Heterometallic Organic Frameworks Research Articles

A Multifunctional CaII-EuIII Heterometallic Organic Framework with Sensing and Selective Adsorption in Water.

With increasing global industrialization, it is urgent and challenging to develop multifunctional species for detection and adsorption in the environment. For this purpose, a novel anionic heterometallic organic framework, [(CH3)2NH2][CaEu(CAM)2(H2O)2]·4H2O·4DMF (CaEuCAM), is hydrothermally synthesized based on chelidamic acid (H3CAM). Single crystal analysis shows that CaEuCAM features two different oxygen-rich channels along the c-axis in which one CAM3- bridges two sextuple-coordinated Ca2+ and two octuple-coordinated Eu3+ with a μ4-η1: η1: η1: η1: η1: η1 new chelating and bridging mode. The characteristic bright red emission and superior hydrostability of CaEuCAM under harsh acidic and basic conditions benefit it by acting as a highly sensitive sensor for Fe3+ and 3-nitrophenol (3-NP) with extremely low LODs through remarkable quenching. The combination of experiments and theoretical calculations for sensing mechanisms shows that the competitive absorption and interaction are responsible for Fe3+-induced selective emission quenching, while that for 3-NP is the result of the synergism of host-guest chemistry and the inner filter effect. Meanwhile, the assimilation of negative charge plus channels renders CaEuCAM a highly selective adsorbent for methylene blue (MB) due to a synergy of electrostatic affinity, ion-dipole interaction, and size matching. Of note is the reusability of CaEuCAM toward Fe3+/3-NP sensing and MB adsorption besides its fast response. These findings could be very useful in guiding the development of multifunctional Ln-MOFs for sensing and adsorption applications in water media.

Heterometallic-organic frameworks containing Fe(II) nodes as high-performance anode materials for Li-ion batteries

Heterometallic-organic frameworks containing Fe(II) nodes as high-performance anode materials for Li-ion batteries

Designing Different Heterometallic Organic Frameworks by Heteroatom and Second Metal Doping Strategies for the Electrocatalytic Oxygen Evolution Reaction.

Metal-organic frameworks (MOFs) are considered one of the most significant electrocatalysts for the sluggish oxygen evolution reaction (OER). Hence, a series of novel N,S-codoped Ni-based heterometallic organic framework (HMOF) (NiM-bptz-HMOF, M = Co, Zn, and Mn; bptz = 2,5-bis((3-pyridyl)methylthio)thiadiazole) precatalysts are constructed by the heteroatom and second metal doping strategies. The effective combination of the two strategies promotes electronic conductivity and optimizes the electronic structure of the metal. By regulation of the type and proportion of metal ions, the electrochemical performance of the OER can be improved. Among them, the optimized Ni6Zn1-bptz-HMOF precatalyst exhibits the best performance with an overpotential of 268 mV at 10 mA cm-2 and a small Tafel slope of 72.5 mV dec-1. This work presents a novel strategy for the design of modest heteroatom-doped OER catalysts.

Efficient purification of CH4 from ternary mixtures by a microporous heterometal-organic framework

Purification of methane (CH4) from multi-component mixtures containing acetylene (C2H2) and carbon dioxide (CO2) is a meaningful but challenging task. We herein reported a heterometal-organic framework, CuIn(ina)4, with microporous channels, which exhibits specific recognition of C2H2 and CO2 through suitable ultramicropores and surface environments. The results of experiments indicate that the title MOF shows high C2H2/CH4 selectivity (20.2) and CO2/CH4 selectivity (5.3). Column breakthrough experiments and theoretical calculations further demonstrate that CuIn(ina)4 can efficiently separate CH4 from ternary mixtures.

Catalytic comparison of cyanosilylation/Knoevenagel condensation reactions by Pb-based heterometallic organic frameworks with different second metal ions

This work explored the catalytic properties of four new 3D isostructural HMOFs in cyanosilylation and Knoevenagel condensation reactions. The study is instructive for the synthesis of HMOFs and effects of different metal ions on catalytic properties.

Heterometallic ZnHoMOF as a Dual-Responsive Luminescence Sensor for Efficient Detection of Hippuric Acid Biomarker and Nitrofuran Antibiotics.

