Construction,Fluoresence And Chiral Sensing Of Functional Complexes Based On Lanthanide And Transition Metal

The pores and tunable structure and properties of Metal-organic frameworks(MOFs)make them potential application value in optics,electricity,magnetism,sensing and separation,catalysis,gas absorption and drug delivery.In this dissertation,based on the principle of crystal engineering and guided by the function of MOFs,we have focused important study on the optics and chiral sensing of MOFs.A series of MOFs are synthesized by the hydrothermal or solvothermal treament of lanthanide and appropriate organic carboxylic ligand as well as d10 transition metal and rationally designed chiral ligand with carboxylic group and nitrogen.Structures,fluorescence or circular dichrorism of these MOFs are characterized and analyzed,and their applications are further explored.These results will be introduced from the following four issues:(1)According to the principle of fluorescence and construction for lanthanide MOFs(LnMOFs),we select appropriate organic ligand by combining theoretical calculation,and design as well as construct a series of multicolor LnMOFs.In light of trichromatic theory,ligand(blue),Tb3+(green),and Eu3+(red)are incorporated into one MOF structure,and two n-UV single-phase white-light MOFs,Eu0.045Tb0.955CPOMBA(?ex = 365 nm)and La0.6Eu0.1Tb0.3 CPOMBA(?ex = 380 nm)are acquired by tuning the excitation wavelength of LnMOFs.Based on the studies of crystal morphology,thermostability,thermal quenching properties,fluorescence properties,quantum yield and lifetime and so on,we found that the white emitting MOFs were well-qualified phosphor applied on UV WLEDs.An n-UV WLED(365 nm)was fabricated,which has low CCT(5733 K),high CRI(Ra = 73.4)and CIE chromaticity coordinate(0.3264,0.3427),and comparable commercially available blue WLED withYAG:Ce3+ phosphor.(2)To develop more efficient white-light MOFs applied on UV WLEDs,we further improve the white light MOFs materials on the basis of previous work(1),and select LnMOFs(Ln BTPCA)with high quantum yield.In light of trichromatic theory,the white light MOFs materials(?ex = 380 nm),Eu0.025Tb0.975(BTPCA)are acquired by doping Tb3+(green),and Eu3+(red)into one MOF structure,which is completely different from reported white emitting MOFs,Eu0.0075Tb0.9925-BTPCA and La0.6Eu0.1Tb0.3-BTPCA(?ex = 365 nm).The reported synthetic method of LnBTPCA was improved,and crystal with uniform particle(particle size in the range of 8-15 ?m)and well-qualified application on LED was acquired.Based on the studies of crystal morphology,thermostability,thermal quenching properties,fluorescence properties,quantum yield and lifetime and so on,we found that the white emitting MOFs were well-qualified phosphor applied on LED.An n-UV WLED(380 nm)was fabricated,which has low CCT(5609 K),high CRI(Ra = 78.9),CIE chromaticity coordinate(0.3281,0.3316),and higher luminous efficiency(lumen,28-35 lm in different drive current).(3)Food is closely linked to the health and life of human.The detection of enantiomer with different properties in food additives is very important.Currently,tradition methods for detecting food additives show the high cost and time-consuming,however,optical sensor have been mainstream of research.Given that the reported MOFs display the excellent recognizable ability for enantiomers as chiral sensor,we decide to develop fluorescence sensor based on chiral MOFs,which is used to detect and recognize enantiomers with different properties in food additives.Chiral organic ligand with stereo-configuration similar to the propeller blades is designed and synthesized by selecting cheap and easy-to-get(1R,2R)-cyclohexane-1,2-dicarboxylic acid as the starting materials.Self-assembly of the organic ligand,pyridine(auxiliary ligand)and Zn salt generate a 2D homochiral MOFs(HMOF-2)with rhombic helical tube,which shows 3.567 ? of distance along a axis and 13.152 ? along c axis,so the specific structure have selectivity for molecule entering into tube.More importantly,HMOF-2 show stronger fluorescence than ligand and HMOF-2 as fluorescence sensor can selectively sense ?-hydroxyl carboxylic acid.Larger-volume mandelic acid molecule show low quench efficiency for fluorescence of HMOF-2 and weak recognized ability,on the contrary,smaller-volume tartaric acid and lactic acid can show high quench efficiency for fluorescence of HMOF-2,and ratio of their quench constant is KD-tartaric acid/KL-tartaric acid = 1.884:1,KD-lactic acid/KL-lactic acid = 1:1.313,which also show their recognized ability.The recognized ability of HMOF-2 for D/L-lactic acid is highest in all reported fluorescence sensor.(4)The biological and chemical activities of living systems are dependent on stereochemistry of chiral building blocks,amino acids etc.Chiral recognition and sensing of different configurations of amino acids in food stuffs and organism are especially important in nutritional analysis and diagnosis of diseases.Given that circular dichroism(CD)spectra can fast and visually show stereo-configuration of molecular,which is superior to conventional chromatography and capillary electrophoresis methods for enantiomeric recognition of amino acids.A new strategy towards rapidly,efficiently and enanioselectively recognizing amino acids could be established by DNA-like homochiral MOF with inherent CD signal interacting with D/L-amino acids.Self-assembly of Zn salt with rationally designed chiral ligand generate 2D homochiral MOF(HMOF-3)with DNA-like right-handed double-helix structure.Emulsion of HMOF-3 with nanoparticles in H2 O shows strong inherent circular dichroism(CD)signal,which can show regular intensity change by induction of amino acids.This chemosensor can be used for rapid,convenient and sensitive detection of micro amount of amino acids.Most remarkably,3?10-8 mol of L-aspartic acid and 4?10-8 mol of D-aspartic acid can completely quench CD signal of emulsified HMOF-3 in H2 O.The LOD(limit of detection)of the proposed sensor for the determination of L-Asp or D-Asp are 13.31 ppm.It is found that the difference of recognition ability between D-and L-proline is the largest in all probed amino acids,and the recognition efficiency for D-and L-proline is as high as 22.9% and 65.7%,respectively.The CD spectrum is first introduced to develop sensor based on MOFs,which set a precedent and broaden the application of MOFs.