CRYSTAL-STRUCTURE AND SPECTRA OF A COMPLEX RESULTING FROM COPPER(II) NITRATE WITH THE BIS SCHIFF-BASE OF THIOPHENE-2-ALDEHYDE AND DIETHYLENE TRIAMINE

The crystal structure of bis(nitrato)-N-(2-thienylmethylene)-N-[2-[(2-thienylmethylene)amino]-ethyl]-1,2-ethanediamine-copper(II) hydrate, C14H17N5 . O6S2Cu . H2O, has been determined by single crystal X-ray diffraction technique. It crystallizes in the orthorhombic system, space group Pbca, with a = 6.7511(6) angstrom, b = 20.3188(16) angstrom, c = 29.053(3) angstrom, V = 3985 angstrom3 and Z = 8. The structure was solved by direct phase determination and refined by least-squares to a final R = 0.039 (R(w) = 0.038) for 1664 observed unique reflections [F(o) > 5sigma(F(o))]. The copper atom is bonded to the three nitrogen atoms of the organic ligand [1.981(5) angstrom, 1.986(5) angstrom, 1.996(4) angstrom] and to an oxygen atom of each of the two nitrate groups [1.992(4) angstrom, 2.294(4) angstrom] in a distorted square pyramidal arrangement. Additionally, there is a very weak Cu-O bond [2.655 angstrom] with one of the nitrate groups. The water molecule, as well as both nitrate groups, participate in hydrogen bond formation. The IR and electronic spectra are in accordance with the established features of the structure. The molar conductivity indicates that the complex is a 1:1 electrolyte, while the magnetic moment is consistent with monomeric copper(II) units.