title: Cyanide-bridged W(V)Mn(III) bimetallic chains composed of a blocked W hexacyanide precursor: geometry-related magnetic couplings and magnetostructural correlation.
abstract: Five one-dimensional bimetallic W(V)Mn(III) complexes 1-5, consisting of [W(CN)6(bpy)](-) anions and [Mn(Schiff base)](+) cations, were prepared. The central coordination geometry around each W atom is determined as a distorted dodecahedron (DD) for 1 and 2, and a distorted square antiprism (SAPR) for 3-5. Magnetic analyses demonstrate that compounds 1, 4, and 5 exhibit antiferromagnetic interactions between magnetic centers, which are different from the ferromagnetic couplings in 2 and 3. For the distorted DD geometry, the Mn-N(ax) (ax = axial) bond length increases when moving from 1 to 2, with the Mn-N(ax)-C(ax) angle remaining constant. The elongation of the bond length is responsible for the reduction in orbital overlap and consequent ferromagnetic coupling in 2. In comparison, for 3-5 with the distorted SAPR geometry, given that the Mn-N(ax) bond lengths are similar across all the samples, the increase in the Mn-N(ax)-C(ax) angles accounts for the enhanced magnetic strength. Notably, a correlation between structure and magnetic exchange coupling is established for the first time in W(V)Mn(III) bimetallic systems based on the [W(CN)6(bpy)](-) precursor.
authors.affiliation: Department of Chemistry, Research Institute for Natural Sciences, Korea University, Seoul 136-713, Korea.
authors.forename: Jin Wuk
authors.initials: JW
authors.lastname: Lee
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lim
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Ryu
authors.forename: Eui Kwan
authors.initials: EK
authors.lastname: Koh
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Yoon
authors.forename: Byoung Jin
authors.initials: BJ
authors.lastname: Suh
authors.forename: Chang Seop
authors.initials: CS
authors.lastname: Hong
mesh_terms: D060328:Magnetic Phenomena; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*
chemical_list: D009570:Nitriles; D009942:Organometallic Compounds; D008345:Manganese; D014414:Tungsten