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Photosensitizing Au(I) Catalysis With Coumarins.
Liliana Capulín Flores1, Jacob J van der Wal1, Johannes E M N Klein1
1Stratingh Institute for Chemistry, University of Groningen, Groningen, The Netherlands.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|June 26, 2026
Summary
Gold catalysis, driven by light, offers new reaction pathways. Intramolecular photosensitization in a gold-coumarin complex shows potential but faces challenges in energy transfer efficiency.
Area of Science:
- Photochemistry
- Organometallic Chemistry
- Catalysis
Background:
- Gold catalysis is versatile in chemical transformations.
- Light-driven reactions offer novel synthetic routes.
- Photosensitization is key for gold photoredox and energy transfer catalysis.
Purpose of the Study:
- Investigate intramolecular photosensitization effects on a gold(I) complex with a 3-amino coumarin chromophore.
- Assess the complex's ability to mediate light-driven electron or energy transfer in cross-coupling reactions.
- Understand factors influencing photophysical and photochemical properties for enhanced gold catalysis.
Main Methods:
- Synthesis of a gold(I) complex attached to a 3-amino coumarin chromophore.
- UV-vis absorption and emission spectroscopy at different temperatures (298 K and 77 K).
- Density Functional Theory (DFT) calculations to support spectroscopic findings.
Main Results:
- The gold-coumarin complex (1) exhibited moderate performance in tested cross-coupling reactions.
- Photophysical studies indicated competing pathways limiting efficiency.
- Weak emission at 298 K attributed to the coumarin, with self-quenching by the amide group.
- Phosphorescence at 77 K, absent in the free coumarin, suggested possible intramolecular energy transfer.
Conclusions:
- Photochemical activation of gold catalysis shows promise for challenging transformations.
- Effective intramolecular energy transfer between the chromophore and gold center remains a significant challenge.
- Further optimization is needed to overcome competing pathways and enhance energy transfer for efficient gold-catalyzed reactions.
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