Heterometallic complexes involving copper(II) and rhenium(VII) centers

The acetonitrile solution of NH4ReO4 added to methanol/acetonitrile solution of Cu(NO3)2 with bis(pyrazol-1-yl)methane leads to the blue heterobimetallic [Cu(bpzm)2][ReO4]2 (1) complex in which perrhenate is linked via oxygen with copper(II) ion. The reaction with bis(3,5-dimethylpyrazol-1-yl)methane under the same conditions gave [Cu(bdmpzm)2][NO3]·[ReO4]·CH3CN (2) complex in which perrhenate exists as counterion. Both complexes were structurally characterized and in solid state by IR, UV–Vis–NIR spectroscopy and magnetic susceptibility measurements. The magnetic data indicated paramagnetism of both complexes with the weak magnetic short-range interactions and without frustration of the spins below 2 K.

The heterobimetallic μ-oxo-bridged [Cu(bpzm)2(ReO4)2] and [Cu(bdmpzm)2][NO3]·[ReO4]·CH3CN complex in which perrhenate occurs as counterion (bpzm = bis(pyrazol-1-yl)methane; bdmpzm = bis(3,5-dimethylpyrazol-1-yl)methane) were synthesized and characterized by X-ray, IR, UV–Vis–NIR. In both paramagnetic complexes the weak magnetic short-range interaction is visible. However the main contribution to the magnetism comes from the spin, but only a small its proportion from the orbital moment.Figure optionsDownload as PowerPoint slide