Video Experimental Relacionado
Updated: Aug 3, 2026
09:48
In Situ Characterization of Hydrated Proteins in Water by SALVI and ToF-SIMS
Published on: February 15, 2016
Pruebas espectroscópicas infrarrojas de grupos de agua protonada que forman jaulas a nanoescala
Mitsuhiko Miyazaki1, Asuka Fujii, Takayuki Ebata
1Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
Science (New York, N.Y.)
|May 1, 2004
Resumen
La red de enlaces de hidrógeno en los grupos de agua protonada (H+(H2O) n) evoluciona con el tamaño. Los pequeños grupos forman cadenas, pasando a redes 2D, y finalmente a jaulas a escala nanométrica a medida que el tamaño aumenta.
Área de la Ciencia:
- La Química Física es la química física.
- La espectroscopia es una técnica de espectroscopia.
- Ciencias del clúster Ciencias del clúster.
Sus antecedentes:
- Las agrupaciones de agua protonada son sistemas fundamentales en química.
- Comprender su red de enlaces de hidrógeno es crucial para varios procesos químicos.
Objetivo del estudio:
- Para investigar la evolución dependiente del tamaño de las estructuras de la red de enlaces de hidrógeno en grupos de agua protonada.
- Para correlacionar el tamaño del clúster con las transiciones estructurales.
Principales métodos:
- Se empleó la espectroscopia infrarroja de los tramos de OH.
- Se estudiaron racimos de agua protonada H+(H2O) n con n = 4 a 27.
Principales resultados:
- Los cambios espectrales observados indican regímenes estructurales distintos basados en el tamaño del clúster.
- Las estructuras de cadena dominan pequeños grupos (n ≤ 10).
- Las estructuras de redes bidimensionales emergen en grupos intermedios (10 < n < 21).
- Las estructuras de jaula a escala nanométrica se forman en grupos más grandes (n ≥ 21).
Conclusiones:
- La estructura de la red de enlaces de hidrógeno de los grupos de agua protonados exhibe un desarrollo significativo dependiente del tamaño.
- Se observa una clara progresión de la cadena a la red 2D a las estructuras de jaula con el aumento del tamaño del racimo.
Más Videos Relacionados
Videos de Conceptos Relacionados
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...
01:10¹H NMR of Labile Protons: Temporal Resolution
Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
00:48¹H NMR of Labile Protons: Deuterium (²H) Substitution
This lesson illustrates the role of deuterium substitution in simplifying the NMR spectrum of compounds comprising labile protons. One method employed is the use of deuterium. Amongst the three isotopes of hydrogen, deuterium (2H) has a nucleus composed of one proton and one neutron. When the D2O solvent is added to a pure dry ethanol solution, its labile proton is substituted with deuterium.
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 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...
01:19NMR Spectroscopy Of Amines
In proton NMR spectroscopy, primary amines and secondary amines showcase their N–H protons as a broad signal in the chemical shift range between δ 0.5 and 5 ppm. The exact position in this range depends on several factors, including sample concentration, hydrogen bonding, and the type of solvent used. Since amine protons undergo fast proton exchange in solution, the protons are labile and therefore do not participate in any splitting with adjacent protons. Thus, the observed peak is broad and...