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

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4751
Author(s):  
Jayashree Ethiraj ◽  
Vinayagam Surya ◽  
Parasuraman Selvam ◽  
Jenny G. Vitillo

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.

2020 ◽  
Vol 11 (34) ◽  
pp. 9173-9180 ◽  
Author(s):  
Naomi Biggins ◽  
Michael E. Ziebel ◽  
Miguel I. Gonzalez ◽  
Jeffrey R. Long

Single-crystal X-ray diffraction reveals structural influences on gas adsorption properties in anionic metal–organic frameworks.


2020 ◽  
Vol 75 (8) ◽  
pp. 727-732
Author(s):  
Chen Zhang ◽  
Jian-Qing Tao

AbstractA new Cu(II) metal-organic framework, [Cu(L)(OBA)·H2O]n (1) [H2OBA = 4,4′-oxybis(benzoic acid), L = 3,5-di(1H-benzimidazol-1-yl)pyridine] was hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis and single-crystal X-ray diffraction. Complex 1 is a four-connected uni-nodal 2D net with a (44·62) topology which shows an emission centered at λ ∼393 nm upon excitation at λ = 245 nm. Moreover, complex 1 possesses high photocatalytic activities for the decomposition of Rhodamine B (RhB) under UV light irradiation.


2019 ◽  
Author(s):  
Christopher A. O’Keefe ◽  
Cristina Mottillo ◽  
László Fábián ◽  
Tomislav Friscic ◽  
Robert W. Schurko

NMR-enhanced crystallography enables the characterization of a novel cadmium-based, open metal-organic framework (MOF) from a solvent-free "accelerated aging" process. Whereas accelerated aging was devised as a clean, mild route for making MOFs, these results highlight how it application in materials discovery and characterization is aided by a combination of X-ray diffraction and solid-state NMR spectroscopy.<br>


2021 ◽  
Vol 12 (1) ◽  
pp. 52
Author(s):  
Arslan Munir ◽  
Ali Ahmad ◽  
Muhammad Tahseen Sadiq ◽  
Ali Sarosh ◽  
Ghulam Abbas ◽  
...  

Recent development shows that carbon-based composites are proving to be the most promising materials in hydrogen energy production, storage and conversion applications. In this study, composites of the copper-based metal-organic framework with different ratios of graphite oxide have been prepared for hydrogen storage application. The developed materials are characterized by X-ray diffraction (XRD), gravimetric thermal analysis (TGA), scanning electron microscopy (SEM) and BET. The newly developed composites have an improved crystalline structure and an increased surface area. The results of the experiment showed that the composite material MOF/GO 20% can store 6.12% of hydrogen at −40 °C.


2021 ◽  
Author(s):  
Hudson de Aguiar Bicalho ◽  
P. Rafael Donnarumma ◽  
Victor Quezada-Novoa ◽  
Hatem M. Titi ◽  
Ashlee J Howarth

<div> <p>Post-synthetic modification (PSM) of metal–organic frameworks (MOFs) is an important strategy for accessing MOF analogues that cannot be easily synthesized <i>de novo</i>. In this work, the rare-earth (RE) cluster-based MOF, Y-CU-10, with <b>shp</b> topology was modified through transmetallation using a series of RE ions, including: La(III), Nd(III), Eu(III), Tb(III), Er(III), Tm(III), and Yb(III). In all cases, metal-exchange higher than 70 % was observed, with reproducible results. All transmetallated materials were fully characterized and compared to the parent MOF, Y-CU-10, in regards to crystallinity, surface area, and morphology. Additionally, single-crystal X-ray diffraction (SCXRD) measurements were performed to provide further evidence of transmetallation occurring in the nonanuclear cluster nodes of the MOF. </p> </div>


Author(s):  
Naomi Biggins ◽  
Michael Ziebel ◽  
Miguel Gonzalez ◽  
Jeffrey R. Long

<div><p>Precisely locating extra-framework cations in anionic metal–organic framework compounds remains a long-standing, yet crucial, challenge for elucidating structure-performance relationships in functional materials. Single-crystal X-ray diffraction is one of the most powerful approaches for this task, but single crystals of frameworks often degrade when subjected to post-synthetic metalation or reduction. Here, we demonstrate the growth of sizable single crystals of the robust metal–organic framework Fe<sub>2</sub>(bdp)<sub>3</sub> (bdp<sup>2−</sup> = benzene-1,4-dipyrazolate) and employ single-crystal-to-single-crystal chemical reductions to access the solvated framework materials A<sub>2</sub>Fe<sub>2</sub>(bdp)<sub>3</sub>∙<i>y</i>THF<sub> </sub>(A = Li<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup>). X-ray diffraction analysis of the sodium and potassium congeners reveals that the cations are located near the center of the triangular framework channels and are stabilized by weak cation–π interactions with the framework ligands. Freeze-drying with benzene enables isolation of activated single crystals of Na<sub>0.5</sub>Fe<sub>2</sub>(bdp)<sub>3 </sub>and Li<sub>2</sub>Fe<sub>2</sub>(bdp)<sub>3</sub> and the first structural characterization of activated metal–organic frameworks wherein extra-framework alkali metal cations are also structurally located. Comparison of the solvated and activated sodium-containing structures reveals that the cation positions differ in the two materials, likely due to cation migration that occurs upon solvent removal to maximize stabilizing cation­–π interactions. Hydrogen adsorption data indicate that these cation-framework interactions are sufficient to diminish the effective cationic charge, leading to little or no enhancement in gas uptake relative to Fe<sub>2</sub>(bdp)<sub>3</sub>. In contrast, Mg<sub>0.85</sub>Fe<sub>2</sub>(bdp)<sub>3</sub> exhibits enhanced H<sub>2</sub> affinity and capacity over the non-reduced parent material. This observation shows that increasing the charge density of the pore-residing cation serves to compensate for charge dampening effects resulting from cation–framework interactions and thereby promotes stronger cation–H<sub>2</sub> interactions.</p></div>


