2.5-dimensional covalent organic frameworks
Tomoki Kitano1,2, Syunto Goto1,2, Xiaohan Wang1,2
1Laboratory for Zero-Carbon Energy, Institute of Integrated Research, Institute of Science Tokyo, Tokyo, Japan.
Nature Communications
|January 2, 2025
Summary
Researchers developed 2.5-dimensional (2.5D) covalent organic frameworks (COFs) with large crystal sizes and high amine density. These novel COFs show promise for efficient carbon dioxide (CO2) capture, overcoming typical selectivity and adsorption heat trade-offs.
Area of Science:
- Materials Science
- Nanotechnology
- Chemistry
Background:
- Covalently bonded crystalline microporous materials, including two-dimensional (2D) and three-dimensional (3D) covalent organic frameworks (COFs), have diverse applications.
- Synthesizing large, high-quality 2D COF crystals (>10 μm) is challenging, while 3D COFs are easier to produce in larger sizes with good crystallinity.
Purpose of the Study:
- To introduce and characterize a new class of 2.5-dimensional (2.5D) covalent organic frameworks (COFs).
- To demonstrate the potential of 2.5D COFs as advanced materials for carbon dioxide (CO2) adsorption.
Main Methods:
- Development of 2.5D COF structures with microscopic 3D bonding and macroscopic 2D planar geometry.
- Characterization of single-crystal sizes and the density/orientation of primary amine groups within the framework.
Main Results:
- Achieved large single-crystal sizes for 2.5D COFs, exceeding 0.1 mm.
- Engineered ultrahigh-density primary amine groups oriented perpendicular to the network plane.
- Demonstrated simultaneous high CO2/N2 selectivity and low heat of adsorption in CO2 capture applications.
Conclusions:
- 2.5D COFs represent a novel structural motif in covalently bonded microporous materials.
- The unique amine arrangement in 2.5D COFs enables efficient and selective CO2 adsorption.
- This advancement is expected to expand the scope and applications of crystalline microporous systems.
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
25.6K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
25.6K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
40.6K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
40.6K
02:18Network Covalent Solids
13.2K
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
13.2K
02:46Covalent Bonding and Lewis Structures
46.3K
Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual attraction of atoms for a “shared” pair of electrons.
46.3K
01:18Aromatic Hydrocarbon Anions: Structural Overview
2.5K
Neutral hydrocarbons like cyclopentadiene with an odd number of carbon atoms and one intervening CH2 group in the ring are not aromatic. Cyclopentadiene with 4 π electrons does not satisfy the 4n + 2 π electron rule. Additionally, the intervening CH2 group is sp3 hybridized and lacks a vacant p orbital, thereby interrupting the overlap of p orbitals in a continuous manner and preventing the delocalization of π electrons throughout the ring.
Due to the absence of continuous...
Due to the absence of continuous...
2.5K
02:40MO Theory and Covalent Bonding
10.2K
The molecular orbital theory describes the distribution of electrons in molecules in a manner similar to the distribution of electrons in atomic orbitals. The region of space in which a valence electron in a molecule is likely to be found is called a molecular orbital. Mathematically, the linear combination of atomic orbitals (LCAO) generates molecular orbitals. Combinations of in-phase atomic orbital wave functions result in regions with a high probability of electron density, while...
10.2K