Syntheses,Structure,Fluorescent Properties And Antibacterial Activity Of Complexes Based On Pyridine Carboxylic Acid

Complexes have attached great interests due to their potential properties.As we known,complexes show intriguing structures,luminescence,easily modified and functionalized.Accordingly,they have multifarious promising application in gas adsorption,catealysis,chemical sensors,and other aspects.Especially,the combination of highly porosity and intensely luminescence made complexes become the potential Luminescence probe for detecting metal ions,inorganic anions,or other small molecules.In this paper,a complex（1）were synthesized with Zn²⁺based on 4-pyridine-4-yl-benzoic acid（HL₁）;three transition complexes（2-4）were synthesized based on3-pyridine-4-yl-benzoic acid（HL₂）,and a 3D Cd-MOF（5）were synthesized based on HL₂,then the Eu³⁺and Tb³⁺were introduced into 5 respectively,got two functionalized MOF composites Eu³⁺@5 and Tb³⁺@5.The details are as follows:1.Based on HL₁,a complex{[Zn（L₁）₂]·2DMF}（1）was synthesized with Zn²⁺.1 is a4-fold-inter-penetrated 3D framework.There exists one crystallographically independent Zn²⁺ion in the fundamental unit,the Zn²⁺center is eight-coordinated,exhibiting a distorted octahedron coordination geometry completed by two nitrogen atoms and two chelate carboxylate groups.Based on HL₂,three transition-metal complexes were synthesized,named[Co（L₂）₂（H₂O）₄]（2）,[Cu（L₂）₂（H₂O）₄]（3）,[Ni（L₂）₂（H₂O）₄]（4）,respectively.Complexes 2-4 are nuclear and isostructural with two pyridine-carboxylate ligands and four water coordinated through their N atoms and O atoms respectively.Neighboring units connected to each other through hydrogen-bonding interactions between coordinated water molecule and uncoordinated O atoms of L₂^-andπ-πstacking interactions between the phenyl and pyridine rings to form a 3D supramolecular network.2.Cd-MOF{[Cd₃K（L₂）₆（H₂O）₃]OH·4DMF}（5）was employed as an MOF matrix,and then photoactive Eu³⁺and Tb³⁺ions were introduced to get two functionalized MOF composites Eu³⁺@5 and Tb³⁺@5.PXRD patterns of Eu³⁺@5 and Tb³⁺@5 are consistent with 5.3.The luminescent studies reveal that complex 1 exhibit intense blue luminescence and show rapid sensing of Fe³⁺,CrO₄^2-,and tetracycline in water,with good cyclability and selectivity.Eu³⁺@5 and Tb³⁺@5 exhibits the characteristic luminescence of Eu³⁺and Tb³⁺,respectively,and Tb³⁺@5 displays a selective sensing ability to Cr³⁺ion.4.The antibacterial activity results suggest that 5 exhibit middle antibacterial activity against S.aureus and P.aeruginosa;Eu³⁺@5 exhibit highly antibacterial activity against S.aureus and P.aeruginosa;Tb³⁺@5 exhibit middle antibacterial activity against P.aeruginosa.