Polyhedral Metal Organic Framework Research Articles

Preparation of rGO/CAU-10 anchored PdPbBi composites and their electrocatalytic ethylene glycol properties

An effective method to improve the catalytic performance of electrocatalytic alcohol oxidation by establishing strong interfacial interactions through novel carrier materials and polymetallic alloys. In this paper, novel polyhedral metal–organic framework Al-based [Al(OH)(mBDC)] (CAU-10) composites with PdPbBi trimetallic particles embedded in folded graphene oxide (rGO) modified by a simple hydrothermal reaction were prepared and applied to the electrocatalytic oxidation reaction of ethylene glycol. The results of electrochemical tests showed that the trimetallic catalysts exhibited excellent electrocatalytic activity compared to commercial Pd/C. In particular, PdPbBi@rGO/CAU-10 has the highest peak current density of 241.82 mA cm−2, which is 8.97 times higher than that of Pd/C (26.92 mA cm−2), and the largest electrochemical active area (ECSA) value of 88.12 mA cm−2, which is 2.40 times higher than that of Pd/C (36.75 mA cm−2). This outstanding electrocatalytic activity is mainly attributed to the polyhedral structure of CAU-10 composite carriers and the abundance of oxygen-containing atoms, which is conducive to the homogeneous loading of metals, at the same time, the strong electronic effect between Pd, Pb and Bi and the abundance of oxygen-containing species provide significant enhancement of electrocatalytic activity and stability, which provides an important reference for the development of electrocatalysts for ethylene glycol fuel cells.

Coassembly of Complementary Polyhedral Metal-Organic Framework Particles into Binary Ordered Superstructures.

Here we report the formation of a 3D NaCl-type binary porous superstructure via coassembly of two colloidal polyhedral metal-organic framework (MOF) particles having complementary sizes, shapes, and charges. We employed a polymeric-attenuated Coulombic self-assembly approach, which also facilitated the coassembly of these MOF particles with spherical polystyrene particles to form 2D binary superstructures. Our results pave the way for using MOFs to create sophisticated superstructures comprising particles of various sizes, shapes, porosities, and chemical compositions.

Coloration in Supraparticles Assembled from Polyhedral Metal-Organic Framework Particles.

Supraparticles are spherical colloidal crystals prepared by confined self‐assembly processes. A particularly appealing property of these microscale structures is the structural color arising from interference of light with their building blocks. Here, we assemble supraparticles with high structural order that exhibit coloration from uniform, polyhedral metal–organic framework (MOF) particles. We analyse the structural coloration as a function of the size of these anisotropic building blocks and their internal structure. We attribute the angle‐dependent coloration of the MOF supraparticles to the presence of ordered, onion‐like layers at the outermost regions. Surprisingly, even though different shapes of the MOF particles have different propensities to form these onion layers, all supraparticle dispersions show well‐visible macroscopic coloration, indicating that local ordering is sufficient to generate interference effects.

Coloration in Supraparticles Assembled from Polyhedral Metal‐Organic Framework Particles

AbstractSupraparticles are spherical colloidal crystals prepared by confined self‐assembly processes. A particularly appealing property of these microscale structures is the structural color arising from interference of light with their building blocks. Here, we assemble supraparticles with high structural order that exhibit coloration from uniform, polyhedral metal–organic framework (MOF) particles. We analyse the structural coloration as a function of the size of these anisotropic building blocks and their internal structure. We attribute the angle‐dependent coloration of the MOF supraparticles to the presence of ordered, onion‐like layers at the outermost regions. Surprisingly, even though different shapes of the MOF particles have different propensities to form these onion layers, all supraparticle dispersions show well‐visible macroscopic coloration, indicating that local ordering is sufficient to generate interference effects.

MWCNT-mesoporous silica nanocomposites inserted in a polyhedral metal–organic framework as an advanced hybrid material for energy storage device

Hybridizing of trimetallic HKUST-1 with mesoporous SBA/CNT is highly desirable fot the improvement of energy and power densities in supercapacitors.

