title: Gradual Thermal Spin-Crossover Mediated by a Reentrant Z' = 1 → Z' = 6 → Z' = 1 Phase Transition.
abstract: The Fe[BF4]2complex of the Schiff base podand tris[4-(thiazol-4-yl)-3-aza-3-butenyl]amine exhibits gradual thermal spin-crossover with T1/2≈ 208 K in the solid state. A weak discontinuity in the magnetic susceptibility curve at 190 K is associated with a reentrant symmetry-breaking transition involving a trebling of the unit cell volume (from P21/c, Z = 4, to P21, Z = 12). The intermediate phase contains six independent cations in puckered layers of low-spin, and high-spin or mixed-spin, molecules with an overall 30% high-spin population at 175 K.
authors.affiliation: School of Chemistry, University of Leeds , Woodhouse Lane, Leeds LS2 9JT, U.K.
authors.forename: Rafal
authors.initials: R
authors.lastname: Kulmaczewski
authors.affiliation: School of Physics and Astronomy, University of Leeds , E. C. Stoner Building, Leeds LS2 9JT, U.K.
authors.forename: Oscar
authors.initials: O
authors.lastname: Cespedes
authors.affiliation: School of Chemistry, University of Leeds , Woodhouse Lane, Leeds LS2 9JT, U.K.
authors.forename: Malcolm A
authors.identifier: http://orcid.org/0000-0001-7491-9034
authors.initials: MA
authors.lastname: Halcrow