As-synthesized Metal-organic Frameworks Research Articles

Methotrexate-loaded Fe-metal organic frameworks: Synthesis, characterizations, and drug release investigations

Efficient diagnoses and effective treatment of diseases like cancer can be achieved by designing and developing targeted and controlled drug delivery systems. Metal-organic frameworks (MOFs) are promising drug delivery systems due to large surface area, tunable pore sizes, and controlled drug release. Herein, we report the loading and release of methotrexate (MTX) in MIL-101-Fe MOF as a drug delivery system. The functional groups, crystal structure, and morphology of the as-synthesized MOF was determined by Fourier transform infrared spectroscopy (FTIR), powdered X-ray diffraction and scanning electron microscopy (SEM), respectively. Interestingly, the MOF exhibited 84 % encapsulation efficiency for MTX and 62 % release in the initial 50 h at pH 5.5, which is ideal for tumor tissue. The MTX@MIL-101-Fe effectively killed the HeLa cells from human cervical cancer. Particularly noteworthy was that neither MIL-101-Fe nor MTX@MIL-101-Fe showed toxicity to healthy Vero cells. It proves that the Methotrexate was released from MTX@MIL-101-Fe in cancer cells at pH 5.5 and caused apoptosis. Theoretical studies used density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to explore three possible Methotrexate-MIL-101-Fe encapsulation complexes. The complex with the drug attached at the carboxylate-bridge site showed the highest binding. Moreover, a decrease in the calculated band gap was also observed during the encapsulation process. This study suggests that MIL-101-Fe can be a promising candidate for target-specific and efficient delivery of Methotrexate to cancer cells with reduced side effects.

Evaluation of Ce-MOFs as Photoanode Materials for the Water Oxidation Reaction: The Effect of Doping with [Ru(bpy)(dcbpy)(H2O)2]2+ Catalyst.

Artificial photosynthesis stands out as a highly effective method for harnessing sunlight to produce clean and renewable energy. The light-absorbing properties, chemical stability, and high redox activity of Ce-based metal-organic frameworks (MOFs) make them attractive materials for visible-light-driven water splitting. Currently, Ce-based MOFs remain a relatively underexplored system for photocatalytic water oxidation in acidic media. In this study, we synthesized a Ce-MOF with different linkers (1,4-benzenedicarboxylic acid, tetrafluoroterephthalic acid, 2-nitroterephthalic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid), which exhibit light-absorbing capability. Ce-based MOFs doped with [Ru(bpy)(dcbpy)(H2O)2]2+ (MOF-1 and MOF-2) water oxidation catalyst showed an enhanced photoelectrocatalytic current of ∼10-4 A·cm-2 at pH = 1, which is comparable with the [Ru(bpy)(dcbpy)(H2O)2]2+-doped MIL-126 Fe-based MOF. We also demonstrated the long-term durability of Ru-doped Ce-MOFs for photoelectrocatalytic water oxidation under acidic conditions. The as-synthesized MOFs were analyzed with powder X-ray diffraction (PXRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy, scanning electron microscopy (SEM), and electric conductivity measurements. This study contributes to the development of cost-effective materials for sustainable photocatalytic water splitting processes.

Facile synthesis of a three-dimensional Ln-MOF@FCNT composite for the fabrication of a symmetric supercapacitor device with ultra-high energy density: overcoming the energy storage barrier.

In order to quench the thirst for efficient energy storage devices, a novel praseodymium-based state-of-the-art three-dimensional metal-organic framework (MOF), {[Pr(pdc)2]Me2NH2}n (YK-1), has been synthesized by using a simple solvothermal method employing a readily available ligand. YK-1 was characterised by single-crystal XRD and crystallographic analysis. The electrochemical measurements of YK-1 show that it exhibits a specific capacitance of 363.5 F g-1 at a current density of 1.5 A g-1 with 83.8% retention after 5000 cycles. In order to enhance its electrochemical performance for practical application, two composites of YK-1 with graphene oxide (GO) and functionalised multi-walled carbon nanotubes (FCNTs), namely YK-1@GO and YK-1@FCNT, were fabricated by employing a facile ultrasonication technique. The as-synthesized MOF and the composites were characterized by PXRD, FTIR, SEM, and TEM techniques. YK-1@GO and YK-1@FCNT offer enhanced specific capacitances of 488.2 F g-1 and 730.2 F g-1 at the same current density with 93.8% and 97.7% capacity retention after 5000 cycles, respectively (at 16 A g-1). Fascinated by the outstanding results shown by YK-1@FCNT, a symmetric supercapacitor device (SSC) based on it was fabricated. The assembled SSC achieved a remarkable energy density (87.6 W h kg-1) and power density (750.2 W kg-1) at a current density of 1 A g-1, along with very good cycling stability of 91.4% even after 5000 GCD cycles. The SSC device was able to power up several LED lights and even operated a DC brushless fan for a significant amount of time. To the best of our knowledge, the assembled SSC device exhibits the highest energy density among the MOF composite-based SSCs reported so far.

