Trimesate Metal Organic Frameworks Research Articles

Rapid Aqueous Medium Organization of Trimesate Metal–Organic Frameworks of Cu, Fe: Exploring Suitability in Gas Separation

Rapid Aqueous Medium Organization of Trimesate Metal–Organic Frameworks of Cu, Fe: Exploring Suitability in Gas Separation

Construction of Well-Defined Two-Dimensional Architectures of Trimetallic Metal-Organic Frameworks for High-Performance Symmetric Supercapacitors.

The high surface-to-volume ratio and extraordinarily large-surface area of two-dimensional (2D) metal-organic framework (MOF) architectures have drawn particular interest for use in supercapacitors. To achieve an excellent electrode material for supercapacitors, well-defined 2D nanostructures of novel trimetallic MOFs were developed for supercapacitor applications. Multivariate MOFs (terephthalate and trimesate MOF) with distinctive nanobrick and nanoplate-like structures were successfully synthesized using a straightforward one-step reflux condensation method by combining Ni, Co, and Zn metal species in equimolar ratios with two different ligands. Furthermore, the effects of the tricarboxylic and dicarboxylic ligands on cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy were studied. The derived terephthalate and trimesate MOFs are supported with stainless-steel mesh and provide a suitable electrolyte environment for rapid faradaic reactions with an elevated specific capacity, excellent rate capability, and exceptional cycling stability. It shows a specific capacitance of 582.8 F g-1, a good energy density of 40.47 W h kg-1, and a power density of 687.5 W kg-1 at 5 mA cm-2 with an excellent cyclic stability of 92.44% for 3000 charge-discharge cycles. A symmetric BDC-MOF//BDC-MOF supercapacitor device shows a specific capacitance of 95.22 F g-1 with low capacitance decay, high energy, and power densities which is used for electronic applications. These brand-new trimetallic MOFs display outstanding electrochemical performance and provide a novel strategy for systematically developing high-efficiency energy storage systems.

Tailoring MOFs to Biomedical Applications: A Chimera or a Concrete Reality? The Case Study of Fe-BTC by bio-friendly Mechanosynthesis

ABSTRACT We point-out an exceptional tailorability of iron(III) trimesate metal-organic framework to bio-friendly conditions. This is particularly attractive in sight of one-pot immobilization of biomolecules for biomedical applications. Synthesis is carried out via mechanochemical approach under green, biocompatible conditions without additional solvents, in just 1 hour, at room temperature. Solvents are proven to be unnecessary to build the framework, in contrast to solution-based methods. Microstructure and thermal stability of the material are not affected by pH. Conversely, textural properties can be tuned by simply varying the amount of base.

Designing Metal-Chelator-like Traps by Encoding Amino Acids in Zirconium-Based Metal–Organic Frameworks

Metal chelators and porous sorbents are two of the forefront technologies applied for the recovery and separation of hazardous and/or valuable metal ions from aqueous solutions (i.e., polluted water sources, metal-rich mining wastewaters, acid leachates, and so forth). The transfer of the metal coordination functions of metal chelators to chemically stable host materials had only limited success so far. Here, we report the installation of natural acids (i.e., malic acid, mercaptosuccinic acid, succinic acid, fumaric acid, and citric acid) and amino acids (i.e., histidine, cysteine, and asparagine) within a porous zirconium-based trimesate metal–organic framework (MOF), namely, MOF-808. Applying this strategy, we were able to produce a pore environment spatially decorated with multiple functional groups usually found in commercial chelator molecules. The chemical stability of the amino acid molecules installed by the solvent-assisted ligand exchange has been studied to delimitate the applicability window of these materials. The adsorption affinity of MOF-808@(amino)acids in static and column-bed configurations can be fine-tuned as a function of the amino acid residues installed in the framework. MOF-808(amino)acid columns can be applied efficiently both for water remediation of heavy metals and for the separation of metal ions with different acidities. For instance, the initial trends for the dispersion of rare-earth elements have been identified. Electron paramagnetic resonance and inelastic neutron scattering spectroscopy reveal that MOF-808@(amino)acids stabilize metal centers as isolated and clustered species in a coordination fashion that involves both the amine and thiol functionals and that affects the vibrational freedom of some of the chemical groups of the amino acid molecules. The metal-ion stabilization within amino acid-decorated MOFs opens the avenue for application for pseudo biocatalysis purposes in the near future.

