![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
弱いO-H結合を持つ水溶性Fe(II) -H2O複合体は,観察可能なモノメリックFe(III) -OHを介して水素原子を転送します
Lisa M Brines1, Michael K Coggins, Penny Chaau Yan Poon
1Department of Chemistry, University of Washington , Campus Box 351700, Seattle, Washington 98195-1700, United States.
Journal of the American Chemical Society
|January 23, 2015
まとめ
この研究では,金属イオンの性質が,O-H結合の裂け方にどのように影響するか詳細に説明しています. 鉄複合体 (Fe (II) -H2O) はより弱いO-H結合を示し,陽子結合電子伝送反応 (PCET) を促進する.
科学分野:
- 無機化学 無機化学とは
- カタリシス カタリシス カタリシス
- 反応メカニズム 反応メカニズム
背景:
- 水酸化はエネルギー変換の重要なステップであり,O-H結合の分裂を困難にします.
- 金属イオン触媒は,陽子結合電子移転 (PCET) によるO-H結合割れを促進するために不可欠です.
- 金属イオン電子構造とリガンド環境のチューニングは,触媒設計に不可欠です.
研究 の 目的:
- メタルイオンの電子構造とリガンド環境がM(H2O) -H結合分裂エネルギーにどのように影響するかを調査する.
- PCETを受けられるFe(II) -H2O複合体を合成し,特徴づけること.
- 合成複合体のO-H結合解離自由エネルギー (BDFE) と関連する金属水イオンを比較する.
主な方法:
- Fe(II) -H2O複合体の合成と特徴付け.
- 水溶液でのプロトン結合電子伝送 (PCET) 実験.
- Pourbaixの図を用いてO-H結合BDFEの計算.
- TEMPO (2,2,6,6-テトラメチルピペリジン-1-イール) オキシルラジカルを使用した反応性研究.
主要な成果:
- 新しいFe(II) -H2O複合体 (1) が合成され,特徴づけられました.
- 複合体1はPCETを受け,希少な単体Fe(III) -OH種を形成する (7).
- 複合体1のO-H BDFEは68.6 kcal/molと計算され,H2Oと[Fe (II) (H2O) ]6 (H2+) よりも有意に弱かった.
- 複合体1はTEMPOに水素原子を寄付した (((•),水素原子を抽象化する関連するM (((n+) -OH複合体とは異なり.
結論:
- 金属イオンの電子構造とリガンド環境は,O-H結合エネルギーを大幅に調整します.
- 合成されたFe (II) -H2O複合体は,弱小したO-H結合を示し,H原子の寄付を促進する.
- これらの要因を理解することは,C-H活性化とH2O酸化のための効率的な触媒を設計する上で鍵となる.
関連する概念動画
03:45Formation of Complex Ions
27.1K
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
27.1K
02:54Ions as Acids and Bases
28.2K
Salts with Acidic Ions
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
28.2K
02:48Ionic Bonding and Electron Transfer
56.2K
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.
56.2K
03:34Ionic Compounds: Formulas and Nomenclature
91.4K
An element composed of atoms that readily lose electrons (a metal) can react with an element composed of atoms that readily gain electrons (a nonmetal) to produce ions through complete electron transfer. The compound formed by this transfer is stabilized by the electrostatic attractions (ionic bonds) between the oppositely charged ions.
91.4K
03:02Colors and Magnetism
14.9K
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...
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...
14.9K
01:43Electron Transport Chain: Complex III and IV
9.9K
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
9.9K