Synthesis and magneto-structural characterization of copper(II) nitrobenzoate complexes containing nicotinamide or methylnicotinamide ligands

Three new copper(II) 4-nitrobenzoato coordination compounds (4-NO2bz− = 4-nitrobenzoate anions) with N-methylnicotinamide (mna) [Cu(4-NO2bz)2(mna)2(H2O)] (1), [Cu(4-NO2bz)2(μ-mna)(H2O)]2 (2) and [Cu(μ-4-NO2bz)2(mna)]2 (3) were synthesized and characterized. Due to a comparison, additional two related compounds [Cu(3,5-(NO2)2bz)2(nia)2(H2O)] (4) (nia = nicotinamide, 3,5-(NO2)2bz− = 3,5-dinitrobenzoate anions) and [Cu(μ-2-NO2bz)2(mna)]2 (5) (2-NO2bz− = 2-nitrobenzoate anions) were isolated. The mononuclear compounds with mna 1 and nia 4 show CuO2N2O chromophores with the water molecule placed at the apex of the square pyramid. The square-pyramidal coordination sphere CuO3NO in 2 differs to CuO2N2O in 1 and 4. Differently, the water molecule is in 2 at the basal-plane, while two mna molecules serve also as bridges via N-py and O-amido enabling a dinuclear molecular structure 1, 2 and 4 are paramagnetic though a dinuclear structure is seen in 2, while a clear-cut strong antiferromagnetic (AFM) coupling (2J −300 cm−1) is found for the compounds 3 and 5.

Graphical abstractA role of the amido moieties and water molecules via coordination and H-bonding in the sensitive self assembly.Two mononuclear and three dimeric copper(II) nitrobenzoates complexes were investigated by taking the susceptibility. Both monomeric compounds are paramagnetic, while the dimeric compounds reveal strong antiferromagnetic (AFM) coupling.Figure optionsDownload full-size imageDownload as PowerPoint slide