title: Two WV-MnIII bimetallic assemblies built by octacyanotungstate(v) and MnIII Schiff bases: molecular structures and a spin-flop transition.
abstract: Two W(V)-Mn(III) bimetallic compounds, [Mn(Cl-salmen)(H(2)O)2]{[Mn(5-Clsalmen)(H(2)O)]2[W(CN)8].2H(2)O (1.2H(2)O) [5-Clsalmen = N,N'-(1-methylethylene)bis(5-chlorosalicylideneiminato) dianion], which contains trinuclear Mn(2)W and isolated Mn(III) moieties, and [Mn(3-MeOsalcy)(H(2)O)2]3[W(CN)(8)].2H(2)O (2.2H(2)O) [3-MeOsalcy = N,N'-(trans-1,2-cyclohexanediylethylene)bis(3-methoxysalicylideneiminato) dianion] molecules were prepared in redox processes and characterized using X-ray analysis and magnetic measurements. Compound 1 is composed of the {[Mn(5-Clsalmen)(H(2)O)]2[W(CN)8]}- trimer, in which two CN groups among eight in [W(CN)8](3-) bridge W(5+) and two Mn(3+) ions and the remaining CN ligands are hydrogen-bonded to water molecules or unbound, and the [Mn(Cl-salmen)(H(2)O)2]+ cation. Subsequently, two water molecules of the isolated cation are subject to hydrogen bonds. For 2, there are no covalent bonds among the subunits and six serial stacks of [Mn(3-MeOsalcy)(H(2)O)2]+ units are all hydrogen-bonded. The many hydrogen bonds found in both complexes eventually lead to three-dimensional networks. The magnetic studies for 1 reveal that antiferromagnetic interactions (J = -5.4 cm(-1)) between W(V) and Mn(III) centers within the trimer are transmitted via the bridging CN groups. Intermolecular antiferromagnetic couplings (zJ' = -0.2 cm(-1)) are also observed. The static and dynamic magnetic data of 1 demonstrate the existence of a field-induced spin-flop transition occurring among the clusters and monomeric molecules.
authors.affiliation: Department of Chemistry and Center for Electro- and Photo-Responsive Molecules, Korea University, Seoul, 136-701, Korea.
authors.forename: Hyun Hee
authors.initials: HH
authors.lastname: Ko
authors.forename: Jeong Hak
authors.initials: JH
authors.lastname: Lim
authors.forename: Houng Sik
authors.initials: HS
authors.lastname: Yoo
authors.forename: Jun Sung
authors.initials: JS
authors.lastname: Kang
authors.forename: Hyoung Chan
authors.initials: HC
authors.lastname: Kim
authors.forename: Eui Kwan
authors.initials: EK
authors.lastname: Koh
authors.forename: Chang Seop
authors.initials: CS
authors.lastname: Hong
mesh_terms: D002412:Cations; D003486:Cyanides / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006860:Hydrogen Bonding; D007536:Isomerism; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012545:Schiff Bases / Q000737:chemistry*; D013696:Temperature; D017973:Tungsten Compounds / Q000737:chemistry*
chemical_list: D002412:Cations; D003486:Cyanides; D005290:Ferric Compounds; D009942:Organometallic Compounds; D012545:Schiff Bases; D017973:Tungsten Compounds; D008345:Manganese; C045951:tungstate