アニオンとカチオンがテトラトピックイオン対の宿主と結合する協力性と複雑性
Ethan N W Howe1, Mohan Bhadbhade, Pall Thordarson
1School of Chemistry, The University of New South Wales , Sydney, NSW 2052, Australia.
Journal of the American Chemical Society
|May 15, 2014
まとめ
この研究は,アニオン結合のためのテトラトピックイオンペアホスト (1) の負の協力性を明らかにしています. カルシウムカチオンのアロステリック活性化塩化物結合は,協同的な超分子システムを設計するための洞察を提供します.
科学分野:
- 超分子化学 超分子化学
- ホスト・ゲスト・ケミストリー
- 分子認識による分子認識
背景:
- 協力的な相互作用は,自然と合成の超分子システムにおいて極めて重要です.
- これらの相互作用を理解することは,高度な機能的材料の設計の鍵です.
- テトラトピックイオンペアホストは,複雑な分子認識イベントのためのプラットフォームを提供します.
研究 の 目的:
- 新しいテトラトピックイオンペアホストの (1) 協力的結合特性を調査する.
- ホスト・ゲスト・システムにおける複雑な協力的相互作用を定量化する.
- カチオンによる結合イベントのアロステリック変調を調査する.
主な方法:
- ホストとそのカルシウム複合体の単結晶X線分析.
- 二次元核磁共振 (2D NMR) スペクトルスコピー. 二次元核磁共振 (2D NMR) スペクトルスコピー.
- 計算研究とバインディングモデルの分析.
主要な成果:
- ホスト1は,塩化物およびアセテートアニオンに対して強い負の協力性 (α = 0.010.05) を示す.
- カチオン結合の結果は変動したが,加熱されたカルシウムはアロステリックに活性化され,それ以外の場合は塩化物結合が欠けていた.
- 詳細な構造データと計算データにより,結合メカニズムが解明されました.
結論:
- テトラトピックイオンペアホスト (1) は,複雑な協力的結合行動を示しています.
- アロステルカチオン結合はアニオン認識を調節し",オン・オフ"の切り替えを可能にします.
- 発見は,触媒と情報転送のための洗練された協力的な超分子システムを設計するための貴重な洞察を提供します.
関連する概念動画
Cooperative Allosteric Transitions
7.4K
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...
7.4K
Complexation Equilibria: Overview
1.6K
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...
1.6K
Complexation Equilibria: Factors Influencing Stability of Complexes
995
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...
995
Complexation Equilibria: The Chelate Effect
1.7K
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...
1.7K
Metal-Ligand Bonds
19.3K
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...
19.3K
Crystal Field Theory - Octahedral Complexes
28.4K
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...
28.4K


