A novel complex dichlorobis(2-ethyl-3-hydroxy-4-pyrone)zirconium(IV) (ZrCl2(ethylpyrone)(2)) was synthesized. Complexation of the pyrone ligand to the zirconium was confirmed by UV, H-1 and C-13-NMR, and electrochemical studies. NMR showed the presence of four isomers and density functional theory calculations indicated that the main isomer had a cis configuration. The catalyst was shown to be active in ethylene polymerization in the presence of the cocatalyst methylaluminoxane. The highest catalyst activity for the zirconium complex was achieved at Al/Zr = 2500, 70 degrees C and when a small concentration of catalyst was used (1 mu mol). (C) 2008 Wiley Periodicals, Inc.