テトラフォスフィン・フェロセニル誘導体の核スピン・スピンJ (PP) カップリングにおける"宇宙を通る"核スピン: (31) P NMRとX線構造の相関研究,調整複合体の研究
Jean-Cyrille Hierso1, Aziz Fihri, Vladimir V Ivanov
1Contribution from the Laboratoire de Synthèse et d'Electrosynthèse Organométalliques, UMR-CNRS 5188, Université de Bourgogne, Facultés des Sciences Mirande, 9 Avenue Alain Savary, BP 47870 F-21078 Dijon Cedex, France. jean-cyrille.hierso@u-bourgogne.fr
Journal of the American Chemical Society
|September 2, 2004
まとめ
我々は,新種の有機金属複合体が,空間を通過した-31のスピン・スピン・カップリング (J(PP)) を示すことを報告する. 幾何学的なパラメータは,結合強度と相関し,単一対の重複理論をリンと金属軌道に拡張します.
科学分野:
- 有機金属化学 有機金属化学
- 核磁共振スペクトロスコーピー 核磁共振スペクトロスコーピー
- 固体化学 固体化学
背景:
- 穿越空間核スピンスピンカップリング (J(PP)) は,分子幾何学への洞察を提供します.
- 既存の単一対の重複理論は,有機分子における結合をうまく説明しています.
- これらの理論を有機金属複合体の-31 (31P) カップリングに適用することはあまり研究されていない.
研究 の 目的:
- 新型有機金属テトラフォスフィンのニッケルとパラジウム複合体を報告する.
- phosphorus-31-phosphorus-31 (31P-31P) の空間間結合定数 (J(PP)) を正確に決定するために.
- ジオメトリックパラメータとJ(PP) の間の相関を確立し,既存のカップリング理論を拡張する.
主な方法:
- 新型テトラフォスフィンニッケルとパラジウム複合体の合成.
- 第2次スペクトルのNMR反復シミュレーションによるJ(PP) 定数の決定.
- 固体構造分析は,X線微分を用いてP−P距離を決定する.
主要な成果:
- 新しい複合体の正確なJ (PP) 値は得られた.
- 幾何学的なパラメータ (P-P距離) と J(PP) の強度との相関が観察されました.
- 単一対の重複理論は,31P-31Pの空間間結合を考慮するために成功裏に拡張されました.
結論:
- 単一対の重複モデルは,31P-31Pの空間間結合を理解するための信頼性の高い基盤を提供します.
- このモデルは,協調複合体における金属軌道貢献を含むように成功裏に拡張されました.
- この研究は,有機金属系における空間間結合を分析するための新しい理論的枠組みを提供します.
さらに関連する動画
関連する概念動画
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...
01:08NMR Spectroscopy: Spin–Spin Coupling
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:17Spin–Spin Coupling: One-Bond Coupling
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...