Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Three-step nucleation of metal-organic framework nanocrystals.

ABSTRACT: Metal-organic frameworks (MOFs) are crystalline nanoporous materials with great potential for a wide range of industrial applications. Understanding the nucleation and early growth stages of these materials from a solution is critical for their design and synthesis. Despite their importance, the pathways through which MOFs nucleate are largely unknown. Using a combination of in situ liquid-phase and cryogenic transmission electron microscopy, we show that zeolitic imidazolate framework-8 MOF nanocrystals nucleate from precursor solution via three distinct steps: 1) liquid-liquid phase separation into solute-rich and solute-poor regions, followed by 2) direct condensation of the solute-rich region into an amorphous aggregate and 3) crystallization of the aggregate into a MOF. The three-step pathway for MOF nucleation shown here cannot be accounted for by conventional nucleation models and provides direct evidence for the nonclassical nucleation pathways in open-framework materials, suggesting that a solute-rich phase is a common precursor for crystallization from a solution.

SUBMITTER: Liu X

PROVIDER: S-EPMC7958460 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Size control over metal-organic framework porous nanocrystals.

Project description:Porous nanocrystals of metal-organic frameworks (MOFs) offer greater bioavailability, higher surface-to-volume ratios, superior control over MOF membrane fabrication, and enhanced guest-sorption kinetics compared to analogous bulk phases, but reliable synthesis of uniformly sized particles remains an outstanding challenge. Here, we identify the smallest and most probable sizes of known MOF nanocrystals and present an exhaustive comparative summary of nano- versus bulk-MOF syntheses. Based on critical analysis of reported size data and experimental conditions, an alternate to the LaMer model is proposed that describes nanocrystal formation as a kinetic competition between acid-base and metal-ligand reactivity. Particle growth terminates when ligands outcompete metal-ion diffusion, thereby arresting polymerization to produce kinetically trapped particle sizes. This model reconciles disparate trends in the literature and postulates that minimum particle sizes can be achieved by minimizing the relative ratios of metal-to-linker local concentrations. By identifying conditions that disfavor small nanocrystal sizes, this model also provides routes towards macroscopic MOF single crystals. A universal "seesaw" relationship between nanocrystal sizes and the concentrations of acidic surface-capping ligands provides a roadmap for achieving precise synthetic control. Best practices in synthesis, characterization, and data presentation are recommended for future investigations so that MOF nanocrystals may achieve their full potential as advanced nanomaterials.

| S-EPMC6979335 | biostudies-literature

Defect Engineering in Metal-Organic Framework Nanocrystals: Implications for Mechanical Properties and Performance.

Project description:The growth process of metal-organic framework (MOF) nanocrystals defines their properties and functions. However, defects may be prevalent during the crystallization of even seemingly perfect MOFs, such as zeolitic imidazolate framework-8 (ZIF-8), and yet direct probing of such structural defects has been challenging because of the lack of nanoscale techniques to locally examine individual nanocrystals. Here, we directly study local defects, such as missing linkers or metal vacancies, in ZIF-8 nano- and microcrystals with near-field IR nanospectroscopy combined with density functional theory calculations. We track the chemical changes during crystallization and show that structural defects like zinc cations that are bound to molecules of the reactant gradually disappear with ripening of the crystals, while dangling and missing linker defects prevail. The resulting defect-terminating groups or open-metal sites produce mechanical anisotropy and reduce the Young's modulus, as measured via tip force microscopy with nanoscale resolution and supported by theoretical modeling. However, these structural defects also open the door for defect engineering to tune the performance of ZIF-8 by offering additional adsorption sites for targeted catalytic reactions, chemical sensing, or gas capture.

| S-EPMC9150067 | biostudies-literature

Heterojunction Incorporating Perovskite and Microporous Metal-Organic Framework Nanocrystals for Efficient and Stable Solar Cells.

Project description:In this paper, we present a facile approach to enhance the efficiency and stability of perovskite solar cells (PSCs) by incorporating perovskite with microporous indium-based metal-organic framework [In12O(OH)16(H2O)5(btc)6]n (In-BTC) nanocrystals and forming heterojunction light-harvesting layer. The interconnected micropores and terminal oxygen sites of In-BTC allow the preferential crystallization of perovskite inside the regular cavities, endowing the derived films with improved morphology/crystallinity and reduced grain boundaries/defects. Consequently, the In-BTC-modified PSC yields enhanced fill factor of 0.79 and power conversion efficiency (PCE) of 20.87%, surpassing the pristine device (0.76 and 19.52%, respectively). More importantly, over 80% of the original PCE is retained after 12 days of exposure to ambient environment (25 °C and relative humidity of ~ 65%) without encapsulation, while only about 35% is left to the pristine device.

| S-EPMC7770709 | biostudies-literature

Single-step synthesis and interface tuning of core-shell metal-organic framework nanoparticles.

Project description:Control over the spatial distribution of components in metal-organic frameworks has potential to unlock improved performance and new behaviour in separations, sensing and catalysis. We report an unprecedented single-step synthesis of multi-component metal-organic framework (MOF) nanoparticles based on the canonical ZIF-8 (Zn) system and its Cd analogue, which form with a core-shell structure whose internal interface can be systematically tuned. We use scanning transmission electron microscopy, X-ray energy dispersive spectroscopy and a new composition gradient model to fit high-resolution X-ray diffraction data to show how core-shell composition and interface characteristics are intricately controlled by synthesis temperature and reaction composition. Particle formation is investigated by in situ X-ray diffraction, which reveals that the spatial distribution of components evolves with time and is determined by the interplay of phase stability, crystallisation kinetics and diffusion. This work opens up new possibilities for the control and characterisation of functionality, component distribution and interfaces in MOF-based materials.

| S-EPMC8179513 | biostudies-literature

Encapsulation of redox polysulphides via chemical interaction with nitrogen atoms in the organic linkers of metal-organic framework nanocrystals.

