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Valence tautomerism interconversion triggers transition to stable charge distribution in solid polymeric
Marco Affronte1, Alessandra Beni, Andrea Dei
1National Research Center on NanoStructures and BioSystems at Surfaces, INFM-CNR, Modena, Italy.
Dalton Transactions (Cambridge, England : 2003)
|February 15, 2008
Summary
This study synthesizes novel cobalt-diazine polymers with a unique mixed-valence ligand. These materials exhibit photoinduced valence tautomerism, transitioning between metastable and stable charge states.
Area of Science:
- Coordination Chemistry
- Materials Science
- Polymer Chemistry
Background:
- Exploration of novel polymeric coordination compounds.
- Investigating mixed-valence systems for unique electronic properties.
- Understanding ligand-metal interactions in complex structures.
Purpose of the Study:
- To synthesize and characterize new polymeric cobalt-diazine derivatives.
- To investigate the valence tautomerism in these materials.
- To explore the photoinduced switching behavior of the metastable states.
Main Methods:
- Synthesis of polymeric cobalt-diazine complexes.
- Characterization using magnetic, EPR, and calorimetric measurements.
- Photomagnetic studies to probe photoinduced valence tautomerism.
Main Results:
- Successful synthesis of [CoL(diazine)]n polymers, where L is a mixed-valence SQ-Cat species.
- Characterization revealed metastable charge distributions attributed to the ligand's class I mixed-valence nature.
- Entropy-driven valence tautomeric interconversion to a stable state was observed.
- Photoinduced valence tautomerism was demonstrated, with a metastable state lifetime of ~2 x 10^5 s at 9 K.
Conclusions:
- The synthesized cobalt-diazine polymers exhibit tunable electronic properties via valence tautomerism.
- Photoinduction offers a potential pathway for controlling charge distribution in these materials.
- The long lifetime of the photoinduced state suggests potential applications in molecular switches or memory devices.
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