Design, Enhanced Photoluminescence Properties of Ti Incorporated Zr-Networked 4-[Formyl (Hydroxymethylidene)-4-Sulfanyl] Benzoic Acid Metal Organic Frameworks

Present study reports the enhanced photoluminescence properties of Ti incorporated Zr networked 4-{formyl (Hydroxymethylidine)-4-Sulfanyl] Benzoic Acid. The as-synthesized metal organic framework (MOF) was synthesized by solvothermal process and was analyzed by SEM (scanning electron microscopy), XRD (X-ray diffraction spectroscopy) and photoluminescence spectroscopy. The as-synthesized MOFs are well crystalline with average particle size of 35 to 56 nm. From XRD data X-ray diffraction patterns which illustrated the well maintained topological structure during the cation exchange process. From scanning electron microscopy study it shows irregular shape of MOFs.

Highly efficient visible-light photocatalytic nitrogen fixation via single-atom iron catalyst site and synergistic effect of Zr-cluster in zirconium-based porphyrinic metal-organic frameworks (PCN-222)

Zirconium-based porphyrinic metal-organic frameworks (MOFs), including PCN-222 (nonmetal), and PCN-222 (Fe) were employed as the photocatalyst for photocatalytic nitrogen (N2) fixation to NH3 under visible light irradiation. The as-synthesized MOFs of PCN-222 (nonmetal) and PCN-222 (Fe) exhibited a notable increase in photocatalytic N2 fixation compared to the pure (Metallo) porphyrin ligands of H2TCPP and FeTCPP, respectively. The comparative studies illustrated that using the Zr-cluster as a stable node and the active redox site is a successful strategy to increase the stability and photocatalytic activity of the MOF-based photocatalysts. On the other, the single-atom Fe site as an active center of absorption and activation of nitrogen molecules improved the N2 fixation activity. Remarkably, among them all, PCN-222 (Fe) demonstrated the highest photocatalytic N2 fixation activity with a rate of 1502.51 μmol g-1h−1 which could be related to the simultaneous presence of Zr-cluster and single-atom Fe site which promote the performance of the photocatalyst. So, the photocatalytic activity of PCN-222 (Fe) is 1.9 and 2.5 times higher than the activity of PCN-222 (nonmetal) and pure FeTCPP, respectively. High photocatalytic activity, sacrificial agent-free conditions, excellent efficiency in short response time, reusability, and mild reaction conditions are the attractive characteristics of the as-synthesized photocatalysts that make them suitable candidates for photocatalytic NH3 production.

Sonochemically synthesized Zn (II) and Cd (II) based metal-organic frameworks as fluoroprobes for sensing of 2,6-dichlorophenol

A sonochemical route for the synthesis of 2-D Zn (II) and Cd (II) based metal - organic frameworks (MOF) formulated as [Zn(apca)2]n and [CdCl2(apca)]n (Hapca ​= ​3-aminopyrazine-2-carboxylic acid) was developed. The MOFs synthesized were characterized using PXRD, FT-IR, SEM, and TGA analysis. The impact of different irradiation time and precursor concentration were investigated for attaining repetitious morphology. The DFT studies provide the detailed calculation of charge density distribution and electron localization function (ELF) of MOFs. The selectivity of the as-synthesized MOFs was studied for detecting phenolic structural analogs such as phenol, 2,6-dichlorophenol (2,6-DCP), 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP), 2-Chlorophenol (2-CP), 2,4,6-trichlorophenol(2,4,6-TCP), 2-methoxyphenol (2-MP), 2-nitrophenol (2-NP), and 4-hydroxyphenol (4-HP) out under optimal conditions. The results revealed that our proposed probes are equipped with excellent recognition ability for almost exclusively 2,6-DCP. Both the MOFs exhibit a good linearity between the fluorescence intensity and analyte concentration in the range of 2–30 ​μmol ​L−1. The calculated limit of detection (LOD) for Zn-MOF and Cd-MOF was 5.6 ​μmol ​L−1 and 2.2 ​μmol ​L−1, respectively. The studies were further extended to fabrication of Zn-MOF@chitosan and Cd-MOF@chitosan membranes and proposed as solid fluoroprobes for detection of 2,6-DCP in real sample analysis.

