Ionic additive strategy to control nucleation and generate larger single crystals of 3D covalent organic frameworks

2021 ◽  
Author(s):  
Xiaohan Wang ◽  
Riku Enomoto ◽  
Yoichi Murakami
Keyword(s):  
Single Crystals ◽  
Crystal Size ◽  
Covalent Organic Frameworks ◽  
Ionic Additive

To generate large single crystals of 3D covalent organic frameworks, the active use of ionic additives, which can greatly impact crystal size, is proposed. The crystal size ranking was found...

Silicate ionic liquid synthesis of zeolite merlinoite: Crystal size control from crystalline nanoaggregates to micron-sized single-crystals

2014 ◽  
Vol 198 ◽  
pp. 35-44 ◽  
Author(s):  
Mohamed Haouas ◽  
Louwanda Lakiss ◽  
Charlotte Martineau ◽  
Jaafar El Fallah ◽  
Valentin Valtchev ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Single Crystals ◽  
Crystal Size ◽  
Size Control

Design of higher valency in covalent organic frameworks

Science ◽  
2020 ◽  
Vol 370 (6515) ◽  
pp. eabd6406 ◽  
Author(s):  
Cornelius Gropp ◽  
Tianqiong Ma ◽  
Nikita Hanikel ◽  
Omar M. Yaghi
Keyword(s):  
Single Crystals ◽  
Powder Diffraction ◽  
Covalent Organic Frameworks ◽  
X Ray

The valency (connectivity) of building units in covalent organic frameworks (COFs) has been primarily 3 and 4, corresponding to triangles and squares or tetrahedrons, respectively. We report a strategy for making COFs with valency 8 (cubes) and “infinity” (rods). The linker 1,4-boronophenylphosphonic acid—designed to have boron and phosphorus as an isoelectronic combination of carbon-group elements—was condensed into a porous, polycubane structure (BP-COF-1) formulated as (–B4P4O12–)(–C6H4–)4. It was characterized by x-ray powder diffraction techniques, which revealed cubes linked with phenyls. The isoreticular forms (BP-COF-2 to 5) were similarly prepared and characterized. Large single crystals of a constitutionally isomeric COF (BP-COF-6), composed of rod units, were also synthesized using the same strategy, thus propelling COF chemistry into a new valency regime.

Preparation and Characterization of Wurtzitic Gan Single Crystals in Nano and Micro Scale

1996 ◽  
Vol 423 ◽  
Author(s):  
San Yu ◽  
Hongdong Li ◽  
Haibin Yang ◽  
Dongmei Li ◽  
Haiping Sun ◽  
...  
Keyword(s):  
Single Crystals ◽  
Crystal Size ◽  
Arc Discharge ◽  
Short Wave ◽  
Wurtzite Structure ◽  
Light Emitters ◽  
X Ray ◽  
Lattice Constants ◽  
Micro Scale ◽  
Transmission Electron

AbstractGallium nitride and its alloys are the most promising materials for short wave light emitters. If high quality GaN single crystals can be prepared, the GaN base light emitters should be fabricated directly on the lattice-matched GaN substrate.In this work, GaN crystals in nano and micro scale with definite faces have been prepared by dc arc discharge using gallium and N2+NH3 as starting materials. Transmission electron microscope, selected area diffraction, x-ray microanalysis of energy dispersive spectroscopy, and x-ray diffraction investigation of the as grown GaN crystals show that the well faceted crystals are single crystalline GaN in wurtzite structure having lattice constants a0=3.18Å and c0=5.18Å. The crystal size of stoichoimetric GaN in wurtzite structure depends on the partial pressure of nitrogen in the plasma. The maximum crystal size in this work is about several micrometers.

Single-crystal x-ray diffraction structures of covalent organic frameworks

Science ◽  
2018 ◽  
Vol 361 (6397) ◽  
pp. 48-52 ◽  
Author(s):  
Tianqiong Ma ◽  
Eugene A. Kapustin ◽  
Shawn X. Yin ◽  
Lin Liang ◽  
Zhengyang Zhou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
General Procedure ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
Covalent Organic Frameworks ◽  
X Ray Diffraction ◽  
X Ray

The crystallization problem is an outstanding challenge in the chemistry of porous covalent organic frameworks (COFs). Their structural characterization has been limited to modeling and solutions based on powder x-ray or electron diffraction data. Single crystals of COFs amenable to x-ray diffraction characterization have not been reported. Here, we developed a general procedure to grow large single crystals of three-dimensional imine-based COFs (COF-300, hydrated form of COF-300, COF-303, LZU-79, and LZU-111). The high quality of the crystals allowed collection of single-crystal x-ray diffraction data of up to 0.83-angstrom resolution, leading to unambiguous solution and precise anisotropic refinement. Characteristics such as degree of interpenetration, arrangement of water guests, the reversed imine connectivity, linker disorder, and uncommon topology were deciphered with atomic precision—aspects impossible to determine without single crystals.

scholarly journals Diverse crystal size effects in covalent organic frameworks

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Tianqiong Ma ◽  
Lei Wei ◽  
Lin Liang ◽  
Shawn Yin ◽  
Le Xu ◽  
...  
Keyword(s):  
Size Effect ◽  
Size Effects ◽  
Crystal Size ◽  
Materials Science ◽  
Covalent Organic Frameworks ◽  
Structure Property ◽  
Practical Applications ◽  
Pore Surface Area ◽  
Properties Of Materials ◽  
Size Controlled

AbstractCrystal size effect is of vital importance in materials science by exerting significant influence on various properties of materials and furthermore their functions. Crystal size effect of covalent organic frameworks (COFs) has never been reported because their controllable synthesis is difficult, despite their promising properties have been exhibited in many aspects. Here, we report the diverse crystal size effects of two representative COFs based on the successful realization of crystal-size-controlled synthesis. For LZU-111 with rigid spiral channels, size effect reflects in pore surface area by influencing the pore integrity, while for flexible COF-300 with straight channels, crystal size controls structural flexibility by altering the number of repeating units, which eventually changes sorption selectivity. With the understanding and insight of the structure-property correlation not only at microscale but also at mesoscale for COFs, this research will push the COF field step forward to a significant advancement in practical applications.