Lanthanides adsorption on metal-organic framework: Experimental insight and spectroscopic evidence

Herein, lanthanides (Samarium: Sm, Lanthanum: La, and Erbium: Er) adsorption mechanism over copper trimesate metal-organic framework (Cu-BTC MOF) was studied. The MOF crystallized as [Cu(HBTC)(H2O)3] and [Cu3(BTC)2] with a rod-like structure and abundant free COOH groups. The Langmuir adsorption capacity of 1007.1, 656.5, and 410.5 mg g−1 was recorded for Sm, La, and Er, respectively. The adsorption process was driven by rapid ion exchange with crystal structure transformation in the first hour of mixing, mediated by the surface ion-exchange phenomenon and free COOH groups. After 1 h, the process was driven by a slow ion-exchange mechanism where Ln ions drifted internally, and Cu ions moved out towards the surface. Among the three lanthanides studied, Er/Cu-BTC system was more sensitive to structural reorganization with the increasing Ln/Cu ratio. The work reported here is one of the first detailed accounts of the Ln-adsorption process in MOFs.

Metal-organic framework-derived NaMxOy adsorbents for low-temperature SO2 removal

This work reported the fabrication of NaMxOy-type adsorbents from air calcination of (Na, M)-trimesate metal-organic frameworks. NaMnxOy (NMO) crystallized as disc-shaped microsheets, whereas NaCoxOy (NCO) crystallized as smooth microsheets with surface deposition of polyhedral nanoparticles. The oxides have a surface area of 1.90–2.56 m2 g−1. The synthesized adsorbents were studied for low-temperature SO2 removal in breakthrough studies. The maximum adsorption capacity of 46.8 mg g−1 was recorded for NMO at 70 °C. The adsorption capacity increased with the increasing temperature due to the chemisorptive nature of the adsorption process. The capacity increased with the increasing bed loading and decreasing flow rate due to the improved SO2 retention time. The elemental mapping confirmed the uniform distribution of sulfur species over the oxide surface. X-ray diffraction showed the absence of metal sulfate nanoparticles in the SO2-exposed samples. The X-ray photoelectron analysis confirmed the formation of surface sulfate and bisulfate. The formation of oxidized sulfur species was mediated by hydroxyl groups over NMO and lattice oxygen over NCO. Thus, the work demonstrated here is the first such report on the use of NaMxOy-type materials for SO2 mineralization.

Microencapsulated Isoniazid-Loaded Metal-Organic Frameworks for Pulmonary Administration of Antituberculosis Drugs.

Tuberculosis (TB) is an infectious disease that causes a great number of deaths in the world (1.5 million people per year). This disease is currently treated by administering high doses of various oral anti-TB drugs for prolonged periods (up to 2 years). While this regimen is normally effective when taken as prescribed, many people with TB experience difficulties in complying with their medication schedule. Furthermore, the oral administration of standard anti-TB drugs causes severe side effects and widespread resistances. Recently, we proposed an original platform for pulmonary TB treatment consisting of mannitol microspheres (Ma MS) containing iron (III) trimesate metal–organic framework (MOF) MIL-100 nanoparticles (NPs). In the present work, we loaded this system with the first-line anti-TB drug isoniazid (INH) and evaluated both the viability and safety of the drug vehicle components, as well as the cell internalization of the formulation in alveolar A549 cells. Results show that INH-loaded MOF (INH@MIL-100) NPs were efficiently microencapsulated in Ma MS, which displayed suitable aerodynamic characteristics for pulmonary administration and non-toxicity. MIL-100 and INH@MIL-100 NPs were efficiently internalized by A549 cells, mainly localized in the cytoplasm. In conclusion, the proposed micro-nanosystem is a good candidate for the pulmonary administration of anti-TB drugs.

Water-Driven Structural Transformation in Cobalt Trimesate Metal-Organic Frameworks

We report on the synthesis and the characterization of a novel cobalt trimesate metal-organic framework, designated as KCL-102. Powder X-ray diffraction pattern of KCL-102 is dominated by a reflection at 10.2° (d-spacing = 8.7 Å), while diffuse reflectance UV-Vis spectroscopy indicates that the divalent cobalt centers are in two different coordination geometries: tetrahedral and octahedral. Further, the material shows low stability in humid air, and it transforms into the well-known phase of hydrous cobalt trimesate, Co3(BTC)2·12H2O. We associated this transition with the conversion of the tetrahedral cobalt to octahedral cobalt.

Solvent-Free and Phase-Selective Synthesis of Aluminum Trimesate Metal-Organic Frameworks.