Rapid synthesis strategy of ultrathin UiO-66 separation membranes: Ultrasonic-assisted nucleation followed with microwave-assisted growth

The Metal-Organic Framework (MOF) materials are ideal molecular sieving membrane materials due to the regular pores with high-density and good designability, which have been widely studied in gas separation, desalination, and nanofiltration, etc. However, most preparation methods of MOF polycrystalline membranes are always time-consuming and the as-synthesized MOF membranes are thick. Here in this work, the ultrathin 210 nm-UiO-66 polycrystalline membranes are rapidly synthesized in 1 h, where sonication is utilized to generate massive tiny nucleation followed with rapid microwave-assisted membrane growth. The Na+ rejection of the UiO-66 membrane maintains at 99.6% for 700 h long-term experiment with 0.16 L/(m2 h bar) of water flux in forward osmosis, indicating the good quality and excellent stability of the as-synthesized membrane. This strategy is also expected to synthesize many other continuous defect-free MOF membranes with ultrathin thickness rapidly.

Three-Dimensional Lanthanide-Based Nanoporous Metal–Organic Frameworks for High-Performance Supercapacitors

Lanthanides have been proved to be unprecedented when it comes to organized nanoporous materials with high coordination environment. In the quest to enhance the applications for energy-storage materials, three lanthanide-based metal–organic frameworks (MOFs) have been synthesized by facile hydrothermal conditions using 5-nitroisophthalic acid (H2L) as a ligand, namely, Ce–H2L, Sm–H2L, and Eu–H2L. These nanoporous MOFs consist of nine coordination sites around the lanthanide metal ion giving rise to distorted monocapped square antiprism geometry and 3D crystal structures. The electrochemical measurements demonstrate that charge storage in these MOFs occurs through faradaic redox reactions. The charge–discharge studies show that these nanoporous MOF materials deliver high specific capacity. Ce–H2L, Sm–H2L, and Eu–H2L deliver specific capacities of 625, 356, and 252 C g–1 (1389, 791, and 560 F g–1), respectively, at a current density of 1 A g–1. A symmetric supercapacitor Swagelok device has been fabricated using Ce–H2L as an electrode to further demonstrate the advantage of as-synthesized MOF. The developed symmetric supercapacitor gives a maximum specific energy of 13.6 Wh kg–1 and a maximum specific power of 7110 W kg–1 in the voltage window of 1.425 V. The energy storage trend in these nanoporous materials is Ce–H2L > Sm–H2L > Eu–H2L, which is further supported by the DFT calculations.

Construction of imide-functionalized aromatic conjugation tetracarboxylate frameworks and adsorption behavior for iodine and selective cationic dyes

Metal-organic frameworks (MOFs) show great potential in environmental contaminants removal owing to their outstanding pore properties and tunable chemical performance. Two new imide-functionalized aromatic conjugation tetracarboxylate frameworks: [Cd4(BDCPPI)2(DMF)2(H2O)3]·2DMF·8H2O (1) and [Zn4(BDCPPI)2(DMF)6]·3DMF·4H2O (2) were designed and synthesized under solvothermal conditions. Due to the micropore size and aromatic conjugation properties with the 3D network structures, complexes 1 and 2 have abundant active sites, resulting in strong iodine capture and dye adsorption capacity. The excellent iodine capture ability on complexes 1 and 2 might due to the interaction of iodine with the carbonyl oxygen atom (I⋯O) and the benzene ring (I···π). The materials were charge and size selective for the adsorption of dyes, and the presence of abundant imide-functionalized groups in the channels can form hydrogen-bonding interactions with dye molecules to promote their adsorption properties. In addition, the high I2 adsorption and release capacity of complexes 1 and 2 indicate their wide application prospects in nuclear waste management. Therefore, the as-synthesized MOFs can be used as potential multifunctional adsorbents for further removal of organic dyes and iodine from wastewater.

