Related Experiment Video
Updated: Nov 15, 2025
10:21
Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
8.7K
Periphery-Fused Chiral A2B-Type Subporphyrin
Shoma Hirokawa1, Nagao Kobayashi1,2, Soji Shimizu3
1Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
Molecules (Basel, Switzerland)
|March 6, 2021
Summary
Chiral subporphyrins were synthesized by adding a pyran ring. Their circular dichroism properties depend on substituents and molecular structure, offering control over chiroptical behavior.
Area of Science:
- Organic Chemistry
- Supramolecular Chemistry
- Spectroscopy
Background:
- Chiroptical properties of subporphyrins remain underexplored due to the difficulty in synthesizing chiral variants.
- Subporphyrins are macrocyclic compounds with unique electronic and photophysical characteristics.
Purpose of the Study:
- To develop inherently chiral subporphyrins by introducing a fused pyran ring.
- To investigate the structure-property relationships governing the chiroptical (circular dichroism) behavior of these novel chiral subporphyrins.
Main Methods:
- Synthesis of A2B-type meso-aryl-substituted subporphyrins with a fused pyran ring.
- Circular Dichroism (CD) spectroscopy to measure chiroptical properties.
- Time-dependent Density Functional Theory (TD-DFT) calculations for structure-property analysis.
Main Results:
- Successfully synthesized inherently chiral subporphyrins with a fused pyran ring.
- Demonstrated that peripheral substituents and dihedral angles significantly influence CD properties.
- Observed weaker CD signals for β-perbromo subporphyrins with orthogonal substituents, and more intense signals for unsubstituted analogs with smaller dihedral angles.
Conclusions:
- Chiral subporphyrins can be effectively designed and synthesized.
- Peripheral substitution and meso-aryl group orientation are key factors in controlling the chiroptical properties of subporphyrins.
- This work provides a foundation for designing subporphyrin-based chiral materials.
More Related Videos
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Related Concept Videos
02:05Prochirality
4.5K
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...
4.5K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
6.5K
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...
6.5K
02:25Chirality
28.2K
Chirality is a term that describes the lack of mirror symmetry in an object. In other words, chiral objects cannot be superposed on their mirror images. For example, our feet are chiral, as the mirror image of the left foot, the right foot, cannot be superposed on the left foot.
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
28.2K
02:25Molecules with Multiple Chiral Centers
14.3K
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...
14.3K
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
3.5K
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
3.5K
00:58¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons
2.9K
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...
2.9K