Synthsis And Luminescent Sensing Investigation Of UMCM-1-NH₂and Umcm-1

Luminescent researches and exploitations of metal-organicframeworks （MOFs） are still at an early stage. The detectable speciesemployed by MOFs are very limited. Meanwhile, it is needed to developothers binding sites to bind with small molecules although pyridylnitrogen, amide group, anionic sulfonate group are employed as bindingsites tosensing small molecules. The structure of UMCM-1-NH₂is almostthe same as that of UMCM-1, including their cell parameters. The largestdifference is that UMCM-1-NH₂has amino group, while UMCM-1hasno it. So we can know the role of amino group by comparing theluminescent sensing of UMCM-1with that of UMCM-1-NH₂.In this work, UMCM-1and UMCM-1-NH₂are synthesized bysovlothermal method and characterized by PL spectra, details are below:（1） UMCM-1and UMCM-1-NH₂were characterized by XRD, TGA, theresults indicate that they have high thermal stability and chemicalstability before and after the free molecules are evacuated. The PLspectra of solid UMCM-1and UMCM-1-NH₂also show that they have strong luminescence.（2） The PL properties of metal ion-incorporated UMCM-1and metalion-incorporated UMCM-1-NH₂were investigated. The results showthat UMCM-1and UMCM-1-NH₂are highly sensitive to Fe³⁺. Theselectivity of UMCM-1on sensing of Fe³⁺is not good, and thequenching coefficient K_svof Fe³⁺is only1.15times of Cr³⁺and6.68times of Cu²⁺, while the selectivity of UMCM-1-NH₂on sensing ofFe³⁺is good, K_svof Fe³⁺is29.5times of Cr³⁺and98.5times of Cu²⁺.（3） The PL properties of anion-incorporated UMCM-1andanion-incorporated UMCM-1-NH₂were also investigated. The resultsshowed that the luminescent intensity of UMCM-1was stronglysensitive to CO₃^2-and Cl-, and it increased with the increase of theconcentration of CO₃^2-, but decreased with the increase of theconcentration of Cl-. The selectivity of UMCM-1was not good, otheranions could interfere sensing of UMCM-1to CO₃^2-and Cl-.UMCM-1-NH₂was strongly sensitive to NO-3, and the luminescentintensity descreased with the increase of the concentration of NO-3.The other anions, especially CO₃^2-, can interfere that the sensing ofUMCM-1-NH₂to NO-3.（4） The PL properties of solvent-incorporated UMCM-1andsolvent-incorporated UMCM-1-NH₂were investigated. UMCM-1canexhibit the solvent effect and can detect chloroform according the shoulder peak. Meanwhile the luminescent intensity of UMCM-1isstrongly sensitive to DMF, while the luminescent intensity ofUMCM-1-NH₂is strongly sensitive to methanol and chloroform.（5） The metal ion-incorported UMCM-1and metal ion-incorportedUMCM-1-NH₂are immersed in chloroform to regenerate theevacuated UMCM-1and evacuated UMCM-1-NH₂. The PLproperties of Fe³⁺-incorporated UMCM-1and Fe³⁺-incorporatedUMCM-1-NH₂were also investigated. The results show that theUMCM-1and UMCM-1-NH₂can be partially activated bychloroform. The effiency of sensing of the activated samples to Fe³⁺isstill good.