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Light and protonation-controlled complex formation between sulfate ions and a stiff-stilbene based bis(cyclopeptide)
Stefan Mommer1, Benedict Wyrwol2, Jasper E Bos1
1Leiden Institute of Chemistry, Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands s.j.wezenberg@lic.leidenuniv.nl.
Chemical Science
|April 3, 2025
Summary
This study introduces a novel sulfate-binding supramolecular assembly controlled by light and pH. The system demonstrates tunable host-guest complexes, showcasing responsive materials driven by anion-ligand coordination.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Chemical Engineering
Background:
- Anion-ligand coordination is key for creating supramolecular structures.
- Stimuli-responsive transformations in metal-ligand complexes are well-documented using photoswitches.
- Responsive systems based on anion-ligand coordination-driven assemblies are less explored.
Purpose of the Study:
- To develop a novel photoswitchable supramolecular assembly driven by sulfate coordination.
- To investigate the interconversion between different assembly states using light and acid/base stimuli.
- To demonstrate the potential of anion-ligand coordination in creating controllable responsive systems.
Main Methods:
- Synthesis of a sulfate-binding bis(cyclopeptide) featuring a photoswitchable stiff-stilbene linker.
- Characterization of assembly states influenced by (E)- and (Z)-isomers of the photoswitch.
- Analysis of host-guest stoichiometries (1:1, 1:2, 2:2) under varying protonation states of sulfate (HSO4- vs. SO42-).
- Demonstration of interconversion between assembly states via light irradiation and acid/base addition.
Main Results:
- The developed bis(cyclopeptide) effectively binds sulfate anions.
- Distinct supramolecular assembly states are achieved, correlating with the photoswitch's isomeric form and sulfate protonation.
- Tunable host-guest stoichiometries (1:1, 1:2, 2:2) were observed and controllable.
- Light irradiation and pH changes successfully induced interconversion between these states.
Conclusions:
- A novel, light- and pH-responsive supramolecular system based on sulfate coordination has been successfully developed.
- The system exhibits controllable transformations between different assembly states and host-guest stoichiometries.
- This work highlights the significant potential of anion-ligand coordination-driven assemblies for creating advanced responsive materials.
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