The crystal structure of 1, 10-phenanthroline-5, 6-dione ligand with Zn (II), tris (1, 10-phenanthroline-5, 6-dione) zinc (II) hexafluorophosphate, [Zn (phen-dione) 3] (PF6) 2, is reported. The complex was characterized by elemental analysis, IR, 1H NMR, electronic absorption spectroscopies, cyclic voltammetry and X-ray crystallography. Yellow crystals of [Zn (phen-dione) 3] (PF6) 2 were formed by ether diffusion into an acetonitrile solution of the complex. The title complex crystallized in monoclinic crystal system (Z=2) with space groups of P21, a=12.0299 (15) Å, b=14.5306 (19) Å, c=13.1879 (17) Å, b=94.058 (2)° and V= 2299.5 (5) Å, b. The structure was refined by using 10048 independent reflections, with I > 2s (I) to an R factor of 0.0490. Singlecrystal structure showed that the coordination geometry around the Zn (II) was a distorted octahedron. The complex showed an intense fluorescence band at visible region (690 nm) in CH3CN with an excitation wavelength of 310 nm at 25.0±0.1oC.
Cyclic voltammogram of the title complex showed two quasi-reversible reduction couples at negative potential, which were assigned to the consecutive reduction of phen-dione ligand to phen-semiquinonate and phen-diolate respectively by analogy to other phen-dione complexes at scan rate 200 mV s-1.