scholarly journals Ultrahigh-field 67Zn NMR reveals short-range disorder in zeolitic imidazolate framework glasses

Science ◽  
2020 ◽  
Vol 367 (6485) ◽  
pp. 1473-1476 ◽  
Author(s):  
Rasmus S. K. Madsen ◽  
Ang Qiao ◽  
Jishnu Sen ◽  
Ivan Hung ◽  
Kuizhi Chen ◽  
...  
Keyword(s):  
Short Range ◽  
Structural Parameters ◽  
Metal Organic Framework ◽  
Tetrahedral Site ◽  
Resonance Spectroscopy ◽  
Structure Property ◽  
Zeolitic Imidazolate Framework ◽  
Ultrahigh Field ◽  
Property Relations ◽  
Metal Organic

The structure of melt-quenched zeolitic imidazole framework (ZIF) glasses can provide insights into their glass-formation mechanism. We directly detected short-range disorder in ZIF glasses using ultrahigh-field zinc-67 solid-state nuclear magnetic resonance spectroscopy. Two distinct Zn sites characteristic of the parent crystals transformed upon melting into a single tetrahedral site with a broad distribution of structural parameters. Moreover, the ligand chemistry in ZIFs appeared to have no controlling effect on the short-range disorder, although the former affected their phase-transition behavior. These findings reveal structure-property relations and could help design metal-organic framework glasses.

scholarly journals Machine learning with persistent homology and chemical word embeddings improves prediction accuracy and interpretability in metal-organic frameworks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aditi S. Krishnapriyan ◽  
Joseph Montoya ◽  
Maciej Haranczyk ◽  
Jens Hummelshøj ◽  
Dmitriy Morozov
Keyword(s):  
Machine Learning ◽  
Language Processing ◽  
Metal Organic Framework ◽  
Persistent Homology ◽  
Level Structure ◽  
Chemical Information ◽  
Material System ◽  
Word Embeddings ◽  
Structure Property ◽  
Metal Organic

AbstractMachine learning has emerged as a powerful approach in materials discovery. Its major challenge is selecting features that create interpretable representations of materials, useful across multiple prediction tasks. We introduce an end-to-end machine learning model that automatically generates descriptors that capture a complex representation of a material’s structure and chemistry. This approach builds on computational topology techniques (namely, persistent homology) and word embeddings from natural language processing. It automatically encapsulates geometric and chemical information directly from the material system. We demonstrate our approach on multiple nanoporous metal–organic framework datasets by predicting methane and carbon dioxide adsorption across different conditions. Our results show considerable improvement in both accuracy and transferability across targets compared to models constructed from the commonly-used, manually-curated features, consistently achieving an average 25–30% decrease in root-mean-squared-deviation and an average increase of 40–50% in R2 scores. A key advantage of our approach is interpretability: Our model identifies the pores that correlate best to adsorption at different pressures, which contributes to understanding atomic-level structure–property relationships for materials design.

scholarly journals Templated interfacial synthesis of metal-organic framework (MOF) nano- and micro-structures with precisely controlled shapes and sizes

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Lingyao Meng ◽  
Binyu Yu ◽  
Yang Qin
Keyword(s):  
Crystal Growth ◽  
Metal Organic Framework ◽  
Reaction Conditions ◽  
Zeolitic Imidazolate Framework ◽  
Crystallographic Preferred Orientation ◽  
Metal Organic ◽  
Interfacial Synthesis ◽  
Oil Water ◽  
Synthesis Methodology ◽  
Micro Structures

