title: Synthesis, crystal structures, and magnetic properties of cyanide-bridged W(V)Mn(III) anionic coordination polymers containing divalent cationic moieties: slow magnetic relaxations and spin crossover phenomenon.
abstract: Two trimetallic coordination complexes were prepared by self-assembly of [W(CN)8](3-) and the Mn(III) Schiff base followed by the addition of a Zn(II) or Fe(II) cationic unit. The octacyanotungstate connects neighboring Mn(III) centers to form a one-dimensional chain. The anionic chain requires cationic units of Zn(II) or Fe(II) to maintain charge balance in the structure. The Zn-containing complex shows ferrimagnetic behavior originating from the antiparallel alignment of W(V) and Mn(III) spins within the chain, which leads to slow magnetic relaxation at low temperatures. For the Fe(II)-containing compound, Fe(II) moieties are integrated into the ferrimagnetic chains, altering their spin states depending on the temperature. It appears that the coexistence of high- and low-spin states in the low temperature regime is responsible for the slower and faster relaxations of the magnetization.
authors.affiliation: Department of Chemistry (BK21), Korea University , Seoul 136-713, Korea.
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Yoon
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lim
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Ryu
authors.forename: Woo Ram
authors.initials: WR
authors.lastname: Lee
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