FTIR光谱和分子层面的洞察力稀释的酸水溶液的酸
Barbara Pem1, Zlatko Brkljača2, Allan Philippe3
1Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
概括
这项研究表明,在水溶液中的酸的光谱特征比以前理解的要复杂得多. 计算和FTIR分析表明,同反异构和水合显著影响观察到的光谱波段.
科学领域:
- 物理化学 物理化学
- 频谱学是一种光谱学.
- 计算化学计算化学
背景情况:
- 几十年来,人们一直在研究酸 (AA) 的水溶液,重点是COOH组的键网络.
- 之前的研究经常将nCO光谱包裹分解为归因于不同水合的单体的频段 (AA···H2O和AA···(H2O) 2).
研究的目的:
- 调查除了简单单体外的其他物种是否有助于在水性酸溶液中的nCO光谱特征.
- 为了探索在水中的乙酸的光谱带分配的复杂性.
主要方法:
- 里叶变换红外光谱法 (FTIR) 测定酸 (CD3COOD) 在D2O和C2Cl4中.
- 密度功能理论 (DFT) 和分子动力学模拟.
- 用于制备CD3COOD和CD3COONa在D2O.O.中的稀释溶液 (0.0010.1mol dm-3) 的方法.
主要成果:
- 在0.1 mol dm-3 D2 O溶液中,CD3COOD的 νCO 波段分为 1706 cm-1 和 1687 cm-1 的两个信号.
- 结合DFT和分子动力学,揭示了光谱带分配比以前假设的更复杂.
- 确定了同反异构和水合是对广泛的nCO外有助于形成的因素.
结论:
- 在水性酸溶液中观察到的 νCO 光谱外受单一单体水化以外的因素的影响.
- 合成-抗异构在溶液中的酸的光谱特征中起作用.
- 需要进一步的研究,以充分阐明酸在水性环境中的光谱行为.
相关概念视频
01:28IR and UV–Vis Spectroscopy of Carboxylic Acids
4.3K
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
4.3K
01:26Spectroscopy of Carboxylic Acid Derivatives
2.5K
Infrared spectroscopy is primarily used to determine the types of bonds and functional groups. In carboxylic acid derivatives, a typical carbonyl bond absorption is observed around 1650–1850 cm−1. For esters, the absorption is recorded at around 1740 cm−1, while acid halides show the absorption at about 1800 cm−1. Another acid derivative, the acid anhydrides, exhibit two carbonyl absorption around 1760 cm−1 and 1820 cm−1, arising from the symmetrical and...
2.5K
01:24IR Spectroscopy: Molecular Vibration Overview
2.5K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
2.5K
01:17Solution Composition During Acid/Base Titrations
613
The titration of a weak acid with a strong base results in the formation of water and the conjugate base of the acid. For instance, titrating acetic acid with sodium hydroxide leads to the formation of water and sodium acetate. A solution of acetic acid and sodium acetate constitutes a buffer whose relative concentration at different stages of the titration is indicated by the α values, which represent percentages of the weak acid and its conjugate base.
The α0 and α1 values...
The α0 and α1 values...
613
02:00Molecular Models
38.7K
Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models makes it easier to visualize the structures and shapes of atoms and molecules.
38.7K
04:02Weak Acid Solutions
38.0K
Few compounds act as strong acids. A far greater number of compounds behave as weak acids and only partially react with water, leaving a large majority of dissolved molecules in their original form and generating a relatively small amount of hydronium ions. Weak acids are commonly encountered in nature, being the substances partly responsible for the tangy taste of citrus fruits, the stinging sensation of insect bites, and the unpleasant smells associated with body odor. A familiar example of a...
38.0K