Generating metal-organic frameworks (MOFs) from photovoltaic modules for wastewater remediation

Upcycling enables the recycling efforts of E-waste to be more feasible and economically viable. Photovoltaic (PV) energy adoption has increased drastically over the years and is expected to become a mainstream energy source for the future due to its sustainability. However, waste management remains a problem as the PV panels gradually reach their end-of-life and start piling up. Many recycling strategies have been executed, but upcycling efforts to form high-value products from these PV panels are underexplored. In this paper, we report three different synthetic routes to generate metal-organic framework (MOF), MIL-53(Al) (Matériaux de l′Institut Lavoisier (MIL)), with the polymeric backsheet and aluminum that can be derived from solar panels. The synthesized MOFs have been evaluated in terms of their morphologies, thermal stability, crystallinity, and specific surface areas. Brunauer-Emmett-Teller (BET) surface areas of 1004 m2 g−1 to 1231 m2 g−1 were recorded across the synthesized MOFs. The MOFs were evaluated for their ability to adsorb commonly used harmful dyes, specifically cationic dye Methylene Blue and anionic dye Methyl Orange. The adsorption performances on MB and MO of as-synthesized MOFs were determined to be ranging from 190.1 to 262.5 mg g−1 and 244.5–296.7 mg g−1 respectively, demonstrating the potential of upcycling solar panels waste to valuable metal-organic framework for wastewater remediation. The findings pave the way for utilising solar panel electronic waste as a valuable resource for upcycled applications.

Metal-organic framework of Zn(Ⅱ) based on 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine as a highly effective and dual-responsive fluorescent chemosensor target for Fe3+ and Cr2O72− ions in aqueous solutions

The excessive release of chemicals, including Fe3+ and Cr2O72−, may endanger the ecological environment as well as human health. Hence, it is of profound significance to develop effective and accurate sensing and removing strategies. In this work, a series of metal-organic frameworks (MOFs), namely, {[Co(Htpta)(bib)(H2O)]·DMF}n (Ⅰ), {[Ni(Htpta)(bib)(H2O)]·DMA}n (Ⅱ), [Cu(Htpta)(bib)0.5(H2O)]n (Ⅲ), {[Zn4(tpta)2(OH)2(bib)4]·H2O}n (Ⅳ) were synthesized by using 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (H3tpta), 1,4-bis(1-imidazolium)benzene (bib) and M(CH3COO)2·4H2O (M = Co, Ni, Cu, Zn) under hydrothermal conditions. X-ray single crystal diffraction analyses display that they are assembled into three-dimensional (3D) frameworks via hydrogen bonding interactions and π···π stacking. All MOFs were characterized by infrared spectroscopy, elemental analysis, thermogravimetric analyses (TGA), powder X-ray diffraction (PXRD), X-ray single crystal diffraction and their photoluminescence properties, magnetic and electrochemical properties were also investigated. Among these as-synthesized MOFs, Zn-MOF (Ⅳ) can be regarded as fluorescent sensors with high selectivity and sensitivity to detect Fe3+ and Cr2O72− in aqueous solutions via fluorescence quenching effects and the KSV and limit of detection (LOD) values are comparable to those sensing materials for Fe3+ and Cr2O72– ions. The fluorescence recognition mechanisms were disclosed by PXRD, ICP-AES, ultraviolet-visible absorption (UV–vis) and XPS analyses in detail.

