Synthesis, structural characterization and thermal properties of a new copper(II) one-dimensional coordination polymer based on bridging N,N′-bis(2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine and dicyanamide ligands

The design and synthesis of polymeric coordination compounds of 3d transition metals are of great interest in the search for functional materials. The coordination chemistry of the copper(II) ion is of interest currently due to potential applications in the areas of molecular biology and magnetochemistry. A novel coordination polymer of Cu-II with bridging N,N'-bis(2-hydroxyphenyl)-2,2- dimethylpropane-1,3-diamine (H2L-DM) and dicyanamide (dca) ligands, catena-poly[[[mu(2)-2,2-dimethyl-N,N'-bis(2-oxidobenzylidene)propane-1,3-diamine-1:2 kappa O-6,N,N',O':O,O']dicopper(II)]-di-mu-dicyanamido-1:2'kappa(2) N-1:N-5; 2:1'kappa(2) N-1:N-5], [Cu-2(C19H20N2O2)(C2N3)(2)](n), has been synthesized and characterized by CHN elemental analysis, IR spectroscopy, thermal analysis and X-ray single-crystal diffraction analysis. Structural studies show that the Cu-II centres in the dimeric asymmetric unit adopt distorted square-pyramidal geometries, as confirmed by the Addison parameter (tau) values. The chelating characteristics of the L-DM2- ligand results in the formation of a Cu-II dimer with a double phenolate bridge in the asymmetric unit. In the crystal, the dimeric units are further linked to adjacent dimeric units through mu(1,5)-dca bridges to produce one-dimensional polymeric chains.