Browse
Submit Data
Databases
API
Help

Dataset Information

20 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Chameleonic layered metal-organic frameworks with variable charge-ordered states triggered by temperature and guest molecules.

ABSTRACT: Molecular materials whose electronic states are multiply varied depending on external stimuli are among the most promising targets for the development of multiply accessible molecular switches. Here, we report a honeycomb layer composed of tetraoxolene-bridged iron (Fe) subunits whose charge-ordered states are multiply variable via thermal treatments and solvation/desolvation with the crystallinity intact. The compound is (NPr₄)₂[Fe₂(Cl₂An)₃] (1-d; NPr₄ ⁺ = tetra-n-propylammonium; Cl₂An^2- = 2,5-dichloro-3,6-dihydroxo-1,4-benzoquinonate), which possesses three charge-ordered states: a low-temperature (LT) phase [(Fe³⁺)₂(Cl₂An^2-)(Cl₂An˙^3-)₂]^2-; an intermediate (IM) phase [(Fe^2.5+)₂(Cl₂An^2-)(Cl₂An^2.5-)₂]^2-; and a high-temperature (HT) phase [(Fe²⁺)₂(Cl₂An^2-)₃]^2- that varies according to temperature. In addition, the LT phase of 1-d is reversibly changeable to another IM phase in its solvated compound 1 via a solvation/desolvation process at room temperature. This example demonstrates a new multiple-switching system based on electron transfer and host-guest chemistry in a charge-flexible metal-organic framework.

SUBMITTER: Chen J

PROVIDER: S-EPMC8152584 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Guest-Triggered Aggregation-Induced Emission in Silver Chalcogenolate Cluster Metal-Organic Frameworks.

Project description:Utilizing aggregation-induced emission luminogens (AIEgens) as ligands has proven to be an effective strategy for constructing metal-organic frameworks (MOFs) with intense luminescent properties. However, highly luminescent AIEgen-based MOFs with adjustable emission properties are rarely achieved because of the rigid conformation of AIEgens in the crystalline state. Here, a dual-node 3D silver chalcogenolate cluster MOF (1) is designed and synthesized, where the AIE ligand shows relatively flexible and rotatable conformations. The conformations of AIE ligands in 1 are switchable by the absorption/desorption of guest molecules. As a result, 1 exhibited not only intense but also guest molecule switched luminescent properties. More importantly, the switching rate is tunable by using different guest molecules. 1 provides a unique visualized prototype to understand the mechanism of guest-triggered aggregation-induced emission in MOFs.

| S-EPMC6343058 | biostudies-literature

Host-Guest Interactions in Metal-Organic Frameworks Doped with Acceptor Molecules as Revealed by Resonance Raman Spectroscopy.

Project description:Metal-organic frameworks (MOFs) represent a class of porous materials whose properties can be altered by doping with redox-active molecules. Despite advanced properties such as enhanced electrical conduction that doped MOFs exhibit, understanding physical mechanisms remains challenging because of their heterogeneous nature hindering experimental observations of host-guest interactions. Here, we show a study of charge transfer between Mn-MOF-74 and electron acceptors, 7,7,8,8-tetracyanoquinodimethane (TCNQ) and XeF2, employing selective enhancement of Raman scattering of different moieties under various optical-resonance conditions. We identify Raman modes of molecular components and elucidate that TCNQ gets oxidized into dicyano-p-toluoyl cyanide (DCTC-) while XeF2 fluorinates the MOF upon infiltration. The framework's linker in both cases acts as an electron donor as deduced from blue shifts of the C-O stretching mode accompanied by the emergence of a quinone-like mode. This work demonstrates a generally applicable methodology for investigating charge transfer in various donor-acceptor systems by means of resonance Raman spectroscopy.

| S-EPMC7651847 | biostudies-literature

Synthesis of ordered carbonaceous frameworks from organic crystals.

