Video Experimental Relacionado

Updated: Sep 25, 2025

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase

Published on: December 4, 2017

Las intensidades de nitrilo infrarrojo caracterizan los campos eléctricos y los enlaces de hidrógeno en entornos

Jared Bryce Weaver¹, Jacek Kozuch², Jacob M Kirsh¹

¹Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States.

Journal of the American Chemical Society

|April 25, 2022

Resumen

Este estudio introduce un nuevo efecto Stark vibratorio (VSE) para los nitriles, lo que permite mediciones precisas del campo eléctrico en diversos entornos, incluidos aquellos con enlaces de hidrógeno. Este método mejora la espectroscopia vibratoria de nitrilo para aplicaciones más amplias.

Área de la Ciencia:

Biofísica y Química
Espectroscopia
Ingeniería de proteínas

Sus antecedentes:

Los nitriles son valiosas sondas vibratorias, pero su interpretación de la frecuencia infrarroja (IR) es un desafío debido al enlace de hidrógeno (enlace H) en entornos protóticos.
Comprender los campos eléctricos dentro de los sistemas biológicos es crucial para descifrar los mecanismos moleculares.

Objetivo del estudio:

Desarrollar un nuevo método vibratorio de efecto Stark (VSE) para cuantificar campos eléctricos utilizando nitriles.
Establecer un enfoque general aplicable tanto a las interacciones con y sin enlaces H.
Para permitir la determinación semiempírica de las contribuciones de enlace H a los desplazamientos de frecuencia del nitrilo.

Principales métodos:

Desarrolló un VSE lineal que correlaciona el campo eléctrico en el enlace de nitrilo (-CN) con el momento de dipolo de transición y el área de pico.
Variantes de nitrilo incorporadas en sitios de proteínas mediante supresión de ámbar.
Se han caracterizado las proteínas que contienen nitrilo mediante un análisis estructural de alta resolución.

Principales resultados:

Se ha demostrado una ESV lineal aplicable tanto a entornos con enlace H como a entornos sin enlace H.
Demostró la utilidad del análisis combinado de frecuencia e intensidad integrada.
Nitrilos validados como sondas versátiles para la determinación de campos eléctricos en diversos entornos.

Conclusiones:

El nuevo VSE proporciona un método robusto para la determinación de campos eléctricos en entornos complejos.
Los nitriles, cuando se analizan con este VSE, ofrecen una herramienta de aplicación general para sondear campos eléctricos locales.
Esta técnica hace avanzar el uso de la espectroscopia vibratoria en la investigación biofísica y química.

Más Videos Relacionados

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States

Published on: June 29, 2021

Videos de Conceptos Relacionados

IR Frequency Region: X–H Stretching

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...

NMR Spectroscopy Of Amines

NMR 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...

IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations

IR 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...

IR Frequency Region: Alkyne and Nitrile Stretching

IR Frequency Region: Alkyne and Nitrile Stretching

Both alkyne (C≡C) and nitrile (C≡N) functional groups contain triple bonds and show stretching absorptions around the wavenumber range of 2100 to 2300 cm−1 in the diagnostic region of the IR spectra.
Comparing the stretching vibrational frequency of C≡C triple bonds with that of double and single bonds, it is evident that C≡C triple bonds exhibit a higher stretching frequency than C=C double and C–C single bonds. Similarly, the C≡N triple bond...

IR Spectrum Peak Broadening: Hydrogen Bonding

IR 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...

Proton (¹H) NMR: Chemical Shift

Proton (¹H) NMR: Chemical Shift

Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
Absorption signals of all the protium nuclei...