関連する実験動画
Updated: Jun 12, 2026
09:48
In Situ Characterization of Hydrated Proteins in Water by SALVI and ToF-SIMS
Published on: February 15, 2016
硫酸イオンパターンは,長距離で水に変化します.
Jeremy T O'Brien1, James S Prell, Matthew F Bush
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|June 4, 2010
まとめ
硫酸塩イオン (SO4−2−) は,水体の構造に影響を及ぼし,その直接の周辺をはるかに超えている. この遠距離効果は,赤外線光解離スペクトロスコーピーを用いて観測され,ホフマイスター系列を理解する上で鍵となるものです.
科学分野:
- 物理化学 物理化学
- 化学物理 化学物理
- スペクトル顕微鏡検査です.
背景:
- ホフマイスターシリーズは,タンパク質溶解性に対するイオンの影響に基づいて,イオンの順序を記述しています.
- ホフマイスター効果を誘発する正確な分子機構は,まだ完全に理解されていない.
- イオンと水の相互作用を調査することは,これらの効果を明らかにするために非常に重要です.
研究 の 目的:
- ホフメイスターシリーズの化学的起源を調査するために.
- 水の構造に硫酸イオンの長距離の影響を理解するために.
主な方法:
- 赤外線光解離 (IRPD) スペクトロスコーピーを用いた.
- 硫酸イオン-水クラスター (SO(4) (((2-) (((H(2) O) ((n)) のIRPDスペクトルは,異なる水分化数 (n) について分析されました.
主要な成果:
- 43個以上の水分子 (n > 43) を有するクラスターには, ~3710 cm(-1) の明確なスペクトル帯が生じた.
- この帯は,散らばった水と同様の,外殻の水分子の"自由"OH群の存在を示します.
- 小規模なクラスター (n <= 43) でこのバンドが存在しないことは,構造的移行を示しています.
結論:
- 硫酸ダイアニオンは,水の構造に長距離の影響を及ぼします.
- この拡張された構造的混乱は,硫酸塩の観察されたホフマイスターの振る舞いに寄与する重要な要因である.
関連する概念動画
01:28Ionic Association
The ionic association is the association of oppositely charged ions in an electrolyte solution to form ion pairs. Bjerrum defined ion pairs as two oppositely charged ions whose electrostatic attraction exceeds the thermal energy of the system, typically expressed as 2kT. Electrostatic attraction depends on ionic charge, separation distance, and the dielectric constant of the medium. Thermal energy, represented by kT, reflects the tendency of ions to move independently due to molecular motion.
02:42Aqueous Solutions and Heats of Hydration
Water and other polar molecules are attracted to ions. The electrostatic attraction between an ion and a molecule with a dipole is called an ion-dipole attraction. These attractions play an important role in the dissolution of ionic compounds in water.
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
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:
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
01:16Solubility Equilibria: Ionic Product of Water
Pure water is a weak electrolyte; only a small amount ionizes into hydrogen and hydroxide ions. At any given temperature, the concentration of undissociated water is almost constant, so the ionic product of water is the product of the hydrogen and hydroxide ion concentrations, denoted as Kw. The square root of Kw gives the individual ion concentrations.
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le Chatelier's...
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le Chatelier's...