Syntheses, structures and magnetic properties of three-dimensional co-ordination polymers constructed by dimer subunits

摘要

The crystal structures and magnetic properties of compounds [M~(II)(apo)(N(CN)_2)_2], where M = Co (1), Ni (2) or Mn (3), apo = 2-aminopyridine N-oxide, have been determined. The structural analysesrevealed that they are isomorphous, and all belong to monoclinic space group P2_1. The metal(II) ions display distorted octahedral co-ordination, with four terminal N atoms of different [N(CN)_2]~- ligands and two O atoms of different apo ligands. Two ions are bridged by two #mu#-O atoms to form a dimer subunit. Those dimers are further linked to each other by [N(CN)_2]~- resulting in a three-dimensional structure. The magnetic properties of the compounds were nvestigated in the temperature range 2-300 K for 1 and 2 and 4-300 K for 3. The values for the intradimer spin coupling constant J were estimated to be -17.8, -40, -1.3, respectively, indicative of antiferromagnetic interaction.