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

Abstract

A copper complex featuring a proton-responsive tripodal ligand reduces nitrite via a proton/electron transfer process, which parallels copper nitrite reductase.

Four‐Coordinate Copper Halonitrosyl {CuNO}10 Complexes

“…[6][7][8] Aw idely accepted mechanism of copper-mediated nitrite reduction implicates the intermediacyo fa{CuNO} 10 species (Enemark-Feltham notation [9] )w hich readily releases NOC (Scheme 1B). [13] Despite the significant interest in the bioinorganic chemistry of copper nitrosyl complexes in the past decades, [14] the study of NOC coordination to copper centers has been relatively underdeveloped. [13] Despite the significant interest in the bioinorganic chemistry of copper nitrosyl complexes in the past decades, [14] the study of NOC coordination to copper centers has been relatively underdeveloped.…”

“…[10][11][12] However,due to the lack of synthetic and biological examples of {CuNO} 10 species,t he validity of a{ CuNO} 10 intermediate in the mechanism of CuNiR has been brought into question. [13] Despite the significant interest in the bioinorganic chemistry of copper nitrosyl complexes in the past decades, [14] the study of NOC coordination to copper centers has been relatively underdeveloped. Kohlschütter originally reported the binding of NOC to copper(II) halides (Cu II X 2 ,X= Cl, Br) to form putative {CuNO} 10 complexes more than 100 years ago.…”

Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex

“…Our lab [11] and others [12] have shown that ligands featuring the 2-hydroxypyridine (2-hp) fragment can be employed for cooperative substrate binding, proton-coupled electron transfer, and catalysis. [13] The combination of a metal halide H-bond acceptor [14] with a rigid planar ligand featuring pendent hydroxyl H-bond donors was hypothesized to bind Cu(I) in a square planar geometry.…”

“…[13] The combination of a metal halide H-bond acceptor [14] with a rigid planar ligand featuring pendent hydroxyl H-bond donors was hypothesized to bind Cu(I) in a square planar geometry. Cu(I) complexes with the ligand, 6,6″-dihydroxyterpyridine (dhtp), [11a] which incorporates two 2-hp fragments, was initially explored. Unfortunately, rather than affording the desired square planar compounds, metalations using CuCl with dhtp resulted in the formation of multinuclear clusters (Figure 1, top).…”

Nitrite Reduction in Aqueous Solution Mediated by Amavadin Homologues: N2O Formation and Water Oxidation

“…[20][21][22][23][24][25][26] Soil bacteria metabolise nitrite to NO by means of nitrite reductases, which are enzymes of the EC 1.7 group [27] with iron-, [28] copper- [29] or molybdenum-based [26] active centres. [21] Despite such great importance,t he chemical homogeneous reduction of nitrites by inorganic transition metals and internal transition-metal compounds has rarely been investigated.M ost studies focusedo ni ron [33][34][35][36][37][38][39][40][41][42][43][44][45] or copper [46][47][48][49][50][51][52] complexes that mimicked nitrite reductases.H owever,N O 2 À reduction with Ru, [53] Mo, [54][55][56] Ti,C r, [56] Co [57][58][59] andU [60] was also reported. Various fungi, including A. muscaria,a lso contribute to the nitrogen cycle with nitrite as possible metabolic substrate.…”