4,4′-bithiazoles as ligands: Crystal and molecular structure of bis(O,O′-nitrato)(2,2′-diphenyl-4,4′-bithiazole)copper(II) (two polymorphs)

A low-temperature single-crystal X-ray structure determination of the 1 : 1 adduct of copper(II) nitrate with 2,2'-diphenyl-4,4'-bithiazole (L) shows it to be a molecular complex with L behaving as a symmetrical N, N' chelate, and the nitrate groups as unsymmetrical O,O' chelates: [LCu(O2NO)(2)]. Two polymorphs, both monoclinic P2(1)/c, have been obtained from acetonitrile ('alpha') and methanol ('beta'), respectively, with one molecule, devoid of crystallographic symmetry, in the asymmetric unit of each structure. The copper environments are distorted planar four-coordinate, cis-N2CuO2 (Cu - N 2.011(1), 1.973(1), Cu-O 1.995(1), 1.962(1) Angstrom), 'in-plane' angle sum Sigma 369.(5degrees), with longer trans, axial contacts (Cu - O 2.455(1), 2.458(2) Angstrom) for the alpha-form; respective values are 1.995(5), 1.991(4), 1.997(4), 1.973(3) Angstrom, 360.(4degrees), 2.500(4), and 2.396(4) Angstrom for the beta-form.