scholarly journals Structural Diversity and Properties of Five 3D Metal–Organic Frameworks Based on a Pyridine-substituted Triazolyl Benzoate Ligand

2014 ◽  
Vol 67 (2) ◽  
pp. 302 ◽  
Author(s):  
Fen-Jun Jiang ◽  
Ming Zhang ◽  
Xiao-Hua Wei ◽  
Lin-Yan Yang ◽  
Sheng-Yun Liao ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Emission Spectra ◽  
Structural Diversity ◽  
Coordination Networks ◽  
Experimental Conditions ◽  
Metal Organic ◽  
New Compounds ◽  
Free Metal ◽  
Secondary Ligand

Three new 3D metal–organic frameworks, namely {[Zn(L)2]}n (2), {[Cu(L)3H2O]3H2O}n (4), and {[Ag(L)]3H2O}n (5) where HL = 4-[3-methyl-5-(pyridin-4-yl)-1,2,4-triazol-4-yl]benzoate, have been synthesized by reaction of the HL ligand and ZnII, CuII, and AgI salts under similar experimental conditions. By introducing the secondary ligand terephthalic acid (H2bdc), another two new compounds {[Zn1.5L2(bdc)0.5]3H2O}n (1) and {[Cu(L)(bdc)0.5H2O]}n (3) with different 3D structures were obtained. Compound 1 possesses a three-fold interpenetrating framework, with {32.42.54.62}2{32.42.56.65} topology. To the best of our knowledge, 2 is an unusual example of four-fold framework guest-free metal organic framework material. Compound 3 reveals a seven-connected ose topology; magnetic susceptibility measurements indicate that it has dominating antiferromagnetic couplings between metal centres. Photoluminescence measurements of 1, 2, and 5 in the solid state at room temperature show that all coordination networks exhibit a red shift in the emission spectra, which can be assigned to an intraligand π-π* transition.

Revisiting the structural homogeneity of NU-1000, a Zr-based metal–organic framework

CrystEngComm ◽  
2018 ◽  
Vol 20 (39) ◽  
pp. 5913-5918 ◽  
Author(s):  
Timur Islamoglu ◽  
Ken-ichi Otake ◽  
Peng Li ◽  
Cassandra T. Buru ◽  
Aaron W. Peters ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Structure Property ◽  
Structural Homogeneity ◽  
Structure Property Relationships ◽  
Phase Pure ◽  
Metal Organic ◽  
Free Metal ◽  
Organic Framework

Synthesis and activation of phase-pure and defect-free metal–organic frameworks (MOFs) are essential for establishing accurate structure–property relationships.

scholarly journals Gas adsorption and structural diversity in a family of Cu(II) pyridyl-isophthalate metal–organic framework materials

2017 ◽  
Vol 375 (2084) ◽  
pp. 20160334 ◽  
Author(s):  
Jamie A. Gould ◽  
Harprit Singh Athwal ◽  
Alexander J. Blake ◽  
William Lewis ◽  
Peter Hubberstey ◽  
...  
Keyword(s):  
Dicarboxylic Acid ◽  
Gas Adsorption ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Structural Diversity ◽  
Isosteric Heat ◽  
Adsorption Properties ◽  
Framework Materials ◽  
Materials By Design ◽  
Metal Organic

A family of Cu(II)-based metal–organic frameworks (MOFs) has been synthesized using three pyridyl-isophthalate ligands, H 2 L 1 (4′-(pyridin-4-yl)biphenyl-3,5-dicarboxylic acid), H 2 L 2 (4′′-(pyridin-4-yl)-1,1′:4′,1′′-terphenyl-3,5-dicarboxylic acid) and H 2 L 3 (5-[4-(pyridin-4-yl)naphthalen-1-yl]benzene-1,3-dicarboxylic acid). Although in each case the pyridyl-isophthalate ligands adopt the same pseudo-octahedral [Cu 2 (O 2 CR) 4 N 2 ] paddlewheel coordination modes, the resulting frameworks are structurally diverse, particularly in the case of the complex of Cu(II) with H 2 L 3 , which leads to three distinct supramolecular isomers, each derived from Kagomé and square nets. In contrast to [Cu(L 2 )] and the isomers of [Cu(L 3 )], [Cu(L 1 )] exhibits permanent porosity. Thus, the gas adsorption properties of [Cu(L 1 )] were investigated with N 2 , CO 2 and H 2 , and the material exhibits an isosteric heat of adsorption competitive with leading MOF sorbents for CO 2 . [Cu(L 1 )] displays high H 2 adsorption, with the density in the pores approaching that of liquid H 2 . This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’.

scholarly journals Porous metal-organic frameworks incorporating mixed ligands

2014 ◽  
Vol 70 (a1) ◽  
pp. C1476-C1476
Author(s):  
Clive Oliver
Keyword(s):  
Single Crystal ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Porous Metal ◽  
Structural Diversity ◽  
3 Dimensional ◽  
Trimesic Acid ◽  
Mixed Ligands ◽  
Cadmium Metal ◽  
Metal Organic

