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Updated: Sep 22, 2025
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Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
3.6K
Photoinduced Jahn-Teller switch in Mn(III) terpyridine complexes.
Kyle Barlow1, Julien Eng2, Iona Ivalo1
1EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, UK. olof.johansson@ed.ac.uk.
Dalton Transactions (Cambridge, England : 2003)
|May 18, 2022
Summary
Researchers studied photoinduced Jahn-Teller (JT) distortion in manganese complexes. They observed wavepacket oscillations and long dephasing times, revealing energy dissipation through vibrational modes.
Area of Science:
- Inorganic Chemistry
- Photochemistry
- Quantum Dynamics
Background:
- Jahn-Teller (JT) distortion significantly influences the properties of transition metal complexes.
- Understanding excited-state dynamics is crucial for designing photoresponsive materials.
Purpose of the Study:
- To investigate photoinduced switching between axial and equatorial Jahn-Teller distortions in [Mn(terpy)X3] complexes (X = Cl, F, N3).
- To explore the dynamics of excited-state wavepackets and their dephasing mechanisms.
Main Methods:
- Ultrafast transient absorption spectroscopy was employed to record spectra.
- Multireference quantum chemistry calculations were performed to elucidate reaction coordinates.
Main Results:
- Strong oscillations (around 115 cm-1) were observed in transient spectra, indicating excited-state wavepacket motion.
- A pincer-like motion of the terpyridine ligand was identified as the reaction coordinate.
- Long wavepacket dephasing times were measured: 620 fs for [Mn(terpy)Cl3], 450 fs for [Mn(terpy)F3], and 370 fs for [Mn(terpy)(N3)3].
- Dephasing times decreased with increasing low-energy vibrational modes, suggesting their role as an energy dissipation bath.
Conclusions:
- The study reveals the intricate relationship between JT distortion, ligand dynamics, and excited-state coherence in manganese complexes.
- Vibrational modes play a critical role in dissipating energy from photoexcited states, influencing wavepacket lifetimes.
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