Facile Nitrite Reduction in a Non-heme Iron System: Formation of an Iron(III)-Oxo

Abstract

Reaction of tetrabutylammonium nitrite with [N(afa(Cy))3Fe(OTf)](OTf) cleanly resulted in the formation of an iron(III)-oxo species, [N(afa(Cy))3Fe(O)](OTf), and NO(g). Formation of NO(g) as a byproduct was confirmed by reaction of the iron(II) starting material with half an equivalent of nitrite, resulting in a mixture of two products, the iron-oxo and an iron-NO species, [N(afa(Cy))3Fe(NO)](OTf)2. Formation of the latter was confirmed through independent synthesis. The results of this study provide insight into the role of hydrogen bonding in the mechanism of nitrite reduction and the binding mode of nitrite in biological heme systems.

Polymer coordination promotes selective CO2reduction by cobalt phthalocyanine

“…These studies have also established the importance of electron and proton relays in these reactions 76–78. In molecular systems, the importance of the hydrogen bonding in the secondary coordination sphere to stabilize reactive intermediates has been demonstrated by several groups 79–85. In particular, second sphere proton relays incorporated into a ligand scaffold can lead to high electrocatalytic activity in reactions that require the delivery of multiple protons 86–89.…”

Nitrite reduction by copper through ligand-mediated proton and electron transfer

“…This is, to our knowledge, the first synthetic copper system to reduce nitrite in such a fashion. 27 Ongoing efforts on this system are focused at utilizing the H 3 thpa scaffold to facilitate multiple H + /e – transfer events to coordinated substrates.…”

Copper(I)‐Dioxygen Adducts and Copper Enzyme Mechanisms

“…[86,87] Earlier, Masuda and coworkers observed similar stabilization effects in a copper system leading to the first crystal structure of a mononuclear cupric hydroperoxide complex. [40] Taking inspiration from these seminal examples of (di)-oxygen stabilization, Karlin and coworkers synthesized [Cu I ( PV TMPA)] + ( PV TMPA = {6-pivalamido-[2-pyridyl-methyl]}-bis[2-pyridylmethyl]amine), a TMPA derivative where one pyridyl ligand contains a pivalamide H-bond donor in the secondary coordination sphere, a ligand previously made by Masuda and coworkers (Figure 5).…”