AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuM

Paper SS1-TuM1
Direct Observation of Metathesis Reactions on a Carbide Surface: The Surface Chemistry of Multiple Bonds.

Tuesday, November 1, 2005, 8:20 am, Room 202

Session: Vibrational Spectroscopy of Surfaces
Presenter: M. Siaj, Université Laval, Canada
Authors: M. Siaj, Université Laval, Canada
P.H. McBreen, Université Laval, Canada
Correspondent: Click to Email
Well-defined metal ligand complexes are a feature of organometallic chemistry, and have long served as a guide to understanding chemisorption systems. However, the entire area of metal-ligand multiple bond chemistry appears to have almost no counterpart in surface science. Reports of surface alkylidene species, M=CR1R2 where M is a single metal atom, are extremely rare. Metal-alkylidenes are catalysts for metathesis chemistry, one of the most powerful synthetic methodologies in modern organic, polymer and materials science. Hence, for a variety of applications, it is very important to develop metathesis chemistry on extended surfaces. An extensive set of surface spectroscopy data will be used to show that alkylidene groups can be prepared and isolated on the surface of molybdenum carbide. Futhermore, it will be shown that vibrational spectroscopy may be used to perform in-situ monitoring of cross-metathesis and ring opening polymerization reactions, isolating both initiator and propagator species. These results illuminate both the reaction mechanism for heterogeneous metathesis and the unique ability of the metal carbide surface to promote highly selective catalysis.