A Tetratopic Phosphonic Acid for the Synthesis of Permanently Porous MOFs: Reactor Size-Dependent Product Formation and Crystal Structure Elucidation via Three-Dimensional Electron Diffraction

2020 ◽  
Vol 59 (18) ◽  
pp. 13343-13352
Author(s):  
Stephan Wöhlbrandt ◽  
Christoph Meier ◽  
Helge Reinsch ◽  
Erik Svensson Grape ◽  
A. Ken Inge ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Phosphonic Acid ◽  
Structure Elucidation ◽  
Three Dimensional ◽  
Product Formation ◽  
Dimensional Electron ◽  
Size Dependent ◽  
Dependent Product

Structure analysis of materials at the order–disorder borderline using three-dimensional electron diffraction

2019 ◽  
Vol 75 (4) ◽  
pp. 550-563 ◽  
Author(s):  
Enrico Mugnaioli ◽  
Tatiana E. Gorelik
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Structure Analysis ◽  
Diffuse Scattering ◽  
Three Dimensional ◽  
Crystal Defects ◽  
Ideal Crystal ◽  
Dimensional Electron ◽  
Electron Crystallography ◽  
Nanocrystalline Structures

Diffuse scattering, observed as intensity distribution between the Bragg peaks, is associated with deviations from the average crystal structure, generally referred to as disorder. In many cases crystal defects are seen as unwanted perturbations of the periodic structure and therefore they are often ignored. Yet, when it comes to the structure analysis of nano-volumes, what electron crystallography is designed for, the significance of defects increases. Twinning and polytypic sequences are other perturbations from ideal crystal structure that are also commonly observed in nanocrystals. Here we present an overview of defect types and review some of the most prominent studies published on the analysis of defective nanocrystalline structures by means of three-dimensional electron diffraction.

Crystal structure analysis of a star-shaped triazine compound: a combination of single-crystal three-dimensional electron diffraction and powder X-ray diffraction

2018 ◽  
Vol 74 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Tatiana E. Gorelik ◽  
Jacco van de Streek ◽  
Herbert Meier ◽  
Lars Andernach ◽  
Till Opatz
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray

The solid-state structure of star-shaped 2,4,6-tris{(E)-2-[4-(dimethylamino)-phenyl]ethenyl}-1,3,5-triazine is determined from a powder sample by exploiting the respective strengths of single-crystal three-dimensional electron diffraction and powder X-ray diffraction data. The unit-cell parameters were determined from single crystal electron diffraction data. Using this information, the powder X-ray diffraction data were indexed, and the crystal structure was determined from the powder diffraction profile. The compound crystallizes in a noncentrosymmetric space group,P212121. The molecular conformation in the crystal structure was used to calculate the molecular dipole moment of 3.22 Debye, which enables the material to show nonlinear optical effects.

A complex pseudo-decagonal quasicrystal approximant, Al37(Co,Ni)15.5, solved by rotation electron diffraction

2014 ◽  
Vol 47 (1) ◽  
pp. 215-221 ◽  
Author(s):  
Devinder Singh ◽  
Yifeng Yun ◽  
Wei Wan ◽  
Benjamin Grushko ◽  
Xiaodong Zou ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Basic Structure ◽  
Electron Diffraction Data ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

Electron diffraction is a complementary technique to single-crystal X-ray diffraction and powder X-ray diffraction for structure solution of unknown crystals. Crystals too small to be studied by single-crystal X-ray diffraction or too complex to be solved by powder X-ray diffraction can be studied by electron diffraction. The main drawbacks of electron diffraction have been the difficulties in collecting complete three-dimensional electron diffraction data by conventional electron diffraction methods and the very time-consuming data collection. In addition, the intensities of electron diffraction suffer from dynamical scattering. Recently, a new electron diffraction method, rotation electron diffraction (RED), was developed, which can overcome the drawbacks and reduce dynamical effects. A complete three-dimensional electron diffraction data set can be collected from a sub-micrometre-sized single crystal in less than 2 h. Here the RED method is applied forab initiostructure determination of an unknown complex intermetallic phase, the pseudo-decagonal (PD) quasicrystal approximant Al37.0(Co,Ni)15.5, denoted as PD2. RED shows that the crystal is F-centered, witha= 46.4,b= 64.6,c= 8.2 Å. However, as with other approximants in the PD series, the reflections with oddlindices are much weaker than those withleven, so it was decided to first solve the PD2 structure in the smaller, primitive unit cell. The basic structure of PD2 with unit-cell parametersa= 23.2,b= 32.3,c= 4.1 Å and space groupPnmmhas been solved in the present study. The structure withc= 8.2 Å will be taken up in the near future. The basic structure contains 55 unique atoms (17 Co/Ni and 38 Al) and is one of the most complex structures solved by electron diffraction. PD2 is built of characteristic 2 nm wheel clusters with fivefold rotational symmetry, which agrees with results from high-resolution electron microscopy images. Simulated electron diffraction patterns for the structure model are in good agreement with the experimental electron diffraction patterns obtained by RED.

scholarly journals On the Completeness of Three-Dimensional Electron Diffraction Data for Structural Analysis of Metal-Organic Frameworks