Aluminum-based metal-organic frameworks (Al-MOFs) have shown promise as commercially valuable materials due to the variety of applications, excellent thermal, hydrothermal, and chemical stabilities, and the abundance of aluminum. In this work, for the first time, we report the solvent-free synthesis of the aluminum trimesate (Al-BTC) MOFs (MIL-100(Al), MIL-96(Al), and MIL-110(Al)) with phase selectivity and high yield. These MOFs were traditionally prepared with HF, HNO3, and bulk solvents, but these methods struggled to produce pure-phase isolations. The solvent-free strategy provides valuable insight into the future industrial scale-up production of the Al-MOFs and promotes the potential commercialization of such materials.

Terephthalate and trimesate metal-organic frameworks of Mn, Co, and Ni: exploring photostability by spectroscopy.

We report a rapid synthesis for the fabrication of terephthalate and trimesate metal–organic frameworks (MOFs) of Mn, Co, and Ni by ultrasonication of organic linkers with freshly prepared metal hydroxides. The MOFs were characterized by various microscopic and spectroscopic techniques to understand their structural, functional, and optical properties. MOFs with low bandgap energy (1.88–2.73 eV) showed strong absorbance in the UV-visible range. MOFs were exposed to UV irradiation for 40 h to understand their photostability. The MOFs showed decreased surface area and porosity with CoBTC as an exception. PXRD was less convincing for exploring functional changes in the UV-irradiated MOFs. XPS predicted changes in the oxidation states of metal nodes, the degradation of the organic linkers, and decarboxylation process in many of the transition MOFs. The study predicted terephthalate-based MOFs as more photostable than corresponding trimesate-based MOFs. This study is one of the first attempts in exploring photostability of MOFs with Mn, Co, and Ni as nodes.

Facile “Green” Aqueous Synthesis of Mono- and Bimetallic Trimesate Metal–Organic Frameworks

Various isoreticular monometallic (Co2+, Ni2+, Cu2+, and Zn2+) and bimetallic (Co-Ni, Co-Zn, Mn-Ni) trimesate MOFs have been prepared by a fast (10 min) and green synthesis method from aqueous solu...

Selective Aerobic Oxidation of Cumene to Cumene Hydroperoxide over Mono- and Bimetallic Trimesate Metal–Organic Frameworks Prepared by a Facile “Green” Aqueous Synthesis

Co–Ni and Mn–Ni bimetallic trimesate MOFs prepared by a fast aqueous synthesis method are excellent and reusable catalysts for the selective aerobic oxidation of cumene to cumene hydroperoxide (CHP). Isolation of Co2+ (or Mn2+) in an inert Ni-BTC framework is a good strategy to optimize CHP selectivity above 90%: since only Co2+ sites catalyze CHP decomposition, a drop of the CHP selectivity is observed as the cobalt content in the bimetallic MOF increases. The statistical probability of having isolated Co2+ sites is calculated as a function of the total cobalt content of the bimetallic compound, assuming homogeneous distribution of Co2+ ions in the Ni-BTC framework and preferential occupation of terminal sites. Thus, in our best sample, with a Co:Ni ratio of 5:95, 73% of the total Co2+ ions are isolated so that CHP decomposition/overoxidation processes at the surface of the catalyst are not likely to occur before CHP desorption. This can explain the excellent CHP selectivity (91%) attained over this mate...

Maghemite-nanoMIL-100(Fe) Bimodal Nanovector as a Platform for Image-Guided Therapy

Summary We report here the design of nano-objects (i.e., denoted as MIL/USPIO-cit) that consist of nanoparticles of mesoporous iron trimesate metal-organic framework MIL-100(Fe), whose surface is decorated by maghemite nanoparticles. Not only is this bimodal nanovector produced through a cost-effective and reliable green approach, but it also exhibits excellent colloidal stability under simulated intravenous conditions, and its ability to encapsulate and progressively release drugs (doxorubicin here) is preserved. According to vibrating sample magnetometry and 57 Fe Mossbauer spectrometry, MIL-USPIO-cit presents a superparamagnetic behavior characterized by a high saturation magnetization at room temperature. More importantly, it combines low toxicity with high anti-tumoral activity and can be used in vivo as an efficient MRI contrast agent because of its excellent relaxivity properties. All these properties make this nano-object a potential candidate as a bimodal therapeutic nanovector coupling drug-delivery and MRI properties.

In vitro biocompatibility of mesoporous metal (III; Fe, Al, Cr) trimesate MOF nanocarriers.

