Generation of a Sulfinamide Species from Facile N–O Bond Cleavage of Nitrosobenzene by a Thiolate-Bridged Diiron Complex

Abstract

The activation of nitrosobenzene promoted by transition-metal complexes has gained considerable interest due to its significance for understanding biological processes and catalytic C–N bond formation processes. Despite intensive studies in the past decades, there are only limited cases where electron-rich metal centers were commonly employed to achieve the N–O or C–N bond cleavage of the coordinated nitrosobenzene. In this regard, it is significant and challenging to construct a suitable functional system for examining its unique reactivity toward reductive activation of nitrosoarene. Herein, we present a {Fe2S2} functional platform that can activate nitrosobenzene via an unprecedented iron-directed thiolate insertion into the N–O bond to selectively generate a well-defined diiron benzenesulfinamide complex. Furthermore, computational studies support a proposal that in this concerted four-electron reduction process of nitrosobenzene the iron center serves as an important electron shuttle. Notably, compared to the intact bridging nitrosoarene ligand, the benzenesulfinamide moiety has priority to convert into aniline in the presence of separate or combined protons and reductants, which may imply the formation of the sulfinamide species accelerates reduction process of nitrosoarene. The reaction pattern presented here represents a novel activation mode of nitrosobenzene realized by a thiolate-bridged diiron complex.

Double Bond Cleavage in Small Molecules Using a Geminal Sc/P Lewis Pair

“…As a versatile molecule in chemistry and biology, nitrosobenzene has attracted much attention and the investigation of its diverse binding modes . However, cleavage of the NO double bond is only limited to a few examples, in which multielectron reduction processes usually occur at electron-rich metal complexes. Although a variety of main group and organometallic FLPs have been proven capable of binding nitrosobenzene, the complete rupture of a NO double bond has not been achieved.…”

Stepwise Reduction of Redox Noninnocent Nitrosobenzene to Aniline via a Rare Phenylhydroxylamino Intermediate on a Thiolate-Bridged Dicobalt Scaffold

“…Compared to monometallic complexes except two special instanses, bimetallic PhNO complexes usually exhibit greater activation degree of PhNO, and can even promote N–O bond cleavage . However, none of them can effect the stepwise transformation of PhNO → PhNHOH → PhNH 2 via PhNHOH as a key intermediate.…”

Synthesis, Characterization, and Catalytic Reactivity of Dithiolate-Bridged Diiron Complexes Supported by Bulky Cyclopentadienyl Ligands

“…Among the synthetic iron thiolate complexes, thiolate-bridged diiron complexes featuring cyclopentadienyl ligands represent a kind of important functional model for the cooperative activation and catalytic transformation of small molecules . In a notable example, a novel diiron thiolate complex featuring a redox non-innocent bdt (bdt = benzene-1,2-dithiolate) bridging ligand can seize a series of reactive N x H y intermediate species during biological nitrogen fixation, which provides significant experimental support for the viewpoint of the potential diiron reaction site in the FeMo-cofactor of nitrogenase .…”