Project description:Lithium polysulphides generated during discharge in the cathode of a lithium-sulphur redox cell are important, but their dissolution into the electrolyte from the cathode during each redox cycle leads to a shortened cycle life. Herein, we use in situ spectroelectrochemical measurements to demonstrate that sp(2) nitrogen atoms in the organic linkers of nanocrystalline metal-organic framework-867 (nMOF-867) are able to encapsulate lithium polysulphides inside the microcages of nMOF-867, thus helping to prevent their dissolution into the electrolyte during discharge/charge cycles. This encapsulation mechanism of lithiated/delithiated polysulphides was further confirmed by observations of shifted FTIR spectra for the C = N and C-N bonds, the XPS spectra for the Li-N bonds from nMOF-867, and a visualization method, demonstrating that nMOF-867 prevents lithium polysulphides from being dissolved in the electrolyte. Indeed, a cathode fabricated using nMOF-867 exhibited excellent capacity retention over a long cycle life of 500 discharge/charge cycles, with a capacity loss of approximately 0.027% per cycle from a discharge capacity of 788 mAh/g at a high current rate of 835 mA/g.

| S-EPMC4857742 | biostudies-literature

Microfluidic one-step synthesis of a metal-organic framework for osteoarthritis therapeutic microRNAs delivery.

Project description:As a class of short non-coding ribonucleic acids (RNAs), microRNAs (miRNA) regulate gene expression in human cells and are expected to be nucleic acid drugs to regulate and treat a variety of biological processes and diseases. However, the issues with potential materials toxicity, quantity production, poor cellular uptake, and endosomal entrapment limit their further applications in clinical practice. Herein, ZIF-8, a metal-organic framework with noncytotoxic zinc (II) as the metal coordination center, was selected as miRNA delivery vector was used to prepare miR-200c-3p@ZIF-8 in one step by Y-shape microfluidic chip to achieve intracellular release with low toxicity, batch size, and efficient cellular uptake. The obtained miR-200c-3p@ZIF-8 was identified by TEM, particle size analysis, XRD, XPS, and zeta potential. Compared with the traditional hydrothermal method, the encapsulation efficiency of miR-200c-3p@ZIF-8 prepared by the microfluidic method is higher, and the particle size is more uniform and controllable. The experimental results in cellular level verified that the ZIF-8 vectors with low cytotoxicity and high miRNAs loading efficiency could significantly improve cellular uptake and endosomal escape of miRNAs, providing a robust and general strategy for nucleic acid drug delivery. As a model, the prepared miR-200c-3p@ZIF-8 is confirmed to be effective in osteoarthritis treatment.

| S-EPMC10415039 | biostudies-literature

Dual Metal-Organic Framework Heterointerface.

Project description:Herein, a core-shell dual metal-organic framework (MOF) heterointerface is synthesized. The Prussian blue (PB) MOF acts as a core for the growth of a porphyrin-doped MOF which is named PB@MOF. Porphyrins can significantly enhance the transfer of photoinspired electrons from PB and suppress the recombination of electrons and holes, thus enhancing the photocatalytic properties and consequently promoting the yields of singlet oxygen rapidly under 660 nm illumination. PB@MOF can exhibit a better photothermal conversion efficiency up to 29.9% under 808 nm near-infrared irradiation (NIR). The PB@MOF heterointerface can possess excellent antibacterial efficacies of 99.31% and 98.68% opposed to Staphylococcus aureus and Escherichia coli, separately, under the dual light illumination of 808 nm NIR and 660 nm red light for 10 min. Furthermore, the trace amount of Fe and Zr ions can trigger the immune system to favor wound healing, promising that PB@MOF achieves the rapid therapy of bacterial infected wounds and environmental disinfection.

| S-EPMC6764158 | biostudies-literature

An electrically switchable metal-organic framework.

Project description:Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication.

| S-EPMC4137262 | biostudies-other

A three-dimensional metal-organic framework for a guest-free ultra-low dielectric material.

Project description:A three-dimensional metal-organic framework compound [NH2(CH3)2]2[Zn3(bpdc)4]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1') possesses an ultra-low κ value of 1.80 (at 100 kHz, it is the lowest value for MOFs reported to date) over a wide temperature range and high thermal stability.

| S-EPMC9064416 | biostudies-literature

Metal-organic frameworks tailor the properties of aluminum nanocrystals.

Project description:Metal-organic frameworks (MOFs) and metal nanoparticles are two classes of materials that have received considerable recent attention, each for controlling chemical reactivities, albeit in very different ways. Here, we report the growth of MOF shell layers surrounding aluminum nanocrystals (Al NCs), an Earth-abundant metal with energetic, plasmonic, and photocatalytic properties. The MOF shell growth proceeds by means of dissolution-and-growth chemistry that uses the intrinsic surface oxide of the NC to obtain the Al3+ ions accommodated into the MOF nodes. Changes in the Al NC plasmon resonance provide an intrinsic optical probe of its dissolution and growth kinetics. This same chemistry enables a highly controlled oxidation of the Al NCs, providing a precise method for reducing NC size in a shape-preserving manner. The MOF shell encapsulation of the Al NCs results in increased efficiencies for plasmon-enhanced photocatalysis, which is observed for the hydrogen-deuterium exchange and reverse water-gas shift reactions.

| S-EPMC6368424 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data