EPR Insights into Switchable and Rigid Derivatives of the Metal–Organic Framework DUT-8(Ni) by NO Adsorption

Mendt, Matthias; Gutt, Felix; Kavoosi, Negar; Bon, Volodymyr; Senkovska, Irena; Kaskel, Stefan; Pöppl, Andreas

doi:10.1021/acs.jpcc.6b04984

Cited by 48 publications

(76 citation statements)

References 46 publications

(144 reference statements)

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“…The combination of microscopic with mesoscopic defects, and in particular their interplay, holds promise for dimensions of advanced materials functional design. One example of progress in this direction is the area of flexible and stimuli responsive MOFs on which the effects of defects are now being realized to similarly impact the property . For instance, the potential to tune flexible behavior via defect incorporation, e.g., the threshold pressure of an external gas or temperature on which the system becomes flexible, is intriguing.…”

Section: Resultsmentioning

confidence: 99%

Defective Metal‐Organic Frameworks

et al. 2018

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The targeted incorporation of defects into crystalline matter allows for the manipulation of many properties and has led to relevant discoveries for optimized and even novel technological applications of materials. It is therefore exciting to see that defects are now recognized to be similarly useful in tailoring properties of metal-organic frameworks (MOFs). For instance, heterogeneous catalysis crucially depends on the number of active catalytic sites as well as on diffusion limitations. By the incorporation of missing linker and missing node defects into MOFs, both parameters can be accessed, improving the catalytic properties. Furthermore, the creation of defects allows for adding properties such as electronic conductivity, which are inherently absent in the parent MOFs. Herein, progress of the rapidly evolving field of the past two years is overviewed, putting a focus on properties that are altered by the incorporation and even tailoring of defects in MOFs. A brief account is also given on the emerging quantitative understanding of defects and heterogeneity in MOFs based on scale-bridging computational modeling and simulations.

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Section: Resultsmentioning

confidence: 99%

Defective Metal‐Organic Frameworks

et al. 2018

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“…Both 2b_op and 2a_op compounds can be characterized by a very wide distribution of the exchange integral J probably due to the structural inhomogeneity in the sample and increased concentration of defects. 42 On the other hand, both 1b_cp and 1a_cp compounds show a rather small average coupling in comparison to the aforementioned samples. This could be possibly related to signicant differences in the structure between the submicron-sized (2) and macro-sized (1) compounds.…”

Section: Magnetic Measurementsmentioning

confidence: 92%

Crystal size versus paddle wheel deformability: selective gated adsorption transitions of the switchable metal–organic frameworks DUT-8(Co) and DUT-8(Ni)

et al. 2019

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Crystal size versus paddle wheel deformability: selective gated adsorption transitions of the switchable metal-organic frameworks and † Switchable pillared layer metal-organic frameworks M 2 (2,6-ndc) 2 (dabco) (DUT-8(M), M ¼ Ni, Co, 2,6-ndc ¼ 2,6naphthalenedicarboxylate, dabco ¼ 1,4-diazabicyclo-[2.2.2]octane, DUT -Dresden University of Technology) were synthesised in two different crystallite size regimes to produce particles up to 300 mm and smaller particles around 0.1 mm, respectively. The textural properties and adsorption-induced switchability of the materials, obtained from both syntheses, were studied by physisorption of N 2 at 77 K, CO 2 at 195 K and nbutane at 273 K, revealing pronounced differences in adsorption behavior for Ni and Co analogues. While the smaller nano-sized particles (50-200 nm) are rigid and show no gating transitions confirming the importance of crystallite size, the large particles show pronounced switchability with characteristic differences for the two metals resulting in distinct recognition effects for various gases and vapours. Adsorption of various vapours demonstrates consistently a higher energetic barrier for the "gate opening" of DUT-8(Co) in contrast to , as the "gate opening" pressure for Co based material is shifted to a higher value for adsorption of dichloromethane at 298 K. Evaluation of crystallographic data, obtained from single crystal and powder X-ray diffraction analysis, showed distinct geometric differences in the paddle wheel units of the respective MOFs.These differences are further disclosed by solid-state UV-vis, FT-IR and Raman spectroscopy. Magnetic properties of DUT-8(Co) and DUT-8(Ni) were investigated, indicating a high-spin state for both materials at room temperature. Density functional theory (DFT) simulations confirmed distinct energetic differences for Ni and Co analogues with a higher energetic penalty for the structural "gate opening" transformation for DUT-8(Co) compared to DUT-8(Ni) explaining the different flexibility behaviour of these isomorphous MOFs.underlying structural phase transitions are triggered by adsorption or desorption of guest molecules and generally characterised by an activation energy barrier, which causes hysteresis in physisorption experiments. Due to their switchable nature, so porous crystals are oen discussed as materials with huge application potential in gas storage, 11 separation processes, 12,13 sensor technology 14,15 and catalysis. 16 Despite rapidly growing research in the eld of exible MOFs, 1,17-21 the role of critical factors inuencing and controlling framework switchability are barely understood. 22 As MOFs are modular networks, the exibility of the linker but also the hinges of the metal node are key features that affect switchability. The importance of metal-node hinges and their energetics for framework switchability has been widely investigated for compounds such as M(bdp) (M ¼ Co, Fe, bdp ¼ 1,4-benzenedipyrazolate), 11,23,24 M(m-OH)(bdc) (MIL-53, M ¼ Cr, Al, Fe, bdc ¼ 1,4-benzenedicarboxylate)...

