Research On Functionalization And Sensing Properties Of Luminescent Metal-organic Framework Materials

Luminescent metal-organic frameworks（LMOFs）are promising luminescent materials with fast response,low detection limit,and good selectivity,which show broad application prospects in the field of chemical sensing.Directly used LMOFs materials usually cannot meet the detection requirements of analytes.At this time,functionalized LMOFs materials come into the public view,especially post-synthetic modification（PSM）,which can introduce new functional sites or groups without destroying the framework structure.LMOFs synthesized via PSM strategy tend to exhibit better fluorescence properties and sensing properties,and the PSM strategy is the most widely functional LMOFs synthesis method at present.So far,a variety of LMOFs sensors prepared via PSM have been used to detect cations,anions,biomolecules,volatile organic compounds,nitroaromatic explosives,gases,etc.,which greatly expands the sensing range of LMOFs materials.In this work,2-pyridinaldehyde（2-PC）and Rhodamine B（Rh B）were used as materials for functionalized LMOFs,respectively,to achieve the fluorescence detection of pyrophosphate（PPi）and hydroquinone（HQ）.The specific investigation contents are as follows:1.The fluorescent sensing material TMU-PC was successfully prepared via the Schiff base reaction between TMU-17-NH₂ and 2-PC,was applied to the fluorescence detection of PPi.The TMU-PC sensor was constructed based on the interaction of metal ions with PPi,and Cu²⁺was selected as the mediating ion here because Cu²⁺can quench the fluorescence of TMU-PC through a photoelectron transfer（PET）mechanism,and then PPi can restore the quenched fluorescence of TMU-PC,forming an"on-off-on"fluorescence sensor,which enables the sequential detection of Cu²⁺and PPi.The TMU-PC sensor has a fast response time of 30 s,a wide linear range of 200-1000μM,a low detection limit of 3.50μM,and good specificity for the detection of PPi.When TMU-PC was used for the detection of PPi in human urine and synovial fluid samples,the sample recoveries were in the range of 97.6%-102.9%,and the relative standard deviation（RSD）of less than 2.0%（n=3）.2.By introducing the fluorescence dye Rh B into the aperture of IRMOF-3,the Rh B@IRMOF-3 material with dual fluorescence emission was prepared and used for ratio fluorescence detection of HQ.In the Rh B@IRMOF-3 sensor,the blue fluorescence of the IRMOF-3 framework was used as indicator,and the red fluorescence of Rh B was used as reference.With the addition of HQ,the blue fluorescence gradually weakened,and the fluorescence of the material gradually changes to red,which is caused by the competitive energy transfer between HQ and Rh B@IRMOF-3 material.The sensor exhibited an extremely fast response to HQ（30s）,a wide linear range（0-140 m M）,and a low detection limit（3.26 m M）.In addition,the sensor was successfully used for the detection of HQ in lake and tap water samples,and sample recoveries are 98.3%-102.0%with RSD<1.9%（n=3）.