Professor Jeremy Smith (Indiana University)
Date and Time
March 13, 2024
04:15PM - 05:15PM EDT
Location
MIT
New Catalysis Enabled by a Metal-Imido Ligand Cooperativity
Significant work has established the utility of low-coordinate iron imido complexes in two-electron nitrene group transfer reactions. We have found that strongly donating bis(carbene)borates ligands expand the scope of iron imido chemistry, including new catalytic transformations that are redox neutral. In addition to providing a platform for accessing rare examples of isolable iron(V) and iron(VI) bis(imido) complexes, a three-coordinate iron(III) imido complex also serves as an entry point to the corresponding iron(II) imido. The high spin (S = 2) state of the iron(II) complex attenuates the iron-nitrogen multiple bond character, helping to create an unusually electrophilic imido ligand with reactivity patterns akin to those of early transition metals. In addition to known transformations such as such as [2+2] cycloadditions, the iron(II) imido is active in new reactions, including the first ene-like reactivity of an imido ligand. Many of these transformations form the basis for new catalytic reactions involving the cooperative action of iron and the imido ligand, including the catalytic a-deuteration of alkynes, the pKa-dictated isomerization of alkenes and regioselective H/D exchange in pyridines.