Metal substitution effect on a three-dimensional cyanido-bridged fe spin-crossover network

Abstract

We report the CoII-substitution effect on a cyanido-bridged three-dimensional FeII spin-crossover network, Fe2[Nb(CN)8](4-pyridinealdoxime)8·2H2O. A series of iron-cobalt octacyanidoniobate, (FexCo1-x)2[Nb(CN)8](4-pyridinealdoxime)8·zH2O, was prepared. In this series, the behavior of FeII spin-crossover changes with the CoII concentration. As the CoII concentration increases, the transition of the spin-crossover becomes gradual and the transition temperature of the spin-crossover shifts towards a lower temperature. Additionally, this series shows magnetic phase transition at a low temperature. In particular, (Fe0.21Co0.79)2[Nb(CN)8](4-pyridinealdoxime)8·zH2O exhibits a Curie temperature of 12 K and a large coercive field of 3100 Oe.