Developing efficient and sensitive MOF-based luminescence sensors for bioactive molecule detection is of great significance and remains a challenge. Benefiting from favorable chemical and thermal stability, as well as excellent luminescence performance, a porous Zn(II)Ho(III) heterometallic-organic framework (ZnHoMOF) was selected here as a bifunctional luminescence sensor for the early diagnosis of a toluene exposure biomarker of hippuric acid (HA) through "turn-on" luminescence enhancing response and the daily monitoring of NFT/NFZ antibiotics through "turn-off" quenching effects in aqueous media with high sensitivity, acceptable selectivity, good anti-interference, exceptional recyclability performance, and low detection limits (LODs) of 0.7 ppm for HA, 0.04 ppm for NFT, and 0.05 ppm for NFZ. Moreover, the developed sensor was employed to quantify HA in diluted urine samples and NFT/NFZ in natural river water with satisfactory results. In addition, the sensing mechanisms of ZnHoMOF as a dual-response chemosensor in efficient detection of HA and NFT/NFZ antibiotics were conducted from the view of photo-induced electron transfer (PET), as well as inner filter effects (IFEs), with the help of time-dependent density functional theory (TD-DFT) and spectral overlap experiments.

Efficient C2H6/C2H4 adsorption separation by a microporous heterometal-organic framework

Purification of ethylene (C2H4) is an essential and energy-intensive process in the petrochemical industry. Adsorption separation using ethane (C2H6)-selective porous adsorbents is a highly efficient and straightforward method for obtaining polymer-grade C2H4 from a binary C2H6/C2H4 mixture. However, the design and construction of C2H6-selective adsorbents are very challenging tasks. Herein, we demonstrate a microporous heterometal-organic framework, CuIn(ina)4, can preferentially enrich C2H6 than C2H4. Experimental results revealed that CuIn(ina)4 exhibited remarkable separation performance for the C2H6/C2H4 mixture with a high C2H6 loading capacity (3.3 mmol/g), high IAST selectivity (2.3) and separation potential (1578 mmol/L for equimolar C2H6/C2H4 mixture) under ambient conditions. The effectiveness of CuIn(ina)4 for C2H6/C2H4 adsorption separation was confirmed by theoretical calculations and breakthrough experiments.

A multifunctional probe based on a heterometallic-organic framework: highly selective detection of 1,3-dinitrobenzene, tryptophan, and visual recognition of pentavalent vanadate ions

Herein, a novel luminescent heterometal-organic framework (HMOF), {[EuZn2(imdc)2(4,4′-bpy) (H2O)4(OH)]·4,4′-bpy}n (1), was synthesized by selecting d-f heterometals and two ligands with abundant coordination sites (H3imdc = 1H-imidazole-4, 5-dicarboxylic acid, 4, 4′-bpy = 4, 4′-bipyridine). The X-ray single crystal diffraction reveals that compound 1 is a three-dimensional framework structure with two kinds of channels, which has good pH fluorescence stability. Compound 1 is demonstrated to be the first known HMOF for selective detection of pentavalent vanadate ions (VO43− or VO3−). It also exhibited high selectivity, sensitivity, and low detection limits for 1,3-dinitrobenzene (1, 3-DNB) and L-tryptophan (L-Trp). More significantly, the portable MOF-based fluorescent paper of compound 1 was also successfully manufactured and might be potentially used as a functional material with naked eye recognition. Furthermore, the fluorescence mechanisms of compound 1 for sensing the above analytes have been elaborated in detail.

Lanthanide(III)-Cu4 I4 Organic Framework Scintillators Sensitized by Cluster-Based Antenna for High-Resolution X-ray Imaging.