Project description:Despite recent advances in the carbonization of organic crystalline solids like metal-organic frameworks or supramolecular frameworks, it has been challenging to convert crystalline organic solids into ordered carbonaceous frameworks. Herein, we report a route to attaining such ordered frameworks via the carbonization of an organic crystal of a Ni-containing cyclic porphyrin dimer (Ni2-CPDPy). This dimer comprises two Ni-porphyrins linked by two butadiyne (diacetylene) moieties through phenyl groups. The Ni2-CPDPy crystal is thermally converted into a crystalline covalent-organic framework at 581 K and is further converted into ordered carbonaceous frameworks equipped with electrical conductivity by subsequent carbonization at 873-1073 K. In addition, the porphyrin's Ni-N4 unit is also well retained and embedded in the final framework. The resulting ordered carbonaceous frameworks exhibit an intermediate structure, between organic-based frameworks and carbon materials, with advantageous electrocatalysis. This principle enables the chemical molecular-level structural design of three-dimensional carbonaceous frameworks.Carbon-based materials are promising alternatives to noble metal catalysts, but their structures are typically disordered and difficult to control. Here, the authors obtain ordered carbonaceous frameworks with advantageous electrocatalytic properties via the carbonization of nickel-containing porphyrin dimer networks.

| S-EPMC5524644 | biostudies-literature

Encoding ordered structural complexity to covalent organic frameworks.

Project description:Installing different chemical entities onto crystalline frameworks with well-defined spatial distributions represents a viable approach to achieve ordered and complex synthetic materials. Herein, a covalent organic framework (COF-305) is constructed from tetrakis(4-aminophenyl)methane and 2,3-dimethoxyterephthalaldehyde, which has the largest unit cell and asymmetric unit among known COFs. The ordered complexity of COF-305 is embodied by nine different stereoisomers of its constituents showing specific sequences on topologically equivalent sites, which can be attributed to its building blocks deviating from their intrinsically preferred simple packing geometries in their molecular crystals to adapt to the framework formation. The insight provided by COF-305 supplements the principle of covalent reticular design from the perspective of non-covalent interactions and opens opportunities for pursuing complex chemical sequences in molecular frameworks.

| S-EPMC10948875 | biostudies-literature

Long-afterglow metal-organic frameworks: reversible guest-induced phosphorescence tunability.

Project description:Luminescent metal-organic frameworks (MOFs) have received much attention due to their wide structural tunability and potential application in light-emitting diodes, biological imaging and chemical sensors. However, successful examples of long-persistent afterglow MOFs are still quite limited to date. In this work, we report that two types of Zn-terephthalate (TPA) MOFs (namely [Zn(TPA)(DMF)] (1-DMF) and MOF-5) could exhibit an obvious room-temperature afterglow emission with a time-resolved luminescence lifetime as high as 0.47 seconds. The phosphorescence-based afterglow was also highly sensitive to the temperature, and the reversible emission intensity could be recycled under high/low temperatures. Moreover, both 1-DMF and MOF-5 showed highly tunable afterglow phosphorescence colors (from cyan to yellow and from green to red, respectively) upon treatment with pyridine solution. The fluorescence/phosphorescence emission color of MOF-5 can be reversibly switched due to the addition and removal of a pyridine guest to and from the host nanochannel, as shown in both experimental and computational studies. Therefore, this work not only shows a facile method to develop MOF-based long-afterglow materials at room temperature, but also presents a strategy to tune their phosphorescence in a wide range based on host-guest interactions.

| S-EPMC6016333 | biostudies-literature

Layered Copper-Metallated Covalent Organic Frameworks for Huisgen Reactions.

Project description:Covalent organic frameworks (COFs) are porous materials formed through condensation reactions of organic molecules via the formation of dynamic covalent bonds. Among COFs, those based on imine and β-ketoenamine linkages offer an excellent platform for binding metallic species such as copper to design efficient heterogeneous catalysts. In this work, imine- and β-ketoenamine-based COF materials were modified with catalytic copper sites following a metallation method, which favored the formation of binding amine defects. The obtained copper-metallated COF materials were tested as heterogeneous catalysts for 1,3-dipolar cycloaddition reactions, resulting in high yields and recyclability.

| S-EPMC8659373 | biostudies-literature

Inside polyMOFs: layered structures in polymer-based metal-organic frameworks.

