn2);BMI(Zn3)),[RMI]2[Zn3(BTeC)2](RMI = EMI(Zn4),BMI(Zn5)).[PMI]2[Zn3(BTeC)2]2H20(Zn6),[EMI]4[Zn16(BTeC)9]·4H2O(Zn7)and[PMI]4[Zn12(BTeC)7](Zn8).Temperature-controlled Zn2 and Zn6 obtained under similar reaction process except the reaction temperature have distinct structural differences coming from the deprotoned degree:Zn2 contains partly deprotoned H2BteC2-ligand;while Zn6 has fully deprotoned BteC4-ligand.The differnce in deprotoned degree cause the different hydrogen bondings,which leads to the adsorption difference of Zn2 and Zn6 in the Ponceau 2R:Zn2 has special removal effect to Ponceau 2R.In the second part,Eu(NO3)3.6H2O and Tb(NO3)3·6H2O reacted with H4BTeC in ionothermal environments to produce two Eu-MOFs and two Tb-MOFs:[RMI][M(BTeC)](RMI = EMI,M=Eu(Eul),Tb(Tbl);RMI = PMI,M = Eu(Eu2),Tb(Tb2).Eul exhibits high selectivity fluorescence quenching to acetyl acetone.With Eul as a reference compound,a Tb/Eu co-doped MOF material was syntheized as a fluorescence probe to use in a rapid detection to uric acid.