Spin-State Tuning at Pseudo-tetrahedral d^6 Ions: Spin Crossover in [BP_3]Fe^(II)–X Complexes
- Creators
- Creutz, Sidney E.
-
Peters, Jonas C.
Abstract
Low-coordinate transition-metal complexes that undergo spin crossover remain rare. We report here a series of four-coordinate, pseudo-tetrahedral P_3Fe^(II)–X complexes supported by tris(phosphine)borate P_3 ([PhBP_3^R]^−) and phosphiniminato X-type ligands (−N=PR3′) that, in combination, tune the spin-crossover behavior of the system. Most of the reported iron complexes undergo spin crossover at temperatures near or above room temperature in solution and in the solid state. The change in spin state coincides with a significant change in the degree of π-bonding between Fe and the bound N atom of the phosphiniminato ligand. Spin crossover is accompanied by striking changes in the ultraviolet–visible (UV-vis) absorption spectra, which allows for quantitative modeling of the thermodynamic parameters of the spin equilibria. These spin equilibria have also been studied by numerous techniques including paramagnetic nuclear magnetic resonance (NMR), infrared, and Mössbauer spectroscopies; X-ray crystallography; and solid-state superconducting quantum interference device (SQUID) magnetometry. These studies allow qualitative correlations to be made between the steric and electronic properties of the ligand substituents and the enthalpy and entropy changes associated with the spin equilibria.
Additional Information
© 2016 American Chemical Society. Received: January 10, 2016. Published: April 4, 2016. Publication Date (Web): April 04, 2016. This work was supported by the Gordon and Betty Moore Foundation and through the NSF via a GRFP award to S.E.C. Larry Henling and Michael Takase are thanked for their assistance with X-ray crystallography. The Molecular Materials Research Center (MMRC) at Caltech is thanked for the use of the SQUID magnetometer. Author Contributions: The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interest.Attached Files
Supplemental Material - ic6b00066_si_001.pdf
Supplemental Material - ic6b00066_si_002.cif
Files
Name | Size | Download all |
---|---|---|
md5:d52691bdbecd948232ebb4c33fa0ed5f
|
3.0 MB | Preview Download |
md5:a03d15e95fe0e5df7da47becd7eecb7a
|
40.6 MB | Download |
Additional details
- Alternative title
- Spin-State Tuning at Pseudo-tetrahedral d6 Ions: Spin Crossover in [BP3]FeII–X Complexes
- Eprint ID
- 67579
- DOI
- 10.1021/acs.inorgchem.6b00066
- Resolver ID
- CaltechAUTHORS:20160602-132307484
- Gordon and Betty Moore Foundation
- NSF Graduate Research Fellowship
- Created
-
2016-06-02Created from EPrint's datestamp field
- Updated
-
2021-11-11Created from EPrint's last_modified field