水中のメタルヒドリド複合体の水分性 d(6)
1Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA. ccreutz@bnl.gov
Journal of the American Chemical Society
|February 10, 2009
まとめ
水中のメタルヒドリド複合体の水分性は,コバルトとロジウムのリドックス特性と酸性測定,ルテニウムの二酸化炭素/フォーマットイオン均衡を用いて決定されました.
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
- 溶液化学について
背景:
- 金属ヒドリド複合体は,触媒と水素貯蔵において極めて重要です.
- 水溶液におけるその安定性を理解することは,実用的な応用に不可欠です.
- 水素ドナーの能力の尺度である水素性は,反応性の鍵です.
研究 の 目的:
- 水中の金属ヒドリド複合体の水分性を計算し比較する.
- 異なる金属中心の水分性を決定するための信頼できる方法を確立する.
- 新しい触媒システムを設計するための基本的なデータを提供すること.
主な方法:
- コバルトとロジウム複合体の水分性計算は,酸化還元特性と酸性測定を介して行われます.
- 二酸化炭素/フォーマットイオンとの均衡によるルテニウム複合体の水分性決定.
- 電気化学的および均衡ベースの技術を水性媒体で利用する.
主要な成果:
- 特定のd(6) メタルヒドリド複合体の定量化水分度値.
- 様々な金属中心に異なる方法の適用性を実証した.
- 水中のヒドリドドナー濃度の比較分析を行った.
結論:
- 水中の金属ヒドリド複合体の水分性を評価するための確立された方法論.
- ハイドリドドナー能力に対する金属アイデンティティの影響を強調した.
- 均質な触媒と水素関連技術の進歩に不可欠なデータを生成しました.
関連する概念動画
03:45Formation of Complex Ions
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...
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
01:20Aldehydes and Ketones with Water: Hydrate Formation
An oxygen-based nucleophile, like water, can undergo addition reactions with aldehydes and ketones. The reaction leads to the formation of hydrates, also referred to as 1,1-diols or geminal diols.
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
02:54Ions as Acids and Bases
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:
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
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...