Structural and spectroscopic characterization of a cationic aquanitrato copper(II) complex with the tetradentate Schiff-base ligand N,N′-bis[1-(2-pyridyl)ethylidene]ethane-1,2-diamine

Cu(NO3)(2). 3H(2)O reacts with 1 equiv. of the tetradentate Schiff base N,N'-bis[1-(2-pyridyl)ethylidene]ethane-1,2-diamine (LA) in refluxing acetone to yield the [CuLA(ONO2)(H2O)](NO3) complex in ca. 80% yield. The structure of this salt has been determined by single-crystal X-ray crystallography. The copper is six-coordinated with the L-A ligand in the equatorial plane and weakly bonded aqua and nitrate ligands above and below this plane. The complex cation is hydrogen-bonded to the nitrate counter-ion. The complex was also characterized by elemental analyses, molar conductivity, room-temperature magnetic susceptibility and spectroscopic (i.r., far-i.r., u.v.-vis, e.s.r.) studies. The data are discussed in terms of the nature of bonding and the known structure.