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) A. 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) A. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/kB=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. - Graphical abstract: 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. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/kB=-0.6 K. Despite the one-dimensional 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 square-lattice Heisenberg magnet with weak interlayer coupling