Synthesis, crystal structures and photoluminescence properties of two 2D coordination polymer compounds with drug ligand enoxacin

Two new 2D coordination polymers of [M(Enox)(2)]center dot C2H5OH (M=Zn, 1 and Co. 2; HEnox=1.4-dihydro- 1-ethyl-6-fluoro-4-oxo-7-piperazine-1,8-naphtyridine-3-carboxylic acid) were synthesized under hydrothermal conditions. The single crystal X-ray diffraction analyses showed that 1 and 2 are isostructural. The Zn(II) in 1 and Co(II) ions in 2 are six-coordinated in an octahedral environment with an equatorial plane composed of four oxygen atoms: two of them from the 4-oxo and the other two from 3-carboxylate of two coordinated Enox ligands, forming a stable six-membered chelating ring with the apical positions occupied by two N atoms of the piperazinyl fings. Thus, the molecules were self-assembled into a 2D neutral square grid with cavity dimensions of 1.3399 nm X 1.3399 nm for 1 and 1.3389 nm X 1.3389 nm for 2, respectively. Compound 1 emits strong blue fluorescence on irradiation by UV light in the solid state at room temperature.