Related Experiment Video
Updated: Apr 28, 2026
11:10
Fabrication and Operation of a Nano-Optical Conveyor Belt
Published on: August 26, 2015
11.2K
Enantiomer-Specific Nucleation Phase Selection under Nonequilibrium Optical Trapping.
Wen-Chi Wang1, Qing-Yu Zhang1, Kazuki Okano1,2
1Department of Applied Chemistry and Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.
The Journal of Physical Chemistry Letters
|April 27, 2026
Summary
Researchers achieved enantiomer-specific control over crystallization using circularly polarized light. This optical trapping method reverses phase selection in binary systems by manipulating kinetic pathways, not just thermodynamics.
Area of Science:
- Crystallization science
- Nonlinear optics
- Materials chemistry
Background:
- Controlling crystallization pathways under nonequilibrium conditions is challenging.
- Optical trapping offers a method to induce and manipulate crystallization.
- Understanding enantioselective crystallization is crucial for materials design.
Purpose of the Study:
- To investigate enantiomer-specific phase selection in binary crystallization induced by optical trapping.
- To explore the role of light polarization in controlling crystallization outcomes.
- To elucidate the kinetic mechanisms governing nonequilibrium crystallization.
Main Methods:
- Utilizing optical trapping with circularly polarized light to induce crystallization of acetaminophen and phenylalanine enantiomers.
- Employing *in situ* Raman spectroscopy to monitor local stoichiometry during irradiation.
- Analyzing phase selection between a stable cocrystal and a metastable phenylalanine phase.
Main Results:
- Switching the handedness of circularly polarized light reversed the dominant crystallization product.
- Raman spectroscopy confirmed no macroscopic concentration gradients, ruling out polarization-induced concentration effects.
- Phase selection was driven by a polarization-dependent kinetic bias, not thermodynamic stability.
Conclusions:
- Optical trapping with circularly polarized light enables enantioselective control over crystallization.
- Kinetic bias, influenced by light polarization and transient cluster dynamics, governs phase selection under nonequilibrium conditions.
- This work presents a novel kinetic strategy for controlling crystallization beyond traditional thermodynamic approaches.
Related Concept Videos
02:15SN1 Reaction: Stereochemistry
8.7K
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
8.7K
01:33Regioselective Formation of Enolates
2.6K
As depicted in the figure below, the unsymmetrical ketones can form two possible enolates: less substituted or more substituted enolates. Usually, the thermodynamic enolates are formed from the more substituted α-carbon atom, while the kinetic enolates are formed faster by deprotonation from the less substituted position. The thermodynamic enolates have lower energy, so they are more stable. But the energy required to form kinetic enolates is less.
2.6K
01:12Stereochemical Effects of Enolization
1.9K
The chiral α-carbon of the carbonyl compound is the stereocenter of the molecule. As shown in the figure below, when such a carbonyl compound undergoes racemization under an acidic or basic condition, an achiral enol is formed.
1.9K
02:24Properties of Enantiomers and Optical Activity
16.0K
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,...
16.0K
02:23SN2 Reaction: Stereochemistry
9.8K
In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...
9.8K
01:06Nuclear Overhauser Enhancement (NOE)
1.3K
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the nuclear Overhauser enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring spin-active...
1.3K