2021 ◽  
Author(s):  
Meng Ge ◽  
Taimin Yang ◽  
Yanzhi Wang ◽  
Francesco Carraro ◽  
Weibin Liang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Electron Diffraction ◽  
Structural Model ◽  
Metal Organic Frameworks ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
Dimensional Electron ◽  
Data Completeness ◽  
Continuous Rotation ◽  
Metal Organic

<p>Three-dimensional electron diffraction (3DED) has been proven as an effective and accurate method for structure determination of nano-sized crystals. In the past decade, the crystal structures of various new complex metal-organic frameworks (MOFs) have been revealed by 3DED, which has been the key to understand their properties. However, due to the design of transmission electron microscopes (TEMs), one drawback of 3DED experiments is the limited tilt range of goniometer, which often leads to incomplete 3DED data, particularly when the crystal symmetry is low. This drawback can be overcome by high throughput data collection using continuous rotation electron diffraction (cRED), where data from a large number of crystals can be collected and merged. Here, we investigate the effects of improving completeness on structural analysis of MOFs. We use ZIF-EC1, a zeolitic imidazolate framework (ZIF), as an example. ZIF-EC1 crystallizes in a monoclinic system with a plate-like morphology. cRED data of ZIF-EC1 with different completeness and resolution were analyzed. The data completeness increased to 92.0% by merging ten datasets. Although the structures could be solved from individual datasets with a completeness as low as 44.5% and refined to a high precession (better than 0.04 Å), we demonstrate that a high data completeness could improve the structural model, especially on the electrostatic potential map. We further discuss the strategy adopted during data merging. We also show that ZIF-EC1 doped with cobalt can act as an efficient electrocatalyst for oxygen reduction reaction. </p>

scholarly journals Three-dimensional electron diffraction for porous crystalline materials: structural determination and beyond

2021 ◽  
Author(s):  
Zhehao Huang ◽  
Tom Willhammar ◽  
Xiaodong Zou
Keyword(s):  
Electron Diffraction ◽  
Three Dimensional ◽  
Structural Determination ◽  
New Materials ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Details

Three-dimensional electron diffraction is a powerful tool for accurate structure determination of zeolite, MOF, and COF crystals that are too small for X-ray diffraction. By revealing the structural details, the properties of the materials can be understood, and new materials and applications can be designed.

scholarly journals UsingFOCUSto solve zeolite structures from three-dimensional electron diffraction data

2013 ◽  
Vol 46 (4) ◽  
pp. 1017-1023 ◽  
Author(s):  
Stef Smeets ◽  
Lynne B. McCusker ◽  
Christian Baerlocher ◽  
Enrico Mugnaioli ◽  
Ute Kolb
Keyword(s):  
Electron Diffraction ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Direct Methods ◽  
Electron Diffraction Data ◽  
Chemical Information ◽  
Data Sets ◽  
Dimensional Electron ◽  
Specific Chemical ◽  
Structure Solution

The programFOCUS[Grosse-Kunstleve, McCusker & Baerlocher (1997).J. Appl. Cryst.30, 985–995] was originally developed to solve zeolite structures from X-ray powder diffraction data. It uses zeolite-specific chemical information (three-dimensional 4-connected framework structure with known bond distances and angles) to supplement the diffraction data. In this way, it is possible to compensate, at least in part, for the ambiguity of the reflection intensities resulting from reflection overlap, and the program has proven to be quite successful. Recently, advances in electron microscopy have led to the development of automated diffraction tomography (ADT) and rotation electron diffraction (RED) techniques for collecting three-dimensional electron diffraction data on very small crystallites. Reasoning that such data are also less than ideal (dynamical scattering, low completeness, beam damage) and that this can lead to failure of structure solution by conventional direct methods for very complex zeolite frameworks,FOCUSwas modified to accommodate electron diffraction data. The modified program was applied successfully to five different data sets (four ADT and one RED) collected on zeolites of different complexities. One of these could not be solved completely by direct methods but emerged easily in theFOCUStrials.

The structure of vitamin B 12 - IV. The X-ray analysis of air-dried crystals of B 12

1962 ◽  
Vol 266 (1327) ◽  
pp. 475-493 ◽  
Keyword(s):  
Crystal Structure ◽  
Density Distribution ◽  
Electron Density Distribution ◽  
Three Dimensional ◽  
Successive Approximations ◽  
Water Molecules ◽  
Vitamin B ◽  
Dimensional Electron ◽  
X Ray ◽  
Vitamin B 12

Measurements were made during 1948-9 of all the intensities of hkl reflexions observable with chromium Koc X-radiation from air-dried crystals of vitamin B 12 . Calculations parallel with those of J. G. White were carried out on these data. The positions of the cobalt atoms in the crystal structure were found from three-dimensional Patterson series and the positions of 90 atoms of the B 12 molecule and 7 water molecules were derived through three successive approximations to the three-dimensional electron density distribution. The choice of atomic positions was checked against superposition maps derived from the original Patterson series, and assisted by comparisons with other B 12 derivatives. Minor differences appear between the positions derived here and in III; some of these may be real differences due to the state of dryness of the crystals.

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