モノ-,ディ-,およびチアニオン系β-ディケチミナートリガンド:計算による研究,および[(YbL) ((3) ((THF) ]の合成と構造,L = [[N (((SiMe)) ((3))) C (((Ph)) ((2) CH]
Odile Eisenstein1, Peter B Hitchcock, Alexei V Khvostov
1LSDSMS (UMR 5636), Université Montpellier 2, 34095, Montpellier Cedex 5, France.
Journal of the American Chemical Society
|September 4, 2003
まとめ
研究者は,混合のYb (II) / Yb (III) 酸化状態を持つ新しい三核イテルビウム (Yb) クラスタを合成しました. このクラスターは,このクラスターです.
科学分野:
- 有機金属化学 有機金属化学
- 協調化化学について
- ランタナイド化学 ランタナイド化学
背景:
- ベータ-ディケチミネートリガンドを持つイテルビウム複合体は興味を惹きます.
- 混合価ランタニドクラスターの電子構造を理解することは困難です.
研究 の 目的:
- 混合のYb (II) とYb (III) の酸化状態を持つ新しい三核イテルビウムクラスタを合成し,特徴づけること.
- このクラスターと関連するYb (II) 複合体内の電子分布を調査する.
主な方法:
- [YbL2]とYb-ナフタレンを用いた三核型Ybクラスタ [(YbL) 3 ((THF) ] (1) の合成.
- X線結晶学による特徴付け.
- 密度関数理論 (DFT) とONIOM (量子力学/分子力学) の計算を用いた計算分析.
主要な成果:
- Yb (II) とYb (III) の両方のセンターを含む新しい三核型Ybクラスター (1) が成功裏に合成され,特徴づけられました.
- X線結晶学により,星団の構造が確認されました.
- DFTとONIOMの計算は,クラスター1とYb (II) 複合体 (2) 内の電子分布についての洞察を提供した.
結論:
- この研究では,Yb (II) /Yb (III) の混合酸化状態を持つ最初の三核型Yb群が報告されています.
- 電子構造分析は,混合価ランタニド系を理解するために貴重な情報を提供します.
さらに関連する動画
関連する概念動画
Coordination Number and Geometry
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.


