Preparation and olefin-metathesis activity of cyclopentylidene-oxo initiator sites on a molybdenum carbide surface

A low surface area planar sample of bulk β-Mo2C can be activated for olefin-metathesis reactions through the dissociative chemisorption of cyclopentanone to yield surface alkylidene-oxo species. This methodology allows the formation of a sufficiently high coverage of active sites to permit investigation of heterogeneous metathesis by surface science techniques. Reflectance absorbance infrared spectroscopy measurements were used to isolate η1 and η2-adsorbed cyclopentanone. The η2-state was found to be the direct precursor for alkylidene-oxo formation. Olefin-metathesis reactions were carried out using propene and cyclopentene. The surface chemistry of cyclopentanone and cyclopentylidene on β-Mo2C is compared to analogous organometallic systems.

Olefin-metathesis initiating sites can be prepared on the surface of β-Mo2C through the carbonyl bond scission dissociative chemisorption of cyclopentanone. The functionalized carbide provides a surface science analogue of organometallic oxo-alkylidene complexes.Figure optionsDownload as PowerPoint slide