A robust ethane-selective metal-organic framework with nonpolar pore surface for efficient C2H6/C2H4 separation

A robust chiral chain-based microporous MOF with nonpolar pore surface and suitable cavity space was designed and synthesized for C 2 H 6 /C 2 H 4 separation. The MOF shows simultaneously high C 2 H 6 uptake and inverse C 2 H 6 /C 2 H 4 selectivity, affording the one-step purification of C 2 H 4 from C 2 H 6 -C 2 H 4 mixture under ambient condition. • Adopting the methyl-modified ligands afforded a Zn-MOF with nonpolar channels. • The MOF shows excellent stability and uncommon preferential adsorption for C 2 H 6 . • The methyl groups in MOF are crucial for the separation of C 2 H 6 over C 2 H 4 . • The MOF achieves effective one-step purification of C 2 H 4 from C 2 H 6 -C 2 H 4 mixture. Due to similar physical and chemical properties, the separation of ethane (C 2 H 6 ) and ethylene (C 2 H 4 ) is an indispensable and extremely challenging task in petrochemical process. Although traditional C 2 H 4 -selective porous materials realize the separation of C 2 H 6 -C 2 H 4 mixture, but subsequent multiple separation operations are required to produce high-purity C 2 H 4 . Herein, we designed a hydrophobic methyl group-modified metal-organic framework (MOF) for one-step efficient purification of C 2 H 4 from C 2 H 6 -C 2 H 4 mixture. The as-synthesized MOF constructed from inexpensive carboxylic acid and pyrazole mixed linkers shows high thermal stability and chemical stability (water resistance). Cooperative study on the pure-component sorption isotherm, Ideal Adsorbed Solution Theory method, adsorption heat calculation and grand canonical Monte Carlo (GCMC) simulation supports the unique C 2 H 6 -selective feature of the MOF. Breakthrough experiments revealed the one-step C 2 H 4 purification from C 2 H 6 -C 2 H 4 (1/1, 1/10 and 1/15) mixtures through the MOF around room temperature condition with nice recyclability.

Two-Dimensional Metal–Organic Frameworks with Unique Oriented Layers for Oxygen Reduction Reaction: Tailoring the Activity through Exposed Crystal Facets

Two-Dimensional Metal–Organic Frameworks with Unique Oriented Layers for Oxygen Reduction Reaction: Tailoring the Activity through Exposed Crystal Facets

Morphology dependent electrocatalytic activity of copper based porous organic frameworks via diverse chain length of linkers and counterions of metal precursor

Morphology controlled synthesis and fabrication of electrode materials are of great importance. But, still it is a great challenge for the construction of porous metal-organic frameworks (MOFs) with desired morphology and size. The present study proposes a simple protocol for the synthesis of morphologically controlled Cu-MOFs using the ligands with different aliphatic chain lengths and metal ions with different counterions as columns and connectors, respectively. Interestingly, irregular, colloidosomal, spherical and agglomerated structures of Cu-MOFs were observed while varying the counterions and alkyl chain length of the ligands. The as-synthesized MOFs were characterized by different analytical tools such as FT-IR, XRD, SEM, XPS and EDX. Among the various Cu-MOFs, the Cu-MOF capped with azelaic acid (AZA) exhibits a well distinguishable colloidosome morphology with a size of ∼8 µm. The tremendous increase in diabetes mellitus has paid a renewed interest in the development of simple, cost-effective and accurate quantification of glucose in real samples. Thus, the present study focuses the investigation of glucose oxidation at different morphological Cu-MOFs coated on glassy carbon electrode (GCE). Due to the formation of well-defined colloidosome morphology and large pore volume, AZA-Cu-MOF showed better electrocatalytic activity towards the oxidation of glucose than the other modified electrodes. It can be applied to determine glucose in a concentration from 500 × 10−9 to 1.5 × 10−3 M and LOD of 9.6 × 10−9 M. Finally, the AZA-Cu-MOF/GCE was used to quantify glucose in serum samples and the obtained results were validated with the commercial glucometer.

