Syntheses and crystal structure of binuclear μ-oxamido copper(II) complexes containing 1,4,7-triazacyclononane as a terminal ligand

Two new binuclear copper(II) complexes, Cu(tacn)Cu(oxpn)(ClO4)(2) center dot C2H5OH (1), and Cu(tacn)Cu(oxap)(ClO4)(2) center dot CH3OH (2), have been prepared from the planar fragment Cu(oxpn) and Cu(oxap) (tacn denotes 1,4,7-triazacyclononane, oxpn and oxap stand for the dianions of N,N'-bis(3-aminopropyl) oxamide, and N,N'-bis(2-aminopropyl) oxamide, respectively). The complexes have been characterized by means of elemental analyses and IR, and UV spectra. The crystal structure of compound 1 shows that copper(II) coordinates to the four nitrogen atoms of oxpn in a square-planar environment and the other copper(II) ion is in a distorted square-pyramidal environment.