scholarly journals Skyrmion Lattices in Chiral Metal–organic Frameworks

2020 ◽  
Author(s):  
Emma Wolpert ◽  
François-Xavier Coudert ◽  
Andrew Goodwin
Keyword(s):  
Simple Model ◽  
Data Storage ◽  
Guest Molecule ◽  
Metal Organic Frameworks ◽  
Orientational Order ◽  
Phase Behaviour ◽  
Smart Devices ◽  
Winding Number ◽  
Metal Organic ◽  
Dynamics Simulations

<p>Skyrmions are knot-like topologically-protected objects of use in data storage and low-energy smart devices. They can be generated by applying a magnetic field to certain chiral ferromagnets, with the knotted state involving a curling of the underlying magnetisation to give a nonzero winding number. Here we explore the possibility that chiral metal–organic frameworks (MOFs) might in principle host skyrmionic phases—realised not through the winding of magnetic spins but through that of guest molecule orientations. We propose a simple model for the interactions governing guest orientational order in chiral MOFs, with uniaxial strain acting as conjugate field. Using Monte Carlo simulations we show that this model gives a rich phase behaviour that includes molecular skyrmion crystals. <i>Ab initio</i> molecular dynamics simulations carried out for a candidate chiral MOF of tractable complexity demonstrate that our simple model effectively captures its underlying energetics. Our results suggest that skyrmionic states may indeed be realisable in MOFs and related porous media and may even arise spontaneously in thin-film samples.</p>

scholarly journals Skyrmion Lattices in Chiral Metal–organic Frameworks

2020 ◽  
Author(s):  
Emma Wolpert ◽  
François-Xavier Coudert ◽  
Andrew Goodwin
Keyword(s):  
Simple Model ◽  
Data Storage ◽  
Guest Molecule ◽  
Metal Organic Frameworks ◽  
Orientational Order ◽  
Phase Behaviour ◽  
Smart Devices ◽  
Winding Number ◽  
Metal Organic ◽  
Dynamics Simulations

<p>Skyrmions are knot-like topologically-protected objects of use in data storage and low-energy smart devices. They can be generated by applying a magnetic field to certain chiral ferromagnets, with the knotted state involving a curling of the underlying magnetisation to give a nonzero winding number. Here we explore the possibility that chiral metal–organic frameworks (MOFs) might in principle host skyrmionic phases—realised not through the winding of magnetic spins but through that of guest molecule orientations. We propose a simple model for the interactions governing guest orientational order in chiral MOFs, with uniaxial strain acting as conjugate field. Using Monte Carlo simulations we show that this model gives a rich phase behaviour that includes molecular skyrmion crystals. <i>Ab initio</i> molecular dynamics simulations carried out for a candidate chiral MOF of tractable complexity demonstrate that our simple model effectively captures its underlying energetics. Our results suggest that skyrmionic states may indeed be realisable in MOFs and related porous media and may even arise spontaneously in thin-film samples.</p>

Diffusion as a function of guest molecule length and functionalization in flexible metal–organic frameworks

2016 ◽  
Vol 3 (4) ◽  
pp. 355-361 ◽  
Author(s):  
B. Zheng ◽  
L. L. Wang ◽  
L. Du ◽  
Y. Pan ◽  
Z. Lai ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Guest Molecule ◽  
Metal Organic Frameworks ◽  
Chemical Separation ◽  
Efficient Design ◽  
Metal Organic ◽  
Drug Delivery Applications ◽  
Flexible Metal

Understanding guest diffusion in nanoporous host–guest systems is crucial in the efficient design of metal–organic frameworks (MOFs) for chemical separation and drug delivery applications.

scholarly journals A Review on Breathing Behaviors of Metal-Organic-Frameworks (MOFs) for Gas Adsorption

2021 ◽  
Author(s):  
Mays Alhamami ◽  
Huu Doan ◽  
Chil-Hung Cheng
Keyword(s):  
Molecular Sieves ◽  
Gas Adsorption ◽  
Metal Organic Frameworks ◽  
Design Strategies ◽  
Surface Areas ◽  
Host Materials ◽  
Potential Applications ◽  
Metal Organic ◽  
Definition Of ◽  
Dynamics Simulations

