Experimental Studies On Fluorescent Prober Of Luminescent Metal-Organic Frameworks

Metal-Organic Frameworks(MOFs),combined by metal ions and ligands,possess the features of high porosity,adjustable pore size,and large internal surface areas.The intrinsic luminescence features of lanthanides together with the advantages of MOFs offer excellent prospects for the design of novel luminescent materials Ln-MOFs for the detection of pH value,ions,small molecules,and temperature through the purposeful selection of composition in advance.Using the "antenna effect",the drawback of Ln? caused by Laporte forbidden f-f transitions for weak absorption extinction coefficients(less than 4 M-1cm-1)could be solved miraculously.This indirect excitation of the lanthanide excited state induces great photophysical properties and makes the Ln-MOFs more selective and sensitive for the detection/monitoring.However,enhancement of the efficiency of overall antenna effect in such systems still remains a great challenge.Therefore,the choice of organic ligands with rational functional groups is vital for the enhancement of efficiency in the sensitisation process from the antenna to the lanthanide excited states,which would lead to remarkable intrinsic luminescence properties,and make the detection capacities more efficient as a result.This work synthesizes a series of Eu-MOFs to explore its fluorescence properties.(1).The new material Eu-FUM has been synthesized through solvothermal method by using 2-fluorobenzoic acid(2-FBA)as modulator.The new material has good selective capability to small molecules explosives(TNP)and still has response in the concentration of 10-8 M,in addition,the MOF can be recycled.(2).The new material Eu-BDC-NH2 has good fluorescence properties to sense Fe3+ ions,Cr2O72-anion and acetone molecules,and we also study their quenching mechanism to make work more scientific.(3).At the same time,we synthesize a series of isostructural luminescent Eu-MOFs:Eu-1,4-NDC,Eu-BDC-NH2,Eu-BDC-F,Eu-BDC-N02,to study the intrinsic luminescence properties and detection capacities systematically.The results indicate that tuning functional groups is crucial to the intrinsic luminescence properties,and the one with higher fluorescence quantum yield displays much more sensitive and efficient detection capacities for different kinds of analytes.Overall,this work indicated that tuning functional groups is vitial to gain Eu-MOFs with high intrinsic luminescence properties,and make the detection capacities more sensitive and efficient.This method is simple to design a Eu-MOF with high fluorescence properties,and has guidance significance.