The high porosity and versatile composition of the benchmarked mesoporous metal (Fe, Al, Cr) trimesate metal-organic frameworks (MIL-100(Fe, Al, Cr)) make them very promising solids in different strategic industrial and societal domains (separation, catalysis, biomedicine, etc.). In particular, MIL-100(Fe) nanoparticles (NPs) have been recently revealed to be one of the most promising and innovative next generation tools enabling multidrug delivery to overcome cancer resistance. Here, we analyzed the in vitro toxicity of the potential drug nanocarrier MIL-100(Fe) NPs and the effect of the constitutive cation by comparing its cytotoxicity with that one of its Cr and Al analogue NPs. Lung (A549 and Calu-3) and hepatic (HepG2 and Hep3B) cell lines were selected considering pulmonary, ingestion or intravenous exposure modes. First, the complete physicochemical characterization (structural, chemical and colloidal stability) of the MIL-100(Fe, Al, Cr) NPs was performed in the cell culture media. Then, their cytotoxicity was evaluated in the four selected cell lines using a combination of methods from cell impedance, cell survival/death and ROS generation to DNA damage for measuring genotoxicity. Thus, MIL-100(Fe, Al, Cr) NPs did not induce in vitro cell toxicity, even at high doses in the p53 wild type cell lines (A549 and calu-3 (lung) and HepG2 (liver)). The only toxic effect of MIL100-Fe was observed in the hepatocarcinoma cell line Hep3B, which is stress sensitive because it does not express TP53, the guardian of the genome.

Host-guest interactions in Fe(III)-trimesate MOF nanoparticles loaded with doxorubicin.

Doxorubicin (DOX) entrapment in porous Fe(III)-trimesate metal organic frameworks (MIL-100(Fe)) nanoparticles was investigated in neutral Tris buffer via UV-vis absorption, circular dichroism (CD), and fluorescence. The binding constants and the absolute spectra of the DOX-MIL-100(Fe) complexes were determined via absorption and fluorescence titrations. A binding model where DOX associates as monomer to the dehydrated Fe3O (OH)(H2O)2 [(C6H3)(CO2)3]2 structural unit in 1:1 stoichiometry, with apparent association constant of (1.1 to 1.8) × 10(4) M(-1), was found to reasonably fit the experimental data. Spectroscopic data indicate that DOX binding occurs via the formation of highly stable coordination bonds between one or both deprotonated hydroxyl groups of the aglycone moiety and coordinatively unsaturated Fe(III) centers. Complete quenching of the DOX fluorescence and remarkable thermal and photochemical stability were observed for DOX incorporated in the MIL-100(Fe) framework.

Rearrangement of α-pinene oxide to campholenic aldehyde over the trimesate metal–organic frameworks MIL-100, MIL-110 and MIL-96

The catalytic performance of porous metal–benzenetricarboxylates, such as MIL-100(Al, Fe and Cr), MIL-110(Al) and MIL-96(Al), was investigated with a combination of physicochemical and catalytic approaches in the rearrangement of α-pinene oxide to campholenic aldehyde (CA). The investigation of Lewis acidity was done by EPR and IR spectroscopy using 2,2′,6,6′-tetramethyl-1-piperidinyoxyl radical and benzonitrile as the probe molecules, respectively. For Al–BTCs, both these methods showed a decrease in the amount of Lewis acid sites as follows: MIL-100>MIL-110>MIL-96. The reaction rate and selectivity toward CA also decreased in the same order. A relatively good correlation between selectivity toward CA and the electronegativity of the metal ion was found for isostructural MIL-100(Al, Fe and Cr). The selectivity toward CA decreased in the order: MIL-100(Al)>MIL-100(Fe)>MIL-100(Cr). The high selectivity toward CA in the presence of MIL-100 has been suggested to originate from the unique structure of this material, which favors shape selectivity.

An Experimental Study of Adsorption Breakthrough Curves for CO2/CH4 Separation in a Fixed Bed of Nanoporous Shaped Copper Trimesate Metal Organic Framework