Project description:In this report, we explore the internal structural features of polyMOFs consisting of equal mass ratios of metal-coordinating poly(benzenedicarboxylic acid) blocks and non-coordinating poly(ethylene glycol) (PEG) blocks. The studies reveal alternating lamellae of metal-rich, crystalline regions and metal-deficient non-crystalline polymer, which span the length of hundreds of nanometers. Polymers consisting of random PEG blocks, PEG end-blocks, or non-coordinating poly(cyclooctadiene) (COD) show similar alternation of metal-rich and metal-deficient regions, indicating a universal self-assembly mechanism. A variety of techniques were employed to interrogate the internal structure of the polyMOFs, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and small-angle synchrotron X-ray scattering (SAXS). Independent of the copolymer architecture or composition, the internal structure of the polyMOF crystals showed similar lamellar self-assembly at single-nanometer length scales.

| S-EPMC8162296 | biostudies-literature

Redox-triggered switching in three-dimensional covalent organic frameworks.

Project description:The tuning of molecular switches in solid state toward stimuli-responsive materials has attracted more and more attention in recent years. Herein, we report a switchable three-dimensional covalent organic framework (3D COF), which can undergo a reversible transformation through a hydroquinone/quinone redox reaction while retaining the crystallinity and porosity. Our results clearly show that the switching process gradually happened through the COF framework, with an almost quantitative conversion yield. In addition, the redox-triggered transformation will form different functional groups on the pore surface and modify the shape of pore channel, which can result in tunable gas separation property. This study strongly demonstrates 3D COFs can provide robust platforms for efficient tuning of molecular switches in solid state. More importantly, switching of these moieties in 3D COFs can remarkably modify the internal pore environment, which will thus enable the resulting materials with interesting stimuli-responsive properties.

| S-EPMC7531008 | biostudies-literature

Guest-host interactions of a rigid organic molecule in porous silica frameworks.

Project description:Molecular-level interactions at organic-inorganic interfaces play crucial roles in many fields including catalysis, drug delivery, and geological mineral precipitation in the presence of organic matter. To seek insights into organic-inorganic interactions in porous framework materials, we investigated the phase evolution and energetics of confinement of a rigid organic guest, N,N,N-trimethyl-1-adamantammonium iodide (TMAAI), in inorganic porous silica frameworks (SSZ-24, MCM-41, and SBA-15) as a function of pore size (0.8 nm to 20.0 nm). We used hydrofluoric acid solution calorimetry to obtain the enthalpies of interaction between silica framework materials and TMAAI, and the values range from -56 to -177 kJ per mole of TMAAI. The phase evolution as a function of pore size was investigated by X-ray diffraction, IR, thermogravimetric differential scanning calorimetry, and solid-state NMR. The results suggest the existence of three types of inclusion depending on the pore size of the framework: single-molecule confinement in a small pore, multiple-molecule confinement/adsorption of an amorphous and possibly mobile assemblage of molecules near the pore walls, and nanocrystal confinement in the pore interior. These changes in structure probably represent equilibrium and minimize the free energy of the system for each pore size, as indicated by trends in the enthalpy of interaction and differential scanning calorimetry profiles, as well as the reversible changes in structure and mobility seen by variable temperature NMR.

| S-EPMC3918769 | biostudies-literature

Role of Host-Guest Interaction in Understanding Polymerisation in Metal-Organic Frameworks.

Project description:Metal-organic frameworks, MOFs, offer an effective template for polymerisation of polymers with precisely controlled structures within the sub-nanometre scales. However, synthetic difficulties such as monomer infiltration, detailed understanding of polymerisation mechanisms within the MOF nanochannels and the mechanism for removing the MOF template post polymerisation have prevented wide scale implementation of polymerisation in MOFs. This is partly due to the significant lack in understanding of the energetic and atomic-scale intermolecular interactions between the monomers and the MOFs. Consequently in this study, we explore the interaction of varied concentration of styrene, and 3,4-ethylenedioxythiophene (EDOT), at the surface and in the nanochannel of Zn2(1,4-ndc)2 (dabco), where 1,4-ndc = 1,4-naphthalenedicarboxylate and dabco = 1,4-diazabicyclo[2.2.2]octane. Our results showed that the interactions between monomers are stronger in the nanochannels than at the surfaces of the MOF. Moreover, the MOF-monomer interactions are strongest in the nanochannels and increase with the number of monomers. However, as the number of monomers increases, the monomers turn to bind more strongly at the surface leading to a potential agglomeration of the monomers at the surface.

| S-EPMC8333864 | 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