A Three-Dimensional sp2 Carbon-Conjugated Covalent Organic Framework.
Shitao Wang1, Xiang-Xiang Li1, Ling Da1
1State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
Journal of the American Chemical Society
|September 17, 2021
Summary
Researchers developed a novel 3D covalent organic framework (COF) with high electron mobility. Doping this sp2 carbon-conjugated material with iodine induces a metal-free ferromagnetic phase transition, a first for 3D COFs.
Area of Science:
- Materials Science
- Organic Chemistry
- Condensed Matter Physics
Background:
- Covalent Organic Frameworks (COFs) are crystalline porous polymers.
- Developing 3D COFs with extended π-conjugation is crucial for advanced electronic applications.
- Exploring metal-free ferromagnetic materials is a key area in condensed matter physics.
Purpose of the Study:
- To synthesize and characterize the first sp2 carbon-conjugated 3D covalent organic framework (COF).
- To investigate the electronic properties and potential for doping in the novel 3D COF.
- To explore the emergence of novel phenomena, such as ferromagnetism, in 3D COF materials.
Main Methods:
- Knoevenagel condensation reaction between specific aldehyde-substituted cyclooctatetrathiophene and 1,4-phenylenediacetonitrile.
- Characterization of the synthesized 3D COF (BUCT-COF-4) using relevant analytical techniques.
- Iodine doping of the 3D COF and subsequent measurement of electron mobility and magnetic properties.
Main Results:
- Successful synthesis of BUCT-COF-4, a 3D sp2 carbon-conjugated COF.
- Achieved high Hall electron mobility of 1.97 cm2 V-1 s-1 at room temperature.
- Iodine doping enhanced electron mobility to 2.62 cm2 V-1 s-1 and induced a metal-free ferromagnetic phase transition.
Conclusions:
- BUCT-COF-4 represents a significant advancement in 3D COF materials.
- The observed metal-free ferromagnetism in a 3D COF opens new avenues for spintronic applications.
- This discovery broadens the potential applications of COF materials in electronics and magnetism.
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
28.4K
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...
28.4K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
45.4K
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 the dxy,...
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 the dxy,...
45.4K
01:24π Molecular Orbitals of 1,3-Butadiene
10.3K
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
10.3K
03:24Hybridization of Atomic Orbitals I
52.6K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
52.6K
02:18Network Covalent Solids
15.1K
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...
15.1K
02:06Newman Projections
18.9K
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
18.9K