A multifunctional 3D Cd-based metal-organic frameworks for the highly luminescence sensitive detection of CrO42−/Cr2O72− and nitro aromatic compounds

A dual-emitting Rhodamine B-encapsulated Zn-based MOF for the selective sensing of Chromium(VI)

A Rhodamine B-Zn-MOF composite (RhB-Zn-MOF) with dual emission intensity was synthesized through one pot synthesis by in-situ encapsulation of Rhodamine-B dye on a new Zn-MOF metal-organic framework [(Zn(OAc)2(4-BrIPh) (1,10-phenonthroline)(H2O)].H2O, (4-BrIPh = 4-Bromoisophthalic acid). The synthesized encapsulated material was characterized by elemental analysis, FTIR, UV-Visible spectroscopy, TGA, single crystal and powder X-ray diffraction and photoluminescence spectroscopy. The results showed that the synthesized composite, RhB-Zn-MOF could be used as an efficient probe for the selective sensing of Cr(VI) in the presence of Cr(III) as well as other metal ions.

Multifunctional luminescent Zr(IV)-MOF for rapid and efficient detection of vanillin, CrO42- and Cr2O72- ions

Fast and efficient detection of pollutants in the food or wastewater is an urgent need for protecting human health and ecological environment. Herein, a luminescent Zr(IV)-MOF (HBU-20) has been conveniently synthesized. It could be used as a fluorescent probe for detection of vanillin, CrO₄^2-, and Cr₂O₇^2- in aqueous medium. All the fluorescence response time is less than 10 s and the detection limits of vanillin, CrO₄^2- and Cr₂O₇^2- achieve 0.38 μM, 0.065 μM and 0.0089 μM, respectively. Interestingly, common anions, cations and amino acids in the solution can not affect the fluorescence detection. Meanwhile, the fluorescence detection process can be successfully implemented even under strong acid or strong alkaline conditions. Further research shows that the inner filter effect (IFE) plays a major role in the sensing process. The rapid and sensitive fluorescence responses indicate that the compound is a promising multifunctional probe for sensing toxic substance. The results can provide an important reference for the design of new fluorescent probes.

A Dihydrotetrazine-Functionalized Metal-Organic Framework as a Highly Selective Luminescent Host-Guest Sensor for Detection of 2,4,6-Trinitrophenol

Pore decoration of metal-organic frameworks (MOFs) with functional groups is a useful strategy to attain high selectivity toward specific analytes, especially in the presence of interfering molecules with similar structures and energy levels, through selective host-guest interactions. In this work, we applied a dihydrotetrazine-decorated MOF, TMU-34, with the formula [Zn(OBA)(H₂DPT)_0.5]_n·DMF, where H₂OBA is 4,4'-oxybis(benzoic acid) and H₂DPT is 3,6-bis(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine, for the highly selective detection of phenolic NACs, especially TNP (94% quenching efficiency, detection limit 8.1 × 10^-6 M, K_SV = 182663 mol L^-1), in the presence of other substituted NACs especially -NH₂-substituted NACs. Investigations reveal that the quenching mechanism is dominated by photoinduced MOF-to-TNP electron transfer through possible hydrogen-bonding interactions between the phenolic hydroxyl group of TNP and dihydrotetrazine functions of TMU-34. Despite extensive publications on the detection of TNP in the presence of other NACs, the significance of this work will be elucidated if attention is paid to the fact that TMU-34 is among the rare and highly selective MOF-based TNP sensors in the presence of -NH₂-substituted NACs as the serious interferers.

A metal complex based fluorescent chemodosimeter for selective detection of 2,4-dinitrophenol and picric acid in aqueous medium

The work in this report describes the syntheses, characterization, crystal structures, absorption and emission spectra and DFT calculations of three dizinc(II) compounds of composition [ZnII2L(μ1,1-N3)(N3)2] (1), [Zn2L'(2,4-dinitrophenolate)2] (2) and [Zn2L'(picrate)2]...