Synthesis Of Imine COFs Materials And Their Applications In Electrochemical Sensing

Covalent Organic Frameworks（COFs）,a new type of porous covalent organic polymers consisted of light elements（B,C,N,O,H）and linked by strong covalent bonds have a variety of merits such as high porosity,well-defined pore size,ordered channel structure,large specific surface area,high stability and multidimensionality and have been more and more widely applied in many filelds including chemical sensing,gas storage and separation,catalysis,optoelectronic devices,small molecule adsorption and drug delivery.In this thesis,several imine COF materials have been designed and synthesized by using the pyrene groups containing four functional groups and a large conjugatedπsystem as the structural units and resulting electrochemical senses with good performances were successfully fabricated.The introduction of pyrene structural units is advantageous to forming 2D layered stacked structure,achieving big specific surface area and good conductivity of the COFs,which hels to improve the sensitivity and selectivity of the resulted sensors.The thesis mainly includes the following three aspects of research contents:（1）Using 1,3,6,8-tetrakis（4-formylphenyl）pyrene（TFPPy）and 1,4-p-phenylenediamine as reactive monomers,a new imine-linked COF material IL COF-1was prepared.And then the obtained COFs were employed to fabricate a novel electrochemical sensor with gold nanoparticles（Au NPs）and aminated carbon nanotubes（MWCNT-NH₂）for highly sensitive and highly selective detection of dopamine（DA）and uric acid（UA）simultaneously.Due to the synergistic effect of IL COF-1 with high specific surface area and Au NPs and MWCNT-NH₂ with excellent conductivity,the developed COF-NH₂-MWCNT/Au NPs/GCE sensing platform showed excellent electrochemical performance and could be applied to detemine simultaneously DA and UA in dopamine injection and human urine samples with low detection limits（LODs）of 0.21μM and 0.29μM.（2）With TFPPy and 1,3,6,8-tetrakis（4-aminophenyl）pyrene（Py TTA）as monomers,a new covalent organic framework material TF-Py COF with a full pyrene structure was designed and synthesized.Then a composite modified electrode based on the prepared TF-Py COF,Au NPs and carbonized polyvinylpyrrolidone（3D NCNF-T）was prepared,which was succeddfully used in simultaneous determination of paracetamol（ACOP）and p-aminophenol（4-AP）in commercially available paracetamol tablet and Yellow water samples with wide linear ranges of 0.4～340μM and 0.4～320μM and low LODs of 0.13μM and 0.05μM.（3）A new COF material DP-Py COF was at first synthesized by using TFPPy and2,6-diaminopyridine as monomers through a solvothermal method and then using the COF and Au NPs as modified materials a novel and simple DP-Py COF/Au NPs/GCE was constracted.The prepare modified electrode was successfully employed for simultaneous determination of theophylline（TP）and caffeine（CAF）in Compound Paracetamol capsules and black tea samples with wide linear ranges of 0.9～400μM and30～600μM and low LODs of 0.19μM and 0.076μM,respectively.