Modulated Formation of MOF-5 Nanoparticles—A SANS Analysis

Nayuk, Roman; Zacher, Denise; Schweins, Ralf; Wiktor, Christian; Fischer, Roland A.; Tendeloo, Gustaaf Van; Huber, Klaus

doi:10.1021/jp3003728

Cited by 33 publications

(34 citation statements)

References 29 publications

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“…[20][21][22] However, it has been shown that basic [Zn 4 6 ] can be used as a starting material to synthesize rapidly MOF-5, although it was not reported whether the [Zn 4 O] 6 + core remained intact during the synthesis process. [48,51] This set of observed heights was replicated in a second separate experiment (H) and the micrographs and height analyses are given in Figure SI Cross-sectional analyses of growing step edges provide some insight into the growth mechanism of the surface monolayer terraces and the relative rates of spreading of the 0.85 nm and 0.45 nm sub-layers making up the complete monolayer. Detailed measurements of the lateral dimensions of several growing step edges of MOF-5 were taken.…”

Section: Resultsmentioning

confidence: 99%

“…Surprisingly, relatively little has been reported on the actual crystallization process of MOF‐5,46, 47 particularly with regard to the actual growth of the MOF‐5 crystallites themselves during the stages of nucleation and crystal growth 32. 48…”

Section: Introductionmentioning

confidence: 99%

“…[40][41][42][43][44][45] Surprisingly, relatively little has been reported on the actual crystallization process of MOF-5, [46,47] particularly with regard to the actual growth of the MOF-5 crystallites themselves during the stages of nucleation and crystal growth. [32,48] Herein we present results from the first AFM study on the crystal growth of nanoporous MOF-5 from a variety of growth solutions. Both real time two-dimensional (2D) and spiral crystal growth were observed providing unique insight into the crystal growth mechanism of MOF-5 and the crystal surface structure.…”

Section: Introductionmentioning

confidence: 99%

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Crystal Growth Mechanisms and Morphological Control of the Prototypical Metal–Organic Framework MOF‐5 Revealed by Atomic Force Microscopy

Cubillas

Anderson

Attfield

2012

Chemistry A European J

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Crystal growth of the metal-organic framework MOF-5 was studied by atomic force microscopy (AFM) for the first time. Growth under low supersaturation conditions was found to occur by a two-dimensional or spiral crystal growth mechanism. Observation of developing nuclei during the former reveals growth occurs through a process of nucleation and spreading of metastable and stable sub-layers revealing that MOFs may be considered as dense phase structures in terms of crystal growth, even though they contain sub-layers consisting of ordered framework and disordered non-framework components. These results also support the notion this may be a general mechanism of surface crystal growth at low supersaturation applicable to crystalline nanoporous materials. The crystal growth mechanism at the atomistic level was also seen to vary as a function of the growth solution Zn/H(2)bdc ratio producing square terraces with steps parallel to the <100> direction or rhombus-shaped terraces with steps parallel to the <110> direction when the Zn/H(2)bdc ratio was >1 or about 1, respectively. The change in relative growth rates can be explained in terms of changes in the solution species concentrations and their influence on growth at different terrace growth sites. These results were successfully applied to the growth of as-synthesized cube-shaped crystals to increase expression of the {111} faces and to grow octahedral crystals of suitable quality to image using AFM. This modulator-free route to control the crystal morphology of MOF-5 crystals should be applicable to a wide variety of MOFs to achieve the desired morphological control for performance enhancement in applications.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crystal Growth Mechanisms and Morphological Control of the Prototypical Metal–Organic Framework MOF‐5 Revealed by Atomic Force Microscopy

Cubillas

Anderson

Attfield

2012

Chemistry A European J

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“…16 Figure 2 shows AFM deflection images taken from experiment A in Table 1. This experiment was started by introducing a standard growth solution (SA-1, Table 1) with a Zn/H 2 BDC > 1 over the MOF-5 seed crystals to induce MOF-5 growth.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Influence of Isomorphous Substituting Cobalt Ions on the Crystal Growth of the MOF-5 Framework Determined by Atomic Force Microscopy of Growing Core–Shell Crystals

