Related Experiment Video
Updated: Jul 4, 2025
06:52
Synthesis of Esters Via a Greener Steglich Esterification in Acetonitrile
Published on: October 30, 2018
35.8K
Conformational isomerism in trans-3-methoxycinnamic acid: From solid to gas phase
Roger Castillo1, Susana Blanco1, Juan Carlos López1
1Departamento de Química Física y Química Inorgánica, IU CINQUIMA, Facultad de Ciencias, Universidad de Valladolid, Valladolid, Spain.
Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
|February 9, 2024
Summary
Researchers observed all eight predicted conformers of trans-3-methoxycinnamic acid using laser ablation chirped-pulse Fourier transform microwave spectroscopy (LA-CP-FTMW). This study reveals their planar structures and population distribution in a supersonic jet.
Area of Science:
- Molecular spectroscopy
- Physical chemistry
- Computational chemistry
Background:
- Trans-3-methoxycinnamic acid is a molecule with potential applications in materials science.
- Understanding its conformational landscape is crucial for predicting its properties and behavior.
- Microwave spectroscopy provides high-resolution data for molecular structure determination.
Purpose of the Study:
- To experimentally detect and characterize all stable conformers of trans-3-methoxycinnamic acid.
- To investigate the conformational population distribution in a supersonic jet.
- To compare experimental findings with theoretical predictions.
Main Methods:
- Chirped-pulse Fourier transform microwave spectroscopy (CP-FTMW) coupled with laser ablation (LA).
- Supersonic jet expansion for cooling and isolation of molecules.
- High-level quantum chemical calculations (B3LYP-D3BJ/6-311++(2d,p)) for conformational prediction.
Main Results:
- All eight theoretically predicted stable conformers of trans-3-methoxycinnamic acid were experimentally detected.
- Experimental rotational parameters confirmed the essentially planar structures of all observed conformers.
- Conformer populations in the supersonic jet approached equilibrium distribution at low temperatures.
Conclusions:
- The study successfully characterized the conformational landscape of trans-3-methoxycinnamic acid in the gas phase.
- Experimental data strongly supports theoretical predictions, validating the computational approach.
- The findings provide insights into molecular structure and population dynamics relevant to condensed-phase behavior.
Related Concept Videos
02:33Stereoisomerism of Cyclic Compounds
8.9K
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,...
8.9K
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
843
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...
843
02:37Disubstituted Cyclohexanes: cis-trans Isomerism
12.0K
Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds.
In cyclohexane, the substituents can occupy different positions generating distinct isomers....
In cyclohexane, the substituents can occupy different positions generating distinct isomers....
12.0K
02:02Chair Conformation of Cyclohexane
14.6K
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...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
14.6K
02:18Conformations of Ethane and Propane
14.0K
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...
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...
14.0K
02:11Conformations of Cyclohexane
12.5K
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...
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...
12.5K