A new catalyst for the copolymerization of ethylene and alpha -olefins, based on (eta (5)-C5Me5)TiCl3, methanol, 2,6-di-t-butylphenol, and methylaluminoxane, is described. The polymerization behavior indicates the necessity of the hindered phenol for high activity, but does not prove that a phenoxide group exists in the coordination sphere of the active site. The titanium K-edge EXAFS spectra of mixtures of various combinations of the four components are best fit to a structure containing a short Ti-O bond, a Ti-arene interaction, and two alkyl carbons. XANES, and to a lesser extent X-ray photoelectron spectroscopy (XPS), spectra show that the presence of the alcohol(s) in the catalyst is correlated with higher titanium absorption energies as well as narrower peak widths.