Cubillas

Anderson

Attfield

2013

Crystal Growth & Design

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Atomic force microscopy is used to conduct the first detailed nanoscopic study on the crystal growth of a complex mixed metal/metal−organic framework based on the MOF-5 framework topology. Shells of isomorphously substituted Co/Zn-MOF-5 and MOF-5 were epitaxially grown on MOF-5 core crystals at room temperature and low supersaturation to produce complex core−shell−shell structures with a hierarchal mixed metal nature involving mixing at the atomic level in the isomorphously substituted Co/Zn-MOF-5 shell and at the nanometer level through segregation of the Co/Zn-MOF-5 and MOF-5 layers. The presence of cobalt in the growth solutions was found to retard the overall rate of surface growth in comparison to a cobalt-free growth solution and stop growth entirely for a growth solution containing a Zn/Co ratio = 0.6. The presence of cobalt in the growth solutions was also found to affect the relative rates of terrace spreading in different crystallographic directions compared to cobalt-free growth with spreading in the ⟨110⟩ directions decreasing relative to the rate along the ⟨100⟩ directions. The work provides new understanding of the crystal growth of complex mixed metal/metal−organic frameworks and a methodology to prepare these complex forms in a more controlled manner.

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“…It was found that modulation slowed down both the initial formation of MOF particles and their growth rate, but had no effect on nal particle size compared to unmodulated syntheses. 37 This suggests inhibition either through competitive metal coordination or pH control, but a follow-up study from the same group where the 4-decylbenzoic acid modulator was added in a larger excess 5 minutes aer the initial mixing of the reagents allowed identication of the modulator at crystallite surfaces by SANS. This was feasible by determining an appropriate mixture of deuterated and protonated DMF solvent which matched the neutron scattering contrast of MOF-5, and therefore allowing scattering by the large alkyl chains of the modulator to be identied.…”

Section: Mechanistic Investigationsmentioning

confidence: 99%

Modulated self-assembly of metal–organic frameworks

2020

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Exercising fine control over the synthesis of metal-organic frameworks (MOFs) is key to ensuring reproducibility of physical properties such as crystallinity, particle size, morphology, porosity, defectivity, and surface chemistry. The principle of modulated self-assemblyincorporation of modulator molecules into synthetic mixtureshas emerged as the primary means to this end. This perspective article will detail the development of modulated synthesis, focusing primarily on coordination modulation, from a technique initially intended to cap the growth of MOF crystals to one that is now used regularly to enhance crystallinity, control particle size, induce defectivity and select specific phases.The various mechanistic driving forces will be discussed, as well as the influence of modulation on physical properties and how this can facilitate potential applications. Modulation is also increasingly being used to exert kinetic control over self-assembly; examples of phase selection and the development of new protocols to induce this will be provided. Finally, the application of modulated selfassembly to alternative materials will be discussed, and future perspectives on the area given. Fig. 18 Solid-state structures of different topologies accessible within the phase space of Zr MOFs linked by linear dicarboxylate ligands. (a) UiO-67 in the fcu topology. (b) The Zr-bdc MOF which is a polymorph of UiO-66 but has hex topology, viewed down the b (left) and c (right) crystallographic axes. (c) The hcp phase formed by Hf and bpdc. (d) The hxl phase formed by Hf and bpdc, which can spontaneously arise from the hcp phase by loss of bpdc. (e) The hns phase of Hf and bpdc, which is a delaminated version of the hxl phase. 4558 | Chem. Sci., 2020, 11, 4546-4562 This journal isFig. 20 (a) Schematic of aniline-modulated self-assembly of imine COFs to modify kinetics. (b) Selected SEM and optical images of COF-300 samples illustrating the particle size control offered by modulation. Reprinted in part (adapted) with permission from ref. 110.

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Modulated Formation of MOF-5 Nanoparticles—A SANS Analysis

Cited by 33 publications

References 29 publications

Crystal Growth Mechanisms and Morphological Control of the Prototypical Metal–Organic Framework MOF‐5 Revealed by Atomic Force Microscopy

Crystal Growth Mechanisms and Morphological Control of the Prototypical Metal–Organic Framework MOF‐5 Revealed by Atomic Force Microscopy

Influence of Isomorphous Substituting Cobalt Ions on the Crystal Growth of the MOF-5 Framework Determined by Atomic Force Microscopy of Growing Core–Shell Crystals

Modulated self-assembly of metal–organic frameworks

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