IRMPDのスペクトロスコピーは,AGGがオクサゾロンb2+イオンを形成することを示しています
Sung Hwan Yoon1, Julia Chamot-Rooke, Brittany R Perkins
1Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA.
Journal of the American Chemical Society
|December 9, 2008
まとめ
赤外線複数の光子解離 (IRMPD) スペクトロスコピーは,陽子化されたサイクルアラニン-グリシン (AG) とAGGからのb(2)(+) イオンの構造を確認しました. この振動スペクトロスコピーの技術は,詳細な分子構造の洞察を提供します.
科学分野:
- 化学物理 化学物理
- スペクトル顕微鏡検査です.
- コンピューティング・ケミストリー
背景:
- 分子構造の探知は化学において極めて重要です.
- 赤外線複数の光子解離 (IRMPD) スペクトロスコピーは,構造分析のための強力な方法を提供します.
- 実験的なIRMPDと理論的な計算を組み合わせることで,構造的な解明が強化されます.
研究 の 目的:
- プロトネートされたサイクルアラニン-グリシン (cAG) の構造を決定する.
- 陽子化されたAGG.から派生したb(2)(+) イオンの構造を調査する.
- 提案された構造を,スペクトロスコピーの証拠を用いて確認する.
主な方法:
- 赤外線複数の光子解離 (IRMPD) スペクトロスコピー. 赤外線複数の光子解離 (IRMPD) スペクトロスコピー.
- 理論的な振動スペクトルの計算.
- 実験スペクトルと理論スペクトルの比較.
主要な成果:
- 陽子化されたcAGの実験スペクトルは,理論的なダイケトピペラジン構造と一致し,アランインとグリシンアミド酸素で陽子化を示唆しています.
- b(2)(+) イオンスペクトルは,環の窒素にプロトン化された理論的なオクサゾロンの構造と一致します.
- カーボニル伸縮帯の明確な青いシフトは,陽子化されたcAGとb(2)(+) イオンとの構造的な違いを確認しています.
結論:
- IRMPDのスペクトロスコピーは,陽子化されたcAGとb(2)(+) イオンの構造を明らかにすることに成功しました.
- 以前提案されたb(2)(+) イオンのオクサゾロン構造は確認された.
- この研究は,ペプチドイオンの詳細な構造分析のためのIRMPDスペクトロスコピーの有用性を実証しています.
さらに関連する動画
08:22Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
関連する概念動画
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single stretching vibration...
01:24IR 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...
00:55IR Spectrum Peak Intensity: Amount of IR-Active Bonds
When infrared radiation is passed through a molecule, absorption occurs if the molecule's vibration leads to a substantial change in its bond dipole moment. Transitions between vibrational energy levels, typically corresponding to infrared frequencies (4000–400 cm−1), allow absorption if the vibration significantly alters the dipole moment, making the molecule infrared active. The molecular bonds have different stretching and bending vibrations, resulting in various peaks with varying...
01:23IR Spectrum Peak Broadening: Hydrogen Bonding
The vibrational frequency of a bond is directly proportional to its bond strength. As a result, stronger bonds vibrate at higher frequencies, while weaker bonds vibrate at lower frequencies. The stretching vibration of the strong O–H bond in alcohols and phenols (very dilute solution or gas phase) appears as a sharp peak at 3600–3650 cm−1.
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular hydrogen bonding...
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular hydrogen bonding...
01:24IR Spectroscopy: Molecular Vibration Overview
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...
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...