Nitrite Activation to Nitric Oxide via One-fold Protonation of Iron(II)‑<i>O</i>,<i>O</i>‑nitrito Complex: Relevance to the Nitrite Reductase Activity of Deoxyhemoglobin and Deoxyhemerythrin

Abstract

The reversible transformations [(Bim)₃Fe­(κ²-O₂N)]­[BF₄] (<b>3</b>) ⇌ [(Bim)₃Fe­(NO)­(κ¹-ONO)]­[BF₄]₂ (<b>4</b>) were demonstrated and characterized. Transformation of <i>O</i>,<i>O</i>-nitrito-containing complex <b>3</b> into [(Bim)₃Fe­(μ-O)­(μ-OAc)­Fe­(Bim)₃]³⁺ (<b>5</b>) along with the release of NO and H₂O triggered by 1 equiv of AcOH implicates that nitrite-to-nitric oxide conversion occurs, in contrast to two protons needed to trigger nitrite reduction producing NO observed in the protonation of [Fe^II-nitro] complexes