Video Experimental Relacionado
Updated: May 20, 2026
10:52
Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
¿Puede una interacción C-H-O ser un determinante de la conformación?
Christopher R Jones1, Pranjal K Baruah, Amber L Thompson
1Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
Journal of the American Chemical Society
|July 14, 2012
Resumen
Los enlaces de hidrógeno no convencionales, como las interacciones C-H··O, pueden determinar la conformación molecular. Este estudio muestra que los enlaces C-H··O pueden anular las preferencias típicas, influyendo en la estructura molecular en varios sistemas.
Área de la Ciencia:
- Química Química es la química.
- Biología Molecular Biología Molecular
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- Se debate el papel de los enlaces de hidrógeno no convencionales en la conformación molecular.
- Las interacciones C-H·O son un tipo de enlace de hidrógeno no convencional.
Objetivo del estudio:
- Para investigar si las interacciones C-H··O pueden dictar la conformación molecular.
- Para determinar si los bonos C-H-O pueden superar las preferencias conformacionales establecidas.
Principales métodos:
- Estudios del estado sólido.
- Cálculos de la mecánica cuántica en los cálculos de la mecánica cuántica
Principales resultados:
- Se observó un cambio conformacional significativo de transplanar a cisplanar.
- Este cambio se produjo al introducir un grupo aceptor para el enlace de hidrógeno C-H·O.
- Los resultados apoyan el papel de las interacciones C-H··O en la determinación de la conformación.
Conclusiones:
- Los enlaces de hidrógeno C-H··O pueden actuar como determinantes de la conformación molecular.
- Estas interacciones influyen en la estructura molecular tanto en los sistemas modelo como en los naturales.
Videos de Conceptos Relacionados
02:02Chair Conformation of Cyclohexane
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
02:11Conformations of Cyclohexane
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
02:30Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
02:18Conformations of Ethane and Propane
In an organic molecule, free rotation about the carbon-carbon single bond results in energetically different conformers of the molecule. Due to this rotation, called the internal rotation, ethane has two major conformations — staggered and eclipsed.
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered ethane, the...
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered ethane, the...