The Crystal Structure of Monoaquobis(1,10-phenanthroline)copper(II) Nitrate, [Cu(H2O)(phen)2](NO3)2

Abstract The crystal structure of the title compound has been determined from three-dimensional X-ray data collected on Weissenberg photographs, using CuKα radiation. The intensities were estimated visually with a standard scale. The structure was solved by the heavy-atom method and refined by the least-squares method. The final R value was 0.118 for 1835 observed reflections. The space group is C2/c, with a=22.58(2), b=7.23(1), c=16.58(2) Å, β=123.6(1)°, and Z=4. The crystal is composed of [Cu(H2O)(phen)2]2+ cations with C2-symmetry and NO3− anions. The copper atom is surrounded by four nitrogen atoms of the two phenanthroline ligands (average Cu–N=2.01 Å) and a water-oxygen atom (Cu–O=2.18 Å) in a distorted trigonal-bipyramidal arrangement. One oxygen atom and two nitrogen atoms of two different phenanthroline ligands are coplanar with the central copper atom, and lines linking the copper atom with each of the axial nitrogen atoms make angles of about 10°, with the normal to the basal N–N–O plane. The electronic reflectance spectrum of this complex shows a characteristic band at about 12.5×103 cm−1, which is analogous to that of [CuI(bipy)2]I.