Polar Molecule Confinement Effects on Dielectric Modulations of Sr-Based Metal–Organic Frameworks

2019 ◽  
Vol 1 (6) ◽  
pp. 836-844 ◽  
Author(s):  
Muhammad Usman ◽  
Pei-Hsuan Feng ◽  
Kuan-Ru Chiou ◽  
Jenq-Wei Chen ◽  
Li-Wei Lee ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Polar Molecule ◽  
Confinement Effects ◽  
Metal Organic

Tunable dielectric performance of porphyrin based metal−organic frameworks with polar molecule confinement

2021 ◽  
pp. 100734
Author(s):  
Dong-Li Zhang ◽  
Qi-Kun Feng ◽  
Shao-Long Zhong ◽  
Di-Fan Liu ◽  
Yu Zhao ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Polar Molecule ◽  
Dielectric Performance ◽  
Metal Organic

scholarly journals Ethylene oligomerization in metal–organic frameworks bearing nickel(ii) 2,2′-bipyridine complexes

2017 ◽  
Vol 201 ◽  
pp. 351-367 ◽  
Author(s):  
Miguel I. Gonzalez ◽  
Julia Oktawiec ◽  
Jeffrey R. Long
Keyword(s):  
Crystal Structure ◽  
Catalytic Activity ◽  
Single Crystal ◽  
Metal Organic Frameworks ◽  
Ethylene Oligomerization ◽  
Confinement Effects ◽  
Polymer Formation ◽  
Metal Organic ◽  
Selectivity Control ◽  
Nickel Species

The metal–organic frameworks Zr6O4(OH)4(bpydc)6 (1; bpydc2− = 2,2′-bipyridine-5,5′-dicarboxylate) and Zr6O4(OH)4(bpydc)0.84(bpdc)5.16 (2; bpdc2− = biphenyl-4,4′-dicarboxylate) were readily metalated with Ni(DME)Br2 (DME = dimethoxyethane) to produce the corresponding metalated frameworks 1(NiBr2)6 and 2(NiBr2)0.84. Both nickel(ii)-containing frameworks catalyze the oligomerization of ethylene in the presence of Et2AlCl. In these systems, the pore environment around the active nickel sites significantly influences their selectivity for formation of oligomers over polymer. Specifically, the single-crystal structure of 1(NiBr2)5.64 reveals that surrounding metal–linker complexes enforce a steric environment on each nickel site that causes polymer formation to become favorable. Minimizing this steric congestion by isolating the nickel(ii) bipyridine complexes in the mixed-linker framework 2(NiBr2)0.84 markedly improves both the catalytic activity and selectivity for oligomers. Furthermore, both frameworks give product mixtures that are enriched in shorter olefins (C4–10), leading to deviations from the expected Schulz–Flory distribution of oligomers. Although these deviations indicate possible pore confinement effects on selectivity, control experiments using the nickel-treated biphenyl framework Zr6O4(OH)4(bpdc)6(NiBr2)0.14 (3(NiBr2)0.14) reveal that they likely arise at least in part from the presence of nickel species that are not ligated by bipyridine within 1(NiBr2)5.64 and 2(NiBr2)0.84.

Metal-Organic Frameworks

2021 ◽  
Author(s):  
Lars Öhrström ◽  
Francoise M. Amombo Noa
Keyword(s):  
Metal Organic Frameworks ◽  
Metal Organic

Substrate templated synthesis of single-phase and uniform Zr-porphyrin-based metal–organic frameworks

2020 ◽  
Vol 7 (1) ◽  
pp. 221-231
Author(s):  
Seong Won Hong ◽  
Ju Won Paik ◽  
Dongju Seo ◽  
Jae-Min Oh ◽  
Young Kyu Jeong ◽  
...  
Keyword(s):  
Chemical Bath Deposition ◽  
Single Phase ◽  
Metal Organic Frameworks ◽  
Templated Synthesis ◽  
Pore Structures ◽  
Phase Pure ◽  
Metal Organic ◽  
Cbd Method

We successfully demonstrate that the chemical bath deposition (CBD) method is a versatile method for synthesizing phase-pure and uniform MOFs by controlling their nucleation stages and pore structures.

Tuning the Redox Activity of Metal−Organic Frameworks for Enhanced, Selective O2 Binding

2019 ◽  
Author(s):  
Andrew Rosen ◽  
M. Rasel Mian ◽  
Timur Islamoglu ◽  
Haoyuan Chen ◽  
Omar Farha ◽  
...  
Keyword(s):  
Density Functional ◽  
Metal Organic Frameworks ◽  
Redox Activity ◽  
Screening Methods ◽  
Bridging Ligands ◽  
Metal Centers ◽  
Computational Screening ◽  
Open Metal Sites ◽  
Metal Organic ◽  
Unsaturated Metal Sites

<p>Metal−organic frameworks (MOFs) with coordinatively unsaturated metal sites are appealing as adsorbent materials due to their tunable functionality and ability to selectively bind small molecules. Through the use of computational screening methods based on periodic density functional theory, we investigate O<sub>2</sub> and N<sub>2</sub> adsorption at the coordinatively unsaturated metal sites of several MOF families. A variety of design handles are identified that can be used to modify the redox activity of the metal centers, including changing the functionalization of the linkers (replacing oxido donors with sulfido donors), anion exchange of bridging ligands (considering μ-Br<sup>-</sup>, μ-Cl<sup>-</sup>, μ-F<sup>-</sup>, μ-SH<sup>-</sup>, or μ-OH<sup>-</sup> groups), and altering the formal oxidation state of the metal. As a result, we show that it is possible to tune the O<sub>2</sub> affinity at the open metal sites of MOFs for applications involving the strong and/or selective binding of O<sub>2</sub>. In contrast with O<sub>2</sub> adsorption, N<sub>2</sub> adsorption at open metal sites is predicted to be relatively weak across the MOF dataset, with the exception of MOFs containing synthetically elusive V<sup>2+</sup> open metal sites. As one example from the screening study, we predict that exchanging the μ-Cl<sup>-</sup> ligands of M<sub>2</sub>Cl<sub>2</sub>(BBTA) (H<sub>2</sub>BBTA = 1<i>H</i>,5<i>H</i>-benzo(1,2-d:4,5-d′)bistriazole) with μ-OH<sup>-</sup> groups would significantly enhance the strength of O<sub>2</sub> adsorption at the open metal sites without a corresponding increase in the N<sub>2</sub> affinity. Experimental investigation of Co<sub>2</sub>Cl<sub>2</sub>(BBTA) and Co<sub>2</sub>(OH)<sub>2</sub>(BBTA) confirms that the former exhibits only weak physisorption, whereas the latter is capable of chemisorbing O<sub>2</sub> at room temperature. The chemisorption behavior is attributed to the greater electron-donating character of the μ-OH<sup>-</sup><sub> </sub>ligands and the presence of H-bonding interactions between the μ-OH<sup>-</sup> bridging ligands and the O<sub>2</sub> adsorbate.</p>

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