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Two-Step Spin Crossover in Hofmann-Type Coordination Polymers [Fe(2-phenylpyrazine)2{M(CN)2}2] (M = Ag, Au)
Volodymyr M Hiiuk1,2, Sergii I Shylin3, Diana D Barakhtii1
1Department of Chemistry, Taras Shevchenko National University of Kyiv, 64 Volodymyrska Street, 01601 Kyiv, Ukraine.
New 2D Hofmann-type complexes featuring iron(II) centers exhibit two-step spin-crossover (SCO) behavior. Advanced supramolecular interactions within these structures are key to their switchable material properties.
Area of Science:
- Coordination Chemistry
- Materials Science
- Solid-State Chemistry
Background:
- Spin-crossover (SCO) materials are promising for switchable electronic devices.
- Hofmann-type coordination polymers offer tunable SCO properties.
- Supramolecular interactions significantly influence material characteristics.
Purpose of the Study:
- Synthesize and characterize novel 2D Hofmann-type complexes with 2-phenylpyrazine (Phpz) ligands.
- Investigate the spin-crossover behavior of these new iron(II) complexes.
- Elucidate the role of supramolecular interactions in dictating SCO properties.
Main Methods:
- Single-crystal X-ray diffraction for structural analysis.
- Superconducting quantum interference device (SQUID) magnetometry to study magnetic properties.
- Optical microscopy to observe phase transitions.
Main Results:
- Two 2D Hofmann-type complexes, [Fe(Phpz)2{M(CN)2}2] (M = Ag, Au), were synthesized.
- Both complexes display reproducible two-step spin-crossover behavior.
- Dense packing and extensive supramolecular interactions (metal-metal, C-H···M, π···π) stabilize the structures and influence SCO.
Conclusions:
- The presence of diverse supramolecular interactions is crucial for the spin-crossover phenomenon in these complexes.
- Bulky substituents on ligands, like phenylpyrazine, impact SCO behavior.
- Substituted pyrazines are viable building blocks for designing novel switchable materials.
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