title: Salen-based coordination polymers of iron and the rare earth elements.
abstract: Reaction of N,N'-bis(4-carboxysalicylidene)ethylenediamine (H(4)L) with iron(III) chloride and lanthanide nitrates resulted in the coordination polymers of composition {[Ln(2)(FeLCl)(2)(NO(3))(2)(DMF)(5)]·(DMF)(4)}(n) (Ln = Y, Eu, Gd, Tb, Dy). The polymers consist of iron-salen-based moieties having carboxylate linkers connected to rare earth atoms in a 1D chain structure. Thus, the iron-salen complex acts as a "metalloligand". Because of the twisting of the chains, porous structures are formed and possess large free void space. The magnetic studies of selected compounds exhibit weak intramolecular antiferromagnetic interactions of Ln-Ln. At 3, 30, and 80 K, the Mössbauer spectra of the iron-dysprosium compound show a strongly asymmetric quadrupole doublet with isomer shift and quadrupole splitting values typical for Fe(III) ions in high spin state. In addition, an anomalous temperature dependence of both isomer shift and quadrupole splitting has been observed.
authors.affiliation: Institut für Anorganische Chemie, Karlsruher Institut für Technologie (KIT), Engesserstrasse 15, 76131 Karlsruhe, Germany.
authors.forename: Asamanjoy
authors.initials: A
authors.lastname: Bhunia
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
authors.forename: Valeriu
authors.initials: V
authors.lastname: Mereacre
authors.forename: Michael T
authors.initials: MT
authors.lastname: Gamer
authors.forename: Annie K
authors.initials: AK
authors.lastname: Powell
authors.forename: Peter W
authors.initials: PW
authors.lastname: Roesky