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Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
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Solid State Collapse of a High-Spin Square-Planar Fe(II) Complex, Solution Phase Dynamics, and Electronic Structure
Matias E Pascualini1, Sebastian A Stoian2, Andrew Ozarowski2
1Department of Chemistry, Center for Catalysis, University of Florida , Gainesville, Florida 32611, United States.
Inorganic Chemistry
|May 17, 2016
Summary
Researchers synthesized a rare square-planar high-spin iron(II) complex using a pincer-type ligand. This complex readily forms a dimer and exhibits unique magnetic properties, offering new avenues in iron chemistry.
Area of Science:
- Inorganic Chemistry
- Coordination Chemistry
- Materials Science
Background:
- Square-planar high-spin Fe(II) complexes are exceptionally rare, with limited examples previously reported.
- Existing non-macrocyclic examples often feature an FeO4 core, highlighting the novelty of alternative ligand systems.
Purpose of the Study:
- To synthesize and characterize a novel square-planar high-spin Fe(II) complex supported by a trianionic pincer-type ligand.
- To investigate the solid-state dimerization, magnetic properties, and solution-state equilibria of the synthesized iron complex.
- To explore the oxidation chemistry of the Fe(II) complex to Fe(III) species.
Main Methods:
- Synthesis of the trianionic pincer-type ligand [CF3-ONO]H3 and its subsequent complexation with Fe(II).
- Solid-state characterization via X-ray crystallography and high-frequency electron paramagnetic resonance (EPR) and (57)Fe Mössbauer spectroscopy.
- Solution-state studies involving frozen solution (57)Fe Mössbauer spectroscopy to elucidate solvent-dependent equilibria.
- Oxidation studies using agents like CuCl2 and TlPF6 to generate Fe(III) complexes.
Main Results:
- The novel square-planar high-spin Fe(II) complex {[CF3-ONO]FeCl}{Li(Sv)2}2 (2) was successfully synthesized.
- Complex 2 readily forms a dimer {[CF3-ONO]Fe}2{(μ-Cl)2(μ-LiTHF)4} (3) in high yield under mild conditions (vacuum or pentane treatment).
- Complex 3 exhibits weak antiferromagnetic exchange interactions and a zero-field splitting tensor with a negative D parameter.
- In solution, complex 2 exists in equilibrium with its solvento complex and the dimer 3, elucidated by spectroscopy and crystallography.
- Oxidation of complex 2 yields stable Fe(III) complexes {[CF3-ONO]FeCl2}{Li(THF)2}2 (4) and [CF3-ONO]Fe(THF)3 (5).
Conclusions:
- The [CF3-ONO] ligand effectively stabilizes rare square-planar high-spin Fe(II) configurations.
- The facile dimerization and unique magnetic properties of the Fe(II) dimer provide insights into iron spin dynamics.
- Understanding the solution-state equilibria is crucial for controlling the reactivity and properties of these iron complexes.
- The demonstrated oxidation pathways offer routes to novel Fe(III) complexes with potential applications.
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