Reactions of the [FeIII(CN)6]3- anion with the [CuII(tn)]2+ ion (tn = 1,3-diaminopropane) afford the compounds [CuII(tn)]2[FeII(CN) 6]3·[Na3FeIII(CN) 6]·12H2O (1) and [Cun(tn)] 2[FeII(CN)6]·KCl·5H 2O (2). Despite the differences concerning their asymmetric units, both structures present strong similar features: in both structures, the Cu(II) ion presents a square-base pyramidal CuN5 environment and each [FeII(CN)6]4- anion is linked to six Cu(II) ions through its six N atoms leading to infinite [CuII(tn)] 2[FeII(CN)6] layers which can be viewed as 2-D layered arrangement generated by the defective cubane units Cu 4Fe3 involving Fe-CN-Cu bridges. The most important differences between the two structures concern essentially the inter-layer arrangement which is occupied, in compound 1, by isolated paramagnetic [Fe(CN)6]3- anions and water molecules, while in compound 2, this interlayer space is occupied by K+, Cl- ions and water molecules. Magnetic data indicate for 1 weak antiferromagnetic interactions and presence of magnetically isolated [FeIII(CN) 6]3-anion and for 2 weak ferromagnetic interactions between the Cu(II) ions. © 2005 Elsevier B.V. All rights reserved.