DFTは,電子を取り除くリガンドを持たない端末Pt(IV) -オクソ複合体の構造と反応性を研究する
Irena Efremenko1, Elena Poverenov, Jan M L Martin
1Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76000, Israel.
Journal of the American Chemical Society
|October 1, 2010
まとめ
安定したプラチナ-オクソ複合体である[(PCN) PtO](+) は,DFTを用いて研究された. 調整された溶媒分子は,その二磁性,酸素伝達,CO酸化能力に影響を与える.
科学分野:
- 無機化学 無機化学とは
- 有機金属化学 有機金属化学
- コンピューティング・ケミストリー
背景:
- 安定したd(6) 終端移行金属オクソ複合体は,電子を取り除くリガンドなしでは稀である.
- オキソ複合体は,酸素伝達反応における重要な中間物質である.
- [(PCN) PtO](+) 複合体は,これらの重要な中間物質のモデルとして機能します.
研究 の 目的:
- [(PCN) PtO](+) 複合体の広範なDFT研究を実施する.
- その幾何学的および電子的構造,溶液組成,および反応性を調査する.
- 補助リガンドと結合相互作用の役割を明らかにする.
主な方法:
- 密度関数理論 (DFT) による計算.
- 熱力学データ分析. 熱力学データ分析.
- (195) Pt NMRの化学シフトの計算.
主要な成果:
- 溶媒の分子 (アセトン) は溶液の中で弱調整し,複合体を安定させます.
- この補助リガンドは二磁性状態を誘導し,分子内酸素伝搬を遅らせ,CO酸化を助長する.
- Pt-oxo結合は,リガンド曲線とPt 5dから6s/6p軌道への電子密度移転により安定化される.
結論:
- 調整された溶媒分子は,複合体の性質と反応性の鍵です.
- Pt-oxoリガンドが電ophilesと相互作用することで,酸素の挿入と水の活性化などの重要な反応機構が動きます.
- 複合体の電子構造と結合は,その安定性と反応性のパターンを合理化します.
関連する概念動画
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,...
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...
01:26EDTA: Auxiliary Complexing Reagents
EDTA titrations are usually carried out in highly basic conditions, where the fully deprotonated form of EDTA, Y4−, actively complexes with the free metal ions in the solution. Several metal ions precipitate as hydrous oxide (hydroxides, oxides, or oxyhydroxides) under these conditions, lowering the concentration of free metal ions in the solution. For this reason, auxiliary complexing agents or ligands such as ammonia, tartrate, citrate, or triethanolamine are used in EDTA titrations to...
02:54Lewis Structures of Molecular Compounds and Polyatomic Ions
To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...