Illustrating Catalysis with Interlocking Building Blocks: A Ruthenium Carbene Complex for Olefin Metathesis Reactions

Although the generally accepted mechanism for olefin metathesis reactions is simple and elegant, it seems hard for students to actually visualize and fully understand the metathesis polymerization mechanisms. A unique activity is described that uses interlocking building blocks equipped with magnets to illustrate the concept of a ruthenium carbene complex for olefin metathesis, including cross metathesis, ring-opening metathesis, and acyclic diene metathesis polymerization. The block model of a ruthenium carbene complex was constructed by mimicking a real molecule [Ru{C(H)Ph}Cl2(PCy3)2], known as the first-generation Grubbs’ catalyst. The block models of reactant olefins were constructed from magnets linking two, 2 × 2 blocks. The ruthenium complex model can produce new olefin models by the successive disassembly and assembly of bonding in the reactant olefin models. Students enjoyed constructing the block models and using them to understand the catalytic olefin metathesis reactions.