A fluorescent paramagnetic Mn metal–organic framework based on semi-rigid pyrene tetracarboxylic acid: sensing of solvent polarity and explosive nitroaromatics

Abstract

Fluorescence quenching by paramagnetic metal ions is attenuated in an Mn metal–organic framework (Mn-MOF) based on a pyrene linker. Based on solvent-dependent emission, the Mn-MOF is shown to serve as a solvent polarity probe. Further, sensing of nitroaromatics is demonstrated with a detection limit of ∼125 p.p.m. for TNT.

Remarkably selective and enantiodifferentiating sensing of histidine by a fluorescent homochiral Zn-MOF based on pyrene-tetralactic acid

“…1 ), exhibit guest inclusion as a consequence of the creation of void spaces in their lattices. 13 We have further shown that the metal-assisted assembly of such molecular systems leads to metal–organic materials that are necessarily porous. 13 f In our recent investigations, a fluorescent Mn-MOF-constructed from pyrene-acetic acid, cf.…”

“…, Zn-PLA ( Fig. 1 ), constructed from a rationally designed fluorescent pyrene-tetralactic acid linker that is endowed inherently with concave features, 13 for the selective sensing as well as enantiodiscrimination of histidine in water.…”

Recent Progress on Luminescent Metal-Organic Framework-Involved Hybrid Materials for Rapid Determination of Contaminants in Environment and Food

“…The sensing application of MOFs has attracted a large amount of attention in recent years. It has been demonstrated that MOFs show a sizeable potential force for the sensing of temperature [97], pH [98], small molecules [99], solvents and explosives [100]. Porous MOFs sensing materials can effectively adsorb the target and concentrate it in the framework, which improves the sensitivity of detection [101].…”

The lighter side of MOFs: structurally photoresponsive metal–organic frameworks

“…The largest subset of these sensors is the detection of high explosives and nitroaromatics. [30][31][32][33][34][35][36][37][38][39][40][41] Other notable examples include: exploitation of an [In(OH)(BDC)]∞ framework (BDC = 1,4-benzenedicarboxylate as a a tifi ial ose to dete t chemical odorants (e.g. cinnamon, vanillin and cumin) by emission changes on adsorption into the porous, hexagonal, rod-like structure; 43 the use of the copper-based MOF, Cu-TCA (H3TCA = tricarboxytriphenyl amine), to detect NO, an important biological small molecule, in aqueous solution and in living cells; 44 the MOF [Cd3(L)(H2O)2(DMF)2]∞ (L = hexa[4-(carboxyphenyl)oxamethyl]-3-oxapentane) reported in 2012, based on a Cd3-containing node, that acts as an acetone detector; 45 the exploitation of the characteristic emission of Eu 3+ in 2014 in a [Eu(bpydb)3(HCOO)(µ3-OH)2(DMF)]∞ framework (bpydbH2 = , -, -bipyridine-2,6-diyl) dibenzoic acid) for the sensing of small organic molecules and inorganic ions; 46 also in 2014, the adsorption of Tb 3+ ions into both CPM-5 and MIL-100(In), MOFs based on In-nodes and the BTC ligand (BTC = 1,3,5-benzenetricarboxylate), yielding materials that act as luminescent oxygen sensors; 47 and, in an interesting variation on the simple perturbation of emissive properties by guest adsorption, in 2010 a detection system for Cu 2+ ions was reported which employed a Zn 2+ -based MOF that can undergo transmetallation, replacing Zn 2+ ions with Cu 2+ and resulting in a strongly photoluminescent framework.…”

“…It is in this context that this review seeks to further divert attention from the vast corpus of porosity and gas sorption literature (estimates of the number of published MOF articles ranges from ~30,000 upwards) ‡ towards a smaller, but by no means insignificant subset of these fascinating materials: those that are photoactive. Photoactive frameworks have been reported with potential applications as luminescent sensors for small molecules, [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] photochromic and thermochromic materials, 48,49 ion sensors, 46,50,51 metal-e t a tio ate ials to ake sola e e g o e te s that e ol e h d oge , 52 photoactive matrices for the generation of metallic microstructures, 53 photocatalysts, 54,55 semiconductors 56 and two-photon patterning hosts. 57 Broadly, we can identify five categories of photoactive frameworks.…”