Synthesis and Catalytic Activity of Ruthenium-Indenylidene Complexes for Olefin Metathesis: Microscale Experiments for the Undergraduate Inorganic or Organometallic Laboratories

A series of experiments for undergraduate laboratory courses (e.g., inorganic, organometallic or advanced organic) have been developed. These experiments focus on understanding the design and catalytic activity of ruthenium-indenylidene complexes for olefin metathesis. Included in the experiments are the syntheses of two ruthenium-indenylidene complexes that can be conveniently prepared from commercially available starting materials. The two complexes differ only by the nature of the phosphine ligand, yet each complex displays drastically different catalytic activity in a ring-closing metathesis (RCM) reaction. When the triphenylphosphine-containing complex is utilized, little or no catalytic activity is observed. Substitution of the complex with tricyclohexylphosphine, however, results in a complex with excellent catalytic activity in a RCM reaction. These experiments demonstrate the importance of catalyst design and expose students to the important field of olefin metathesis. Students also utilize several analytical methods ([superscript 1]H and [superscript 31]P NMR, GC-MS, FT-IR) in characterizing the complexes and quantifying catalytic activity. (Contains 4 figures and 2 schemes.)