Study On The Fluorescence Property Regulation And Application Of UiO Series MOFs Materials On DMSP

Metal organic framework materials（MOFs）have been widely developed and applied in various fields such as catalytic activation,gas adsorption and separation,drug transportation,and biosensors since their discovery due to their high specific surface area,open active sites,ease of pore size and size regulation,and ease of chemical modification.They are still excellent materials active in various fields.MOFs can provide stable pores for small molecules,which can achieve the goal of dispersing molecules.Open active sites may interact with small molecules,which can provide a completely different environment for small molecules from the solution system.The regulation of fluorescent molecules by MOFs materials has been widely reported.Their porous and ordered structure can effectively disperse fluorescent molecules,avoiding negative effects such as self aggregation induced quenching（ACQ）andπ-πstacking of fluorescent molecules.The interaction between their surface active sites and fluorescent molecules can effectively regulate fluorescent color and intensity.Finally,providing a rigid environment for fluorescent molecules can adjust fluorescence lifetime and quantum yield by changing radiation channels.In recent years,fluorescent molecule@MOFs composite materials have flourished,and have been widely developed in various fields such as biological imaging,OLED,drug monitoring,and temperature sensitive materials.At the same time,more and more efficient requirements have been put forward for such composite materials,such as:how to achieve efficient fluorescence with low load,how to conduct fast and effective monitoring during drug loading transportation,and how to further improve the sensitivity of temperature sensitive materials.Researchers are waiting for research breakthroughs.Based on this work,trans-4-[4-（N,N’-dimethylamino）styryl]pyridine（DMSP）was regulated using UiO series materials DMSP@UiO-66 and DMSP@UiO-66-NH2.T he application of o rganic fluorescent molecules with electron donor acceptor（D-π-A）configuration have attracted much attention in the field of materials science due to their significant intramolecular charge transfer characteristics and unique photoelectric properties,and are currently one of the research hotspots.However,its inherent shortcomings such as aggregation induced quenching（ACQ）effect,photobleaching,and low fluorescence lifetime have greatly hindered the development of D-π-A type molecules.Using the concept of Host-Guest chemistry,introducing DMSP into classic MOF materials such as the UiO series with carboxylic acid sites can not only play a protonation effect,achieve a fluorescence transition from green to red,but also effectively improve the stability of DMSP and extend its fluorescence lifetime.At the same time,uniform pores can also avoid the ACQ effect of DMSP molecules themselves.（1）DMSP molecules are organic fluorescent molecules with an electron donor acceptor（D-π-A）configuration.They are sensitive to acids and are prone to intramolecular electron transfer（ICT）effects under acid stimulation,achieving fluorescence discoloration.However,their inherent shortcomings such as aggregation induced quenching（ACQ）effects,photobleaching,and low fluorescence lifetime greatly limit the development of DMSP.Using the concept of host-guest chemistry,introducing a small amount of DMSP into classic MOF materials such as the UiO series with carboxylic acid sites can not only trigger the ICT effect to play a protonation effect,achieve fluorescence from green to red,provide a rigid environment,but also change the radiation path to effectively improve the stability of DMSP and extend fluorescence lifetime,At the same time,dispersed in uniform pores can also avoid the ACQ effect of DMSP molecules themselves,achieving efficient regulation of low load.（2）Low load allows for DMSP@UiO-66 With excellent fluorescence characteristics,the remaining excess space can be further utilized in drug loaded systems.The composite material retains the advantages of UiO-66 such as good biocompatibility and low toxicity.When PO₄^3-degrades,the green fluorescence of DMSP will be turned on again,and the drug release and degradation rate are synchronized during degradation,achieving visual monitoring of drug release.（3）DMSP@UiO-66-NH₂ The composite material has been successfully constructed with the introduction of a single fluorescent molecule,which is an excellent material for ratio temperature sensing,while possessing the advantages of simple synthesis and high resolution.When the ambient temperature rises,DMSP molecules will dissociate from the pores,and then the red peak will drop and the blue peak will rise.This feature allows the material to have excellent sensitivity,with a sensitivity value of up to 5.3%·℃^-1,which will have a higher resolution.The mutual transformation between reversible and irreversible cycles is achieved by controlling the ionic strength to achieve use in more situations.