scholarly journals Crystallisation and conformation-controlled breathing of the Al-MOF CAU-13

2014 ◽  
Vol 70 (a1) ◽  
pp. C62-C62
Author(s):  
Alexandra Lieb ◽  
Felicitas Niekiel ◽  
Norbert Stock
Keyword(s):  
Conformational Changes ◽  
Structural Changes ◽  
Metal Organic Frameworks ◽  
Structural Topology ◽  
Time Resolved ◽  
Metal Organic ◽  
Synchotron Radiation ◽  
Induction Times ◽  
Linker Molecules

Within the last couple of years an enormous variety of metal-organic frameworks (MOFs) has been synthesized. Besides characteristics like large specific surface area or a defined interaction with gas molecules a "breathing" effect was described as well. During this breathing the atoms can undergo certain movements keeping the same structural topology and without losing crystallinity. Most known MOFs contain rigid aromatic linker molecules. A rare example of a MOF with flexible aliphatic linkers is [Al(OH)(trans CDC)] (CDC = cyclohexanedicarboxylate), known as CAU 13.[1] The structure was determined from PXRD-data using synchotron radiation. In analogy to Al-MIL 53,[2] CAU 13 is build up from chains of corner-sharing AlO6-octahedra interconnected by the linker molecules. Interestingly, the trans-CDC ion is incorporated in a,a- as well as e,e-conformation. Time-resolved in-situ EDXRD experiments at HASYLAB (DESY, Hamburg) show short induction times for the crystallization of CAU-13. Full crystallization occurs within two hours even at low reaction temperatures. CAU-13[3] shows porosity towards different adsoptives after thermal activation. In-situ temperature dependent PXRD experiments show a widening of the pores along the b-axis up to 3500C. The flexibility of the linker molecules allows structural changes of the compound during adsorption. While the adsorption of hydrophilic molecules only cause a small breathing effect, the adsorption of xylene leads to drastic changes in the crystal structure. The a,a-CDC2- ions change conformation to e,e-type to increase the cell volume per formula sum by 25 %. This combination of pore widening and conformational changes constitutes a new type of breathing in Metal-Organic Frameworks.

Time-Resolved In Situ Diffraction Study of the Solvothermal Crystallization of Some Prototypical Metal-Organic Frameworks

2009 ◽  
Vol 122 (4) ◽  
pp. 775-778 ◽  
Author(s):  
Franck Millange ◽  
Manuela I. Medina ◽  
Nathalie Guillou ◽  
Gérard Férey ◽  
Kathryn M. Golden ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Metal Organic Frameworks ◽  
Time Resolved ◽  
Metal Organic ◽  
In Situ Diffraction

scholarly journals Time-Resolved In Situ Diffraction Study of the Solvothermal Crystallization of Some Prototypical Metal-Organic Frameworks

2009 ◽  
Vol 49 (4) ◽  
pp. 763-766 ◽  
Author(s):  
Franck Millange ◽  
Manuela I. Medina ◽  
Nathalie Guillou ◽  
Gérard Férey ◽  
Kathryn M. Golden ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Metal Organic Frameworks ◽  
Time Resolved ◽  
Metal Organic ◽  
In Situ Diffraction

scholarly journals Exciton Coupling and Conformational Changes Impacting the Excited State Properties of Metal Organic Frameworks

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4230
Author(s):  
Andreas Windischbacher ◽  
Luca Steiner ◽  
Ritesh Haldar ◽  
Christof Wöll ◽  
Egbert Zojer ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Photophysical Properties ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Red Shift ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Exciton Coupling ◽  
Metal Organic ◽  
Crystalline Metal

