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Stereochemical Control of Redox CoII/CoIII-Cages with Switchable Cotton Effects Based on Labile-Static States
Yu-Lin Lu1, Kai Wu1, Yin-Hui Huang1
1MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, GBRCE for Functional Molecular Engineering, LIFM, IGCME, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China.
Journal of the American Chemical Society
|July 10, 2024
Summary
Researchers developed redox-switchable chiral metal-organic cages that act as an on-off chirality logic gate. These cages exhibit tunable stereostructural dynamics controlled by cobalt redox states, enabling new bioinspired applications.
Area of Science:
- Supramolecular Chemistry
- Coordination Chemistry
- Materials Science
Background:
- Artificial assemblies with tunable structural dynamics are key for bioinspired applications.
- Metal-organic cages offer versatile platforms for designing functional molecular architectures.
Purpose of the Study:
- To synthesize and characterize redox-switchable chiral metal-organic cages.
- To investigate the on-off chirality logic gate behavior controlled by redox transitions.
- To explore the stereochemical dynamics and chiral induction capabilities of these cages.
Main Methods:
- Synthesis of cobalt-containing metal-organic cages.
- Redox manipulation using chemical reduction and oxidation.
- Characterization via Nuclear Magnetic Resonance (NMR), Electrospray Ionization Mass Spectrometry (ESI-MS), Cyclic Voltammetry (CV), Circular Dichroism (CD), and X-ray crystallography.
- Kinetic studies to determine isomerization rates and activation energies.
Main Results:
- Assembly of redox-switchable chiral cages (Λ8/Δ8-[Pd6(CoII L3)8]28+ and Λ8/Δ8-[Pd6(CoIII L3)8]36+).
- Demonstration of an on-off chirality logic gate controlled by cobalt redox states (CoII vs. CoIII).
- CoII cages exhibit labile stereochemistry and chiral induction, enabling enantiomeric isomerization.
- CoIII cages are chemically inert, stabilizing specific chiral forms.
- Kinetic data show significantly slower isomerization rates and higher activation energy for CoIII cages compared to CoII cages.
Conclusions:
- Redox transitions effectively control the chirality and stereostructural dynamics of the metal-organic cages.
- The labile CoII state facilitates chiral induction and isomerization, while the static CoIII state locks chirality.
- These findings provide a blueprint for designing advanced molecular logic gates and chiral materials with tunable properties.
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