Photo-responsive [2]catenanes: synthesis and properties

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Photochemistry

Background:

• Dithienylethenes are photochromic compounds with potential applications in molecular switches.
• Macrocyclic compounds can serve as templates for constructing complex supramolecular architectures.
• Dynamic covalent chemistry offers a versatile approach for synthesizing interlocked molecules.

Purpose of the Study:

• To synthesize novel dithienylethene-based macrocycles containing ammonium groups.
• To utilize these macrocycles as templates for the construction of [2]catenanes via dynamic covalent chemistry.
• To investigate the photoisomerization and photochromic properties of the synthesized [2]catenanes.

Main Methods:

• Synthesis of dithienylethene-based macrocycles with ammonium moieties.
• Templated synthesis of [2]catenanes using dynamic covalent chemistry.
• Structural characterization using NMR, ESI-MS, MALDI-QTOF-MS, and elemental analysis.
• Theoretical calculations for energy minimization of open- and closed-ring isomers.
• Photochromic property evaluation under UV and visible light irradiation.

Main Results:

• Successful synthesis of novel dithienylethene-based macrocycles and their corresponding [2]catenanes.
• Confirmation of structures through comprehensive spectroscopic and analytical techniques.
• Demonstration of photoisomerization in the [2]catenanes upon light irradiation.
• Observation of good reversibility and excellent fatigue resistance in the photochromic switching.
• Enhanced photochromic performance of [2]catenanes compared to macrocyclic precursors.

Conclusions:

• Dithienylethene-based macrocycles effectively template the formation of photoisomerizable [2]catenanes.
• The synthesized [2]catenanes exhibit robust and reversible photochromic behavior.
• The supramolecular structure of the [2]catenanes positively influences their photoswitchable properties.