AbstractMetal-organic frameworks (MOF) are an emerging class of microporous materials with promising applications. MOF nanocrystals, and their assembled super-structures, can display unique properties and reactivities when compared with their bulk analogues. MOF nanostructures of 0-D, 2-D, and 3-D dimensions can be routinely obtained by controlling reaction conditions and ligand additives, while formation of 1-D MOF nanocrystals (nanowires and nanorods) and super-structures has been relatively rare. We report here a facile templated interfacial synthesis methodology for the preparation of a series of 1-D MOF nano- and micro-structures with precisely controlled shapes and sizes. Specifically, by applying track-etched polycarbonate (PCTE) membranes as the templates and at the oil/water interface, we rapidly and reproducibly synthesize zeolitic imidazolate framework-8 (ZIF-8) and ZIF-67 nano- and micro structures of sizes ranging from 10 nm to 20 μm. We also identify a size confinement effect on MOF crystal growth, which leads to single crystals under the most restricted conditions and inter-grown polycrystals at larger template pore sizes, as well as surface directing effects that influence the crystallographic preferred orientation. Our findings provide a potentially generalizable method for controlling the size, morphology, and crystal orientations of MOF nanomaterials, as well as offering fundamental understanding into MOF crystal growth mechanisms.

scholarly journals Hydrogen adsorption on MoS2-surfaces: a DFT study on preferential sites and the effect of sulfur and hydrogen coverage

2017 ◽  
Vol 19 (24) ◽  
pp. 16231-16241 ◽  
Author(s):  
Rasmus Kronberg ◽  
Mikko Hakala ◽  
Nico Holmberg ◽  
Kari Laasonen
Keyword(s):  
Hydrogen Adsorption ◽  
Structural Parameters ◽  
Dft Study ◽  
Structure Property ◽  
Property Relations

H-Adsorption on MoS2-surfaces is studied as a function of structural parameters and an assessment of the intricate structure–property relations is conducted.

Metal–organic framework-derived CoSe2/(NiCo)Se2 box-in-box hollow nanocubes with enhanced electrochemical properties for sodium-ion storage and hydrogen evolution

2017 ◽  
Vol 5 (35) ◽  
pp. 18823-18830 ◽  
Author(s):  
Seung-Keun Park ◽  
Jin Koo Kim ◽  
Yun Chan Kang
Keyword(s):  
Electrochemical Properties ◽  
Hydrogen Evolution ◽  
Metal Organic Framework ◽  
Sodium Ion ◽  
Zeolitic Imidazolate Framework ◽  
Box Structures ◽  
Ion Storage ◽  
Metal Organic ◽  
Sodium Ion Storage ◽  
Organic Framework

Multishell structured metal selenide nanocubes, namely, Co/(NiCo)Se2 box-in-box structures with different shell compositions, were successfully synthesized by applying zeolitic imidazolate framework-67 (ZIF-67) as a template.

scholarly journals High-Throughput Electron Diffraction Reveals a Hidden Novel Metal-Organic Framework for Electrocatalysis

2021 ◽  
Author(s):  
Meng Ge ◽  
Yanzhi Wang ◽  
Francesco Carraro ◽  
Weibin Liang ◽  
Morteza Roostaeinia ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
High Throughput ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Reduction Reaction ◽  
New Materials ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
Wide Range ◽  
Metal Organic

<p>Metal-organic frameworks (MOFs) are known for their versatile combination of inorganic building units and organic linkers, which offers immense opportunities in a wide range of applications. However, many MOFs are typically synthesized as multiphasic polycrystalline powders, which are challenging for studies by X-ray diffraction. Therefore, developing new structural characterization techniques is highly desired in order to accelerate discoveries of new materials. Here, we report a high-throughput approach for structural analysis of MOF nano- and sub-microcrystals by three-dimensional electron diffraction (3DED). A new zeolitic-imidazolate framework (ZIF), denoted ZIF-EC1<a>, </a>was first discovered in a trace amount during the study of a known ZIF-CO<sub>3</sub>-1 material by 3DED. The structures of both ZIFs were solved and refined using 3DED data. ZIF-EC1 has a dense 3D framework structure, which is built by linking mono- and bi-nuclear Zn clusters and 2-methylimidazolates (mIm<sup>-</sup>). With a composition of Zn<sub>3</sub>(mIm)<sub>5</sub>(OH), ZIF-EC1 exhibits high N and Zn densities. We show that the N-doped carbon material derived from ZIF-EC1 is a promising electrocatalysis for oxygen reduction reaction (ORR). The discovery of this new MOF and its conversion to an efficient electrocatalyst highlights the power of 3DED in developing new materials and their applications. </p>

