First report on a dinuclear Cu(II) complex based on pyridine dicarboxamido ligand having benzimidazole moieties in the amide side arms: Synthesis, structure and magnetic properties of [Cu(GBPA)]2•4H2O, GBPA = N,N'-bis(2-methylbenzimidazolyl)-pyridine-1,3-dicarboxamide

A first report on the X-ray crystal structure of a dinuclear Cu(II) complex of a pyridine dicarboxamide ligand, having benzimidazole moieties appended to the amide arms and coordinating through the deprotonated amide nitrogen atoms instead of the carbonyl oxygens, is presented. The coordination sphere around each metal ion is square planar due to coordination by the pyridine and amide nitregens with the fourth position being occupied by N of the benzimidazole moiety of the symmetry related molecule in the dimer. The non-bonding Cu center dot center dot center dot Cu distance in the dimer is 3.07 angstrom. Two water molecules in the asymmetric unit self assemble to form a water dimer through H-bonding interactions between them. These water dimers are in turn, involved in hydrogen bonding interactions with the complex molecules thereby linking the successive dinuclear entities to form a 1D tape extending along the c axis. The variable temperature magnetic susceptibility measurements data for the complex shows weak antiferromagnetic coupling between the Cu(II) ions in the dinuclear unit. (c) 2012 Elsevier Ltd. All rights reserved.