Polyhedral metal–organic framework monolayer colloidal crystals with sharpened and crystal facet-dependent selectivity for organic vapor sensing

Polyhedral metal–organic framework monolayer colloidal crystals demonstrate sharpened and crystal facet-dependent selectivity for organic vapors by eliminating grain boundaries and randomly exposed crystal surfaces.

RETRACTED ARTICLE: A Heterometallic MOF for Highly Selective Al3+ Ion Detection and Protective Effect Against Periodontitis by Reducing P. gingivalis CFU and Inflammatory Cytokines Levels

By employment of an amide-functionalized tetracarboxylic ligand 5,5′-(carbonylbis(azanediyl))-diisophthalic acid (H4cbab), a new polyhedral metal–organic framework (MOF) with the chemical formula of {[InZn2(cbda)2(H2O)2](NMF)3}n (1, NMF = N-methylformamide) has been synthesized under the solvothermal reaction condition. The structural feature was studied via the single crystal X-ray diffraction along with ultimate analysis. This as-prepared MOF shows excellent luminescence performance which can be able to detect Al3+ ions selectively. In aqueous solutions, the detection limitation for Al3+ ion is 0.56 µM, which is significantly below the highest standard of 7.41 µM for Al3+ ion in drinking water that is defined by the World Health Organization (WHO). The protective effect of compound against periodontitis was further explored. The viable cell counts (CFU) number was counted to evaluate the inhibitory effect of compound on bacterial growth. The enzyme linked immunosorbent assay (ELISA) was carried on in order to measure accurately the proportion of inflammatory cytokines in gingival fluid around the implant. The potential binding modes of the synthesized compounds as well as the targeted protein was explored by calculating docking with high accuracy as well as pose scoring process.

A Gold Quartet Framework with Reversible Anisotropic Structural Transformation Accompanied by Luminescence Response

Summary Hierarchy and chirality are the fundamental characteristics of biomolecules. Chemistry on hierarchical self-assembly and spontaneous symmetry breaking helps to uncover the mechanism of living activities and the origin of chirality in nature. Herein, we describe a chiral gold quartet framework (GQF) with C4-symmetric structure hierarchically aggregated from an achiral anionic [Au10(dpptrz)4S4]2− (dpptrz-Au10), which was acquired via click-reaction-induced and Au(I)⋅⋅⋅Au(I)-interaction-directed cluster-to-cluster transformation (CCT) from the rationally designed [(dppa)6Au18S8]2+ (dppa-Au18). Inter-cluster hydrogen bonding and alkali ion coordination were observed to assist the hierarchical self-assembly and chiral self-organization of the GQF. Upon exposing the crystal to vacuum, the bottom-up constructed GQF showed an anisotropic structural transformation accompanied by a visual luminescence change in a single-crystal-to-single-crystal (SCSC) manner that became reversible upon removal of vacuum. This research largely advances the potential of polynuclear gold(I)-sulfido clusters in hierarchical self-assembly and luminescent materials.

A polyhedral metal-organic framework based on rigid precursor for photocatalytic properties

A 3D polyhedral metal organic framework, [Cu4(L)2(H2O)4∙5DMF]n (1) (H4L = 3,5‑di(3,5‑dicarboxyphenyl)nitrobenzene), has been designed and successfully synthesized. 1 shows a 3D mfj topological framework with 1D triangular channels. The UV diffuse reflectance spectroscopy of the MOF indicates its semiconducting nature which induces photocatalytic property in the MOF. The photocatalytic property of 1 in photo-degradation of organic dyes viz. methyl violet and Rhodamine B have been investigated. The possible mechanism for the photocatalytic activity of 1 against organic dyes has been addressed using density of states (DOS) and partial DOS (pDOS) calculations.

A 3D polyhedral metal–organic framework as drug carrier for controllable release

A new fabrication of {[H 3 O][Cu 6 (tpta) 3 (DMA) 4 (COO)]∙12H 2 O∙7DMA} ( 1 ) was used as a drug vehicle of 5-fluorouracil (5-FU) for drug delivery. The incorporation of the drug 5-FU into the 1 was around 47.3 wt% per gram of dehydrated 1 . Cargo release behavior and material degradation profile were also investigated under different mdeium. 5-FU is released in a highly controlled and progressive manner with 92% of the drug release after 96 h at acidic condition and with 88% after 96 h at PBS. In vitro cytotoxicity assays indicated that the 1 possesses no obvious cytotoxicity. The results provide a new avenue for MOFs to be used as potential drug delivery. KEY WORDS : Drug delivery, Release, Porous MOF Bull. Chem. Soc. Ethiop. 2017 , 31(3), 457-463. DOI: http://dx.doi.org/10.4314/bcse.v31i3.9

Self-assembly of polyhedral metal-organic framework particles into three-dimensional ordered superstructures.

