Synthesis, Crystal Structures, and Magnetic Properties of Cyanide-Bridged W^VMn^III Anionic Coordination Polymers Containing Divalent Cationic Moieties: Slow Magnetic Relaxations and Spin Crossover Phenomenon

다국어 초록 (Multilingual Abstract)

<P>Two trimetallic coordination complexes were prepared by self-assembly of [W(CN)<SUB>8</SUB>]<SUP>3–</SUP> 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.</P><P>Trimetallic complexes were prepared by self-assembly of [W(CN)<SUB>8</SUB>]<SUP>3−</SUP> and the Mn(III) Schiff base, followed by the addition of a Zn(II) or Fe(II) cationic unit. The W<SUP>V</SUP>Mn<SUP>III</SUP> anionic chains were separated by the cationic moieties, which causes the slow magnetization relaxation. The Fe(II)-containing compound showed a distinct single-chain magnet behavior at low temperatures and spin crossover at high temperatures.</P><P><B>Graphic Abstract</B>
<IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-19/ic501506s/production/images/medium/ic-2014-01506s_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic501506s'>ACS Electronic Supporting Info</A></P>