scholarly journals An fcu Th-MOF Constructed from In Situ Coupling of Monovalent Ligands

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1332
Author(s):  
Ting Song ◽  
Wenlei Tang ◽  
Chuer Bao ◽  
Qiuxue Lai ◽  
Zhiyuan Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Metal Organic Frameworks ◽  
Face Centered Cubic ◽  
Reductive Coupling ◽  
Assembly Process ◽  
Cluster Surface ◽  
Metal Organic ◽  
Face Centered ◽  
And Behavior

Synthetic efforts targeting highly symmetrical metal–organic frameworks (MOFs) have always been relentless, for the symmetry of a MOF’s pore environment and overall crystal structure are relevant to the MOF’s properties and behavior. Herein, we report a novel Th-based MOF constructed from assembling highly symmetrical Th-oxo clusters via in situ reductive coupling of nitroso groups on the cluster surface. Nitroso groups have long been known to dimerize in a reversible fashion. Putting them on the monovalent ligands that decorate the Th-oxo clusters can facilitate a downstream assembly process that link the said clusters in a controllable and predictable manner, preserving the overall symmetry in the MOF product. Moreover, the assembly can be made permanent by reducing the azodioxy moiety to azo, effectively locking the symmetrical MOF form. We believe this process of assembling pre-formed Th-oxo clusters helps the overall MOF adopt a highly symmetrical topology (face-centered cubic, fcu) resembling the well-known UiO series MOFs based on tetravalent Zr/Hf.

The Crystal Structure of Pressure-Induced Phases of In2Te3and Ga2Te3

1992 ◽  
Vol 7 (2) ◽  
pp. 99-102 ◽  
Author(s):  
N.R. Serebryanaya
Keyword(s):  
Crystal Structure ◽  
Metastable Phase ◽  
Face Centered Cubic ◽  
Volume Changes ◽  
X Ray ◽  
The Face ◽  
Crystal Structure Transformation ◽  
Face Centered ◽  
Heating Up

AbstractPhase transitions were found with use of an in situX-ray anvil-type of apparatus with a boron annulus at pressures up to 12 GPa. The disordering of vacancies in the In sub-structure, or α→βtransition, was found in In2Te3at p > 1.9 GPa. The next transformation from the β-form into the Bi2Te3type of structure was observed in both sesquitellurides at 2.0 GPa and 5.0 GPa for In2TGe3and Ga2Te3respectively. The In2Te3metastable phase of the Bi2Te3resulted from heating up to 200° C at p > 4.0 GPa, and it remained in a normal condition on release of the pressure. The X-ray powder diffraction data of pressure-induced phases, volume changes and bulk modulus of both sesquitellurides are given. The compressibility anisotropy of the layer pressure-induced phase was observed. The mechanism of the crystal structure transformation from the face-centered cubic structure into the Bi2Te3type is proposed to be due to the displacement of atoms from the space diagonal of the cube [111] into [112]-cubic direction and the rhombohedral distortion of the angle between these directions.

Synthesis, crystal structure, luminescence, and photocatalytic properties of a 2D Cu(II) metal-organic frameworks based on 3,5-di(1H-benzimidazol-1-yl)pyridine and 4,4′-oxybis(benzoate) ligands

2020 ◽  
Vol 75 (8) ◽  
pp. 727-732
Author(s):  
Chen Zhang ◽  
Jian-Qing Tao
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Uv Light ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Light Irradiation ◽  
Photocatalytic Activities ◽  
Metal Organic

AbstractA new Cu(II) metal-organic framework, [Cu(L)(OBA)·H2O]n (1) [H2OBA = 4,4′-oxybis(benzoic acid), L = 3,5-di(1H-benzimidazol-1-yl)pyridine] was hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis and single-crystal X-ray diffraction. Complex 1 is a four-connected uni-nodal 2D net with a (44·62) topology which shows an emission centered at λ ∼393 nm upon excitation at λ = 245 nm. Moreover, complex 1 possesses high photocatalytic activities for the decomposition of Rhodamine B (RhB) under UV light irradiation.

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

Microstructure Characterization of Ag Nanoparticles Prepared by Hydrothermal Method

2012 ◽  
Vol 476-478 ◽  
pp. 1138-1141
Author(s):  
Zhi Qiang Wei ◽  
Qiang Wei ◽  
Li Gang Liu ◽  
Hua Yang ◽  
Xiao Juan Wu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Hydrothermal Method ◽  
Ag Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Face Centered

Ag nanoparticles were successfully synthesized by hydrothermal method under the polyol system combined with traces of sodium chloride, Silver nitrate(AgNO3) and polyvinylpyrrolidone (PVP) acted as the silver source and dispersant respectively. The samples by this process were characterized via X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) to determine the chemical composition, particle size, crystal structure and morphology. The experiment results indicate that the crystal structure of the samples is face centered cubic (FCC) structure as same as the bulk materials, The specific surface area is 24 m2/g, the particle size distribution ranging from10 to 50 nm, with an average particle size about 26 nm obtained by TEM and confirmed by XRD and BET results.

scholarly journals In-Situ TEM Annealing Observation of Helium Bubble Evolution in Pre-Irradiated FeCoNiCrTi0.2 Alloys

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3727
Author(s):  
Huanhuan He ◽  
Zhiwei Lin ◽  
Shengming Jiang ◽  
Xiaotian Hu ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Vacuum Arc ◽  
In Situ Tem ◽  
Face Centered Cubic ◽  
Helium Bubble ◽  
High Entropy ◽  
Helium Bubbles ◽  
Transmission Electron ◽  
Bubble Evolution ◽  
Face Centered

The FeCoNiCrTi0.2 high-entropy alloys fabricated by vacuum arc melting method, and the annealed pristine material, are face centered cubic structures with coherent γ’ precipitation. Samples were irradiated with 50 keV He+ ions to a fluence of 2 × 1016 ions/cm2 at 723 K, and an in situ annealing experiment was carried out to monitor the evolution of helium bubbles during heating to 823 and 923 K. The pristine structure of FeCoNiCrTi0.2 samples and the evolution of helium bubbles during in situ annealing were both characterized by transmission electron microscopy. The annealing temperature and annealing time affect the process of helium bubbles evolution and formation. Meanwhile, the grain boundaries act as sinks to accumulate helium bubbles. However, the precipitation phase seems have few effects on the helium bubble evolution, which may be due to the coherent interface and same structure of γ’ precipitation and matrix.

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...

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