Related Experiment Video
Updated: Oct 8, 2025
05:27
Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools
Published on: July 20, 2022
2.0K
Coordination Flexibility Aided CO2 -specific Gating in an Iron Isonicotinate MOF
Himan Dev Singh1, Shyamapada Nandi1, Debanjan Chakraborty1
1Department of Chemistry, Indian Institute of Science Education and research Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
Chemistry, an Asian Journal
|December 31, 2021
Summary
This study introduces an iron-isonicotinate metal-organic framework (MOF) with a unique CO2-specific gate opening mechanism. This flexible MOF demonstrates enhanced CO2 adsorption and selective gas separation capabilities, particularly for CO2/N2 and CO2/CH4 mixtures.
Area of Science:
- Materials Science
- Chemistry
- Chemical Engineering
Background:
- Metal-organic frameworks (MOFs) offer tunable porosity for gas storage and separation.
- Coordination flexibility in MOFs can lead to stimuli-responsive behaviors like gate opening.
- Understanding the interplay between framework flexibility and guest molecule interactions is crucial for designing advanced MOFs.
Purpose of the Study:
- To introduce coordination flexibility into an iron-isonicotinate MOF for CO2-specific gate opening.
- To investigate the physisorptive properties and gas adsorption behavior of the MOF towards CO2, CH4, and N2.
- To evaluate the MOF's potential for CO2/N2 and CO2/CH4 gas separation using a gate opening mechanism.
Main Methods:
- Synthesis of an iron-isonicotinate MOF with coordination flexibility.
- Gas adsorption measurements at various temperatures and pressures to observe gate opening.
- Investigation of CO2, CH4, and N2 adsorption isotherms.
- Application of the Ideal Adsorption Solution Theory (IAST) model for gas selectivity calculations.
- X-ray photoelectron spectroscopy (XPS) and magnetism for metal oxidation state confirmation.
Main Results:
- The iron-isonicotinate MOF exhibited CO2-specific gate opening behavior, tunable by temperature and pressure.
- CO2 uptake increased significantly (from 0.70 to 1.57 mmol/g) at 333 mmHg and 298 K upon gate opening.
- IAST model predicted a substantial increase in CO2/N2 selectivity (from 325 to 3131) and a threefold increase in CO2/CH4 selectivity.
- The MOF's behavior deviated from previously studied isostructural M2+-isonicotinate MOFs, attributed to the Fe3+ oxidation state.
Conclusions:
- Coordination flexibility in the iron-isonicotinate MOF enables a CO2-specific gate opening phenomenon.
- This gate opening significantly enhances CO2 adsorption and improves CO2/N2 and CO2/CH4 gas separation performance.
- The study highlights the importance of metal oxidation state in dictating MOF gate control mechanisms, offering insights for designing selective gas separation materials.
Related Concept Videos
02:51Metal-Ligand Bonds
21.8K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
21.8K
01:58Cooperative Allosteric Transitions
8.2K
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
8.2K
03:02Colors and Magnetism
12.5K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.5K
02:34Structural Isomerism
19.9K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
19.9K
02:42Valence Bond Theory
9.8K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
9.8K
02:13Cooperative Binding of Transcription Regulators
2.1K
2.1K