Two novel zinc-based MOFs as luminescence sensors to detect phenylglyoxylic acid

Automobile exhaust gases, plastic pollutants, smoking, and other harmful substances can cause serious harm to human beings and the environment. Styrene, as a common airborne toxin, enters the human body through breathing or the skin and is discharged in the form of phenylglyoxylic acid (PGA). Therefore, specific, sensitive and trace detection of PGA is particularly important. Here, two zinc-based metal-organic frameworks {[Zn₂L₁(DMF)₂H₂O](DMF)₂H₂O}_n, {[Zn₄(L₂)₂(DMF)₂(H₂O)₃](DMF)₈}_n (L₁ = 2,5-bis((3-carboxylphenyl)amino)terephthalic acid, L₂ = 2,5-bis((4-carboxyphenyl)amino)terephthalic acid) have been reported as 1 and 2, respectively. Both 1 and 2 present 3D structures, which can both be simplified as 4,4,4-c net topology. It is worth mentioning that 2 has two different kinds of Zn SBUs as connecting nodes in the structure. Besides, compared with the other materials for the detection of PGA, 1 and 2 exhibit relatively low detection limits (LODs), both in water and in urine (where the LODs for 1 in water and urine were 0.33 μM and 0.43 μM in the range of 0-0.39 mM, and those for 2 were 0.28 μM and 0.49 μM in the range of 0-0.59 mM, respectively). In addition, the sensors have excellent anti-interference ability, high stability, rapid response, and can easily distinguish between different concentrations of PGA with the naked eye. The developed paper probes were suitable for practical sensing applications for portable detection of PGA in urine.

A new zinc-organic framework with 1D channel for constructing a ratiometric Al3+-selective sensor and four inputs INHIBIT logic gate

To develop Al³⁺ fluorescent sensor is significant because the abnormal levels of Al³⁺ in environment may pose great threat to human body. Herein, a novel metal-organic framework {Zn(Dpada)(Imdba)·H₂O}_n (Dpada = 3, 6-di(1H-imidazol-1-yl) pyridazine and Imdba = 2, 2'-iminodibenzoic acid), named Zn-MOF, has been architected with one-dimensional channel under hydrothermal conditions. Zn-MOF exhibits good thermal and solvent stability and can also keep structural integrity over the pH range of 5.0 - 9.0. Fluorescent experiments show that Zn-MOF has high selectivity and sensitivity towards Al³⁺ via ratiometric fluorescence signal changes (F_{470 nm}/F_{390 nm}) and the detection limit is evaluated to be 0.69 μM. In addition, Zn-MOF performs good recyclability in sensing of Al³⁺ with at least 5 cycles. Besides, an INHIBIT logic gate has been constructed with chemical ions (Al³⁺, Cr³⁺, Fe³⁺ and Hg²⁺) as input signals and emission ratio (F_{470 nm}/F_{390 nm}) as output signal. Significantly, Zn-MOF can be applied to tracing Al³⁺ using real water samples, presenting great potential in water quality monitoring application.

Luminescent binuclear Zinc(II) organic framework as bifunctional water-stable chemosensor for efficient detection of antibiotics and Cr(VI) anions in water

To achieve the ultrastable LMOFs with predominant luminescent sensing performances, the aromatic π-electron mixed ligands strategy was introduced, and the ternary LMOF of {[Zn₂(HDDB)(bib)_1.5]·3H₂O}_n (1), was fabricated based on 3,5-di(2',4'-dicarboxylphenyl)benozoic acid (H₅DDB) and the N-donor of meta-bis(imidazol-1-yl)benzene (bib) under mixed solvothermal condition. LMOF 1 features the first reported 3D 3,4,4-c {6².8³.10}{6².8}₂{6³.8².10}₂ framework with 21.2 % porosity as well as high thermal and chemical stability. Further luminescent sensing showed that LMOF 1 as a bifunctional chemosensor possessing predominant detectability for sensitive detect the hexavalent chromates and nitroimidazoles/nitrofurans antibiotics in water through strong luminescent quenching effects, with excellent reusability as well as trace detection limits. Moreover, luminescent quenching mechanisms were further investigated from electron transfer and energy transfer viewpoints.

Two robust Zn(ii)-organic frameworks as dual-functional fluorescent probes for efficient sensing of enrofloxacin and MnO4− anions

Two robust Zn-MOFs were employed as visual and ultra-sensitive indicators toward enrofloxacin (ENR) and MnO4− anions in aqueous phase.

A Highly Stable Eu−MOF Multifunctional Luminescent Sensor for the Effective Detection of Fe3+, Cr2O72−/CrO42− and Aspartic Acid in Aqueous Systems

Heavy metal ions were common pollutants in water pollution. Amino acids, as important substances in organisms, participate in many life activities. The detection of heavy metal ions and amino acids...