ZrBDC-Based Functional Adsorbents for Small-Scale Methane Storage Systems

Metal-organic frameworks (MOF), potentially porous coordination structures, are envisioned for adsorption-based natural gas (ANG) storage, including mobile applications. The factors affecting the performance of the ANG system with a zirconium-based MOF with benzene dicarboxylic acid as a linker (ZrBDC) as an adsorbent were considered: textural properties of the adsorbent and thermal effect arising upon adsorption. The high-density ZrBDC-based pellets were prepared by mechanical compaction of the as-synthesized MOF powder at different pressures from 30 to 240 MPa at 298 K without a binder and mixed with polymer binders: polyvinyl alcohol (PVA) and carboxyl methylcellulose (CMC). The structural investigations revealed that the compaction of ZrBDC with PVA under 30 MPa was optimal to produce the ZrBDC-PVA adsorbent with more than a twofold increase in the packing density and the lowest degradation of the porous structure. The specific total and deliverable volumetric methane storage capacities of the ZrBDC-based adsorbents were evaluated from the experimental data on methane adsorption measured up to 10 MPa and within a temperature range from 253 to 333 K. It was measured experimentally that at 253 K, an 100 mL adsorption tank loaded with the ZrBDC-PVA pellets exhibited the deliverable methane storage capacity of 172 m3(NTP)/m3 when the pressure dropped from 10 to 0.1 MPa. The methane adsorption data for the ZrBDC powder and ZrBDC-PVA pellets were used to calculate the important thermodynamic characteristic of the ZrBDC/CH4 adsorption system—the differential molar isosteric heat of adsorption, which was used to evaluate the state thermodynamic functions: entropy, enthalpy, and heat capacity. The initial heats of methane adsorption in powdered ZrBDC evaluated from the experimental adsorption isosteres were found to be ~19.3 kJ/mol, and then these values in the ZrBDC/CH4 system decreased at different rates during adsorption. In contrast, the heat of methane adsorption onto the ZrBDC-PVA pellets increased from 19.4 kJ/mol to a maximum with a magnitude, width, and position depended on temperature, and then it fell. The behaviors of the thermodynamic state functions of the ZrBDC/CH4 adsorption system were interpreted as a variation in the state of adsorbed molecules determined by a ratio of CH4-CH4 and CH4-ZrBDC interactions. The heat of adsorption was used to calculate the temperature changes of the ANG systems loaded with ZrBDC powder and ZrBDC pellets during methane adsorption under adiabatic conditions; the maximum integrated heat of adsorption was found at 273 K. The maximum temperature changes of the ANG system with the ZrBDC materials during the adsorption (charging) process did not exceed 14 K that are much lower than those reported for the systems loaded with activated carbons. The results obtained are of direct relevance for designing the adsorption-based methane storage systems for the automotive industry, developing new gas-power robotics systems and uncrewed aerial vehicles.

Post-Synthetic Modification of Metal-Organic Frameworks Bearing Phenazine Radical Cations for aza-Diels-Alder Reactions.

Metal-organic frameworks (MOFs) consisting of organic radicals are of great interest because they have exhibited unique and intriguing optical, electronic, magnetic, and chemo-catalytic properties, and thus have demonstrated great potential applications in optical, electronic, and magnetic devices, and as catalysts. However, the preparation of MOFs bearing stable organic radicals is very challenging because most organic radicals are highly reactive and difficult to incorporate into the framework of MOFs. Herein we reported a post-synthetic modification strategy to prepare a novel MOF containing phenazine radical cations, which was used as heterogeneous catalyst for aza-Diels-Alder reaction. The zinc-based metal-organic framework Zn2 (PHZ)2 (dabco) (N) was successfully synthesized from 5,10-di(4-benzoic acid)-5,10-dihydrophenazine (PHZ), triethylene diamine (dabco) with Zn(NO3 )2 ⋅ 6H2 O by solvothermal method. The as-synthesized MOF N was partially oxidized by AgSbF6 to form MOF R containing ∼10% phenazine radical cation species. The resultant MOF R was found to keep the original crystal type of N and very persistent under ambient conditions. Consequently, MOF R was successfully employed in radical cation-catalyzed aza-Diels-Alder reactions with various imine substrates at room temperature with high reaction conversion. Moreover, heterogeneous catalyst MOF R was reusable up to five times without much loss of catalytic activity, demonstrating its excellent stability and recyclability. Therefore, the post-synthetic modification developed in this work is expected to become a versatile strategy to prepare radical-based MOFs for the application of heterogeneous catalysts in organic synthesis.

Polymer-Assisted Space-Confined Strategy for the Foot-Scale Synthesis of Flexible Metal-Organic Framework-Based Composite Films.

