Syntheses, structures and magnetic properties of [M^II(dca)₂(CH₃OH)₂]_n , where M = Co or Cu and dca^- = dicyanamide, N (CN)₂^-

Two isomorphous µ_1,5-dicyanamide bridged compounds formulated as [M^II(dca)₂(CH₃OH)₂]_n , where dca = dicyanamide and M = Co (1) or Cu (2), have been synthesized and characterized by X-ray powder and single crystal X-ray diffraction studies and low temperature (300-2 K) magnetic measurement. The structural analyses revealed that 1 and 2 consist of infinite double stranded chains of Co(II) and Cu(II), respectively, connected through the dca bridges which make 1D chain like polymers. These infinite chains are further connected via a hydrogen bonding interaction between the methanol and dicyanamido ligands giving rise to the supramolecular 2D solid-state architectures. The variable temperature magnetic susceptibility measurement shows that the global feature of the ?_MT versus T curve for 2 is characteristic of a very weak antiferromagnetic interaction, and between 300 and 2 K the best fit parameter was determined as J = -2.34 cm^-1. 1 readily changes to pink a-Co(dca)₂ compound which is confirmed from the elemental analyses, IR, X-ray powder diffraction study and variable temperature magnetic susceptibility measurement. © 2006 Elsevier B.V. All rights reserved.