Copper trimesate (Cu-BTC) MOF has been pointed out as a promising adsorbent for separating carbon dioxide from methane. However, MOF’s need to be shaped prior to their use in packed bed adsorbers in order to reduce pressure drop; on the other hand, the production of mechanically resistant shaped bodies reduces their adsorption performance. In this work, Cu-BTC tablets provided by BASF are evaluated to perform CO2/CH4 separation through adsorption. The adsorption capacity of pure carbon dioxide from methane was measured in a magnetic suspension balance between temperatures of 308 and 373 K up to a pressure of 700 kPa. The evaluated material presents higher adsorption capacity than previously studied shaped samples with a carbon dioxide and methane adsorption capacity up to 3.07 and 0.63 mol/kg at 100 kPa and 308 K respectively. Moreover, the experimental data were fitted with the Langmuir model. Isosteric heats of adsorption were obtained to be 22.8 and 15.1 kJ/mol for CO2 and CH4 on Cu-BTC tablets respectively, which indicates a strong adsorption of carbon dioxide on these adsorbents. Also, single and binary breakthrough curves were measured in the same temperature range and atmospheric pressure by using Cu-BTC tablets as the adsorbent. The preferential adsorption capacity of CO2 on nanoporous copper trimesate (Cu-BTC) indicates that this material can be used for methane purification from natural gas.

Preparation and thiols sensing of luminescent metal–organic framework films functionalized with lanthanide ions

Continuous and well-attached thin films of indium trimesate metal–organic framework (MOF) were prepared rapidly by in situ solvothermal synthesis method on silicon wafer modified with platinum nanoparticles. The film growth process and possible mechanism were studied in detail. Luminescent metal–organic framework thin films, In-BTC⊃Ln, were achieved by the post-functionalization of the resulted MOF film In-BTC with lanthanide ions (Eu3+, Tb3+, Dy3+ or Sm3+). The structure and morphology of the films were investigated by XRD and SEM. The luminescent properties of the In-BTC⊃Ln films indicate that lanthanide ions are sensitized by organic linker via the metal carboxylates in the pores. More interestingly, the luminescent In-BTC⊃Ln films show good performance in fast detection of volatile thiols such as 1,2-ethanedithiol and 1-butanethiol.

Remarkable Lewis acid catalytic performance of the scandium trimesate metal organic framework MIL-100(Sc) for C–C and CN bond-forming reactions

The porous metal organic frameworks scandium trimesate MIL-100(Sc), scandium terephthalates MIL-101(Sc), MIL-88B(Sc) and MIL-68(Sc), scandium 4,4′-biphenyl-dicarboxylate MIL-88D(Sc) and the scandium 3,3′,5,5-azobenzene-tetracarboxylate socMOF(Sc) have been compared as Lewis acid catalysts against Sc3+-exchanged zeolite Beta, MIL-100(Cr), MIL-101(Cr), MIL-100(Fe) and the divalent MOFs HKUST-1(Cu), CPO-27(Ni) and STA-12(Ni), each of which can be prepared with coordinatively unsaturated metal sites. The performance of these MOFs has been investigated in several Lewis acid-catalysed reactions that are of importance in organic synthesis but have rarely been studied using MOF catalysts. These reactions were (i) the intermolecular carbonyl ene reaction of nucleophilic alkenes and electron-poor aldehydes, (ii) a Friedel–Crafts type Michael addition between electron-rich heterocycles and electron-deficient alkenes and (iii) ketimine and aldimine formation. In each of these, MIL-100(Sc) is both active and selective and significantly outperforms the other catalysts. Filtration and recycle tests indicate that catalysis over MIL-100(Sc) is heterogeneous. The study of Michael addition reactions carried out over scandium-bearing MOFs with different window sizes on indole-based substrates of varying molecular dimensions indicates that most of the catalysis that involves molecules small enough to enter the pores occurs within the internal pore space. These results indicate MIL-100(Sc) is an exceptional Lewis acidic MOF catalyst, and suggest that MIL-100(Sc) and new derivatives of it could find application as recyclable solid catalysts in synthetic chemistry.

Impact of phosphorylation on the encapsulation of nucleoside analogues within porous iron(iii) metal–organic framework MIL-100(Fe) nanoparticles

Encapsulation of azidothymidine (AZT) or its phosphorylated derivatives (AZT-MP and AZT-TP) has been performed using nanoparticles of the porous crystalline iron(iii) trimesate metal-organic framework MIL-100(Fe). The number of phosphate groups per nucleoside analogue has a high impact on the drug loading capacity, and their interaction with the Lewis acid sites from the nanoMOFs is also discussed through a combination of techniques such as UV-vis absorption, circular dichroism, isothermal titration calorimetry, HPLC and molecular simulations. Finally, the effect of the differences in terms of host-guest interactions is discussed through the release in physiological buffers of AZT, AZT-MP and AZT-TP. New perspectives for the nanoencapsulation of monophosphorylated nucleoside analogues for effective anti-cancer and anti-viral therapies are then discussed.