title: Two-step spin-transition iron(III) compound with a wide [high spin-low spin] plateau.
abstract: A new iron(III) coordination compound exhibiting a two-step spin-transition behavior with a remarkably wide [HS-LS] plateau of about 45 K has been synthesized from a hydrazino Schiff-base ligand with an N,N,O donor set, namely 2-methoxy-6-(pyridine-2-ylhydrazonomethyl)phenol (Hmph). The single-crystal X-ray structure of the coordination compound {[Fe(mph)(2)](ClO(4))(MeOH)(0.5)(H(2)O)(0.5)}(2) (1) determined at 150 K reveals the presence of two slightly different iron(III) centers in pseudo-octahedral environments generated by two deprotonated tridentate mph ligands. The presence of hydrogen bonding interactions, instigated by the well-designed ligand, may justify the occurrence of the abrupt transitions. 1 has been characterized by temperature-dependent magnetic susceptibility measurements, EPR spectroscopy, differential scanning calorimetry, and (57)Fe Mossbauer spectroscopy, which all confirm the occurrence of a two-step transition. In addition, the iron(III) species in the high-spin state has been trapped and characterized by rapid cooling EPR studies.
authors.affiliation: Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: Jinkui
authors.initials: J
authors.lastname: Tang
authors.forename: José
authors.initials: J
authors.lastname: Sánchez Costa
authors.forename: Simon
authors.initials: S
authors.lastname: Smulders
authors.forename: Gábor
authors.initials: G
authors.lastname: Molnár
authors.forename: Azzedine
authors.initials: A
authors.lastname: Bousseksou
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Teat
authors.forename: Yangguang
authors.initials: Y
authors.lastname: Li
authors.forename: Gerard A
authors.initials: GA
authors.lastname: van Albada
authors.forename: Patrick
authors.initials: P
authors.lastname: Gamez
authors.forename: Jan
authors.initials: J
authors.lastname: Reedijk