London Dispersion Governs the Interaction Mechanism of Small Polar and Non-Polar Molecules in Metal-Organic Frameworks

2020 ◽  
Author(s):  
Patrick Melix ◽  
Thomas Heine
Keyword(s):  
Dipole Moments ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Interaction Mechanism ◽  
Ligand Field ◽  
Dispersion Interactions ◽  
Guest Molecules ◽  
Metal Organic ◽  
London Dispersion ◽  
Chlorinated Methanes

<div>In this work we investigate the adsorption of chlorinated methanes (CH<sub>x</sub>Cl<sub>4-x</sub>, x=0-4) in a representative layer-pillar Metal-Organic Framework (MOF), the flexible MOF Ni<sub>2</sub>(ndc)<sub>2</sub>(dabco) (ndc = 2,6-naphthalene-dicarboxylate, dabco = 1,4-diazabicyclo-[2.2.2]-octane), also known as DUT-8(Ni). The guest molecules show a systematic increase of polarizability with increasing number of chlorine atoms, while the dipole moment exceeds 2 Debye for x = 2 and 3. Our ligand field molecular mechanics (LFMM) simulations show that, counter-intuitively, the host-guest interactions are mainly characterized by London dispersion, despite the molecular dipole moments reaching magnitudes as large as water. This highlights the importance of London dispersion interactions in the description of host-guest interactions.<br></div>

scholarly journals London Dispersion Governs the Interaction Mechanism of Small Polar and Non-Polar Molecules in Metal-Organic Frameworks

2020 ◽  
Author(s):  
Patrick Melix ◽  
Thomas Heine
Keyword(s):  
Dipole Moments ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Interaction Mechanism ◽  
Ligand Field ◽  
Dispersion Interactions ◽  
Guest Molecules ◽  
Metal Organic ◽  
London Dispersion ◽  
Chlorinated Methanes

<div>In this work we investigate the adsorption of chlorinated methanes (CH<sub>x</sub>Cl<sub>4-x</sub>, x=0-4) in a representative layer-pillar Metal-Organic Framework (MOF), the flexible MOF Ni<sub>2</sub>(ndc)<sub>2</sub>(dabco) (ndc = 2,6-naphthalene-dicarboxylate, dabco = 1,4-diazabicyclo-[2.2.2]-octane), also known as DUT-8(Ni). The guest molecules show a systematic increase of polarizability with increasing number of chlorine atoms, while the dipole moment exceeds 2 Debye for x = 2 and 3. Our ligand field molecular mechanics (LFMM) simulations show that, counter-intuitively, the host-guest interactions are mainly characterized by London dispersion, despite the molecular dipole moments reaching magnitudes as large as water. This highlights the importance of London dispersion interactions in the description of host-guest interactions.<br></div>

scholarly journals London Dispersion Governs the Interaction Mechanism of Small Polar and Non-Polar Molecules in Metal-Organic Frameworks

2020 ◽  
Author(s):  
Patrick Melix ◽  
Thomas Heine
Keyword(s):  
Dipole Moments ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Interaction Mechanism ◽  
Ligand Field ◽  
Dispersion Interactions ◽  
Guest Molecules ◽  
Metal Organic ◽  
London Dispersion ◽  
Chlorinated Methanes

<div>In this work we investigate the adsorption of chlorinated methanes (CH<sub>x</sub>Cl<sub>4-x</sub>, x=0-4) in a representative layer-pillar Metal-Organic Framework (MOF), the flexible MOF Ni<sub>2</sub>(ndc)<sub>2</sub>(dabco) (ndc = 2,6-naphthalene-dicarboxylate, dabco = 1,4-diazabicyclo-[2.2.2]-octane), also known as DUT-8(Ni). The guest molecules show a systematic increase of polarizability with increasing number of chlorine atoms, while the dipole moment exceeds 2 Debye for x = 2 and 3. Our ligand field molecular mechanics (LFMM) simulations show that, counter-intuitively, the host-guest interactions are mainly characterized by London dispersion, despite the molecular dipole moments reaching magnitudes as large as water. This highlights the importance of London dispersion interactions in the description of host-guest interactions.<br></div>

scholarly journals Charge-transfer interactions between fullerenes and a mesoporous tetrathiafulvalene-based metal–organic framework

