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Updated: Jun 12, 2026
09:33
Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Photoacid Mediated Spin State Switching in Spin-Crossover Systems: The Example of an Fe(II)-Acylhydrazone Complex
Peng-Xuan Zheng1, Huang-Jing Long1, Meng-Ting Chen1
1School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Journal of the American Chemical Society
|June 11, 2026
Summary
This study introduces a novel method for controlling molecular spin states using light. A photoacid and spin-crossover complex enable reversible spin switching in solution at room temperature.
Area of Science:
- Materials Science
- Chemistry
Background:
- Designing molecular materials with switchable spin states at ambient conditions is challenging.
- Existing methods often involve complex synthesis, unpredictable switching, or lack of reversibility.
Purpose of the Study:
- To develop a general, efficient, and easy-to-use method for reversible, optically controlled spin switching.
- To achieve spin switching in solution at room temperature.
Main Methods:
- Combined a spin-crossover complex with a reversible protonation-capable ligand and a photoacid.
- Utilized a merocyanine-based photoacid and a spin-crossover Fe(II)-acylhydrazone complex.
- Irradiated the solution with light (400-450 nm) to trigger proton release and spin state change, followed by dark incubation for reversal.
Main Results:
- Demonstrated reversible, optically controlled spin switching of the Fe(II) complex in solution at room temperature.
- Protonation of the acylhydrazone ligand by the photoacid induced a low-spin to high-spin state transition.
- The system fully restored to its original state in the dark, confirmed by magnetic and spectroscopic analyses over multiple cycles.
Conclusions:
- The presented method offers a robust and versatile approach for designing advanced materials with switchable spin states.
- This strategy overcomes limitations of previous methods, paving the way for new applications in molecular electronics and data storage.
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