Related Experiment Video
Updated: Jul 24, 2025
08:51
Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers
Published on: August 18, 2017
10.4K
Helical dichroism in enantiomeric solutions
Ashish Jain1, Jean-Luc Bégin1, Ravi Bhardwaj1
1Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
The Journal of Chemical Physics
|July 5, 2023
Summary
This study introduces a new chiroptical sensing method using helical light to detect chiral molecules. This technique shows significantly higher sensitivity for chiral powders compared to traditional methods.
Area of Science:
- Chiroptical sensing
- Nonlinear spectroscopy
- Structured light applications
Background:
- Chiral molecules are crucial in pharmaceuticals and biology.
- Conventional chiroptical techniques often lack sensitivity or tunability.
- Previous work introduced helical light as a chiral reagent for liquids.
Purpose of the Study:
- To extend helical light chiroptical sensing to solid chiral samples.
- To quantify the sensitivity of this technique for enantiopure powders.
- To explore the underlying physics of helicity-dependent absorption.
Main Methods:
- Dissolving enantiopure alanine and camphor powders in solvents of varying concentrations.
- Measuring differential absorbance of helical light.
- Comparing results with conventional linear and nonlinear techniques.
Main Results:
- Achieved an order of magnitude higher differential absorbance for helical light compared to linear techniques.
- Demonstrated sensitivity comparable to nonlinear techniques using circularly polarized light.
- Observed helicity-dependent absorption attributed to induced multipole moments.
Conclusions:
- Helical light is a versatile chiral reagent for sensing chiral powders.
- The technique offers tunable and scalable chiral signal detection.
- This opens new avenues for nonlinear spectroscopic analysis of chiral matter.
Related Concept Videos
02:24Properties of Enantiomers and Optical Activity
17.2K
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...
17.2K
00:58¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons
1.8K
Replacing each alpha-hydrogen in chloroethane by bromine (or a different functional group) yields a pair of enantiomers. Such protons are called prochiral or enantiotopic and are related by a mirror plane. Enantiotopic protons are chemically equivalent in an achiral environment. Because most proton NMR spectra are recorded using achiral solvents, enantiotopic hydrogens yield a single signal.
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...
1.8K
02:30Racemic Mixtures and the Resolution of Enantiomers
18.5K
A racemic mixture, or racemate, is an equimolar mixture of enantiomers of a molecule that can be separated using their unique interaction with chiral molecules or media. Racemic mixtures are denoted by the (±)- prefix. This ‘optical rotation descriptor’ applies to the whole solution of a racemic mixture rather than a specific stereoisomer. Enantiomers typically have the same physical and chemical properties. Hence, they are not easily separable. However, enantiomers can exhibit...
18.5K
02:52Stereoisomerism
12.2K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
12.2K
02:05Prochirality
3.8K
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
3.8K
02:33Stereoisomerism of Cyclic Compounds
9.0K
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,...
9.0K