Metathesis in Metal–Organic Gels (MOGs): A Facile Strategy to Construct Robust Fluorescent Ln‐MOG Sensors for Antibiotics and Explosives

Abstract

It is essential to develop new effective sensor materials for the detection of antibiotics and organic explosives, due to their negative impacts on ecosystems and human health. In this work, guided by an in situ metal-node metathesis approach, a fluorescent metal-organic gel [MOG(Eu) gel] has been synthesized for the first time by metal-ion exchange between Eu 3+ and Al 3+ in the nonfluorescent MOG(Al) gel. More importantly, the postsynthetic MOG(Eu) xerogel shows remarkable se-Synthesis of MOG(Al) Gel Material: MOG(Al) gel was synthesized easily from a mixture of Al(NO 3 ) 3 ·9H 2 O (0.5627 g, 1.5 mmol), 1,3,5benzentricarboxylic acid (0.2101 g, 1 mmol), and ethanol (16 mL), as explained in literature. [31] The mixture was stirred to solution at room temperature before being transferred to a Teflon-lined steel autoclave, and then heated at 120°C for 6 h. The light-yellow wet gel formed upon cooling to room temperature, and was washed with ethanol three times. Synthesis of MOG(Eu) Xerogel Material:The wet MOG(Eu) gel was obtained by soaking the above-synthesized MOG(Al) gel in an ethanol solution of Eu(NO 3 ) 3 ·6H 2 O (30 mL, 3.5 mmol) for seven days. The in situ central-metal exchange led to the fresh wet MOG(Eu) gel. The wet gel was washed with ethanol to remove redundant Eu 3+ and Al 3+ ions, and then xerogel products were prepared by drying the gel in vacuo in an oven at 80°C for 12 h. The pH and Water Stability Tests:To test the stability of the MOG(Eu) xerogel, samples were soaked in aqueous solutions with different pH values (pH 1, 3, 5, 7, 9, 11, and 12) for 24 h. After soaking and drying, the samples were used to determine PXRD mpatterns. Luminescent Experiments:The suspensions of MOG(Eu) xerogel/ antibiotics and MOG(Eu) xerogel/explosives were prepared by adding pulverous xerogel (5 mg) into aqueous solutions (10 mL, 5 × 10 -4 mol L -1 ) of explosives or antibiotics at room temperature. Before the luminescence measurements, all of the mixtures were treated by ultrasonication for 30 min to form stable emulsions. In a set of experiments of selective detection, 5 mg of MOG(Eu) xerogel was added to separate solutions (5 × 10 -4 mol L -1 each) of dimetridazole, metronidazole, ornidazole, and ronidazole in the presence of other antibiotics (5 × 10 -4 mol L -1 ). Similarly, a sample (5 mg) was added to a solution (5 × 10 -4 mol L -1 ) of 4-nitrophenol in the presence of another analytes (5 × 10 -4 mol L -1 ). Before the luminescence measurements, all of the mixtures were treated by ultrasonication for 30 min to form stable emulsions.

A Water-Stable Tb-MOF As a Rapid, Accurate, and Highly Sensitive Ratiometric Luminescent Sensor for the Discriminative Sensing of Antibiotics and D2O in H2O

“…The LOD of 1a toward DTZ was estimated to be 1.39 μM, which is better than those of the previously reported MOFs (Table S4). − These above results demonstrate that the single MOF material exhibits a dual-emission self-calibrating luminescent sensor for distinguishing NFs, NMs, and SAs from each other for the first time.…”

White-Light-Emitting Decoding Sensing for Eight Frequently-Used Antibiotics Based on a Lanthanide Metal-Organic Framework

“…The eight antibiotics@ 4 hold the minimal LOD order of NZF > SDZ > TC > CBZ > DTZ > MDZ > NFT > ODZ. According to Table 1, the K SV and LODs of antibiotics@ 4 in this contribution are far superior to most reported fluorescence probes for these antibiotics [42,48,49,50,51,52,53,54], and meets the standard of U.S. Environmental Protection Agency and World Health Organization for the maximum allowable level of antibiotics in drinking water (Table 1) [5,55]. Additionally, we find that complex 4 can be regenerated and reused for a significant number of cycles by centrifugation of the solution after use and washing several times with water.…”

Lanthanide–Organic Frameworks Constructed from 2,7-Naphthalenedisulfonate and 1H-Imidazo[4,5-f][1,10]-phenanthroline: Synthesis, Structure, and Luminescence with Near-Visible Light Excitation and Magnetic Properties

“…However, the detection limits are comparable to that of other reported MOFs for Fe 3+ and ODZ/RDZ detection (Table S3). ,,,− The highlight is that fluorescence sensing of the Eu-MOF can be achieved under a long excitation wavelength of 385 nm, which is longer than that of our recently developed Eu-MOF . Such significantly fluorescence sensing at a long excitation wavelength is really remarkable.…”