Self-assembly of particles into long-range, three-dimensional, ordered superstructures is crucial for the design of a variety of materials, including plasmonic sensing materials, energy or gas storage systems, catalysts and photonic crystals. Here, we have combined experimental and simulation data to show that truncated rhombic dodecahedral particles of the metal-organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying three-dimensional rhombohedral lattice that behave as photonic crystals. Those superstructures feature a photonic bandgap that can be tuned by controlling the size of the ZIF-8 particles and is also responsive to the adsorption of guest substances in the micropores of the ZIF-8 particles. In addition, superstructures with different lattices can also be assembled by tuning the truncation of ZIF-8 particles, or by using octahedral UiO-66 MOF particles instead. These well-ordered, sub-micrometre-sized superstructures might ultimately facilitate the design of three-dimensional photonic materials for applications in sensing.

From Metal-Organic Framework to Porous Carbon Polyhedron: Toward Highly Reversible Lithium Storage.

By application of a newly designed T-shaped ligand 5-(4-pyridin-4-yl-benzoylamino)isophthalic acid (H2PBAI) to assemble with Zn(II) ions under solvothermal conditions, a novel porous polyhedral metal-organic framework (Zn-PBAI) with pcu topology has been obtained. When treated as a precursor by annealing of Zn-PBAI at various temperatures, porous carbon polyhedra (PCP) were prepared and tested as an anode material for lithium-ion batteries. The results show that PCP carbonized at 1000 °C (PCP-1000) manifest the highest reversible specific capacity of about 1125 mAh g-1 at a current of 500 mA g-1 after 200 cycles, which is supposed to benefit from the large accessible specific area and high electric conductivity. Moreover, PCP-1000 electrode materials also exhibit superior cyclic stability and good rate capacity.

Rational synthesis of a porous polyhedral metal-organic framework carrier for controllable drug release

A new fabrication of [Cu3(μ2-H2O)(PHB)(H2O)]·(DMF)3(H2O)6 (GDMU-2) was synthesized and used as a drug vehicle of 5-Fluorouracil (5-FU) for drug delivery. The incorporation of the drug 5-FU into the GDMU-2 was around 53.7wt% per gram of dehydrated GDMU-2. Cargo release behavior and material degradation profile were also investigated under different pH. 5-FU is released in a highly controlled and progressive manner with 100% of the drug release after 97h at acidic condition and with 83% after 132h at PBS. In vitro cytotoxicity assays indicated that the GDMU-2 possesses no obvious cytotoxicity. The result from this work provides a new avenue for MOF to be used as potential drug delivery.

A Polyhedral Metal–Organic Framework Based on Supramolecular Building Blocks: Catalysis and Luminescent Sensing of Solvent Molecules

A multifunctional polyhedral metal–organic framework with a pcu network topology based on supramolecular building blocks can be constructed by the reaction of Eu(NO3)3 and pyridine-3,5-dicarboxylic acid (H2PDC). The basic EuIII paddlewheel nodes as secondary building units (SBUs) are connected by PDC ligands to generate nanosized metal–organic cuboctahedra (MOCs), which are further connected by sharing the paddlewheel SBUs to give rise to a three-dimensional primitive cubic network arrangement. The obtained metal–organic frameworks (MOFs) exhibit excellent catalytic activity toward the cyanosilylation of aromatic aldehydes and could be reused without loss of activity. In addition, they can also be considered as a fluorescent probe for nitrobenzene sensing based on luminescence quenching effects arising from host–guest interactions. This porous MOF combining catalytic and fluorescent properties could further meet the requirement as a multifunctional material.

