Syntheses, crystal structures and magnetic properties of two novel layered compounds:: [Fe3(C2O4)3(4,4′-bpy)4] and [Co(C2O4)-(4,4′-bpy)] (4,4′-bpy=4,4′-bipyridine)

The combination of 4,4'-bipyridine (4,4'-bpy) and oxalate ligands has resulted in the formation of two novel layered compounds [Fe-3(C2O4)(3)(4,4'-bpy)(4)] 1 and [Co(C2O4)(4,4'-bpy)] 2. Both compounds exhibit two-dimensional layer structures. That of 1 consists of iron(II) oxalate chains, with the terminal and the bridging 4,4'-bpy stacking alternately between the chains. The structure of 2 contains linear chains of cobalt(II) oxalate which are cross-linked by 4,4'-bpy molecules in a perpendicular manner, leading to square grid sheets with rectangular windows. Magnetic measurements reveal that weak antiferromagnetic interactions are mediated in both compounds.