The burning and explosion of single crystals

1957 ◽  
Vol 238 (1214) ◽  
pp. 325-333 ◽  
Keyword(s):  
Single Crystals ◽  
High Speed ◽  
Crystal Size ◽  
Initial Temperature ◽  
Silver Azide ◽  
Break Up

A study has been made of the combustion and explosion of single crystals of a number of compounds. These include the styphnates, fulminates and azides. A high-speed ciné microscope developed by Courtney-Pratt has been used. This enables magnified pictures of events lasting several milliseconds to be recorded. Crystals which have faults break up during combustion, and particles fly off at high speed. When the crystals are relatively free from faults the combustion may be followed along the length of the crystal and burning speeds may be measured. A variation in speed with crystal size and initial temperature has been observed, and this is discussed in relation to thermal losses during burning. The combustion of cyanuric triazide under water has also been recorded. The behaviour of the compounds such as silver and thallous azide which can melt is different from that of crystals which explode without melting. The effect of crystal size on the development of combustion and explosion is discussed with particular reference to silver azide.

scholarly journals Effects of crystal size on methanol to hydrocarbon conversion over single crystals of ZSM-5 studied by synchrotron infrared microspectroscopy

2020 ◽  
Vol 22 (34) ◽  
pp. 18849-18859
Author(s):  
Ivalina B. Minova ◽  
Santhosh K. Matam ◽  
Alex Greenaway ◽  
C. Richard A. Catlow ◽  
Mark D. Frogley ◽  
...  
Keyword(s):  
Induction Period ◽  
Single Crystals ◽  
Crystal Size ◽  
Hydrocarbon Conversion ◽  
Infrared Microspectroscopy ◽  
Hydrocarbon Pool ◽  
Methanol To Hydrocarbon ◽  
Increasing Temperature

The induction period for alkene formation from methanol in single crystals of HZSM-5 decreases with decreasing crystal size and increasing temperature and hydrocarbon pool species are formed almost instantaneously at higher temperatures.

Nucleation-Elongation Dynamics of Two-Dimensional Covalent Organic Frameworks

2019 ◽  
Author(s):  
Haoyuan Li ◽  
Austin Evans ◽  
Ioannina Castano ◽  
Michael Strauss ◽  
William Dichtel ◽  
...  
Keyword(s):  
Single Crystals ◽  
Growth Rates ◽  
Kinetic Monte Carlo ◽  
Monomer Concentration ◽  
Nucleation And Growth ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Concentration Dependences ◽  
Experimental Findings

<p>Homogeneous two-dimensional (2D) polymerization is a poorly understood process in which topologically planar monomers react to form planar macromolecules, often termed 2D covalent organic frameworks (COFs). While these COFs have traditionally been limited to weakly crystalline aggregated powders, they were recently grown as micron-sized single crystals by temporally resolving the growth and nucleation processes. Here, we present a quantitative analysis of the nucleation and growth rates of 2D COFs via kinetic Monte Carlo (KMC) simulations, which show that nucleation and growth have second-order and first-order dependences on monomer concentration, respectively. The computational results were confirmed experimentally by systematic measurements of COF nucleation and growth rates performed via <i>in situ </i>X-ray scattering, which validated the respective monomer concentration dependences of the nucleation and elongation processes. A major consequence is that there exists a threshold monomer concentration below which growth dominates over nucleation. Our computational and experimental findings rationalize recent empirical observations that, in the formation of 2D COF single crystals, growth dominates over nucleation when monomers are added slowly, so as to limit their steady-state concentration. This mechanistic understanding of the nucleation and growth processes will inform the rational control of polymerization in two dimensions and ultimately enable access to high-quality samples of designed two-dimensional polymers. </p>

Synthesis of [Ca2(Co1-xCux)2O4] yCoO2 Single Crystals and Their Intrinsic Properties

2002 ◽  
Vol 755 ◽  
Author(s):  
M. Suzuki ◽  
S. Horii ◽  
M. Sano ◽  
K. Fujie ◽  
K. Otzschi ◽  
...  
Keyword(s):  
Single Crystals ◽  
Crystal Size ◽  
Present System ◽  
Intrinsic Properties ◽  
Flux Method ◽  
Solid Solution Range ◽  
High Seebeck Coefficient ◽  
Irreversible Magnetization ◽  
Magnetization Behavior ◽  
Anisotropic Magnetization

ABSTRACTThin plate-like [Ca2(Co1-xCux)2O4] y CoO2 single crystals were successfully grown by the flux method using SrCl2 solvent. The largest crystal size was approximately 3 × 3 × 0.01 mm3. The copper concentrations, x, in the crystals were found to be depending on each crystal, suggesting a certain solid-solution range of copper in the present system. The obtained crystal showed low resistivity (∼4.3mQcm) and high Seebeck coefficient (∼160μVK-1) at 300K. The crystal showed anisotropic magnetization with larger magnetization under H ∥ c. Irreversible magnetization behavior below ∼90K was also found under H ∥ c.

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