2019 ◽  
Vol 10 ◽  
pp. 1883-1893 ◽  
Author(s):  
Manuel Souto ◽  
Joaquín Calbo ◽  
Samuel Mañas-Valero ◽  
Aron Walsh ◽  
Guillermo Mínguez Espallargas
Keyword(s):  
Electrical Conductivity ◽  
Charge Transfer ◽  
Density Functional ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Spectroscopic Techniques ◽  
Functional Theory ◽  
Guest Molecules ◽  
Crucial Step ◽  
Metal Organic

The design of metal–organic frameworks (MOFs) incorporating electroactive guest molecules in the pores has become a subject of great interest in order to obtain additional electrical functionalities within the framework while maintaining porosity. Understanding the charge-transfer (CT) process between the framework and the guest molecules is a crucial step towards the design of new electroactive MOFs. Herein, we present the encapsulation of fullerenes (C60) in a mesoporous tetrathiafulvalene (TTF)-based MOF. The CT process between the electron-acceptor C60 guest and the electron-donor TTF ligand is studied in detail by means of different spectroscopic techniques and density functional theory (DFT) calculations. Importantly, gas sorption measurements demonstrate that sorption capacity is maintained after encapsulation of fullerenes, whereas the electrical conductivity is increased by two orders of magnitude due to the CT interactions between C60 and the TTF-based framework.

scholarly journals Investigation of Charge-Transfer Interactions Induced by Encapsulating Fullerene in a Mesoporous Tetrathiafulvalene-Based Metal-Organic Framework

2019 ◽  
Author(s):  
Manuel Souto ◽  
Joaquín Calbo ◽  
Samuel Mañas-Valero ◽  
Aron Walsh ◽  
Guillermo Minguez Espallargas
Keyword(s):  
Electrical Conductivity ◽  
Charge Transfer ◽  
Density Functional ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Techniques ◽  
Functional Theory ◽  
Guest Molecules ◽  
Metal Organic

<p>The design of Metal-Organic Frameworks (MOFs) incorporating electroactive guest molecules in the pores has become a subject of great interest in order to install additional electrical functionalities within the framework while maintaining porosity. In this direction, understanding the charge-transfer (CT) process between the framework and the guest molecules is crucial towards the design of new electroactive MOFs. Herein, we present the encapsulation of fullerenes (C<sub>60</sub>) in a mesoporous tetrathiafulvalene(TTF)-based MOF. The CT process between the electron-acceptor C<sub>60 </sub>guest and the electron-donor TTF ligand is studied in detail by means of different spectroscopic techniques and density functional theory calculations. Importantly, gas sorption measurements demonstrate that sorption capacity is maintained after encapsulation of fullerenes, whereas the electrical conductivity is increased by two orders of magnitude due to the CT interactions between C<sub>60</sub>and the TTF-based framework. </p>

Investigation of Charge-Transfer Interactions Induced by Encapsulating Fullerene in a Mesoporous Tetrathiafulvalene-Based Metal-Organic Framework

2019 ◽  
Author(s):  
Manuel Souto ◽  
Joaquín Calbo ◽  
Samuel Mañas-Valero ◽  
Aron Walsh ◽  
Guillermo Minguez Espallargas
Keyword(s):  
Electrical Conductivity ◽  
Charge Transfer ◽  
Density Functional ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Techniques ◽  
Functional Theory ◽  
Guest Molecules ◽  
Metal Organic

<p>The design of Metal-Organic Frameworks (MOFs) incorporating electroactive guest molecules in the pores has become a subject of great interest in order to install additional electrical functionalities within the framework while maintaining porosity. In this direction, understanding the charge-transfer (CT) process between the framework and the guest molecules is crucial towards the design of new electroactive MOFs. Herein, we present the encapsulation of fullerenes (C<sub>60</sub>) in a mesoporous tetrathiafulvalene(TTF)-based MOF. The CT process between the electron-acceptor C<sub>60 </sub>guest and the electron-donor TTF ligand is studied in detail by means of different spectroscopic techniques and density functional theory calculations. Importantly, gas sorption measurements demonstrate that sorption capacity is maintained after encapsulation of fullerenes, whereas the electrical conductivity is increased by two orders of magnitude due to the CT interactions between C<sub>60</sub>and the TTF-based framework. </p>

scholarly journals Guest-Dependent Stabilization of the Low Spin State in Spin-Crossover Metal-Organic Frameworks

