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Published on: September 26, 2016
Remarkable scan rate dependence for a highly constrained dinuclear iron(II) spin crossover complex with a wide
Rafal Kulmaczewski1, Juan Olguín, Jonathan A Kitchen
1Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago , P.O. Box 56, Dunedin 9054, New Zealand.
A new diiron(II) complex exhibits abrupt spin crossover, achieving a record hysteresis loop width for dinuclear complexes. Its cooling rate dependence offers insights into spin transition dynamics.
Area of Science:
- Coordination Chemistry
- Materials Science
- Magnetism
Background:
- Spin crossover (SCO) complexes are molecular switches responding to external stimuli.
- Dinuclear SCO complexes offer unique cooperative effects and potential for complex magnetic behavior.
Purpose of the Study:
- To synthesize and characterize a novel triazole-based diiron(II) complex.
- To investigate the spin crossover properties, including thermal hysteresis and scan rate dependence.
Main Methods:
- Synthesis of a new triazole-based diiron(II) complex.
- Magnetic susceptibility measurements using a SQUID magnetometer.
- Differential Scanning Calorimetry (DSC) for thermal analysis.
- Mössbauer spectroscopy for detailed electronic structure investigation.
Main Results:
- The complex displays abrupt spin crossover transitions between high-spin (HS) and low-spin (LS) states.
- A record-equaling thermal hysteresis loop width (ΔT = 22 K) was observed for a dinuclear complex.
- A notable scan rate dependence was found exclusively on the cooling branch of the hysteresis loop.
Conclusions:
- The new diiron(II) complex demonstrates efficient spin crossover with significant cooperativity.
- The observed hysteresis and scan rate dependence highlight the complex's potential for molecular switching applications.
- This study contributes to the understanding of spin dynamics in dinuclear SCO systems.
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