title: Syntheses, structures, and magnetic characterizations of cyanide-bridged Fe(III)Mn(III) chains constructed by mer-Fe(III)tricyanide and Mn(III) Schiff bases: magnetostructural relationship.
abstract: Five Fe(III)Mn(III) bimetallic compounds [Fe(iqc)(CN)(3)][Mn(5-Xsalen)]·pMeOH·qMeCN·rH(2)O [Hiqc = N-(quinolin-8-yl)isoquinoline-1-carboxamide; salen = N,N'-ethylenebis(salicylideneiminato) dianion; X = H(2), F(3, 3a), Cl(4), Br(5)] were prepared by assembling a newly designed mer-Fe tricyanide (Ph(4)P)[Fe(iqc)(CN)(3)]·0.5H(2)O (1) and the respective Mn Schiff bases Mn(5-Xsalen)(+). Compounds 2-4 show linear chain structures in which trans-positioned cyanides of the Fe precursor bridge neighbouring Mn atoms, while 5 is a zigzag chain coordination polymer where two cyanide groups of the precursor in the cis mode act as bridges. The structural change from linear to zigzag may arise from the size effect of the halogens. The reversible structural transformation occurs between 3 and 3a upon the solvation-desolvation protocol and the corresponding magnetic behaviours are affected. Furthermore, in 4 and 5, the helical chains are established through hydrogen bonding of solvent molecules. From a magnetostructural point of view, within the linear chain system, the ferromagnetic coupling in 2, contrary to antiferromagnetic interactions in 3-4, is associated with the large torsion angle of C(eq)-Fe-Mn-N(O)(eq) (eq = equatorial) as well as almost the linear Mn-N≡C angle.
authors.affiliation: Department of Chemistry, Research Institute for Natural Sciences, Korea University, Seoul, 136-713, Korea.
authors.forename: In Young
authors.initials: IY
authors.lastname: Yoo
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Ryu
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Yoon
authors.forename: Ah Ram
authors.initials: AR
authors.lastname: Sohn
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lim
authors.forename: Beong Ki
authors.initials: BK
authors.lastname: Cho
authors.forename: Eui Kwan
authors.initials: EK
authors.lastname: Koh
authors.forename: Chang Seop
authors.initials: CS
authors.lastname: Hong
mesh_terms: D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D005292:Ferricyanides / Q000138:chemical synthesis / Q000737:chemistry*; D059346:Magnets / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D005292:Ferricyanides; D012545:Schiff Bases; D008345:Manganese