Pyrazolato-bridged 1-D Co(II) coordination polymer and dinuclear Ni(II) and Cu(II) complexes: Syntheses, crystal structures and magnetic properties

Three complexes of composition [Co-3(Hdcp)(2)(phen)(3)(H2O)(2)](n) center dot nH(2)O (1), [Ni-2(Hdcp)(2)(H2O)(4)](Im)(2) (2) and [Cu-2(Hpca)(2)(H2O)(2)(Im)(2)] (3) (H(3)dcp = 3,5-pyrazoledicarboxylic acid, H(2)pca = 1H-pyrazole-5-carboxylic acid, Im = imidazole and phen = 1,10-phenanthroline) have been synthesized via hydrothermal reactions and their structures have been characterized. Complex 1 is mainly constructed by Hdcp and ancillary ligand 1,10-phenanthroline and exhibits one-dimensional linear chain structure. Complexes 2 and 3 are pyrazolato-bridged dinuclear complexes. The ancillary imidazole ligand was not involved in the coordination and stacked to the lattice of the complex in 2. In the process of synthesis 3, imidazole ligand was coordinated to the metal centre; with one of the carboxylic group of the H(3)dcp ligand was eliminated to form [Cu-2(Hpca)(2)(H2O)(2)(Im)(2)] (3) in situ. The results of magnetic susceptibility measurements indicate that there exist antiferromagnetic interactions between Co(II)and Ni(II) centres in compounds 1 and 2, respectively. (c) 2008 Elsevier B.V. All rights reserved.