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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 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)Å. 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)Å. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/kB =0.6K. 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. [Copyright &y& Elsevier]

Abstract: Violet crystals of [Cu(en)2][Pt(CN)4] and blue crystals of [Cu(dmen)2][Pt(CN)4] were crystallized from the water–methanol solution containing CuCl2·2H2O, ethylenediamine (en) or N,N-dimethylethylenediamine (dmen) and K2[Pt(CN)4]·3H2O. Both compounds were characterized using elemental analysis, infrared and UV-VIS spectroscopy, magnetic measurements, specific heat measurements and thermal analysis. X-ray structure analysis revealed chain-like structure in both compounds. The covalent chains are built of Cu(II) ions linked by [Pt(CN)4]2− anions in the [111] and [101] direction, respectively. The Cu(II) atoms are hexacoordinated by four nitrogen atoms in the equatorial plane from two molecules of bidentate ligands L with average Cu–N distance of 2.022(2) and 2.049(4)Å, respectively. Axial positions are occupied by two nitrogen atoms from bridging [Pt(CN)4]2− anions at longer Cu–N distance of 2.537(2) and 2.600(5)Å, respectively. Both materials are characterized by the presence of weak antiferromagnetic exchange coupling. Despite the one-dimensional (1D) character of the structure, the analysis of magnetic properties and specific heat at very low temperatures shows that [Cu(en)2][Pt(CN)4] behaves as two-dimensional (2D) spatially anisotropic square lattice Heisenberg magnet, while more pronounced influence of interlayer coupling is observed in [Cu(dmen)2][Pt(CN)4]. [Copyright &y& Elsevier]