Synthesis and structure of a square-planar copper-norflaxacin coordination complex.

The title coordination complex, bis-[4-(3-carboxyl-ato-1-ethyl-6-fluoro-4-oxo-1,4-di-hydro-quinolin-7-yl)piperazin-1-ium-κ2 O 3,O 4]copper(II) dinitrate, [Cu(C16H18FN3O3)2](NO3)2, was synthesized from norfloxacin (NF) and Cu(NO3)2·3H2O. The asymmetric unit contains half a mol-ecule of [Cu(NF)2] and one nitrate anion, with the copper atom located at a special crystallographic position with 1 site symmetry. The NF ligands are zwitterionic and coordinate to the metal atom via two oxygen atoms and the nitrate ions remain uncoordinated as counter-ions. The supra-molecular features include π-π stacking inter-actions as well as N-H⋯O and C-H⋯F hydrogen bonds and short [2.718 (3) Å] F⋯F inter-actions, which facilitate the formation of a columnar assembly parallel to the b-axis. Hirshfeld surface and two-dimensional fingerprint plot analysis were used to qu-antify the supra-molecular inter-actions of the compound.