title: Steric and electronic control of the spin state in three-fold symmetric, four-coordinate iron(II) complexes.
abstract: The three-fold symmetric, four-coordinate iron(II) phosphoraminimato complexes PhB(MesIm)3Fe-N═PRR'R″ (PRR'R″ = PMePh2, PMe2Ph, PMe3, and P(n)Pr3) undergo a thermally induced S = 0 to S = 2 spin-crossover in fluid solution. Smaller phosphoraminimato ligands stabilize the low-spin state, and an excellent correlation is observed between the characteristic temperature of the spin-crossover (T1/2) and the Tolman cone angle (θ). Complexes with para-substituted triaryl phosphoraminimato ligands (p-XC6H4)3P═N(-) (X = H, Me and OMe) also undergo spin-crossover in solution. These isosteric phosphoraminimato ligands reveal that the low-spin state is stabilized by more strongly donating ligands. This control over the spin state provides important insights for modulating the magnetic properties of four-coordinate iron(II) complexes.
authors.affiliation: Department of Chemistry and Biochemistry, New Mexico State University , Las Cruces, New Mexico 88003, United States.
authors.forename: Hsiu-Jung
authors.initials: HJ
authors.lastname: Lin
authors.forename: Diana
authors.initials: D
authors.lastname: Siretanu
authors.forename: Diane A
authors.initials: DA
authors.lastname: Dickie
authors.forename: Deepak
authors.initials: D
authors.lastname: Subedi
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Scepaniak
authors.forename: Dmitri
authors.initials: D
authors.lastname: Mitcov
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Clérac
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Smith