scholarly journals On the elusive nature of oxygen binding at coordinatively unsaturated 3d transition metal centers in metal–organic frameworks

2017 ◽  
Vol 19 (38) ◽  
pp. 26346-26357 ◽  
Author(s):  
Mali H. Rosnes ◽  
Denis Sheptyakov ◽  
Alexandra Franz ◽  
Matthias Frontzek ◽  
Pascal D. C. Dietzel ◽  
...  
Keyword(s):  
Transition Metal ◽  
Ambient Temperature ◽  
Metal Organic Frameworks ◽  
Oxygen Binding ◽  
Metal Centers ◽  
Framework Materials ◽  
Metal Organic

Low and ambient temperature binding of oxygen, O2, in MOF-74, CPO-27-M (M = Mn, Co, Ni, Cu, Zn) framework materials remains in the physisorption regime, with energetics very similar to that of nitrogen, N2, sorption.

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>

Metal-organic frameworks for electrochemical reduction of carbon dioxide: The role of metal centers

2020 ◽  
Vol 40 ◽  
pp. 156-170 ◽  
Author(s):  
Ping Shao ◽  
Luocai Yi ◽  
Shumei Chen ◽  
Tianhua Zhou ◽  
Jian Zhang
Keyword(s):  
Carbon Dioxide ◽  
Electrochemical Reduction ◽  
Metal Organic Frameworks ◽  
Metal Centers ◽  
Metal Organic

Metal–organic frameworks for radionuclide sequestration from aqueous solution: a brief overview and outlook

2017 ◽  
Vol 46 (47) ◽  
pp. 16381-16386 ◽  
Author(s):  
Chengliang Xiao ◽  
Mark A. Silver ◽  
Shuao Wang
Keyword(s):  
Aqueous Solution ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Framework Materials ◽  
Metal Organic ◽  
Organic Framework

137Cs, 90Sr, 238U, 79Se, and 99Tc sequestrations from aqueous solution by metal–organic framework materials are summarized in this Frontier article.

Vapor-assisted self-conversion of basic carbonates in metal–organic frameworks

Nanoscale ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 5069-5076
Author(s):  
Miaomiao Jia ◽  
Jingyi Su ◽  
Pengcheng Su ◽  
Wanbin Li
Keyword(s):  
Carbon Capture ◽  
Metal Organic Frameworks ◽  
Solvent Vapor ◽  
Metal Centers ◽  
Metal Organic ◽  
High Alkalinity

Basic carbonates with high alkalinity are incorporated into metal–organic frameworks by solvent vapor-assisted self-conversion of partial metal centers to improve carbon capture performance.

Selective adsorption behaviour of carbon dioxide in OH-functionalized metal–organic framework materials

CrystEngComm ◽  
2017 ◽  
Vol 19 (36) ◽  
pp. 5346-5350 ◽  
Author(s):  
Jinjie Qian ◽  
Jinni Shen ◽  
Qipeng Li ◽  
Yue Hu ◽  
Shaoming Huang
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bond ◽  
Selective Adsorption ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Adsorption Behaviour ◽  
Weak Hydrogen Bond ◽  
Oh Groups ◽  
Framework Materials ◽  
Metal Organic

The theoretically optimal adsorption locations in hydroxyl (OH)-decorated metal–organic frameworks show that the captured CO2 molecules interact with the cis-μ2-OH groups in an end-on mode, which shows a moderate to weak hydrogen bond.

scholarly journals X-ray crystallographic insights into post-synthetic metalation products in a metal–organic framework

2017 ◽  
Vol 375 (2084) ◽  
pp. 20160028 ◽  
Author(s):  
Michael T. Huxley ◽  
Campbell J. Coghlan ◽  
Witold M. Bloch ◽  
Alexandre Burgun ◽  
Christian J. Doonan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Coordination Sphere ◽  
Metal Organic Frameworks ◽  
Void Space ◽  
X Ray ◽  
X Ray Crystallography ◽  
Metal Nitrates ◽  
Metal Organic

Post-synthetic modification of metal–organic frameworks (MOFs) facilitates a strategic transformation of potentially inert frameworks into functionalized materials, tailoring them for specific applications. In particular, the post-synthetic incorporation of transition-metal complexes within MOFs, a process known as ‘metalation’, is a particularly promising avenue towards functionalizing MOFs. Herein, we describe the post-synthetic metalation of a microporous MOF with various transition-metal nitrates. The parent framework, 1 , contains free-nitrogen donor chelation sites, which readily coordinate metal complexes in a single-crystal to single-crystal transformation which, remarkably, can be readily monitored by X-ray crystallography. The presence of an open void surrounding the chelation site in 1 prompted us to investigate the effect of the MOF pore environment on included metal complexes, particularly examining whether void space would induce changes in the coordination sphere of chelated complexes reminiscent of those found in the solution state. To test this hypothesis, we systematically metalated 1 with first-row transition-metal nitrates and elucidated the coordination environment of the respective transition-metal complexes using X-ray crystallography. Comparison of the coordination sphere parameters of coordinated transition-metal complexes in 1 against equivalent solid- and solution-state species suggests that the void space in 1 does not markedly influence the coordination sphere of chelated species but we show notably different post-synthetic metalation outcomes when different solvents are used. This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’.

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