Insights into Molecular Magnetism in Metal-Metal Bonded Systems as Revealed by a Spectroscopic and Computational Analysis of Diiron Complexes

Samuel M Greer; Kathryn M Gramigna; Christine M Thomas; Sebastian A Stoian; Stephen Hill

doi:10.1021/acs.inorgchem.0c02605

Insights into Molecular Magnetism in Metal-Metal Bonded Systems as Revealed by a Spectroscopic and Computational Analysis of Diiron Complexes

Inorg Chem. 2020 Dec 21;59(24):18141-18155. doi: 10.1021/acs.inorgchem.0c02605. Epub 2020 Nov 30.

Authors

Samuel M Greer^{1

2}, Kathryn M Gramigna³, Christine M Thomas⁴, Sebastian A Stoian⁵, Stephen Hill^{1

6}

Affiliations

¹ National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.
² Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
³ Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States.
⁴ Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
⁵ Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States.
⁶ Department of Physics, Florida State University, Tallahassee, Florida 32306, United States.

PMID: 33253552
DOI: 10.1021/acs.inorgchem.0c02605

Abstract

A pair of bimetallic compounds featuring Fe-Fe bonds, [Fe(ⁱPrNPPh₂)₃FeR] (R = PMe₃, ≡N^tBu), have been investigated using High-Frequency Electron Paramagnetic Resonance (HFEPR) as well as field- and temperature-dependent ⁵⁷Fe nuclear γ resonance (Mössbauer) spectroscopy. To gain insight into the local site electronic structure, we have concurrently studied a compound containing a single Fe(II) in a geometry analogous to that of one of the dimer sites. Our spectroscopic studies have allowed for the assessment of the electronic structure via the determination of the zero-field splitting and ⁵⁷Fe hyperfine parameters for the entire series. We also report on our efforts to correlate structure with physical properties in metal-metal bonded systems using ligand field theory guided by quantum chemical calculations. Through the insight gained in this study, we discuss strategies for the design of single-molecule magnets based on polymetallic compounds linked via direct metal-metal bonds.