离子大小和π-相互作用在稳定Calix[4]arene皇冠以太金属复合物的作用
Thomas Sittel1, Karolin Becker2, Robert Polly1
1Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021, Karlsruhe, Germany.
Chemistry (Weinheim an der Bergstrasse, Germany)
|May 9, 2025
概括
卡利克斯[4]烯冠以太 MAXCalix 结合了各种和土金属离子. 离子大小决定了复杂的结构和稳定性,像Cs+这样的大离子由于pi相互作用而表现出增强的结合.
科学领域:
- 超分子化学 超分子化学
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
背景情况:
- 卡力克斯[4]烯衍生物是具有可调节性质的多功能宿主分子.
- 皇冠以它们选择性地结合金属阳离子的能力而闻名.
- 了解离子-连接体相互作用对于开发新材料和分离技术至关重要.
研究的目的:
- 研究离子大小对MAXCalix与和土金属离子的复合行为的影响.
- 阐明形成的复合体的结构方面和稳定性.
- 探索非共价相互作用,特别是pi相互作用在复杂稳定中的作用.
主要方法:
- 核磁共振 (NMR) 光谱被用来研究复杂的形成和结构.
- 密度函数理论 (DFT) 的计算被用来建模和理解复杂的几何.
- 进行了竞争性NMR研究,以评估相对复杂的稳定性.
主要成果:
- MAXCalix通过协调大 (Cs+) 和小 (Na+) 离子来证明了多功能性.
- 确定了两个不同的结构亚型的复合体,受离子大小的影响.
- 阴离子与基[4]基骨架之间的Pi相互作用显著促进了复杂的稳定性,特别是对于像Cs+这样的大离子.
结论:
- 金属离子的大小是MAXCalix复合物的结构和稳定性的关键决定因素.
- 对较大的离子增强的亲和力和稳定性归因于有利的pi相互作用.
- MAXCalix表现出可调整的复杂化行为,使其成为用于离子识别和分离的有希望的配体.
相关概念视频
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
315
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
315
02:36Crown Ethers
5.1K
Crown ethers are cyclic polyethers that contain multiple oxygen atoms, usually arranged in a regular pattern. The first crown ether was synthesized by Charles Pederson while working at DuPont in 1967. For this work, Pedersen was co-awarded the 1987 Nobel Prize in Chemistry. Crown ethers are named using the formula x-crown-y, where x is the total number of atoms in the ring and y is the number of ether oxygen atoms. The term 'crown' refers to the crown-like shape that these ether...
5.1K
01:19Complexation Equilibria: The Chelate Effect
416
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
416
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
41.1K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2âÃÂÃÂy2 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 dx2âÃÂÃÂy2 and dz2 orbitals (along the Cartesian axes)...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2âÃÂÃÂy2 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 dx2âÃÂÃÂy2 and dz2 orbitals (along the Cartesian axes)...
41.1K
02:58Crystal Field Theory - Octahedral Complexes
25.9K
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...
25.9K
02:51Metal-Ligand Bonds
20.4K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
20.4K