可调节的介层转移在二维共价有机框架中由CO2吸附触发
Chengjun Kang1, Zhaoqiang Zhang1, Adam K Usadi2
1Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585, Singapore.
Journal of the American Chemical Society
|October 31, 2022
概括
由于层间移动,二维共价有机框架 (2D COF) 在二氧化碳吸附中表现出意想不到的歇斯底里. 这一发现揭示了二维COF可以作为"软"材料,为气体储存和分离技术开辟了新的途径.
科学领域:
- 材料科学
- 化学学
- 纳米技术
背景情况:
- 二维共价有机框架 (2D COF) 通常被认为是刚性多孔材料.
- 它们的气体吸附等热体通常是光滑的和可逆的.
研究的目的:
- 在二维COF的二氧化碳吸附同热体中观察到的异常歇斯底里阶段,TAPB-OMeTA.
- 了解二维COF在气体吸附过程中的结构动态.
主要方法:
- 在现场测量粉末X射线衍射 (PXRD).
- 计算模型和保利的精细化.
- 密度函数理论 (DFT) 的计算.
- 表面启动的原子转移基聚合 (SI-ATRP) 用于功能化.
主要成果:
- TAPB-OMeTA在其二氧化碳吸附同热体中表现出一个歇斯底里阶段,这归因于层间的移动.
- 在二氧化碳吸附过程中,由于甲氧基之间的吸引力和排斥力减弱,形成了准AA堆叠结构.
- 使用聚烯烯胺) 寡合体的功能化诱导了第二个层间转移和两个吸附步骤,证明了可调性.
- DFT的计算证实了在二氧化碳大气层下的准AA堆叠结构的能量偏好.
结论:
- 在与气体相互作用时,二维COF可以表现出"柔软"的多孔性行为,挑战了传统的对其刚性的看法.
- 由气体相互作用和功能群排斥影响的层间转移是这种行为的关键机制.
- 层间转移的调节性为设计用于先进气体存储和分离应用的二维COF提供了新的可能性.
更多相关视频
相关概念视频
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
2.8K
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
2.8K
Crystal Field Theory - Octahedral Complexes
27.2K
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...
27.2K
Cooperative Allosteric Transitions
8.0K
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...
8.0K
Network Covalent Solids
13.7K
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...
13.7K
Chemical Shift: Internal References and Solvent Effects
730
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
730
Inductive Effects on Chemical Shift: Overview
1.3K
The protons in unsubstituted alkanes are strongly shielded with chemical shifts below 1.8 ppm. Methine, methylene, and methyl protons appear at approximately 1.7, 1.2 and 0.7 ppm, while the proton signal from methane appears at 0.23 ppm. An electronegative substituent, such as chlorine, withdraws the electron density from the protons, increasing their chemical shift. Progressive substitution of the hydrogens in methane by chlorine shifts the proton signals increasingly downfield, to 3.05 ppm in...
1.3K