Rational synthesis of a novel 3,3,5-c polyhedral metal–organic framework with high thermal stability and hydrogen storage capability

By using a functionalized ligand strategy, an uncommon (3,3,5)-c polyhedron-based metal–organic framework named GDMU-2 has been constructed, which has a high H2 uptake of 240.7 cm3 g−1 (2.16 wt%) at 77 K and 1 bar.

A polyhedral metal–organic framework based on the supermolecular building block strategy exhibiting high performance for carbon dioxide capture and separation of light hydrocarbons

By using the supermolecular building block (SBB) strategy, a polyhedron-based metal-organic framework (PMOF), which features three types of cages with multiple sizes and shapes, has been synthesized. It exhibits high performance for CO2 capture (170 cm(3) g(-1) at 273 K under 1 bar) and selectivity of CO2/CH4 (9.4) and C3H8/CH4 (271.5).

Construction of a Polyhedral Metal–Organic Framework via a Flexible Octacarboxylate Ligand for Gas Adsorption and Separation

A flexible octacarboxylate ligand, tetrakis[(3,5-dicarboxyphenyl)oxamethyl]methane (H8X), has been used to construct a highly porous metal-organic framework (In2X)(Me2NH2)2(DMF)9(H2O)5 (1), which is comprised of octahedral and cuboctahedral cages and shows a rare (4,8)-connected scu topology. Gas adsorption studies of N2, H2 on the actived 1 at 77 K reveal a Langmuir surface area of 1707 m(2) g(-1), a BET surface area of 1555 m(2) g(-1), a total pore volume of 0.62 cm(3) g(-1), and a H2 uptake of 1.49 wt % at 1 bar and 3.05 wt % at 16 bar. CO2, CH4, and N2 adsorption studies at 195, 273, 285, and 298 K and also ideal adsorbed solution theory (IAST) calculations demonstrate that 1 has high selectivites of CO2 over CH4 and N2. The resulting framework represents a MOF with the highest gas uptakes and gas selectivities (CO2 over CH4 and N2) constructed by flexible ligands.

Sorption behaviour in a unique 3,12-connected zinc–organic framework with 2.4 nm cages

A polyhedral metal–organic framework (FJI-2) has been synthesized based on rare hexanuclear zinc clusters, which comprises 2.4 nm double-walled octahedral cages topologically featuring a new 3,12-connected structure. FJI-2 has a good H2 uptake capacity of 149.7 cm3 g−1 (1.34 wt %) at 77 K and 1.0 bar, and the IAST calculation predicts highly selective adsorption of CO2 over N2 and CH4.

Electric Field-Induced Assembly of Monodisperse Polyhedral Metal–Organic Framework Crystals

Monodisperse polyhedral metal-organic framework (MOF) particles up to 5 μm in size, large enough to enable in situ optical imaging of particle orientation, were synthesized by the strategy of simultaneous addition of two capping ligands with different binding strength during crystallization. Upon dispersing them in ethylene glycol and applying AC electric field, the particles facets link to form linear chains. We observe well-regulated crystal orientation not only for rhombic dodecahedra all of whose facets are equivalent, but also for truncated cubes with nondegenerate facets. After removing the electric field, chains disassemble if their facets contain even modest curvature, but remain intact if their facets are planar. This assembly strategy offers a general route to fabricate oriented polyhedral crystal arrays of potential interest for new applications and functions.

Interpenetrating Polyhedral MOF with a Primitive Cubic Network Based on Supermolecular Building Blocks Constructed of a Semirigid C3-Symmetric Carboxylate Ligand

By application of a newly developed C(3)-symmetric tripodal carboxylate ligand, 1,1',1''-(benzene-1,3,5-triyl)tripiperidine-4-carboxylic acid (H(3)BTPCA) to assemble with zinc ion in the presence of pyridine, a novel 2-fold interpenetrating polyhedral metal-organic framework with a primitive cubic network based on supermolecular building blocks (SBBs) has been synthesized. The basic paddlewheel secondary building units (SBUs) are connected by deprotonated BTPCA ligands to generate an octahedron as the SBB, which is further connected through the six vertexes by sharing the paddlewheel SBUs to give rise to the 3D primitive cubic network.