화학공학소재연구정보센터
Inorganic Chemistry, Vol.52, No.2, 1061-1068, 2013
Synthesis, Crystal Structure, and Magnetic Properties of the Coordination Polymer [Fe(NCS)(2)(1,2-bis(4-pyridyl)-ethylene)](n) Showing a Two Step Metamagnetic Transition
Reaction of iron(II) thiocyanate with an excess of trans-1,2-bis(4-pyridyl)-ethylene (bpe) in acetonitrile at room temperature leads to the formation of [Fe(NCS)(2)(bpe)(2)center dot(bpe)] (1), which is isotypic to its Co(II) analogue. Using slightly different reaction conditions the literature known compound [Fe(NCS)(2)(bpe)(2)(H2O)(2)] (2) was obtained as a phase pure material. Simultaneous differential thermoanalysis and thermogravimetry prove that the hydrate 2 transforms into the anhydrate [Fe(NCS)(2)(bpe)(2)] (3), that decomposes on further heating into the new ligand-deficient 1:1 compound of composition [Fe(NCS)(2)(bpe)](n) (4), which can also be obtained directly by thermal decomposition of 1. Further investigations reveal that 4 can also be prepared under solvothermal conditions, and single crystal structure analysis shows that the iron(II) cations are linked via mu-1,3 bridging thiocyanato anions into chains, that are further connected into layers by the bpe ligands. Magnetic measurements, performed on powder samples, prove that 1 and 2 show only Curie Weiss behavior, whereas in 4 antiferromagnetic ordering with a Neel temperature of 5.0 K is observed. At T < 4.0 K a two-step metamagnetic transition occurs at applied magnetic fields of 1300 and 1775 Oe. The magnetic properties are discussed and compared with those of related compounds.