Related Experiment Video
Updated: May 10, 2026
16:16
Genetically-encoded Molecular Probes to Study G Protein-coupled Receptors
Published on: September 13, 2013
An azobenzene unit embedded in a cyclopeptide as a type-specific and spatially directed switch
Gebhard Haberhauer1, Christine Kallweit, Christoph Wölper
1Institut für Organische Chemie, Fakultät für Chemie, Universität Duisburg-Essen, Universitätsstrasse 7, 45117 Essen, Germany. gebhard.haberhauer@uni-due.de
Angewandte Chemie (International Ed. in English)
|June 21, 2013
Summary
Researchers embedded azobenzene into a chiral scaffold, enabling controlled trans-to-cis isomerization. This chiral embedding restricts phenyl ring movement during switching, demonstrating a novel photomechanical control mechanism.
Area of Science:
- Molecular Chemistry
- Photochemistry
- Chiral Materials
Background:
- Azobenzene derivatives are widely studied for their photoresponsive properties.
- Chiral scaffolds can influence molecular behavior and introduce unique functionalities.
- Controlling isomerization pathways is crucial for developing advanced molecular devices.
Purpose of the Study:
- To investigate the effect of embedding an azobenzene unit within a chiral scaffold.
- To achieve controlled photoisomerization of azobenzene.
- To explore the mechanism of switching in a confined chiral environment.
Main Methods:
- Synthesis of a novel chiral scaffold incorporating an azobenzene moiety.
- Photoisomerization studies using UV-Vis spectroscopy to monitor trans-to-cis and cis-to-trans switching.
- Structural analysis to understand the influence of the chiral scaffold on molecular motion.
Main Results:
- Successful embedding of azobenzene into a chiral scaffold was confirmed.
- Photoisomerization between trans-(P) and cis-(P) azobenzene isomers was achieved upon light irradiation.
- The chiral scaffold restricted the phenyl rings' movement, forcing them to move directly towards each other during switching.
Conclusions:
- Embedding azobenzene within a chiral scaffold enables controlled photoisomerization.
- The chiral environment dictates a specific flipping process during azobenzene switching.
- This work provides a foundation for designing sophisticated photo-switchable chiral materials.
Related Concept Videos
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
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 position.
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
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...
01:10Nomenclature of Aryl and Heterocyclic Amines
The simplest aromatic amine is phenylamine, which contains an –NH2 functionality directly attached to an aromatic ring. The name aniline is designated for this skeleton. As shown in Figure 1, the common names of the functionalized anilines involve prefixes ortho-, meta-, and para- to indicate the substitution position. Different functionalized aniline derivatives also have notable trivial names.
01:18Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...
01:19Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.