Metal-organic frameworks (MOFs), infinite systems built up of metal ions and organic ligands have been extensively studied in materials and supramolecular chemistry due their structural diversity and application as porous materials, in catalysis, ion exchange, gas storage and purification. [1] A novel, 2-fold interpenetrated, pillared, cadmium metal-organic framework was synthesized using trimesic acid and 1,2-bis(4-pyridyl)ethane.[2] Single crystal X-ray analysis revealed a 2-fold interpenetrated, 3-dimensional framework which exhibits a 3,5-connected network with the Schläfli symbol of [(6^3)(6^9.8)] and hms topology. This compound exhibits a temperature-induced single-to-crystal-single-crystal (SC–SC) transformation upon the release of N,N'-dimethylformamide (stable up to 3000C). SC–SC transformation was also observed when the desolvated form absorbed selected polar and non-polar organic solvents. In addition, gas (N_2, CO_2 and N_2O) sorption experiments were performed showing 2.5% N_2, 4.5% CO_2 and 3.4% N_2O absorption by mass at room temperature and moderate gas pressures (~10 bar). A similar MOF was produced when 1,3,5-benzenetricarboxylic acid was replaced with 5-nitro-1,3-benzenedicarboxylic acid. This MOF displays 4-fold interpenetration and also maintains the host framework structure upon heating.

scholarly journals Carbon Support Tuned Electrocatalytic Activity of Single-Site Metal-organic Framework toward Oxygen Reduction Reaction

2021 ◽  
Author(s):  
Wenjie Ma ◽  
Fei Wu ◽  
Ping Yu ◽  
Lanqun Mao
Keyword(s):  
Electrocatalytic Activity ◽  
Active Sites ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Structural Diversity ◽  
Carbon Support ◽  
Reduction Reaction ◽  
Single Site ◽  
Metal Organic ◽  
Single Site Catalysts

Metal-organic frameworks (MOFs) possess fantastic features such as structural diversity, tunable accessible pores and atomically dispersed active sites, holding tremendous potentials as high versatile platforms for fabricating single-site catalysts. The...

Bifunctional PGM-free metal organic framework-based electrocatalysts for alkaline electrolyzers: trends in the activity with different metal centers

Nanoscale ◽  
2021 ◽  
Author(s):  
Wenjamin Moschkowitsch ◽  
Shmuel Gonen ◽  
Kapil Dhaka ◽  
Noam Zion ◽  
Hilah Honig ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Electrocatalytic Activity ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Metal Centers ◽  
Metal Organic ◽  
Free Metal ◽  
Organic Framework

Several composites of metal organic frameworks with electrocatalytic activity toward OER and HER were studied. A trend of the activity among the different metals was observed for both reactions and was confirmed by DFT calculations.

Magnetic Ordering via Itinerant Ferromagnetism in a Metal-Organic Framework

2020 ◽  
Author(s):  
Jesse Park ◽  
Brianna Collins ◽  
Lucy Darago ◽  
Tomce Runcevski ◽  
Michael Aubrey ◽  
...  
Keyword(s):  
Charge Transport ◽  
Magnetic Order ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Magnetic Ordering ◽  
Double Exchange ◽  
Itinerant Ferromagnetism ◽  
Organic Solids ◽  
Metal Organic ◽  
Organic Framework

<b>Materials that combine magnetic order with other desirable physical attributes offer to revolutionize our energy landscape. Indeed, such materials could find transformative applications in spintronics, quantum sensing, low-density magnets, and gas separations. As a result, efforts to design multifunctional magnetic materials have recently moved beyond traditional solid-state materials to metal–organic solids. Among these, metal–organic frameworks in particular bear structures that offer intrinsic porosity, vast chemical and structural programmability, and tunability of electronic properties. Nevertheless, magnetic order within metal–organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating strong magnetic exchange in extended metal–organic solids. Here, we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at <i>T</i><sub>C</sub> = 225 K in a mixed-valence chromium(II/III) triazolate compound, representing the highest ferromagnetic ordering temperature yet observed in a metal–organic framework. The itinerant ferromagnetism is shown to proceed via a double-exchange mechanism, the first such observation in any metal–organic material. Critically, this mechanism results in variable-temperature conductivity with barrierless charge transport below <i>T</i><sub>C</sub> and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics. Taken together, the insights gleaned from these results are expected to provide a blueprint for the design and synthesis of porous materials with synergistic high-temperature magnetic and charge transport properties. </b>

