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Does the solid-liquid crystal phase transition provoke the spin-state change in spin-crossover metallomesogens?
M Seredyuk1, A B Gaspar, V Ksenofontov
1Institut für Anorganische und Analystiche Chemie, Johannes-Gutenberg-Universität, Staudinger-Weg 9, D-55099 Mainz, Germany.
Journal of the American Chemical Society
|January 10, 2008
Summary
This study introduces new iron(II) metallomesogens exhibiting tunable spin-crossover (SCO) and liquid crystalline (LC) properties. These materials demonstrate coupled, coexisting, or uncoupled phase transitions, offering versatile applications in materials science.
Area of Science:
- Coordination Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Spin-crossover (SCO) and liquid crystalline (LC) phase transitions are crucial phenomena in materials science.
- Interplay between SCO and LC transitions can lead to novel material properties and functionalities.
- Understanding these interplays is key to designing advanced materials for various applications.
Purpose of the Study:
- To synthesize and characterize a new family of iron(II) metallomesogens.
- To investigate the interplay between spin-crossover and liquid crystalline phase transitions in these complexes.
- To explore the potential for tunable SCO and LC behaviors in these novel materials.
Main Methods:
- Synthesis of iron(II) complexes with novel tris[3-aza-4-((5-C(n))(6-R)(2-pyridyl))but-3-enyl]amine ligands.
- Single-crystal X-ray diffraction for structural analysis at various temperatures.
- Differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction for phase transition studies.
- Investigation of light-induced excited spin state trapping (LIESST) effect.
Main Results:
- A new family of Fe(II) metallomesogens displaying coupled, coexisting, and uncoupled SCO-LC transitions was synthesized.
- Structural characterization revealed pseudo-octahedral iron(II) centers with varying Fe-N bond lengths indicative of spin states.
- Compounds exhibited spin crossover behavior with distinct color changes and LIESST effects.
- Smectic mesophases were identified in several derivatives, with transitions influenced by hydration and temperature.
Conclusions:
- The synthesized iron(II) metallomesogens offer a versatile platform for studying SCO-LC interplay.
- Tunable phase transitions and properties were achieved by modifying ligand structure and hydration.
- These materials hold promise for applications in molecular switches, sensors, and advanced functional materials.
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