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Pressure versus temperature effects on intramolecular electron transfer in mixed-valence complexes
Stephan Scheins1, Jacob Overgaard, Grigore A Timco
1Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|November 22, 2012
Summary
Pressure does not trigger valence trapping in mixed-valence trinuclear iron carboxylates. Anisotropic changes in intermolecular interactions, not pressure, modulate electron transfer, highlighting temperature
Area of Science:
- Inorganic Chemistry
- Materials Science
- Solid State Chemistry
Background:
- Mixed-valence trinuclear carboxylates exhibit subtle energy differences between metal oxidation states, leading to structural sensitivity.
- Electron transfer (ET) in these compounds is known to be influenced by temperature and crystal environment.
Purpose of the Study:
- To investigate the effect of external pressure on the electron transfer (ET) process in mixed-valence trinuclear iron carboxylates.
- To compare the pressure-induced effects with temperature-dependent behavior and understand the governing interactions.
Main Methods:
- Single-crystal X-ray diffraction at variable temperatures (15-298 K).
- High-pressure single-crystal X-ray diffraction (up to 0.96 GPa).
- Hirshfeld surface analysis to probe intermolecular interactions.
Main Results:
- A phase transition related to valence trapping was observed around 130 K, influenced by C-H⋅⋅⋅π and π⋅⋅⋅π interactions.
- Application of external pressure did not induce the observed phase transition or valence trapping.
- Unit-cell volume reduction under pressure did not significantly alter the electron transfer dynamics.
Conclusions:
- Modulation of the ET process in these mixed-valence compounds requires anisotropic changes in intermolecular interactions.
- Temperature affects these interactions directionally, unlike isotropic pressure application.
- Pressure is not an effective external stimulus for controlling valence trapping in this system.
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