Low-field 1H NMR relaxometry of water molecules confined in microporous UiO-66

2021 ◽  
Author(s):  
Xinxin Fan ◽  
Xindi Lu ◽  
Qianhong Wu ◽  
Yajun Deng ◽  
Yi Zeng ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Relaxation Times ◽  
Filling Ratio ◽  
Water Molecules ◽  
Low Field ◽  
Nmr Relaxometry ◽  
Incomplete Coverage ◽  
Metal Organic ◽  
Water Filling ◽  
Exchange Regime

Water molecules confined in a microporous metal–organic framework (MOF) UiO-66 are characterized by a low-field 1H nuclear magnetic resonance (NMR) spectroscopy. Measurements are performed of the longitudinal ([Formula: see text] and transverse ([Formula: see text] relaxation times as a function of water content from fully saturated to incomplete coverage of the first-adsorbed monolayer. The results obtained indicate that the relaxation of water molecules confined in UiO-66 is within the fast-exchange regime. When the amount of water exceeds filling ratio [Formula: see text] = 0.4, the averaged relaxation time is approximately linearly dependent on water filling ratio in pore. When the water amount cannot support a full coverage of surface monolayer, the relaxation rate increases with less filling ratio, illustrating that the mobility of water molecules is more restricted. Analysis of the measured values and the simulated ones leads to the conclusion that the surface-affected zone in UiO-66 is not confined to the surface monolayer.

scholarly journals Facile Proton Conduction via Ordered Water Molecules in a Phosphonate Metal−Organic Framework

2010 ◽  
Vol 132 (40) ◽  
pp. 14055-14057 ◽  
Author(s):  
Jared M. Taylor ◽  
Roger K. Mah ◽  
Igor L. Moudrakovski ◽  
Christopher I. Ratcliffe ◽  
Ramanathan Vaidhyanathan ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Proton Conduction ◽  
Water Molecules ◽  
Metal Organic ◽  
Ordered Water ◽  
Organic Framework

Intrinsic low dielectric behaviour of a highly thermally stable Sr-based metal–organic framework for interlayer dielectric materials

2014 ◽  
Vol 2 (19) ◽  
pp. 3762-3768 ◽  
Author(s):  
Muhammad Usman ◽  
Cheng-Hua Lee ◽  
Dung-Shing Hung ◽  
Shang-Fan Lee ◽  
Chih-Chieh Wang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Metal Organic Framework ◽  
Dielectric Materials ◽  
Low Dielectric Constant ◽  
Water Molecules ◽  
Compound A ◽  
Interlayer Dielectric ◽  
Low Dielectric ◽  
Metal Organic ◽  
Organic Framework

A Sr-based metal–organic framework exhibits an intrinsic low dielectric constant after removing the water molecules. A low dielectric constant and high thermal stability make this compound a candidate for use as a low-k material.

The effects of framework dynamics on the behavior of water adsorbed in the [Zn(l-L)(Cl)] and Co-MOF-74 metal–organic frameworks

2016 ◽  
Vol 18 (11) ◽  
pp. 8196-8204 ◽  
Author(s):  
Zachary L. Terranova ◽  
Francesco Paesani
Keyword(s):  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Water Molecules ◽  
Density Distributions ◽  
Metal Organic ◽  
Organic Framework

Density distributions of water molecules in the pores of the [Zn(l-L)(Cl)] metal–organic framework.

The Different Organization of Water in Zeolite L and Its MOF Mimic

2019 ◽  
Author(s):  
gloria tabacchi ◽  
Ettore Fois
Keyword(s):  
Hydrogen Bonds ◽  
Metal Organic Framework ◽  
Water Molecules ◽  
One Dimensional ◽  
Zeolite L ◽  
High Proton ◽  
Metal Organic ◽  
The One ◽  
The Individual ◽  
Water Hydrogen

Abstract:<div>Confinement of molecules inside one dimensional arrays of channel-shaped cavities has led to an impressive number of technologically interesting materials. However, the interactions governing the properties of the supramolecular aggregates still remain obscure, even in the case of the most common guest molecule: water. Herein, we use computational chemistry methods (#compchem) to study the water organization inside two different channel-type environments: zeolite L – a widely used matrix for inclusion of dye molecules, and ZLMOF – the closest metal-organic-framework mimic of zeolite L. In ZLMOF, the methyl groups of the ligands protrude inside the channels, creating nearly isolated nanocavities. These cavities host well-separated ring-shaped clusters of water molecules, dominated mainly by water-water hydrogen bonds. ZLMOF channels thus provide arrays of „isolated supramolecule“ environments, which might be exploited for the individual confinement of small species with interesting optical or catalytic properties. In contrast, the one dimensional nanochannels of zeolite L contain a continuous supramolecular structure, governed by the water interactions with potassium cations and by water-water hydrogen bonds. Water molecules impart a significant energetic stabilization to both materials, which increases by increasing the water content in ZLMOF, while the opposite trend is observed in zeolite L. The water network in zeolite L contains an intriguing hyper-coordinated structure, where a water molecule is surrounded by 5 strong hydrogen bonds. Such a structure, here described for the first time in zeolites, can be considered as a water pre-dissociation complex and might explain the experimentally detected high proton activity in zeolite L nanochannels. </div>

scholarly journals In situ variable-temperature single crystal X-ray diffraction studies of the single-crystal-to-single-crystal dehydration and rehydration of a mixed-ligand 2D zinc metal–organic framework using trimesate and 4,4′-bipyridine-N,N′-dioxide as ligands

CrystEngComm ◽  
2015 ◽  
Vol 17 (46) ◽  
pp. 8946-8956 ◽  
Author(s):  
Tayyibah Tahier ◽  
Clive L. Oliver
Keyword(s):  
Single Crystal ◽  
Variable Temperature ◽  
Metal Organic Framework ◽  
Mixed Ligand ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Metal Organic ◽  
Reversible Loss ◽  
Coordinated Water

A mixed-ligand 2D MOF based on ZnSO4, trimesate and 4,4′-bipyridine-N,N′-dioxide shows reversible loss of uncoordinated and coordinated water molecules.

Sign in / Sign up

Export Citation Format

Share Document