Related Experiment Video
Updated: Dec 22, 2025
04:38
Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions
Published on: July 28, 2022
3.3K
Configurational Selection in Azobenzene-Based Supramolecular Systems Through Dual-Stimuli Processes
Paolo Tecilla1, Davide Bonifazi2
1Dipartimento di Matematica e Geoscienze Università degli Studi di Trieste Via Weiss 2 1 34127 Trieste Italy.
Chemistryopen
|May 7, 2020
Summary
Azobenzene molecular switches enable control over supramolecular systems. Molecular recognition events allow predictable E/Z isomerization, creating metastable states beyond thermodynamic equilibrium.
Area of Science:
- Supramolecular Chemistry
- Photochemistry
- Molecular Switches
Background:
- Azobenzene is a well-studied photoactive molecule used in supramolecular systems.
- Its unique photoisomerization drives systems out of thermodynamic equilibrium.
- Controlling isomeric distribution is key for predictable system behavior.
Purpose of the Study:
- To review photoswitchable systems utilizing azobenzene for controlled configurational equilibrium.
- To highlight how molecular recognition influences azobenzene isomerization.
- To showcase systems with predictable, reversible control over supramolecular composition.
Main Methods:
- Review of existing literature on azobenzene-containing photoswitchable systems.
- Analysis of systems employing molecular recognition for isomer control.
- Categorization of systems based on guest type (cations, anions, neutral).
Main Results:
- Azobenzene's E/Z photoisomerization can create metastable supramolecular states.
- Molecular recognition events provide an additional trigger for controlling isomeric ratios.
- Programmed architectures successfully bind various guests, influencing configurational distribution.
Conclusions:
- Molecular recognition combined with light stimuli offers precise control over azobenzene-based supramolecular systems.
- This approach enables the design of systems with predictable and reversible configurational composition.
- These findings advance the development of advanced photoresponsive materials.
![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
01:26Photochemical Electrocyclic Reactions: Stereochemistry
2.1K
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
2.1K
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
3.5K
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para...
3.5K
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
3.7K
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...
3.7K
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
9.4K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
9.4K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.5K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.5K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.4K
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.
2.4K