scholarly journals Emission dependence on guest molecule structure in luminescent metal-organic frameworks doped with polypyridyl osmium complexes

Author(s):  
Jeffrey Rood ◽  
Sarah Moyer ◽  
Kristi Kneas
2020 ◽  
Author(s):  
Emma Wolpert ◽  
François-Xavier Coudert ◽  
Andrew Goodwin

<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>


2016 ◽  
Vol 3 (4) ◽  
pp. 355-361 ◽  
Author(s):  
B. Zheng ◽  
L. L. Wang ◽  
L. Du ◽  
Y. Pan ◽  
Z. Lai ◽  
...  

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.


IUCrJ ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 324-330
Author(s):  
In-Hyeok Park ◽  
Atanu Dey ◽  
Kenta Sasaki ◽  
Masaaki Ohba ◽  
Shim Sung Lee ◽  
...  

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.


2017 ◽  
Vol 23 (53) ◽  
pp. 13000-13005 ◽  
Author(s):  
Roland Thoma ◽  
Jörg Kärger ◽  
Nader de Sousa Amadeu ◽  
Sandra Nießing ◽  
Christoph Janiak

2020 ◽  
Author(s):  
Emma Wolpert ◽  
François-Xavier Coudert ◽  
Andrew Goodwin

<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>


2018 ◽  
Author(s):  
C. Huy Pham ◽  
Francesco Paesani

<div> <div> <div> <p>Computer simulations are carried out to characterize the variation of spin crossover (SCO) behavior of the prototypical {Fe(pz)[Pt(CN)4]} metal-organic framework (MOF) upon adsorption of chemically and structurally different guest molecules. A detailed analysis of both strength and anisotropy of guest molecule-framework interactions reveals direct correlations between the mobility of the guest molecules inside the MOF pores, the rotational mobility of the pyrazine rings of the framework, and the stabilization of the low-spin state of the material. Based on these correlations, precise molecular criteria are established for predicting the spin state of {Fe(pz)[Pt(CN)4]} upon guest adsorption. Finally, predictions of the SCO temperature upon adsorption of various toxic gases demonstrate that in silico modeling can provide fundamental insights and design principles for the development of spin-crossover MOFs for applications in gas detection and chemical sensing. </p> </div> </div> </div>


2018 ◽  
Author(s):  
C. Huy Pham ◽  
Francesco Paesani

<div> <div> <div> <p>Computer simulations are carried out to characterize the variation of spin crossover (SCO) behavior of the prototypical {Fe(pz)[Pt(CN)4]} metal-organic framework (MOF) upon adsorption of chemically and structurally different guest molecules. A detailed analysis of both strength and anisotropy of guest molecule-framework interactions reveals direct correlations between the mobility of the guest molecules inside the MOF pores, the rotational mobility of the pyrazine rings of the framework, and the stabilization of the low-spin state of the material. Based on these correlations, precise molecular criteria are established for predicting the spin state of {Fe(pz)[Pt(CN)4]} upon guest adsorption. Finally, predictions of the SCO temperature upon adsorption of various toxic gases demonstrate that in silico modeling can provide fundamental insights and design principles for the development of spin-crossover MOFs for applications in gas detection and chemical sensing. </p> </div> </div> </div>


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