Synthesis and Reactions of a Tungsten Dioxo Complex

SYNTHESIS AND REACTIONS OF A TUNGSTEN DIOXO COMPLEX Deborah M. Bryant, BS Marquette University, 2010 Metal dioxo complexes are largely known for their ability to epoxidize olefins. The importance of these reactions is reflected in the patents for the ARCO and Halcon processes from the late 1960’s. It is very difficult to find literature that shows other indications for metal dioxo complexes. Catalytic olefin dimerization has become significant in the realm of green chemistry for “atom economical” reactions. Many transition metals have been examined as catalysts for olefin dimerization, but the largest volume of work has been performed using group 8 transition metals, particularly nickel, palladium and platinum. This is especially true for the specific case of styrene dimerization. Herein, we wish to report the synthesis and X-ray crystal structure for Cp*W(=O)2CH3 (1), as well as the X-ray crystal structure for Cp*W(CO)3CH3 (2). The tungsten dioxo complex (1) was found to have high selectivity for the dimerization of some para-substituted styrenes, yielding the desired trans-1,3-diaryl-1-butene products. We also wish to report the X-ray crystal structure of trans-1,3-di-(4-bromophenyl)-1butene which helped to confirm the structure of our products.