Chiroptical switches and sensors based on ligand conformational changes in labile coordination complexes

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Analytical Chemistry

Background:

• Circular dichroism (CD) spectroscopy is a powerful tool for probing molecular chirality.
• Developing selective and sensitive molecular sensors for metal ions remains a significant challenge.
• Chiroptical switches responsive to redox stimuli are crucial for advanced molecular devices.

Purpose of the Study:

• To design and synthesize novel molecules exhibiting differentiated circular dichroic (CD) signals.
• To explore the application of these molecules as sensors for metal ions and as redox-mediated chiroptical switches.
• To investigate the mechanism of CD signal generation, including excitonic coupling.

Main Methods:

• Synthesis of novel chiral molecular complexes.
• Circular dichroism (CD) spectroscopy for signal detection.
• Metal ion titration experiments.
• Redox potential measurements and electrochemical analysis.
• Computational modeling to understand excitonic coupling.

Main Results:

• Developed molecules show significantly differentiated CD signals in response to specific metal ions.
• Demonstrated metal ion exchange detection using CD signal changes.
• Achieved redox-mediated switching of CD signals.
• Observed excitonic coupling in certain complexes, correlating CD signals with ligand conformation and absolute configuration.

Conclusions:

• The synthesized molecules serve as effective prototypes for metal ion sensors and chiroptical switches.
• Excitonic coupling provides valuable information on molecular structure and stereochemistry.
• These findings open avenues for advanced chiroptical sensing and molecular electronics.