Probing for Four-Coordinate Zerovalent Iron in a π‑Acidic Ligand Field: A Functional Source of FeL4 Enabled by Labile Dinitrogen Binding
journal contributionposted on 10.09.2020, 12:05 by Myles J. Drance, Shuai Wang, Milan Gembicky, Arnold L. Rheingold, Joshua S. Figueroa
It has long been recognized that the first intermediate in chemical reactions mediated by Fe(CO)5 is Fe(CO)4. However, the extreme instability of this unsaturated, high-spin species has hampered detailed structural and stoichiometric reactivity studies. The previously reported heteroleptic complex Fe(N2)(CO)2(CNArTripp2)2 (ArTripp2 = 2,6-(2,4,6-(i-Pr)3C6H2)2C6H3), which is isolobal to Fe(CO)5, is shown here to possess a labile dinitrogen ligand that allows it to perform reactions analogous to Fe(CO)4. Specifically, Fe(N2)(CO)2(CNArTripp2)2 oxidatively adds dihydrogen, white phosphorus, and the Si–H bonds of triethylsilane and phenylsilane readily at room temperature and also binds tetrahydrofuran in the absence of N2. Accordingly, Fe(N2)(CO)2(CNArTripp2)2 effectively serves as a masked form of Fe(CO)4, allowing for well-defined reactivity and structurally characterizable reaction products.