Facile Fabrication of an AIE-Active Metal–Organic Framework for Sensitive Detection of Explosives in Liquid and Solid Phases

Abstract

Nowadays, the practical applications of metal− organic framework (MOF)-based fluorescence detectors are severely hindered because of the complex synthesis process of linkers or heavy metal contamination. The development of a simple, inexpensive, and environmentally friendly fluorescence sensing system remains a huge challenge. In this study, we designed and synthesized a TPE@γ-CD-MOF-K complex using the facile in situ encapsulation method. The unique pore structure of γ-CD-MOF allowed it to effectively include TPE and explosives as guests simultaneously. The TPE@γ-CD-MOF-K showed stronger fluorescence emission than TPE and sensitive fluorescence quenching activities in response to nitro-aromatic compounds in the liquid phase with detection limits as low as 3 ppm. Furthermore, TPE@γ-CD-MOF-K can also effectively detect nitro-aromatic compounds in the solid state, which is very convenient for practical detection of explosives. The unique pore structure of γ-CD-MOF-K and the interaction between K + and nitro compounds play important roles in solid-state quenching.

Cyclodextrin metal–organic frameworks and derivatives: recent developments and applications

“…One of such sensors is based on a g-CD-MOF with tetraphenylethylene (TPE) molecules incorporated in its framework. 143 Notably, TPE@K-g-CD-MOF exhibited enhanced fluorescence compared to TPE alone. Furthermore, in the presence of nitro-aromatic compounds, TPE@K-g-CD-MOF showed quenching of its fluorescence intensity endowing it with sensing properties.…”

“…These hybrids not only have improved properties over native CD-MOFs but also extend their applications to various fields like sensing and detection, catalysis, separation and removal sciences, anticancer therapy, or more potent drug delivery systems. 72,76,96,136,[139][140][141][142][143][144][145][146][147][148] It has also been noted in some cases that the formation of CD-MOFs hybrids significantly improves the moisture stability of pristine CD-MOFs. 135,136,149,150 3.2.1 Synthesis of CD-MOF hybrids.…”

“…More specifically, such materials have been used for the detection of insulin, prostate-specific antigen, Cr(VI) ions, ethambutol, or explosives. [140][141][142][143]153 The main factor governing the sensing ability of CD-MOF hybrids is the enhancement of the response signal of pristine CD-MOFs via the formation of hybrids with suitable materials. The choice usually falls on materials that are already established in the various fields and have pronounced (photo)chemical properties.…”

“…142 In another study, Qiu et al designed a K-g-CD-MOF sensor which showed enhanced sensitivity after hybrid formation with the strongly photoluminescent tetraphenylethylene. 143 Another interesting feature of CD-MOF hybrids is their applicability in catalysis by the incorporation of catalytically active components in the framework of CD-MOFs. The pristine CD-MOFs usually show poor activity towards catalysing reactions but upon their hybridization with catalytically active species, the resultant CD-MOF hybrids exhibit better performance in catalysis while adding the benefits of a porous matrix.…”

Structural Design of Low Toxicity Metal–Organic Frameworks for Multifunction Detection of Organic and Inorganic Contaminants from Water

“…Recently, metal–organic frameworks (MOFs) as a class of porous crystalline materials with the advantages of adjustable structure, functionalized nature, and high crystallinity have been applied as the detection of target analytes, and it is helpful to further analyze and understand the mechanism of their detecting behavior. − As is known, the fluorescence quenching or enhancement of MOFs is mainly attributed to the host–guest interaction. , To date, a number of MOFs for TNP, Fe 3+ , and Cr 2 O 7 2– detection have been reported; for example, Liu et al reported a luminescent Zn-LMOF (JLU-MOF71) which showed highly selective detection of TNP and Fe 3+ . Zang et al reported a 3D MOF (Tb-DSOA) for Fe 3+ detection via luminescence quenching, and the excellent detection performance of Tb-DSOA was attributed to the existence of the noncoordinated sulfonate oxygen atoms in the channels of Tb-DSOA .…”