title: A Redox-Induced Spin-State Cascade in a Mixed-Valent Fe3(μ3-O) Triangle.
abstract: One-electron reduction of a pyrazolate-bridged triangular Fe3(μ3-O) core induces a cascade wherein all three metal centers switch from high-spin Fe3+to low-spin Fe2.66+. This hypothesis is supported by spectroscopic data (1H-NMR, UV-vis-NIR, infra-red,57Fe-Mössbauer, EPR), X-ray crystallographic characterization of the cluster in both oxidation states and also density functional theory. The reduction induces substantial contraction in all bond lengths around the metal centers, along with diagnostic shifts in the spectroscopic parameters. This is, to the best of our knowledge, the first example of a one-electron redox event causing concerted change in multiple iron centers.
authors.affiliation: Department of Chemistry and Biochemistry and the Biomedical Sciences Institute, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA.
authors.forename: Evgen V
authors.initials: EV
authors.lastname: Govor
authors.affiliation: Department of Chemistry, University of Oxford, South Parks Road, OX1 3QZ, UK.|Faculty of Science, University of Kufa, Kufa St., Najaf, Iraq.
authors.forename: Karrar
authors.identifier: 0000-0002-8333-3868
authors.initials: K
authors.lastname: Al-Ameed
authors.affiliation: Department of Chemistry, University of Puerto Rico, San Juan, PR, 00934, USA.
authors.forename: Indranil
authors.initials: I
authors.lastname: Chakraborty
authors.affiliation: Department of Chemistry, University of Puerto Rico, San Juan, PR, 00934, USA.
authors.forename: Carla S
authors.initials: CS
authors.lastname: Coste
authors.affiliation: Department of Chemistry and Biochemistry and the Biomedical Sciences Institute, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA.
authors.forename: Olena
authors.initials: O
authors.lastname: Govor
authors.affiliation: Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", Ag. Paraskevi, 15310, Attiki, Greece.
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Sanakis
authors.affiliation: Department of Chemistry, University of Oxford, South Parks Road, OX1 3QZ, UK.
authors.forename: John E
authors.initials: JE
authors.lastname: McGrady
authors.affiliation: Department of Chemistry and Biochemistry and the Biomedical Sciences Institute, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA.
authors.forename: Raphael G
authors.identifier: 0000-0002-9522-0369
authors.initials: RG
authors.lastname: Raptis
keywords: Mössbauer spectroscopy; density functional theory; high-spin/low-spin transition; iron complexes; mixed-valence