関連する実験動画
Updated: Jul 16, 2026

10:35
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
超高速UVポンプ/IRプローブの研究で,線形,周期性,およびアリル炭化水素におけるC-H活性化に関する研究が行われました
Matthew C Asplund1, Preston T Snee, Jake S Yeston
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|August 29, 2002
まとめ
ロジウム複合体による光化学的C-H結合活性化が研究されました. 基板構造は活性化に影響を与え,芳香C-H結合は,溶解した中間物質を含む異なる経路を経由して進行します.
科学分野:
- 有機金属化学 有機金属化学
- フォトケミストリー フォトケミストリー
- 反応ダイナミクス 反応ダイナミクス
背景:
- ロジウム複合体は,有機合成における重要な触媒である.
- C-H活性化メカニズムの理解は,新しい触媒プロセスの開発に不可欠です.
- 光化学的活性化は,ユニークな反応経路を提供します.
研究 の 目的:
- 複合体eta(3) -TpRh(CO) ((2) とCpRh(CO) ((2) の光化学C-H活性化反応を調査する.
- 炭化水素基板構造がC−H結合活性化ダイナミクスに及ぼす影響を明らかにする.
- eta(3) -TpRh ((CO) ((2) とCpRh ((CO) ((2) の反応機構を比較する.
主な方法:
- フェムト秒からマイクロ秒までの時間解像度スペクトルスコピー.
- 様々な線形,周期性,および芳香的炭化水素溶媒における反応の研究.
- eta(3) -TpRh ((CO) ((2) とCpRh ((CO) ((2) 複合体の比較分析.
主要な成果:
- 炭化水素基板構造が最終的なC-H結合活性化ステップを決定し,主要なC-H部位を好む.
- アロマティックC-Hの活性化は,シグマとピの溶解した中間物質を持つ平行チャネルを通過する.
- CpRh (((CO)) (((2) のサイクロペンタディエニルリガンドは,eta (((3) -TpRh (((CO)) (((2) と異なり,反応動力学に直接影響を与えない.
結論:
- 基質のC-H結合のアクセシビリティと電子的要因は,光化学的C-H活性化における重要な決定因子である.
- eta(3) -TpRh ((CO) ((2) の反応機構は,リガンド作用により,CpRh ((CO) ((2) と大きく異なっている.
- これらの発見は,選択的なC-H機能化戦略の洞察を提供します.
関連する概念動画
Ultraviolet and Visible (UV–Vis) Spectroscopy: Overview
Ultraviolet–visible (UV–visible or UV–Vis) spectroscopy is an analytical technique that investigates the interaction between matter and UV–Vis light within the electromagnetic spectrum. This method is widely used for its versatility, simplicity, and relatively quick data acquisition, making it valuable for both qualitative and quantitative analysis. When UV–Vis radiation passes through a material, molecules absorb light depending on the energy required for electronic transitions. As a result...
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the C=O stretching, is...
IR and UV–Vis Spectroscopy of Carboxylic Acids
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, 1710 cm−1. The C=O bond of the...
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, 1710 cm−1. The C=O bond of the...
UV–Vis Spectrometers
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell. Samples for...
IR Spectrometers
There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR spectrometer, a beam of infrared radiation produced by a hot wire is divided into two parallel equal-intensity beams using mirrors. One beam passes through the sample, while another is a reference beam. The beams then move through the monochromator, which separates the radiations into a continuous spectrum of different frequencies. The...
IR Frequency Region: X–H Stretching
In IR spectroscopy, signals produced by the X−H bonds (such as C−H, O−H, or N−H) can be observed in the frequency range of 2700–4000 cm–1. The C−H stretching vibration forms sharp bands in the region 2850–3000 cm–1. The presence of the O−H stretching vibration leads to the forming of an absorption band in the frequency range 3650–3200 cm−1. At the same time, N−H stretching can be confirmed by absorption bands in the 3500–3100 cm−1 range. Even though both O−H and N−H bonds vibrate at a similar...

