関連する実験動画
Updated: Jan 6, 2026
16:20
Hyperpolarized Xenon for NMR and MRI Applications
Published on: September 6, 2012
20.1K
強いπ-バックボンドは,シアン化物を通して磁気交換コップリングを記録します
Juan A Valdez-Moreira1, Agnes E Thorarinsdottir2, Jordan A DeGayner2
1Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , Indiana 47405 , United States.
Journal of the American Chemical Society
|October 12, 2019
まとめ
研究者は新しいパラマグネティック複合体 PhB ((tBuIm)) 3Fe-NC-Mo ((NtBuAr)) 3を組み立て,シアン化物を通じてこれまでに記録された最も強い磁気交換結合を示しました. この発見は,強力な磁気相互作用を促進する低座標の金属断片の役割を強調しています.
科学分野:
- 無機化学
- 材料科学
- マグネト化学
背景:
- パラマグネティックなシアノブリッジ複合体は,その磁性特性に興味があります.
- このような複合体における電子移位を理解することは,磁気交換相互作用の調整に不可欠です.
研究 の 目的:
- 新しいパラマグネティックサイアノブリッジ複合体を合成し特徴づけること
- 複合体の磁気交換カップリングと電子構造を調査する
- 低座標の金属断片が磁気相互作用を媒介する役割を調査する.
主な方法:
- 4座標の鉄 (II) モノシアン化物複合体と3座標のモリブデン (III) 複合体の合成
- 構造と結合分析のためのX線 difraktionとIRスペクトル.
- 直流 (dc) の磁気感受性測定
- 電子構造の計算
主要な成果:
- パラマグネティック複合体PhB{\ tBuIm) 3Fe-NC-Mo{\ NtBuAr) 3の組み立てに成功した.
- X線 difraktionとIRスペクトロスコピーは,C−N結合の順序を減らすサイアニド π*軌道にペア化されていない電子密度の移転を示した.
- 磁気感受性の測定は,J = -122 (((2) cm−1で強い反鉄磁気交換を明らかにし,これはシアン化物を通して最も強く観察された.
- 電子構造の計算は実験結果を支持した.
結論:
- この研究は,これまでで最も強い 磁気交換結合をシアン化物で示しています.
- 低座標の金属断片は,シアン化物リガンドへのπ-バックボンドによって,非常に強い磁気交換を誘導することができる.
- この研究は,調整可能な性質を持つ新しい磁気材料を設計するための道を開きます.
さらに関連する動画
関連する概念動画
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.5K
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...
1.5K
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.4K
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...
1.4K
01:17Spin–Spin Coupling: One-Bond Coupling
1.4K
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,...
1.4K
01:27¹H NMR: Long-Range Coupling
2.5K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
2.5K
02:32Bonding in Metals
51.6K
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
51.6K
02:40Chemical Bonds
20.6K
Atoms participate in a chemical bond formation to acquire a completed valence-shell electron configuration similar to that of the noble gas nearest to it in atomic number. Ionic, covalent, and metallic bonds are some of the important types of chemical bonds. Bond energy and bond length determine the strength of a chemical bond.
Types of Chemical Bonds
An ionic bond is formed due to electrostatic attraction between cations and anions. Often, the ions are formed by the transfer of electrons...
20.6K