Scintillator-based X-ray imaging has attracted great attention from industrial quality inspection and security to medical diagnostics. Herein, a series of lanthanide(III)-Cu4 I4 heterometallic organic frameworks (Ln-Cu4 I4 MOFs)-based X-ray scintillators are developed by rationally assembling X-ray absorption centers ([Cu4 I4 ] clusters) and luminescent chromophores (Ln(III) ions) in a specific manner. Under X-ray irradiation, the heavy inorganic units ([Cu4 I4 ] clusters) absorb the X-ray energy to populate triplet excitons via halide-to-ligand charge transfer (XLCT) combined with the metal-to-ligand charge-transfer (MLCT) state (defined as the X/MLCT state), and then the 3 X/MLCT excited state sensitizes Tb3+ for intense X-ray-excited luminescence via excitation energy transfer. The obtained Tb-Cu4 I4 MOF scintillators exhibit high resistance to humidity and radiation, excellent linear response to X-ray dose rate, and high X-ray relative light yield of 29 379±3000 photons MeV-1 . The relative light yield of Tb-Cu4 I4 MOFs is ≈3 times higher than that of the control Tb(III) complex. X-ray imaging tests show that the Tb-Cu4 I4 MOFs-based flexible scintillator film exhibits a high spatial resolution of 12.6lpmm-1 . These findings not only provide a promising design strategy to develop lanthanide-MOF-based scintillators with excellent scintillation performance, but also exhibit high-resolution X-ray imaging for biological specimens and electronic chips.

Design and Synthesis of Four Newly Water-Stable Pb-Based Heterometallic Organic Frameworks: How Do the Second Metals (Zn, Cd, Co, and Mn) Optimize Their Fluorescent and Catalytic Properties?

Design and Synthesis of Four Newly Water-Stable Pb-Based Heterometallic Organic Frameworks: How Do the Second Metals (Zn, Cd, Co, and Mn) Optimize Their Fluorescent and Catalytic Properties?

Heterometallic organic framework: a highly selective functional probe for carmine and TNP molecules

Heterometallic organic framework: a highly selective functional probe for carmine and TNP molecules.

Heterometallic–Organic Framework from [Cu2I2] and [PbO]n Chains: Photoluminescence, Sensing, and Photocatalytic Performance

Heterometallic–Organic Framework from [Cu₂I₂] and [PbO]_<i>n</i> Chains: Photoluminescence, Sensing, and Photocatalytic Performance

Synthesis and CO2 photoreduction of two 3d–4f heterometal–organic frameworks

Two 3d–4f heterometal–organic frameworks with similar structures were synthesized by a steam-assisted conversion method and exhibited high activity and selectivity for the photoreduction of CO2.

Two Zr-based heterometal–organic frameworks for efficient CO2 reduction under visible light

Two novel zirconium-based heterometal–organic framework catalysts can effectively improve photocatalytic activities for CO2 photoreduction under visible light.

A Co(salen)-based metal–organic framework: suppresses breast cancer cell proliferation, migration and invasion

In this research, by using the metalloligands approach, a new heterometallic–organic framework has been successfully prepared by one-step synthesis of reacting H4L with metal acetate in water and EtOH mixed solvent, and its chemical formula is {CdNa2(H2O)3[(CoL)2Na(OH)(H2O)]}·6H2O (1, H4L = 3,3′-((1E,1′E)-(cyclohexane-1,2-diylbis(azanylylidene))bis(methanylylidene))bis(4-hydroxybenzoic acid)). In the biological study, the CCK-8 method was exploited to determine the survival rate of MCF7 breast cancer cells after compound treatment. The plate colony formation test was used to confirm the inhibitory effect of this compound on the proliferation of MCF7 cancer cell. Besides, the Annexin V-FITC/PI assay were performed to evaluate the apoptosis of compound-treated MCF7 cells in flow cytometer, the intracellular ROS level was also measured via Reactive Oxygen Species Assay Kit in this study.

Rational Stepwise Construction of Different Heterometallic-Organic Frameworks (HMOFs) for Highly Efficient CO2 Conversion.