2018 ◽  
Author(s):  
C. Huy Pham ◽  
Francesco Paesani
Keyword(s):  
Spin State ◽  
Guest Molecule ◽  
Spin Crossover ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Gas Detection ◽  
Rotational Mobility ◽  
Guest Molecules ◽  
In Silico Modeling ◽  
Metal Organic

<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>

scholarly journals Guest-Dependent Stabilization of the Low Spin State in Spin-Crossover Metal-Organic Frameworks

2018 ◽  
Author(s):  
C. Huy Pham ◽  
Francesco Paesani
Keyword(s):  
Spin State ◽  
Guest Molecule ◽  
Spin Crossover ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Gas Detection ◽  
Rotational Mobility ◽  
Guest Molecules ◽  
In Silico Modeling ◽  
Metal Organic

<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>

Magnetic Ordering via Itinerant Ferromagnetism in a Metal-Organic Framework

2020 ◽  
Author(s):  
Jesse Park ◽  
Brianna Collins ◽  
Lucy Darago ◽  
Tomce Runcevski ◽  
Michael Aubrey ◽  
...  
Keyword(s):  
Charge Transport ◽  
Magnetic Order ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Magnetic Ordering ◽  
Double Exchange ◽  
Itinerant Ferromagnetism ◽  
Organic Solids ◽  
Metal Organic ◽  
Organic Framework

<b>Materials that combine magnetic order with other desirable physical attributes offer to revolutionize our energy landscape. Indeed, such materials could find transformative applications in spintronics, quantum sensing, low-density magnets, and gas separations. As a result, efforts to design multifunctional magnetic materials have recently moved beyond traditional solid-state materials to metal–organic solids. Among these, metal–organic frameworks in particular bear structures that offer intrinsic porosity, vast chemical and structural programmability, and tunability of electronic properties. Nevertheless, magnetic order within metal–organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating strong magnetic exchange in extended metal–organic solids. Here, we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at <i>T</i><sub>C</sub> = 225 K in a mixed-valence chromium(II/III) triazolate compound, representing the highest ferromagnetic ordering temperature yet observed in a metal–organic framework. The itinerant ferromagnetism is shown to proceed via a double-exchange mechanism, the first such observation in any metal–organic material. Critically, this mechanism results in variable-temperature conductivity with barrierless charge transport below <i>T</i><sub>C</sub> and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics. Taken together, the insights gleaned from these results are expected to provide a blueprint for the design and synthesis of porous materials with synergistic high-temperature magnetic and charge transport properties. </b>

Engineering Porosity Through Defects in a Giant Pore Metal–Organic Framework

2020 ◽  
Author(s):  
Adam Sapnik ◽  
Duncan Johnstone ◽  
Sean M. Collins ◽  
Giorgio Divitini ◽  
Alice Bumstead ◽  
...  
Keyword(s):  
Distribution Function ◽  
Ball Milling ◽  
Local Structure ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Defect Engineering ◽  
Metal Organic ◽  
Unsaturated Metal Sites

<p>Defect engineering is a powerful tool that can be used to tailor the properties of metal–organic frameworks (MOFs). Here, we incorporate defects through ball milling to systematically vary the porosity of the giant pore MOF, MIL-100 (Fe). We show that milling leads to the breaking of metal–linker bonds, generating more coordinatively unsaturated metal sites, and ultimately causes amorphisation. Pair distribution function analysis shows the hierarchical local structure is partially</p><p>retained, even in the amorphised material. We find that the solvent toluene stabilises the MIL-100 (Fe) framework against collapse and leads to a substantial rentention of porosity over the non-stabilised material.</p>

Sign in / Sign up

Export Citation Format

Share Document