At the gas-liquid interface, the confined synthesis of metal-organic framework (MOF) films has been extensively developed by spreading an ultrathin oil layer on the aqueous surface as a reactor. However, this interface is susceptible to various disturbances and incapable of synthesizing large-area crystalline MOF films. Herein, we developed a polymer-assisted space-confined strategy to synthesize large-area films by blending poly(methyl methacrylate) (PMMA) into the oil layer, which improved the stability of the gas-liquid interface and the self-shrinkage of the oil layer on the water surface. Meanwhile, the as-synthesized MOFs as a quasi-solid substrate immobilized the edge of the oil layer, which maintained a large spreading area. Thanks to this synergistic effect, we synthesized the freestanding MOF-based film with a foot-level (0.66 ft) lateral dimension, which is the largest size reported so far. Besides, due to the phase separation of the two components, the MOF-PMMA composite film combined the conductivity of MOFs (1.13 S/m) with the flexibility of PMMA and exhibited excellent mechanical properties. More importantly, this strategy could be extended to the preparation of other MOFs, coordination polymers (CPs), and even inorganic material composite films, bringing light to the design and large-scale synthesis of various composite films for practical applications.

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Synthesis of Copper Metal Organic Framework Based on Schiff Base Tricarboxylate Ligand for Highly Selective and Sensitive Detection of 2,4,6-Trinitrophenol in Aqueous Medium.

By using Schiff base tricarboxylate ligand 5-(4-carboxybenzylideneamino)isophthalic acid (H3CIP), a new imine functionalized copper metal organic framework (MOF) has been synthesized solvothermally. It was fully characterized by Fourier Transform Infrared (FTIR) Spectroscopy, Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), and elemental mapping techniques. The as-synthesized MOF has been utilized as fluorescent probe for detection of nitro aromatic explosives (NAEs). The results show that the copper MOF can be developed into highly selective and sensitive sensor for detection of TNP in the aqueous medium via the "turn-off" quenching response. The linear fitting of the Stern-Volmer plot for TNP offered large quenching constant of 1.07 × 104 M-1 for Cu-MOF indicating the high sensitivity of the sensing process. Outstanding sensitivity of prepared material towards TNP detection was further validated by the low detection limit of 80 ppb (0.35 µM). The detailed mechanistic studies for their mode of action and density functional theory (DFT) calculations reveals that photo-induced electron transfer (PET) and fluorescence resonance energy transfer (FRET) processes, as well as electrostatic interactions (i.e. H-bonding) are the key factors for the turn-off response toward TNP by this fluorescent sensor. Thus, this new LMOF owing to their high water stability and remarkable functional features are potential candidates which can be developed into selective and sensitive TNP detection devices.

Greener route for the removal of toxic heavy metals and synthesis of 14-aryl-14H dibenzo[a,j] xanthene using a novel and efficient Ag-Mg bimetallic MOF as a recyclable heterogeneous nanocatalyst

Removing of heavy metal ions from aqueous solutions has become a serious challenge from both biological and environmental viewpoints. Recently, metal-organic frameworks (MOF) including two metal ions in its framework have been enhanced as promising structure in the capture of various hazardous and toxic substances. Herein, Ag-Mg-MOF were synthesized through a one-step approach using solvothermal technique. Then, the as-synthesized Bimetallic MOFs were characterized by TEM, SEM, EDS, XRD, FTIR and N2 adsorption. The as-synthesized Ag-Mg-MOF samples were used for heavy metal removal. The results showed that the adsorption of cadmium, lead and Cupper ions on MOF was improved by the pH increasing. The experimental data were examined through Freundlich and Langmuir models. The fabricated Ag-Mg MOFs exhibit enhanced decontaminant performance toward Cu2+, Cd2+and Pb2 ions in terms of high adsorption capacities, Pb2+ (350 mg/g)> Cd2+ (270 mg/g)> Cu2+ (202 mg/g), and ultrafast kinetics compared to the monometallic Mg-MOF. FT-IR spectra of adsorbed pyridine methods and non-aqueous potentiometric titration were used for measuring surface acidity of the prepared MOF. It was observed that the surface acidity and the catalytic activity were increased in bimetallic MOF compared to monometallic MOF. The catalytic results of the formation of free solvent 14-aryl-14-Hdibenzo[a,j]xanthene compound by Ag-Mg MOF showed a high yield at a lower time. Also, the prepared MOF catalysts still preserved their initial catalytic activity even after the 4th run. The results of this work demonstrate that the novel Ag-Mg MOFs nanocatalysts have great potential for applications in environmental protection, especially in heavy metal ions removal present in wastewaters and in the synthesis of pharmacologically and biologically active compound.