螺旋型のランタニド (((III) 複合体は,キラルなノンアザマクロサイクルを持つ
Janusz Gregoliński1, Przemysław Starynowicz, KimNgan T Hua
1Department of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
Journal of the American Chemical Society
|December 5, 2008
まとめ
チラルのマクロサイクリックアミンLは,エナティオピュアヘリコランタニド (((III)) 複合体を形成する. この研究は,初期のランタニドと遅いランタニドの異なる螺旋的な好みを明らかにし,遅いランタニド複合体の溶液で観察されたゆっくりとした螺旋性の逆転を示しています.
科学分野:
- 協調化化学について
- 超分子化学 超分子化学
- ランタナイド化学 ランタナイド化学
背景:
- チラルのマクロサイクリックリガンドは,エナチオピュア金属複合体を生成するために不可欠です.
- ランタニド (III) イオンは,複合体の形成のためにユニークな電子および磁気特性を提供します.
- マクロサイクル複合におけるステレオ選択性を理解することは,キラル材料の開発の鍵です.
研究 の 目的:
- 各種のランタニド (((III)) イオンのエナティオプア螺旋複合体を,キラルなノンアザマクロサイクルアミン (L) を含む合成および特徴づけること.
- これらの複合体のステレオ化学的好みと溶液の振る舞いを調査する.
- 潜在的な応用のために,選択されたランタニド複合体の光物理学的性質を探求する.
主な方法:
- キラルなノンアザマクロサイクルアミンLとそのランタニド ((III)) 複合体の合成.
- スペクトロスコーピック方法 (NMR,CD) とX線結晶学を用いた特徴付け.
- 光物理学的測定は,発光と円周的に偏光された発光 (CPL) を含む.
主要な成果:
- L を含むCe(III),Pr(III),Nd(III),Eu(III),Gd(III),Tb(III),Er(III),Yb(III,Lu(III) のエナティオプア螺旋複合体を成功裏に合成した.
- X線構造は,明確な熱力学的螺旋的な好みを明らかにした ((M) は初期のLn, (P) は後のLn).
- NMRとCDの研究では, (M) -ヘリシティの運動偏好が示され,溶液中の遅ランタニドではゆっくりとしたヘリシティの逆転が観察されました.
- 光物理学的研究では,Eu (III) とTb (III) の効率的なエネルギー転送が示されましたが,CPLによって確認された安定したキラル発射種にもかかわらず,低い量子収量でした.
結論:
- キラルマクロサイクルLは,ランタニド (((III)) 複合体におけるエナティオプアヘリコ構造を効果的に誘導する.
- 熱力学的螺旋的な好みに明確な区別があるのは,初期のランタニドイオンと後のランタニドイオンである.
- 後期ランタニド複合体は,溶液中のダイナミックなヘリシティの逆転を示し,複雑なステレオ化学的振る舞いを強調する.
- エネルギー伝達は効率的ですが,発光特性には,システム間交差や非放射性崩壊などの要因が制限されています.
さらに関連する動画
13:21Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
関連する概念動画
01:19Complexation Equilibria: The Chelate Effect
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...
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
02:52Stereoisomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
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,...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
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...