Engineering Porosity Through Defects in a Giant Pore Metal–Organic Framework

2020 ◽  
Author(s):  
Adam Sapnik ◽  
Duncan Johnstone ◽  
Sean M. Collins ◽  
Giorgio Divitini ◽  
Alice Bumstead ◽  
...  
Keyword(s):  
Distribution Function ◽  
Ball Milling ◽  
Local Structure ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Defect Engineering ◽  
Metal Organic ◽  
Unsaturated Metal Sites

<p>Defect engineering is a powerful tool that can be used to tailor the properties of metal–organic frameworks (MOFs). Here, we incorporate defects through ball milling to systematically vary the porosity of the giant pore MOF, MIL-100 (Fe). We show that milling leads to the breaking of metal–linker bonds, generating more coordinatively unsaturated metal sites, and ultimately causes amorphisation. Pair distribution function analysis shows the hierarchical local structure is partially</p><p>retained, even in the amorphised material. We find that the solvent toluene stabilises the MIL-100 (Fe) framework against collapse and leads to a substantial rentention of porosity over the non-stabilised material.</p>

Metal-Organic Frameworks vs. Buffers: Case Study of UiO-66 Stability

2020 ◽  
Author(s):  
Daniel Bůžek ◽  
Slavomír Adamec ◽  
Kamil Lang ◽  
Jan Demel
Keyword(s):  
Inductively Coupled Plasma ◽  
Buffer Capacity ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Analytical Techniques ◽  
Aqueous Dispersions ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Metal Organic

<div><p>UiO-66 is a zirconium-based metal-organic framework (MOF) that has numerous applications. Our group recently determined that UiO-66 is not as inert in aqueous dispersions as previously reported in the literature. The present work therefore assessed the behaviour of UiO-66 in buffers: 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS), 4-(2-hydroxyethyl)piperazine-1-ethane sulfonic acid (HEPES), N-ethylmorpholine (NEM) and phosphate buffer (PB), all of which are commonly used in many UiO-66 applications. High pressure liquid chromatography and inductively coupled plasma mass spectrometry were used to monitor degradation of the MOF. In each buffer, the terephthalate linker was released to some extent, with a more pronounced leaching effect in the saline forms of these buffers. The HEPES buffer was found to be the most benign, whereas NEM and PB should be avoided at any concentration as they were shown to rapidly degrade the UiO-66 framework. Low concentration TRIS buffers are also recommended, although these offer minimal buffer capacity to adjust pH. Regardless of the buffer used, rapid terephthalate release was observed, indicating that the UiO-66 was attacked immediately after mixing with the buffer. In addition, the dissolution of zirconium, observed in some cases, intensified the UiO-66 decomposition process. These results demonstrate that sensitive analytical techniques have to be used to monitor the release of MOF components so as to quantify the stabilities of these materials in liquid environments.</p></div>

Green Synthesis and Enhanced CO2 Capture Performance of Perfluorinated Cerium-Based Metal-Organic Frameworks with UiO-66 and MIL-140 Topology

2018 ◽  
Author(s):  
Roberto D’Amato ◽  
Anna Donnadio ◽  
Mariolino Carta ◽  
Claudio Sangregorio ◽  
Riccardo Vivani ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Organic Frameworks ◽  
Isosteric Heat ◽  
Experimental Conditions ◽  
Cerium Ammonium Nitrate ◽  
Ideal Adsorbed Solution Theory ◽  
Metal Organic ◽  
Adsorbed Solution ◽  
Better Than ◽  
The Ideal

Reaction of cerium ammonium nitrate and tetrafluoroterephthalic acid in water afforded two new metal-organic frameworks with UiO-66 [F4_UiO-66(Ce)] and MIL-140 [F4_MIL-140A(Ce)] topologies. The two compounds can be obtained in the same experimental conditions, just by varying the amount of acetic acid used as crystallization modulator in the synthesis. Both F4_UiO-66(Ce) and F4_MIL-140A(Ce) feature pores with size < 8 Å, which classifies them as ultramicroporous. Combination of X-ray photoelectron spectroscopy and magnetic susceptibility measurements revealed that both compounds contain a small amount of Ce(III), which is preferentially accumulated near the surface of the crystallites. The CO<sub>2</sub> sorption properties of F4_UiO-66(Ce) and F4_MIL-140A(Ce) were investigated, finding that they perform better than their Zr-based analogues. F4_MIL-140A(Ce) displays an unusual S-shaped isotherm with steep uptake increase at pressure < 0.2 bar at 298 K. This makes F4_MIL-140A(Ce) exceptionally selective for CO<sub>2</sub> over N<sub>2</sub>: the calculated selectivity, according to the ideal adsorbed solution theory for a 0.15:0.85 mixture at 1 bar and 293 K, is higher than 1900, amongst the highest ever reported for metal-organic frameworks. The calculated isosteric heat of CO<sub>2 </sub>adsorption is in the range of 38-40 kJ mol<sup>-1</sup>, indicating a strong physisorptive character.

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