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Author Spotlight: Functionalizing Metal-Organic Frameworks: Advancements, Challenges, and the Power of Post-Synthetic Ligand Exchange
Published on: June 23, 2023
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Photoinduced Dynamic Ligation in Metal-Organic Frameworks
Qingyu Ye1, Daniel R Cairnie1, Diego Troya1
1Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24060, United States.
Journal of the American Chemical Society
|December 27, 2023
Summary
Researchers discovered light-induced bond changes in metal-organic frameworks (MOFs). This finding challenges the view of static bonds during photoexcitation, offering new insights into MOF photocatalysis mechanisms.
Area of Science:
- Materials Science
- Photocatalysis
- Spectroscopy
Background:
- Metal-organic frameworks (MOFs) are promising photocatalysts due to their high surface area and tunable properties.
- Existing understanding assumes static bonds within MOFs during photoexcitation, with active sites on metal nodes.
- The photoinduced structural dynamics of MOFs remain largely unexplored.
Purpose of the Study:
- To investigate the photoinduced structural dynamics in metal-organic frameworks (MOFs).
- To elucidate the role of coordination bond changes in MOF photocatalysis.
Main Methods:
- Time-resolved visible and infrared (IR) spectroscopy.
- Computational studies.
- Transient absorption spectroscopy.
Main Results:
- First observation of light-induced dissociation and reformation of carboxylate-metal bonds (COO-M) in MIL-101(Fe).
- Identified ligand-to-metal charge transfer (LMCT) with a long excited-state lifetime of approximately 30 μs.
- Observed reversible transition of carboxylate-iron bonds from bidentate to monodentate modes.
Conclusions:
- Photoexcitation induces dynamic structural changes in MOFs, specifically bond dissociation and reformation.
- These dynamics occur on the timescale of the excited state lifetime, facilitating charge separation.
- The findings provide a new foundation for understanding MOF-based photocatalytic mechanisms.
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