C22H122+/2•/2-的芳香规则:二维超原子分子电子结构的灵活性
Lijiao Guo1, Dandan Zhang1, Kaidong Shen1
1Department of Chemistry, Anhui University, Hefei 230601, P. R. China.
The journal of physical chemistry letters
|May 22, 2024
概括
三角烯及其带电形式具有芳香性,由新的二维超原子分子理论解释. 这一理论还预测了电子应用的稳定,宽带间隙纳米多孔石墨烯.
科学领域:
- 计算化学的计算化学
- 材料科学 材料科学 材料科学
- 有机化学 有机化学
背景情况:
- 三角烯 (C22H12^2•) 是一种非经典的非Kekulé的多环芳碳化合物,具有备受争议的芳香度.
- 现有的结构和磁性标准证实了它的芳香性质,但其起源仍然不清楚.
研究的目的:
- 研究有关三角烯 (C22H12^2•) 和其带电物种 (C22H12^2+/2-) 的芳香规则.
- 应用一种新的二维 (2D) 超原子分子理论来理解它们的电子结构.
- 根据这些发现,预测新的二维材料.
主要方法:
- 应用最近开发的二维超原子分子理论.
- 分析三角烯及其充电对应物的电子结构和粘合模式.
- 计算机预测杂的纳米多孔石墨烯材料.
主要成果:
- 三角烯物种[C22H12]^2+/2•/2-表现出局部芳香特征,模拟为超原子分子[◊N3◊O3]+,[◊N3◊O3]-和◊N3◊F3.3.
- 二维超原子 ◊N, ◊O, 和 ◊F 分别代表 3π, 4π 和 5π 电子.
- 预测了一个稳定的C9N12B单层,带间隔为2.77 eV,显示出极好的动态和热力学稳定性.
结论:
- 2D超原子分子理论成功地解释了三角烯及其带电形式的芳香性.
- 预测的C9N12B单层是未来电子应用的有希望的二维材料,因为它的稳定性和宽带间隙.
相关概念视频
Criteria for Aromaticity and the Hückel 4n + 2 Rule
10.5K
Like benzene, cyclobutadiene and cyclooctatetraene are cyclic compounds with alternate single and double bonds. However, their chemical behavior differs from benzene, as they are unstable and not aromatic. So, what are the structural characteristics of unsaturated compounds categorized as aromatic?
For the first time, Eric Hückel, a German chemical physicist, derived a set of structural features for a compound to be classified as aromatic. This is now known as...
For the first time, Eric Hückel, a German chemical physicist, derived a set of structural features for a compound to be classified as aromatic. This is now known as...
10.5K
Aromatic Hydrocarbon Anions: Structural Overview
2.8K
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...
2.8K
Frost Circles for Different Conjugated Systems
2.7K
The inscribed polygon method is consistent with Hückel’s 4n + 2 rule and helps to learn whether the given cyclic compound is aromatic or not. The compound is stable and aromatic if every bonding molecular orbital (MO) is completely filled with a pair of electrons. However, if the non-bonding or antibonding orbitals are filled with electrons, the compound is unstable and not aromatic. Consider the Frost circle diagrams for cycloalkenes containing 4 to 8 carbons.
2.7K
Aromatic Hydrocarbon Cations: Structural Overview
2.8K
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group...
Removing one hydrogen from the intervening CH2 group...
2.8K
Five-Membered Heterocyclic Aromatic Compounds: Overview
3.9K
Heterocyclic aromatic compounds are cyclic compounds that are aromatic and have one or more heteroatoms—atoms other than carbon, in the ring. Depending upon the number of atoms present in the ring, they can be either five or six-membered. Examples of five-membered heterocyclic aromatic compounds include pyrrole, furan, thiophene, and imidazole. Pyrrole consists of one nitrogen atom having one lone pair of electrons. Furan and thiophene have one oxygen and one sulfur heteroatom,...
3.9K
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
1.2K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
1.2K


