Construction Of Transitional Metal-organic Frameworks And Their Application In Electrochemical Sensors

Metal-Organic frameworks(MOFs),as a new type of multifunctional material in the field of coordination chemistry,have both of the flexibility of organic materials and the stability of inorganic materials.MOFs materials not only have central metal ions with various coordination numbers,but also have important effects on the structure of coordination polymers due to the variety of organic ligands,the number of coordination sites,coordination modes and coordination configurations.MOFs have various structural characteristics,unique functions,and potential applications,such as catalysis,adsorption separation,fluorescence,magnetism and electrical sensing.In this work,we designed and synthesized MOFs materials based on Co2+,Zn2+,Cu2+ ions with three different aromatic polycarboxylic acid ligands,and N-containing auxiliary ligands.All structures of the complexes were characterized by thermogravimetric analysis(TGA),infrared spectra analysis,powder X-ray diffraction,scanning electron microscopy(SEM),transmission electron microscopy(TEM).The electrochemical properties of MOFs materials were mainly studied,and included in three parts:Firstly,1D Co-MOF(Co-1)was synthesized from Co2+ and 2,5-pyridine dicarboxylic acid as the ligand by solvothermal method,and then Co-1was coated at an Au electrode(Au E)surface to assemble a modified electrode(Co-1/Au E).It was used as an electrochemical sensor for recognizing and distinguishing isomeric aromatic derivatives 1-naphthylamine(1-NA)and 2-naphthylamine(2-NA).Furthermore,Co-1/Au E was also tested as a chemicalsensor for the selectivity detection of 1-NA and 2-NA in a single interferent component solution or a mimic environment,respectively.The experiments indicated that Co-1 shows high selectivity,stability and anti-interference ability,and perhaps,provides a new method for detecting aromatic amines in the environmental and clinical medical fields.Secondly,an interesting scissors mode 1D Zn-MOF(Zn-1)was synthesized based 1,3,5-benzenetricarboxylic acid and 2,2'-dipyridylas the ligand by solvothermal method.Due to its excellent solvent,water and air stability,without more modification,Zn-1 was used as electrode modified material to construct sensors for electro-catalytic oxidation of three structure isomers(ortho,meta,para)of nitrobenzaldehydes(NBA)in 0.2M PBS.The sensor showed high selectivity,stability and anti-interference ability.Thirdly,Cu-MOF(Cu-1)was synthesized based on 2,5-furandicarboxylic acid and 1,2-bis(4-pyridyl)ethylene as the ligand by solvothermal method,and then Cu-1 was coated at an glassy carbon electrode(GCE)surface to assemble a modified electrode(Cu-1/GCE)for recognizing tyrosine(L-Tyr).Furthermore,Cu-1/GCE was also used as a chemical sensor for the selectivity detection of L-Tyr under a single interferent component solution and a mimic environment,respectively.The sensor showed excellent selectivity and anti-interference ability.It was important for detecting L-Tyr,a marker of metabolic diseases,in the clinical medical fields.