Polymorphism in a Two-Dimensional Copper(I) Metal-Organic Framework with the ligand bis(4-pyridylthio)methane

CrystEngComm ◽  
2021 ◽  
Author(s):  
Olaya Paz Gomez ◽  
Rosa Carballo ◽  
Ana Belen Lago ◽  
Ezequiel M. Vazquez-Lopez
Keyword(s):  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Common Phenomenon ◽  
Two Dimensional ◽  
Structure Property ◽  
Crystalline Materials ◽  
Metal Organic ◽  
Organic Framework

Polymorphism is a common phenomenon in crystalline materials but it has barely been studied in the field of metal organic frameworks. The study of polymorphism is useful to investigate structure–property...

scholarly journals Direct evidence for 2-fold to 3-fold change of interpenetration in a MOF

2014 ◽  
Vol 70 (a1) ◽  
pp. C636-C636
Author(s):  
Himanshu Aggarwal ◽  
Prashant Bhatt ◽  
Charl Benzuidenhout ◽  
Leonard Barbour
Keyword(s):  
Single Crystal ◽  
Crystal Engineering ◽  
Molecular Level ◽  
Metal Organic Framework ◽  
Structural Rearrangement ◽  
Structure Property ◽  
Ambient Conditions ◽  
Physical Conditions ◽  
Structure Property Relationships ◽  
Metal Organic

Single-crystal to single-crystal transformations has recently received much attention in the field of crystal engineering. Such transformations not only provide insight into the changes taking place within the crystal at the molecular level, but they also aid our understanding of the structure-property relationships. Discrete crystals have been shown to tolerate considerable dynamic behavior at the molecular level while maintaining their single-crystal character. Examples that are common in the literature include bond formation/cleavage,[1] guest uptake,[2] release or exchange as well as polymorphic phase transformations. However, there are rare examples of the structural transformations on the host framework initiated by removal of guest or change in physical conditions such as temperature or pressure. We have investigated a known doubly-interpenetrated metal organic framework with the formula [Zn2(ndc)2(bpy)] which possesses minimal porosity when activated. We have shown not only that the material converts to its triply-interpenetrated analogue upon desolvation, but that the transformation occurs in a single-crystal to single-crystal manner under ambient conditions.[3] This contribution probes the limits to which a single-crystal material can undergo structural rearrangement while still maintaining the macroscopic integrity of the crystal as a discrete entity.

scholarly journals Tailoring of the electronic property of Zn-BTC metal–organic framework via ligand functionalization: an ab initio investigation

RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 14260-14267 ◽  
Author(s):  
Gemechis D. Degaga ◽  
Ravindra Pandey ◽  
Chansi Gupta ◽  
Lalit Bharadwaj
Keyword(s):  
Ab Initio ◽  
Electronic Property ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Metal Organic ◽  
Organic Framework

The structure–property relationships of pristine and functionalized Zn-BTC (Zn3(BTC)2) metal–organic frameworks are investigated.

A yolk–shell structured metal–organic framework with encapsulated iron-porphyrin and its derived bimetallic nitrogen-doped porous carbon for an efficient oxygen reduction reaction

2020 ◽  
Vol 8 (19) ◽  
pp. 9536-9544 ◽  
Author(s):  
Chaochao Zhang ◽  
Hao Yang ◽  
Dan Zhong ◽  
Yang Xu ◽  
Yanzhi Wang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Porous Carbon ◽  
Metal Organic Framework ◽  
Reduction Reaction ◽  
Iron Porphyrin ◽  
Zeolitic Imidazolate Framework ◽  
Nitrogen Doped ◽  
Metal Organic ◽  
Organic Framework

A yolk–shell structured metal–organic framework (MOF) with encapsulated 5,10,15,20-tetraphenylporphyrinatoiron (FeTPP) in a zeolitic imidazolate framework (ZIF)-L-ZIF-8 is reported.

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