title: Direct observation of the role of lanthanides in stabilizing a ferromagnetic spin orientation in a weak Fe(III)-Fe(III) antiferromagnet.
abstract: [Fe(III)2Ln(III)2(OH)2(L(1))2(HL(2))2(NO3)4(H2O)1½(MeOH)½]·6MeCN (Ln = Y (1), Dy (2); H2L(1) = 2,3-dihydroxybenzaldehyde and H2L(2) is the Schiff base of this aldehyde with furfurylamine) have unusually weak antiferromagnetic interactions between the Fe(III) centres in comparison with other (μ-dihydroxo)diiron(III) complexes. For 1, it was established that modulation of the hydroxo bridges by coordination to the Y(III) ions results in long Fe-O bonds and small Fe-O-Fe angles, leading to J = -0.4 cm(-1). Analysis of the Mössbauer spectra reveals that the intramolecular magnetic field generated by the anisotropic Dy(III) ions in 2 is sufficient to overcome the Fe-Fe antiferromagnetic coupling and reorientate the Fe(III) moments into a ferromagnetic spin orientation.
authors.affiliation: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76128 Karlsruhe, Germany.
authors.forename: Hua
authors.initials: H
authors.lastname: Xiang
authors.forename: Valeriu
authors.initials: V
authors.lastname: Mereacre
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
authors.forename: Tong-Bu
authors.initials: TB
authors.lastname: Lu
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Anson
authors.forename: Annie K
authors.initials: AK
authors.lastname: Powell