椅子和船构之间的区别

Thekey differencebetweenchair and boat conformationis that椅子构象的能量低，而船构象具有高能量。

椅式构象和船式构象come under organic chemistry, and they are mainly applicable tocyclohexane. These are two different structures in which the cyclohexane molecule can exist, but they have different stabilities depending on the energy of their structure.

内容

1.Overview and Key Difference
2.What is Chair Conformation
3.What is Boat Conformation
4.并排比较 - 椅子与船构象以表格形式
5.概括

What is Chair Conformation

Chair conformation is the most stable structure of cyclohexane. This is because it has low energy. Usually, at room temperature (around 25°C), all the molecules of cyclohexane occur in chair conformation. If there is a mixture of different structures of the same compound at this temperature, around 99.99% of the molecules convert into chair conformation. When considering the symmetry of this molecule, we can name it as D_3d. Here, all the carbon centres are equivalent.

轴向位置存在六个氢原子。其他六个hydrogen atoms位于几乎垂直于对称轴的位置，即赤道位置。如果我们考虑碳原子，则每个碳原子都包含两个氢原子：一个氢原子“向上”，另一个“向下”。由于C-H键在交错的构象.

什么是船构象？

Boat conformation is a less stable structure of cyclohexane since this structure has high energy. There is a considerable steric strain in this structure because of the interaction between two flagpole hydrogens, and there is a considerable torsional strain as well. These strains also cause the unstable nature of the boat conformation. The symmetry of this structure is named C_2v.

Moreover, the boat conformation tends to convert into the boat-twist conformation spontaneously. Its symmetry is D₂. This structure appears as a slight twist of the boat conformation. Rapid cooling of the cyclohexane converts boat conformation into boat-twist conformation, which converts into chair conformation upon heating.

椅子和船构之间有什么区别？

椅式构象和船式构象apply mainly to cyclohexane. The key difference between chair and boat conformation is that a chair conformation has low energy, whereas boat conformation has high energy. Due to this reason, chair conformation is stable than boat conformation. Usually, chair conformation is the most stable conformation, and at room temperature, about 99.99% of cyclohexane in a mixture of different conformation exists in this conformation.

Moreover, the symmetry of chair conformation is D_3dwhile boat symmetry has the symmetry C_2v. Besides, boat conformation tends to convert into the boat-twist conformation spontaneously. However, both these structures tend to convert into the chair conformation upon heating. Furthermore, another difference between chair and boat conformation is that the torsional strain and steric hindrance in chair conformation are low compared to boat conformation.

概括– Chair vs Boat Conformation

椅式构象和船式构象apply mainly to cyclohexane. The key difference between chair and boat conformation is that a chair conformation has low energy, whereas a boat conformation has high energy. Therefore, the chair conformation is more stable than boat conformation at room temperature. Generally, the chair conformation is the most stable structure of cyclohexane at room temperature.

Reference:

1. “Cyclohexane Conformation.” Wikipedia, Wikimedia Foundation, 24 Nov. 2019,Available here.
2. “Boat Conformation.” Chemistry LibreTexts, Libretexts, 5 June 2019,Available here.
3. “Conformation of Cyclohexane.” Chemistry LibreTexts, Libretexts, 5 June 2019,Available here.

Image Courtesy:

1. “Cyclohexane-chair-colour-coded-3D-balls” By Benjah-bmm27 – Own work (Public Domain) viaCommons Wikimedia
2. “Cyclohexane ring flip and relative conformation energies” By Keministi – Own work (CC0) viaCommons Wikimedia