Metal-organic frameworks (MOFs) are a new class of microporous materials that possess framework flexibility, large surface areas, “tailor-made” framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel with designing new structures and new chemistry of MOFs, the observation of unique breathing behaviors upon adsorption of gases or solvents stimulates their potential applications as host materials in gas storage for renewable energy. This has attracted intense research energy to understand the causes at the atomic level, using in situ X-ray diffraction, calorimetry, Fourier transform infrared spectroscopy, and molecular dynamics simulations. This article is developed in the following order: first to introduce the definition of MOFs and the observation of their framework flexibility. Second, synthesis routes of MOFs are summarized with the emphasis on the hydrothermal synthesis, owing to the environmental-benign and economically availability of water. Third, MOFs exhibiting breathing behaviors are summarized, followed by rationales from thermodynamic viewpoint. Subsequently, effects of various functionalities on breathing behaviors are appraised, including using post-synthetic modification routes. Finally, possible framework spatial requirements of MOFs for yielding breathing behaviors are highlighted as the design strategies for new syntheses.

scholarly journals Disappeared supramolecular isomer reappears with perylene guest

IUCrJ ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 324-330
Author(s):  
In-Hyeok Park ◽  
Atanu Dey ◽  
Kenta Sasaki ◽  
Masaaki Ohba ◽  
Shim Sung Lee ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Guest Molecule ◽  
Metal Organic Frameworks ◽  
Guest Molecules ◽  
Supramolecular Isomerism ◽  
The World ◽  
Different Types ◽  
Metal Organic ◽  
The Disappeared ◽  
Kinetic Form

Among different types of polymorphism, disappearing polymorphism deals with the metastable kinetic form which can not be reproduced after its first isolation. In the world of coordination polymers (CPs) and metal–organic frameworks (MOFs), despite the fact that many types of supramolecular isomerism exist, we are unaware of disappearing supramolecular isomerism akin to disappearing polymorphism. This work reports a MOF with dia topology that could not be reproduced, but subsequent synthesis yielded another supramolecular isomer, a double-pillared-layer MOF. When perylene was added in the same reaction, the disappeared dia MOF reappeared with perylene as a guest in the channels. Interestingly, the photoluminescence of the dia MOF with a perylene guest is dominated by the emission of the guest molecule. The influence of guest molecules on the stabilization of the supramolecular isomers of a MOF opens up a strategy to access MOFs with different structures.

Assessing Guest-Molecule Diffusion in Heterogeneous Powder Samples of Metal-Organic Frameworks through Pulsed-Field-Gradient (PFG) NMR Spectroscopy

2017 ◽  
Vol 23 (53) ◽  
pp. 13000-13005 ◽  
Author(s):  
Roland Thoma ◽  
Jörg Kärger ◽  
Nader de Sousa Amadeu ◽  
Sandra Nießing ◽  
Christoph Janiak
Keyword(s):  
Nmr Spectroscopy ◽  
Field Gradient ◽  
Guest Molecule ◽  
Metal Organic Frameworks ◽  
Pulsed Field ◽  
Powder Samples ◽  
Metal Organic ◽  
Pfg Nmr

Simulation of metal–organic framework self-assembly

2015 ◽  
Vol 17 (14) ◽  
pp. 8649-8652 ◽  
Author(s):  
Makoto Yoneya ◽  
Seiji Tsuzuki ◽  
Masaru Aoyagi
Keyword(s):  
Molecular Dynamics ◽  
Metal Ions ◽  
Molecular Dynamics Simulations ◽  
Self Assembly ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Spontaneous Growth ◽  
Metal Organic ◽  
Initial Placement ◽  
Dynamics Simulations

Spontaneous growth of metal–organic frameworks (MOFs) composed of metal ions and 4,4′-bipyridine ligands was successfully demonstrated by molecular dynamics simulations, starting from a random initial placement of the metals and the ligands.

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