Co (III) と Rh (III) のトリスダイアミン複合体における光学活動の起源について:時間依存密度関数理論に基づく単純なモデル
Francisco Elias Jorge1, Jochen Autschbach, Tom Ziegler
1Department of Chemistry, University of Calgary, Calgary, Alberta, T2N-1N4, Canada.
Journal of the American Chemical Society
|January 20, 2005
まとめ
時間依存密度関数理論は,コバルト複合体の円形二重化スペクトルを正確に予測します. ラムダとデルタの構成の違いは,八面体幾何学の歪みに関連しています.
科学分野:
- 無機化学 無機化学とは
- コンピューティング・ケミストリー
- スペクトル顕微鏡検査です.
背景:
- 円形二重化 (CD) スペクトロスコピーは,キラル金属複合体の絶対的構成を決定するために重要である.
- 分子構造とCDスペクトルの関係を理解することは,複雑な無機化合物の特徴づけに役立ちます.
研究 の 目的:
- 時間依存密度関数理論 (TD-DFT) を適用して,様々なコバルト (III) 複合体のCDスペクトルを計算および分析する.
- CDのスペクトル特性に対するステレオアイソメリズム (ラムダ対デルタ構成) の影響を調査する.
- 理想の八面体対称性からの幾何学的歪みとスペクトル差を相関させる.
主な方法:
- 時間依存密度関数理論 (TD-DFT) の計算.
- d-dとリガンドから金属への電荷移転 (CT) 領域におけるCDスペクトルの分析.
- コバルト (III) 複合体とロジウム (III) 複合体の実験データと計算されたスペクトルの比較.
主要な成果:
- TD-DFTは,コバルト複合体のLambdaとDelta構成のCDスペクトルの大きな違いを成功裏に再現しました.
- ラムダ形状における八面体幾何学からのより大きなアジムタル歪みは,スペクトルパターンに影響を与える重要な要因として特定されました.
- この研究では,ロジウム複合体の特定の同位体に対するCDスペクトルも検討した.
結論:
- TD-DFTは,キラル協調複合体のCDスペクトルの予測と解釈のための信頼できるツールです.
- 幾何学的歪みは,金属複合体のCDスペクトル特性を決定する上で重要な役割を果たします.
- この発見は,コバルトとロジウム複合体のステレオ化学的性質についての洞察を提供します.
さらに関連する動画
08:54Vibrational Spectra of a N719-Chromophore/Titania Interface from Empirical-Potential Molecular-Dynamics Simulation, Solvated by a Room Temperature Ionic Liquid
Published on: January 25, 2020
08:04Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
関連する概念動画
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...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
02:58Crystal Field Theory - Octahedral Complexes
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...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 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 dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 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 dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
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.
02:24Properties of Enantiomers and Optical Activity
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...