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“…Motivated by its outstanding properties, DUT-8(Ni) is being investigated extensively recently. [12][13][14][15][16][17][18][19][20][21][22][23] Some examples of the properties of interest are the enormous volume change upon opening (more than 140 %), [14] its isomorphism, [22] the property dependence on the metal center, [14] and crystallite size effects. [19] Alzahrani and Deeth [24] already employed LFMM to investigate clusters of Zn 2 (bdc) 2 (dabco) and showed the applicability to this structurally related flexible MOF.…”

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A Ligand Field Molecular Mechanics Study of CO₂‐Induced Breathing in the Metal–Organic Framework DUT‐8(Ni)

Melix

Paesani

Heine

2019

Advcd Theory and Sims

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Flexible metal-organic Frameworks (MOFs) are an interesting class of materials due to their diverse properties. One representative of this class is the layered-pillar MOF DUT-8(Ni). This MOF consists of Ni 2 paddle wheels interconnected by naphthalene dicarboxylate linkers and dabco pillars (Ni 2 (ndc) 2 (dabco), ndc = 2,6-naphthalene-dicarboxylate, dabco = 1,4-diazabicyclo-[2.2.2]-octane). DUT-8(Ni) undergoes a volume change of over 140% upon adsorption of guest molecules. Herein, a ligand field molecular mechanics (LFMM) study of the CO 2 -induced flexibility of DUT-8(Ni) is presented. LFMM is able to reproduce experimental and DFT structural features as well as properties that require large simulation cells. It is shown that the transformation energy from a closed to open state of the MOF is overcompensated fivefold by the host-guest interactions. Structural characteristics of the MOF explain the shape of the energy profile at different loading states and provide useful insights to the interpretation of previous experimental results.the possibilities of employing ligand field molecular mechanics (LFMM) simulations to study flexible MOFs and their processes. The method employed is not limited to adsorption processes but as has been shown previously [8][9][10][11] to be applicable to other properties, for example, spin states or magnetic properties. Our goal is to present simulations using the example of CO 2induced breathing in the pillared layer MOF DUT-8(Ni) [12] (Ni 2 (ndc) 2 (dabco), ndc = 2,6naphthalenedicarboxylate, dabco = 1,4diazabicyclo-[2.2.2]-octane, see Figure 1) using an LFMM approach. Motivated by its outstanding properties, DUT-8(Ni) is being investigated extensively recently. [12][13][14][15][16][17][18][19][20][21][22][23] Some examples of the properties of interest are the enormous volume change upon opening (more than 140 %), [14] its isomorphism, [22] the property dependence on the metal center, [14] and crystallite size effects. [19] Alzahrani and Deeth [24] already employed LFMM to investigate clusters of Zn 2 (bdc) 2 (dabco) and showed the applicability to this structurally related flexible MOF. We present here the first application of LFMM to simulate the breathing of an openshell transition-metal paddle wheel pillared layer MOF in periodic boundary conditions.

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EPR Insights into Switchable and Rigid Derivatives of the Metal–Organic Framework DUT-8(Ni) by NO Adsorption

Cited by 48 publications

References 46 publications

Defective Metal‐Organic Frameworks

Defective Metal‐Organic Frameworks

Crystal size versus paddle wheel deformability: selective gated adsorption transitions of the switchable metal–organic frameworks DUT-8(Co) and DUT-8(Ni)

A Ligand Field Molecular Mechanics Study of CO₂‐Induced Breathing in the Metal–Organic Framework DUT‐8(Ni)

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EPR Insights into Switchable and Rigid Derivatives of the Metal–Organic Framework DUT-8(Ni) by NO Adsorption

Cited by 48 publications

References 46 publications

Defective Metal‐Organic Frameworks

Defective Metal‐Organic Frameworks

Crystal size versus paddle wheel deformability: selective gated adsorption transitions of the switchable metal–organic frameworks DUT-8(Co) and DUT-8(Ni)

A Ligand Field Molecular Mechanics Study of CO2‐Induced Breathing in the Metal–Organic Framework DUT‐8(Ni)

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A Ligand Field Molecular Mechanics Study of CO₂‐Induced Breathing in the Metal–Organic Framework DUT‐8(Ni)