强大的,大小选择性和电子调节的C-H...化物结合,具有对合成模块化,形状持久 [34]triazolophanes聚合物的固体控制
1Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
Journal of the American Chemical Society
|August 15, 2008
概括
形状持久的三醇因其固定腔体大小而选择性地结合化物和化物离子. 替代剂的修改调整了结合强度和聚合,强调了受体设计对于离子识别的重要性.
科学领域:
- 超分子化学 超分子化学
- 主机和客人的化学反应
- 有机合成 有机合成
背景情况:
- 阳离子识别在生物和化学过程中至关重要.
- 开发对阳离子的选择性合成受体仍然是一个重大挑战.
- 结合相互作用是受体-离子结合的关键.
研究的目的:
- 为了合成新型形状持久的 [3(4) ]triazolophanes.
- 为了研究这些受体的离子结合亲和力和选择性.
- 了解结构特征和替代剂在调节结合强度和聚合中的作用.
主要方法:
- 用不同的替代剂 (t-丁,OTg) 合成 [3(4) ]triazolophanes 的模块化合成.
- 紫外线定位以确定化离子结合亲和力.
- 扩散NMR实验用于研究聚合行为.
- 与折叠机模拟器进行比较,以评估预组织效应.
主要成果:
- [3(4)]三醇对Cl(-) 和Br(-) 离子 (Ka > 1,000,000 M(-1)) 具有选择性的结合.
- 结合亲和力可以通过修改烯链接子替代剂来调整,从而影响电子捐赠特性.
- 预先组织显著提高结合亲和力,与折叠模拟器相比.
- 通过电子捐赠的OTg替代剂观察到聚合的增加.
结论:
- 对于选择性阴离子识别而言,三醇的固定腔体大小至关重要.
- 烯连接剂替代剂在调整结合强度和控制聚合方面发挥着双重作用.
- 这些发现为设计针对特定应用的先进离子受体提供了洞察力.
相关概念视频
01:18Aromatic Hydrocarbon Cations: Structural Overview
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 with both...
Removing one hydrogen from the intervening CH2 group with both...
02:30Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
02:11Conformations of Cyclohexane
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
![[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12422.jpg&w=3840&q=75)
01:21[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
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.
02:02Chair Conformation of Cyclohexane
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...