Singlet Oxygen Responsive Molecular Receptor to Modulate Atropisomerism and Cation Binding

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Chemical Sensing

Background:

• Switchable molecular recognition is crucial for advanced chemical systems.
• ¹O₂ (singlet oxygen) stimulus-responsive receptors offer unique, rarely exploited structural changes.
• Anthracene derivatives readily undergo [4+2] cycloaddition with ¹O₂, providing a quantitative and reversible reaction.

Purpose of the Study:

• To design and evaluate a non-macrocyclic anthracene-based host for switchable cation binding.
• To investigate the ¹O₂-controlled atropisomerism and its effect on molecular recognition.
• To assess the binding properties and fatigue resistance of the developed host system.

Main Methods:

• Design of a novel anthracene-based host molecule.
• Utilizing the [4+2] cycloaddition/cycloreversion reaction with ¹O₂.
• Structural investigation of host-guest complexes and binding studies (association constants).
• Monitoring of host-guest system fatigue over multiple reaction cycles.

Main Results:

• ¹O₂ effectively controlled atropisomerism in the anthracene-based host in an on/off manner.
• The endoperoxide receptor exhibited higher cation binding affinity compared to the parent anthracene host.
• The preorganization of the recognition site in the endoperoxide form was found to be more favorable for binding.
• The ¹O₂ switchable host and its complexes demonstrated good stability over five tested cycles.

Conclusions:

• ¹O₂ serves as a potent stimulus for reversible control over molecular recognition in anthracene-based hosts.
• The designed host system demonstrates potential for applications in switchable sensing and molecular devices.
• The study highlights the utility of exploiting ¹O₂-induced structural changes for dynamic molecular recognition.