2019 ◽  
Author(s):  
Christopher A. O’Keefe ◽  
Cristina Mottillo ◽  
László Fábián ◽  
Tomislav Friscic ◽  
Robert W. Schurko

NMR-enhanced crystallography enables the characterization of a novel cadmium-based, open metal-organic framework (MOF) from a solvent-free "accelerated aging" process. Whereas accelerated aging was devised as a clean, mild route for making MOFs, these results highlight how it application in materials discovery and characterization is aided by a combination of X-ray diffraction and solid-state NMR spectroscopy.<br>


2020 ◽  
Author(s):  
Naomi Biggins ◽  
Michael Ziebel ◽  
Miguel Gonzalez ◽  
Jeffrey R. Long

<div><p>Precisely locating extra-framework cations in anionic metal–organic framework compounds remains a long-standing, yet crucial, challenge for elucidating structure-performance relationships in functional materials. Single-crystal X-ray diffraction is one of the most powerful approaches for this task, but single crystals of frameworks often degrade when subjected to post-synthetic metalation or reduction. Here, we demonstrate the growth of sizable single crystals of the robust metal–organic framework Fe<sub>2</sub>(bdp)<sub>3</sub> (bdp<sup>2−</sup> = benzene-1,4-dipyrazolate) and employ single-crystal-to-single-crystal chemical reductions to access the solvated framework materials A<sub>2</sub>Fe<sub>2</sub>(bdp)<sub>3</sub>∙<i>y</i>THF<sub> </sub>(A = Li<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup>). X-ray diffraction analysis of the sodium and potassium congeners reveals that the cations are located near the center of the triangular framework channels and are stabilized by weak cation–π interactions with the framework ligands. Freeze-drying with benzene enables isolation of activated single crystals of Na<sub>0.5</sub>Fe<sub>2</sub>(bdp)<sub>3 </sub>and Li<sub>2</sub>Fe<sub>2</sub>(bdp)<sub>3</sub> and the first structural characterization of activated metal–organic frameworks wherein extra-framework alkali metal cations are also structurally located. Comparison of the solvated and activated sodium-containing structures reveals that the cation positions differ in the two materials, likely due to cation migration that occurs upon solvent removal to maximize stabilizing cation­–π interactions. Hydrogen adsorption data indicate that these cation-framework interactions are sufficient to diminish the effective cationic charge, leading to little or no enhancement in gas uptake relative to Fe<sub>2</sub>(bdp)<sub>3</sub>. In contrast, Mg<sub>0.85</sub>Fe<sub>2</sub>(bdp)<sub>3</sub> exhibits enhanced H<sub>2</sub> affinity and capacity over the non-reduced parent material. This observation shows that increasing the charge density of the pore-residing cation serves to compensate for charge dampening effects resulting from cation–framework interactions and thereby promotes stronger cation–H<sub>2</sub> interactions.</p></div>


Author(s):  
R. F. Kesuma ◽  
L. Yuliati ◽  
T. H. P. Brotosudarmo

Eosin Y telah berhasil diembankan pada Metal-Organic Framework Zirkonium Naftalendikarboksilat (MOF Zr-NDC) dengan cara menambahkan Eosin Y dalam pelarut etanol (0,034 ml, 10-4 M) pada MOF Zr-NDC (0,3 g). Pengukuran Powder X-Ray Diffraction (PXRD) dilakukan untuk mengkonfirmasi pembentukan MOF Zr-NDC dengan puncak khas pada 2θ di 6.47 dan 7.45. Spektra UV-vis Diffuse Reflectance Spectra diperoleh dengan menggunakan spektrofotometer UV-vis. MOF Zr-NDC memberikan serapan pada 274 nm yang berhubungan dengan energi celah sebesar 4.32 eV, sedangkan Eosin Y menunjukkan serapan pada 524 nm. Di sisi lain, Eosin Y@MOF Zr-NDC menunjukkan puncak-puncak serapan pada 300, 357, dan 524 nm yang berkorelasi dengan energi celah masing-masing sebesar 3,65, 3,15, dan 2,19 eV


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