Stable bifunctional ZnII-based sensor toward acetylacetone and L-histidine by fluorescence red shift and turn-on effect

A new coordination polymer [Zn(bbip)(NH2-BDC)]n (JXUST-15, bbip = 2,6-bis(benzimidazol-1-yl)pyridine and NH2-H2BDC = 2-aminoterephthalic acid) has been synthesized by mixed ligand strategy. The structure analysis shows that JXUST-15 takes a two-dimensional...

A Ni-MOF based luminescent sensor for selective and rapid sensing of Fe(ii) and Fe(iii) ions

In this work, a bis(N,N-trimellitoyl)-4,4′-oxydianiline linker was synthesized and characterized by spectroscopic techniques. The molecular structure and luminescence intensity of the Ni-MOF treated with different metal ions were investigated.

Two chemically robust Cd(II)-frameworks for efficient sensing of levofloxacin, benzaldehyde, and Fe3+ ions

Two luminescent Cd(II)-organic frameworks [Cd₂(L1)(tdc)₂(H₂O)]_n (1) and [Cd(L2)_0.5(tdc)]_n (2) (L1 = 1,5-bis(1-(pyridine-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)pentane, L2 = 1,6-bis(1-(pyridine-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)hexane, and H₂tdc = 2,5-thiophenedicarboxylic acid) were hydrothermally synthesized and characterized. 1 displays a rare binodal (3,4)-connected 2D cem-d network, while 2 exhibits a 3D mog (moganite) framework. The two MOFs are highly thermally durable and water-stable in a wide pH range from 3 to 12. Interestingly, 1 and 2 represent the first reported examples of multi-responsive probes based on MOFs for selectively detecting levofloxacin, benzaldehyde, and Fe³⁺ ions with reusability. The luminescence sensing mechanisms of the two CPs were explored in detail.

Construction of a new luminescent Cd(ii) compound for the detection of Fe3+ and treatment of Hepatitis B

A novel porous Cd(ii) metal–organic framework (MOF) with the chemical composition of {[H3O][Cd(bci)]} n ·2n(H2O) (1, H3bci = bis(2-carboxyethyl)isocyanurate) was prepared via hydrothermal responses of H3bci and Cd(NO3)2·4H2O. Luminescent property investigations indicated that compound 1 had high sensitivity toward Fe3+, and the detection limit of Fe3+ was as low as 2.15 × 10−4 M. The application values of Fe3+ on Hepatitis B were assessed, and its associated mechanism was identified simultaneously. First, the cytotoxic mediator (TNF-α) substance released into plasma was measured through the ELISA. In addition, real-time RT-PCR was employed to determine the Hepatitis B viral replication gene relative expression levels. Finally, the novel compound’s toxicity against human normal liver cells was tested by using the CCK-8 assay.

Eight-Fold Interpenetrating Diamondoid Coordination Polymers for Sensing Volatile Organic Compounds and Metal Ions

Reactions of divalent metal salts with 4,4-oxybis(N-(pyridine-4-yl)-benzamide), L, and naphthalene-1,4-dicarboxylic acid (1,4-H₂NDC) in various solvents gave [Zn(L)(1,4-NDC)·H₂O]_n, 1, [Cd(L)(1,4-NDC)(H₂O)·MeOH]_n, 2, and [Co(L)(1,4-NDC)(H₂O)_0.5·MeOH]_n, 3, which have been structurally characterized. Complexes 1–3 show eight-fold interpenetrating frameworks with the dia topology, which exhibit porosities substantiated by CO₂ adsorption, whereas 1 and 2 manifest stability in aqueous environments and show high selectivity toward sensing of mesitylene molecules and Fe³⁺ ions with low detection limits and good reusability up to five cycles.

Two Cd(ii)-based metal–organic frameworks for the highly effective detection of Fe3+ ions and levofloxacin in aqueous media

Two new Cd(ii)-MOFs are hydrothermally synthesized and can be applied as dual-response sensors to identify Fe3+ and levofloxacin (LVX) with high selectivity, sensitivity and excellent reusability.

A multi-responsive MOF-based fluorescent probe for detecting Fe3+, Cr2O72− and acetylacetone

A novel ZnII-based MOF can selectively and sensitively recognize Fe3+, Cr2O72− and acetylacetone, simultaneously.

Various carboxylates induced eight Zn(ii)/Cd(ii) coordination polymers with fluorescence sensing activities for Fe(iii), Cr(vi) and oxytetracycline

Eight new Zn(ii)/Cd(ii) coordination polymers constructed from a naphthalene-amide-pyridyl ligand and various carboxylates were synthesized and characterized, which show multifunctional fluorescence responses for cations, anions and antibiotics.