Dr. Henry Fong (Caltech)
4:00pm - 5:00pm
Catalytic bond activation and bond forming reactions are often catalyzed with noble metal complexes, due in part to their ability to facilitate multielectron processes (e.g., oxidative addition and reductive elimination). There is great interest in replacing these noble metal catalysts with abundant mid to late first-row transition metals. However, first-row transition metal complexes often undergo undesirable one-electron reactions. One promising strategy to circumvent the one-electron reactions is to use ligands that operate cooperatively with the metal. In this talk, I will show that the metallaboratrane complex tris-phosphino-borane-iron, (TPB)Fe, which contains a retro-dative FeàB σ-interaction, can reversibly activate E–H bonds across the Fe–B interaction, forming Fe–E and B–H linkages. The (TPB)Fe complexes are catalytically competent for olefin hydrogenation, and stoichiometric studies indicate that the iron and boron operate in tandem to hydrogenate olefin substrates. (TPB)Fe is incompetent for CO2 hydrogenation, in contrast to related iron complexes. The collective findings suggest that metallaboratranes are a promising class of compounds that can leverage the M–B interaction for cooperative E–H bond activation and, in some instances, catalysis.