Low-dimensional compounds containing cyano groups. XVII. Crystal structure, spectroscopic, thermal and magnetic properties of [Cu(bmen)2][Pt(CN)4] (bmen = N,N′-dimethylethylenediamine)

The synthesis, structural analysis, spectroscopic studies, susceptibility and specific-heat measurements of {[Cu(bmen)(2)][Pt(CN)(4)]}(n) (bmen = N,N'-dimethylethylenediamine) are presented. X-ray crystal-structure analysis revealed that the [Pt(CN)(4)](2-) building blocks are combined with [Cu(bmen)(2)](2+) units to form a chain-like structure along the a axis. The Cu(II) atoms are hexacoordinated by four nitrogen atoms in the equatorial plane belonging to two molecules of bidentate bmen ligands with average Cu-N distance of 2.043(18)angstrom. The axial positions are occupied by two nitrogen atoms from bridging [Pt(CN)(4)](2-) anions at a longer axial Cu-N distance of 2.490(4)angstrom. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/k(B) = 0.6 K. Despite the one-dimensional (1D) character of the structure, the analysis of the magnetic properties and specific heat at very low temperatures shows that [Cu(bmen)(2)][Pt(CN)(4)] behaves as a two-dimensional (2D) square-lattice Heisenberg magnet with weak interlayer coupling. (C) 2008 Elsevier Inc. All rights reserved.