Synthesis And Fluorescent Probe Properties Of MOFs Constructed By Triazine And Polycarboxylic Acid Ligands

Metal-organic frameworks（MOFs）have received extensive attention because of their intriguing structural diversities and fascinating topology,providing an opportunity for the application in catalysis,magnetism,luminescence sensors and other fields.Among various applications,luminescence sensing based on MOFs attracts more attention because of their high efficiency,ease of synthesis,low cost,portability and operability.In this paper,three kinds of excellent luminescent MOFs materials were constructed with tris（4-pyridyl）triazine（tpt）,polycarboxylic acid ligands and metal ions by solvothermal method.Its structure was characterized and analyzed by X-ray single crystal diffractometer.MOFs were studied as a fluorescent probe to detect aromatic nitro compounds and anions in water.The main research contents and results are as follows:Firstly,two three-dimensional luminescent MOF[Cd3（btc）2（tpt）（H₂O）2]·4H₂O（complex 1）and[Zn3（btc）2（tpt）（H₂O）2]·4H₂O（complex 2）were synthesized based on tpt and trimesic acid（Hsbtc）with Cd metal salts and Zn metal salts by solvothermal method,respectively.Complex 1 and 2 not only have good thermal and chemical stability,but also have excellent luminescent properties in water.Complex 1 and 2 also can detect 2,4,6-trinitrophenol（TNP）in water with high selectivity via the luminescent quenching,and the Ksv were 1.43 × 105 ^M-1 and 8.42 × 104 ^M-1,respectively.Moreover,Complex 1 can also detect CrO₄^2-/Cr₂O₇^2-anions with high sensitivity and selectivity,and the Ksv were 4.40 × 104 ^M-1 and 2.27 × 104 ^M-1,respectively.In addition,complex 1 and 2 have great anti-interference ability and renewable ability for detection target analytes,which creates favorable conditions for practical application.Secondly,a four-connected three-dimensional MOF,Ni4（tpt）4（m-bdc）4-H₂O（complex 3）,was successfully synthesized based on tpt and m-phthalic acid（m-H₂bdc）with Ni metal salt by solvothermal method.In complex 3,two N atoms in the tpt ligand are bridged with two NiⅡcenters to form a one-dimensional zigzag chain,and two adjacent NiⅡ atoms are bridged by a pair of carboxylate from two m-bdc2-anions to form a[Ni2（CO）2]subunit,which is further bridged with m-bdc2-anions to form a straight double chain.The double chains and symmetry-related ones are linked by the zigzag chains generating a three-dimensional network structure of complex 3.Complex 3 has significant thermal and chemical stability.Complex 3 not only has significant thermal stability and chemical stability,but also can selectively detect TNP and CrO₄^2-in water,and the Ksv were 4.40 × 104 ^M-1 and 2.27 × 104 ^M-1,respectively.In addition,Complex 3 can also detect TNP and CrO₄^2-anions with high selectivity and recyclability through the fluorescence quenching effect,which is an efficient dual-function fluorescence sensor.