The coordination preference of different metal ions and ligands have an immense influence on the constructions of functional MOF materials. In this work, two new monometallic complexes, namely [Ag(HL)(bipy)0.5 ] (1) and {[Tb(L)1.5 (H2 O)]⋅4 H2 O}n (2) (bipy=4,4-bipyridine), have been synthesized successfully by employing a bifunctional 2-(imidazol-1-yl)terephthalic acid (H2 L) ligand. After that, two new different heterometallic-organic frameworks (HMOFs), namely {[TbAg(L)2 (H2 O)3 ]⋅H2 O}n (3) and [TbAg(L)2 (H2 O)]n (4), were obtained from complexes 1 and 2 as the precursors based on a rational stepwise construction strategy and the theory of hard and soft acids and bases (HSAB principle), respectively. The HMOFs bearing dual metallic catalytic sites (Tb and Ag) can be used as heterogeneous catalysts without losing performance for the chemical fixation of CO2 with epoxides including the sterically hindered epoxides, demonstrating some of the highest reported catalytic activity values. This work may provide a new synthetic route toward tailoring new HMOFs with excellent catalytic activity.

Syntheses, structures and properties of a series of heterometallic-organic frameworks based on pyridinedicarboxylic acids

Six novel heterometallic-organic frameworks (HMOFs), namely [LaCu(2,5-pydc)2(H2O)4]Cl (1), [LaNi(2.5-pydc)2(H2O)4]Cl·4H2O (2), [LaCu2Cl3(4,4′-bpdc)2(H2O)3]·H2O (3), [CeCuCl2(5,5′-bpdc)(HCO3)(H2O)] (4), and [MSr2Cl(3,5-pydc)2(NO3)(H2O)]·3.5H2O [M ​= ​Ni (5), Co (6)] (2,5-pydc ​= ​pyridine-2,5-dicarboxylic acid, 4,4′-bpdc ​= ​2,2′-bipyridyl-4,4′-dicarboxylic acid, 5,5′-bpdc ​= ​2,2′-bipyridyl-5,5′-dicarboxylic acid, 3,5-pydc ​= ​pyridine-3,5-dicarboxylic acid), have been solvothermally synthesized on the basis of the coordination between alkaline earth/rare earth/transition metal ions and pyridinedicarboxylic acids. These HMOFs were characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis. All these HMOFs have three-dimensional frameworks except compound 3 featuring a two-dimensional neutral layer. Magnetic property of 4 and luminescent spectra of 1–4 were studied.

Construction of a heterometallic organic framework based on cuprous-halide clusters and lanthanide clusters with CO2 storage and transformation

A novel 3D porous heterometallic organic framework based on cuprous-halide clusters and lanthanide clusters, [(Cu4I4)2Tb3(NA)9·(H2O)6·(DEF)6]n, was successfully designed and synthesized during the solvothermal synthesis. The as-made sample was analysed by many methods. This material has the preferable stability and CO2 capture capacity, so it can be used as a potential heterogeneous catalyst for the chemical fixation of CO2 and epoxides to generate cyclocarbonates. Furthermore, this MOF can preserve its pristine structure after reusing four times.

Coordination-driven assembly of a 3d-4f heterometallic organic framework with 1D Cu4I4 and Eu-based chains: syntheses, structures and various properties.

A three-dimensional porous 3d-4f heterometallic organic framework, namely, {[Eu3(Cu4I4)3(INA)9(DMF)4]·3DMF}n (YNU-2), was successfully prepared under solvothermal conditions. There are two different one-dimensional metal chains in the structure, namely, Cu4I4 and EuIII-based chains, resulting in an excellent stability of the prepared sample. A N2 sorption isotherm at 77 K revealed that the activated sample exhibits a Brunauer-Emmett-Teller surface area of 371 m2 g-1, while, YNU-2 can adsorb obviously higher CO2 amounts than CH4 at 273 K and 298 K under 1 atm because of the stronger interaction force between CO2 and the porous skeleton. Furthermore, YNU-2 is highly efficient heterogeneous catalyst for chemical fixation of the CO2 and epoxides into cyclic carbonates with a preferable recyclability. Taking into account its excellent stability, the prepared sample can be used to construct an electrochemical adapter sensor for detecting cocaine with a detection limit of 0.27 pg mL-1 in the wide range of 0.001-0.5 ng mL-1.

Engineering a hetero-MOF-derived TiO2–Co3O4 heterojunction decorated with nickel nanoparticles for enhanced photocatalytic activity even in pure water

A highly porous TiO2/Co3O4/Ni ternary heterostructure with excellent photocatalytic activity is successfully constructed by adopting hetero-metal organic frameworks as a template and a facile photoreduction method.