In recent years, the photophysical properties of crystalline metal-organic frameworks (MOFs) have become increasingly relevant for their potential application in light-emitting devices, photovoltaics, nonlinear optics and sensing. The availability of high-quality experimental data for such systems makes them ideally suited for a validation of quantum mechanical simulations, aiming at an in-depth atomistic understanding of photophysical phenomena. Here we present a computational DFT study of the absorption and emission characteristics of a Zn-based surface-anchored metal-organic framework (Zn-SURMOF-2) containing anthracenedibenzoic acid (ADB) as linker. Combining band-structure and cluster-based simulations on ADB chromophores in various conformations and aggregation states, we are able to provide a detailed explanation of the experimentally observed photophysical properties of Zn-ADB SURMOF-2: The unexpected (weak) red-shift of the absorption maxima upon incorporating ADB chromophores into SURMOF-2 can be explained by a combination of excitonic coupling effects with conformational changes of the chromophores already in their ground state. As far as the unusually large red-shift of the emission of Zn-ADB SURMOF-2 is concerned, based on our simulations, we attribute it to a modification of the exciton coupling compared to conventional H-aggregates, which results from a relative slip of the centers of neighboring chromophores upon incorporation in Zn-ADB SURMOF-2.

scholarly journals In situ X‐ray Diffraction Investigation of the Crystallisation of Perfluorinated Ce(IV)‐based Metal‐Organic Frameworks with UiO‐66 and MIL‐140 architectures

2021 ◽  
Author(s):  
Stephen J. I. Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic

scholarly journals Degradation Mechanism of Porous Metal-Organic Frameworks by In Situ Atomic Force Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 722
Author(s):  
Ioanna Christodoulou ◽  
Tom Bourguignon ◽  
Xue Li ◽  
Gilles Patriarche ◽  
Christian Serre ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Degradation Mechanism ◽  
Metal Organic Frameworks ◽  
Porous Metal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
The Media ◽  
Ph Conditions

In recent years, Metal-Organic Frameworks (MOFs) have attracted a growing interest for biomedical applications. The design of MOFs should take into consideration the subtle balance between stability and biodegradability. However, only few studies have focused on the MOFs’ stability in physiological media and their degradation mechanism. Here, we investigate the degradation of mesoporous iron (III) carboxylate MOFs, which are among the most employed MOFs for drug delivery, by a set of complementary methods. In situ AFM allowed monitoring with nanoscale resolution the morphological, dimensional, and mechanical properties of a series of MOFs in phosphate buffer saline and in real time. Depending on the synthetic route, the external surface presented either well-defined crystalline planes or initial defects, which influenced the degradation mechanism of the particles. Moreover, MOF stability was investigated under different pH conditions, from acidic to neutral. Interestingly, despite pronounced erosion, especially at neutral pH, the dimensions of the crystals were unchanged. It was revealed that the external surfaces of MOF crystals rapidly respond to in situ changes of the composition of the media they are in contact with. These observations are of a crucial importance for the design of nanosized MOFs for drug delivery applications.

In-situ growth of ZIF-8 on gold nanoparticles/magnetic carbon nanotubes for electrochemical detection of bisphenol A

2021 ◽  
Author(s):  
Hexiang Li ◽  
Fawei Zhu ◽  
Jun Xiang ◽  
Fangbin Wang ◽  
Qi Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Bisphenol A ◽  
Electrochemical Detection ◽  
Metal Organic Frameworks ◽  
In Situ Growth ◽  
Metal Organic ◽  
Magnetic Carbon ◽  
Magnetic Carbon Nanotubes

We herein report a facile and scalable strategy for fabrication of the metal organic frameworks (MOFs) based composite by in-situ growing ZIF-8 on the gold nanoparticles (AuNPs) loaded magnetic carbon...

Development of Au-Pd@UiO-66-on-ZIF-L/CC as a self-supported electrochemical sensor for in situ monitoring of cellular hydrogen peroxide

2021 ◽  
Author(s):  
Jilin Zheng ◽  
Peng Zhao ◽  
Shiying Zhou ◽  
Sha Chen ◽  
Yi Liang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electrochemical Sensor ◽  
Noble Metals ◽  
Electrochemical Sensors ◽  
Metal Organic Frameworks ◽  
Electrochemical Sensing ◽  
In Situ Monitoring ◽  
Metal Organic

Integrating metal-organic frameworks (MOFs) of different components or structures together and exploiting them as electrochemical sensors for electrochemical sensing have aroused great interest. And the incorporation of noble metals with...

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