RESUMO
The severity of the volatile organic compounds (VOCs) issue calls for effective detection and management of VOC materials. Metal-organic frameworks (MOFs) are organic-inorganic hybrid crystals with promising prospects in luminescent sensing for VOC detection and identification. However, MOFs have limitations, including weak response signals and poor sensitivity towards VOCs, limiting their application to specific types of VOC gases. To address the issue of limited recognition and single luminosity for specific VOCs, we have introduced fluorescent guest molecules into MOFs as reference emission centers to enhance sensitivity. This composite material combines the gas adsorption ability of MOFs to effectively adsorb VOCs. We utilized (MIL-125/NH2-MIL-125) as the parent material for adsorbing fluorescent molecules and selected suitable solid fluorescent probes (FGFL-B1) through fluorescence enhancement using thioflavin T and MIL-125. FGFL-B1 exhibited a heightened fluorescence response to various VOCs through charge transfer between fluorescent guest molecules and ligands. The fluorescence enhancement effect of FGFL-B1 on tetrahydrofuran (THF) was particularly pronounced, accompanied by a color change from yellow to yellowish green in the presence of CCl4. FGFL-B1 demonstrated excellent adsorption properties for THF and CCl4, with saturated adsorption capacities of 655.4 mg g-1 and 811.2 mg g-1, respectively. Furthermore, FGFL-B1 displayed strong luminescence stability and reusability, making it an excellent sensing candidate. This study addresses the limitations of MOFs in VOC detection, opening avenues for industrial and environmental applications.
RESUMO
In the present work, we selected hexamethylcucurbit[3,3]uril (Me6Q[3,3]) as a building block and obtained two Me6Q[3,3]-based porous supramolecular assemblies from neutral water (A) and aqueous HCl solutions (B), respectively. Both Me6Q[3,3]-based assemblies are constructed of Me6Q[3,3] molecules through the typical outer surface interaction of cucurbit[n]urils, as well as hydrogen bonding between latticed water molecules and portal carbonyl oxygens of Me6Q[3,3]. The assemblies present different porous structure features and exhibit different adsorption properties for eight common volatile organic compounds. However, the two porous assemblies exhibit similar adsorption properties for certain fluorophore dyes, including rhodamine B (G1), fluorescein (G2), and pyrene (G3), and form solid colored fluorescent compounds, some of which exhibit responses to the selected volatile organic compounds.
