Design,Synthesis And Sensing Properties Of Functionalized Tb/Zn-MOFs

Metal-organic frameworks（MOFs）,which are composed of organic ligands and bridging metal ions,have been recognized as an excellent platform for host-guest chemistry and have been intensively investigated in the last decade.These solids have a regular and highly tunable pore structure,along with an enormous variability in secondary building units connected by multitopic organic ligands and linker topology.These MOFs materials have rich connection forms and regular structure,which opens up a new research direction for the development of modern material chemistry.In this paper,to discuss and study the design and preparation of functionalized metal-organic framework compounds and their application in sensors.The specific content is as follows.1.Tb-MOF:A Naked-eye and Regenerable Fluorescent Probe for Selective and Quantitative Detection of Fe³⁺and Al³⁺Ions.Sensitiveness and selectiveness for metal ions detection are of crucial importance in protecting human health.Here,with 4,4’,4’’-tricarboxytriphenylamine（H₃TCA）as ligand,anuniqueterbiumbasedmetal-organicframework（Tb-MOF）,namely[Tb₃（TCA）₂（DMA）_0.5（OH）₃（H₂O）_0.5]·3H₂O（1）,has been prepared,structurally identified and further employed as fluorescent probe to construct sensor for selective and quantitative detection of metal ions.Compound 1 displays the selective sensing of Fe³⁺and Al³⁺through fluorescence quenching effect at 549 nm as well as fluorescence enhancement at463 nm,respectively,among 19 kinds of metal ions without interference.Most notably,1with Fe³⁺leads to a clear color change from yellow to deep brown,of which the detection limit of 8×10^-6M.As the fluorescent probe of Al³⁺,1 can be simply and quickly regenerated,of which the detection limit of 7×10^-7M is significantly lower than the higher limit of the WHO recommendation of Al³⁺for drinking water（7.41μM）,representing a rare example in reported fluorescent sensors for Al³⁺.The Tb-MOFs fluorescent probe examples naked-eye,regenerable features and presents the high selectivity and sensitivity to quantitative detection of Fe³⁺and Al³⁺ions.2.Ferrocene Covalent-Confined in Porous MOF as Signal Tags for Highly Sens itive Electrochemical Immunoassay of Amyloid-β.Here a new type of ferrocene confined in metal-organic framework（Fc-Zn-MOF）as electrochemical signal tag has been synthesized and applied in an immunosensor for highly sensitive amyloid-β（Aβ,as a model protein）detection.In the present work,electrochemically active molecule of Fc was covalent-bonded in a Zn-MOF via postsynthetic modification to obtain a flower-like Fc-Zn-MOF,in which the high-content Fc signal units were periodically arranged in well-defined porous structure,showing enhanced electrochemical activity.As noticed,Fc molecules are chemically anchored on Zn-MOF that avoids leakage of signal molecules,protects those electrochemical activities from potential damages and exhibits good stability.Fc-Zn-MOF signal tag was further explored in constructing an electrochemical immunosensor for Aβdetection,with a linear ranging from 0.0001 to 100 ng m L^-1and a detection limit of 0.03 pg mL^-1,showing an improved analytical performance.This work presents an example of Fc-MOF as signal tag for Aβdetection,which would encourage research lines atypical for MOFs in bioassay.