Related Experiment Video
Updated: Jun 6, 2026
10:33
An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation
Published on: February 27, 2019
Three-State Electrochiroptical Switches Derived from Chiral Stable Carbenes
Patrick Yorkgitis1, Nicolas Vanthuyne2, Marie Cordier3
1UCSD-CNRS Joint Research Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
Journal of the American Chemical Society
|June 4, 2026
Summary
Chiral stable carbenes enable new three-state electrochiroptical switches. These switches utilize redox-driven changes in chirality for tunable electronic and optical properties in stimuli-responsive materials.
Area of Science:
- Organic Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Chiral redox switches are key for stimuli-responsive materials and organic electronics.
- Stable carbenes are widely used in redox-active materials and asymmetric synthesis.
- The integration of stable carbenes into chiral redox switches is an underexplored area.
Purpose of the Study:
- To explore the use of chiral stable carbenes in constructing novel chiral redox switches.
- To develop three-state electrochiroptical switches based on these new materials.
- To demonstrate the tunable chiroptical properties driven by redox-induced chirality exchange.
Main Methods:
- Synthesis of helically chiral overcrowded alkenes using chiral stable carbenes.
- Electrochemical characterization to induce redox-driven (de)aromatization.
- Chiroptical property measurements (electronic circular dichroism) to monitor chirality changes.
Main Results:
- Successfully constructed helically chiral overcrowded alkenes that act as three-state switches.
- Demonstrated reversible exchange between helical and axial chirality via a π-radical cation intermediate.
- Observed distinct chiroptical properties for each state due to significant electronic and geometric structure changes, including chirality inversion.
- Showcased multiple cycles of electrochemical ON-OFF switching and sign inversion of the circular dichroism response.
Conclusions:
- Chiral stable carbenes are effective building blocks for chiral redox-switchable materials.
- This work establishes a new platform for designing advanced electrochiroptical switches.
- The developed materials offer promising applications in stimuli-responsive systems and organic electronics.
Related Concept Videos
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
02:05Prochirality
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...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
00:58¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons
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...
02:25Molecules with Multiple Chiral Centers
Molecules that possess multiple chiral centers can afford a large number of stereoisomers. For instance, while some molecules like 2-butanol have one chiral center, defined as a tetrahedral carbon atom with four different substituents attached, several molecules like butane-2,3-diol have multiple chiral centers. A simple formula to predict the number of stereoisomers possible for a molecule with n chiral centers is 2n. However, there can be a lower number where some of the stereoisomers are...