Preparation And Fluorescent Sensor Properties Of MOFs Based On 1H-Benzotriazole

Metal-organic frameworks(MOFs)are a new type of multifunctional composite materials with frame structure.MOFs with luminescent properties have become an excellent platform for the design of luminescent sensors.The inexpensive,easy synthesis,high efficiency and modifiable luminescent MOFs(LMOFs)have received extensive attention.In this paper,six kinds of MOFs with excellent luminescent properties were synthesized using benzotriazole(BTA)as the core,and then four kinds of luminescent complexes were synthesized by modifying BTA.After characterizing structures,we focus on their luminescent properties and detection ability as fluorescent sensors.First,BTA was used as the core,and co-ligands(5-tbuip or oba)were used to self-assemble with transition metal salts.Six LMOFs were obtained by hydrothermal method.[Zn3(BTA)2(5-tbuip)2]n(MOF-1),[Zn6Na5(BTA)6(oba)6(DMF)2]n(MOF-2),[Zn(BTA)2]n(MOF-3),[Cd9(BTA)6(5-tbuip)6O2]n(MOF-4),[Cd3(BTA)2(5-tbuip)2]n(MOF-5)and[Co3(BTA)2(5-tbuip)2]n(MOF-6).All the LMOFs have excellent thermal and chemical stability.Based on fluorescence quenching,MOF-1,3,4,5 can recognize Fe3+ and Cr2O72-in aqueous solution with anti-interference ability.The limit of detection(LOD)of MOF-4 for Fe3+was 2.79 × 10-7 M,MOF-1 for Cr2O72-was 9.81 × 10-6 M.In the presence of Pb2+ in aqueous solution,the fluorescence of MOF-2 was enhanced and the emission peak was red shifted.In addition,Tb3+ can be selectively recognized in lanthanide ions with a detection limit of 2.94×1015 M.The characteristics of MOF-2 are of great significance for the identification of heavy metals in water.Then the synthesis of three benzotriazole derivatives is discussed:BTA-1,BTA-2 and BTA-3.Four new luminescent metal complexes were obtained synthesized by volatilization method.[PbI3(BTA-1)]n(7),[Cu2I3(BTA-2)]n(8),[ZnI3(BTA-3)]n(9)and[ZnBr3(BTA-3)]n(10).The experiments showed that the four complexes have excellent thermal stability and luminescent properties.This suggests that they are promising luminescent materials.