Bioinspired Trinuclear Copper Catalyst for Water Oxidation with a Turnover Frequency up to 20000 s^–1

Abstract

Solar-powered water splitting is a dream reaction for constructing an artificial photosynthetic system for producing solar fuels. Natural photosystem II is a prototype template for research on artificial solar energy conversion by oxidizing water into molecular oxygen and supplying four electrons for fuel production. Although a range of synthetic molecular water oxidation catalysts have been developed, the understanding of O−O bond formation in this multielectron and multiproton catalytic process is limited, and thus water oxidation is still a big challenge. Herein, we report a trinuclear copper cluster that displays outstanding reactivity toward catalytic water oxidation inspired by multicopper oxidases (MCOs), which provides efficient catalytic four-electron reduction of O 2 to water. This synthetic mimic exhibits a turnover frequency of 20000 s −1 in sodium bicarbonate solution, which is about 150 and 15 times higher than that of the mononuclear Cu catalyst (F−N 2 O 2 Cu, 131.6 s −1 ) and binuclear Cu 2 complex (HappCu 2 , 1375 s −1 ), respectively. This work shows that the cooperation between multiple metals is an effective strategy to regulate the formation of O−O bond in water oxidation catalysis.

Understanding the factors governing the water oxidation reaction pathway of mononuclear and binuclear cobalt phthalocyanine catalysts

“…[7][8][9][10][11][12] Taking advantage of the well-dened coordination structure, homogeneous metal complexes have been developed as typical OER catalysts and models for understanding the fundamental reaction pathways of water oxidation. [13][14][15][16][17][18][19] For example, a copper bipyridine complex was reported for water oxidation, and Cu(III)-OH intermediate species was determined to be responsible for O-O bond formation via a water nucleophilic attack mechanism. 20,21 Besides, metal complexes with macrocyclic ligands, such as porphyrin and corrole ligands, 17,22,23 were also investigated as OER catalysts owing to their robust coordination environment during the oxidation process, in which O-O bond formation proceeds mostly through a macrocyclic radical cation intermediate species and the macrocyclic ligand could serve as an oxidation charge reservoir for the OER.…”

Repurposing a peptide antibiotic as a catalyst: a multicopper–daptomycin complex as a cooperative O–O bond formation and activation catalyst

“…47,58,76 This reversibility has led to the discovery of Cu-based OER catalysts being designed to furnish di-or multinuclear structures. 16,17,55,58,65 To see if this reversible nature of copper-oxygen intermediates (i.e., Cu 2 O 2 cores) is involved in our multicopper system, we investigated the OER activity of Cu n -dap complexes in an electrochemical reaction setup.…”

“…Inspired by natural metalloenzymes, [8][9][10] organometallic catalysts have been designed to construct a compact structure around the microenvironment of the active site with mono-, 11 di-, [12][13][14][15][16] or trimetallic cores. 17 Catalytic active centers with multiple metals (i.e., >3) have been constructed employing complexation with polydentate ligands, 18,19 the self-assembly of amyloid-like peptides, 20,21 the stabilization of cubane (M 4 O 4 )like clusters, 22 and the formation of substrate-accessible metal-organic frameworks (MOFs). 23 These multimetallic sites resembling metalloenzymes commonly exhibit oxidase-like activities with cooperative rate enhancement.…”

Efficient homogeneous electrochemical water oxidation by a copper(ii) complex with a hexaaza macrotricyclic ligand

“…15,16 Among them, Cu complexes have received much more attention because copper is relatively cheap and/or less toxic. 17,18 Since the report of Meyer et al on a Cu-based bis-mhydroxide cation [(bpy)Cu(m-OH)] 2+ , which is the first example of a molecular electrocatalyst for water oxidation, 19 numerous Cu complexes, including mononuclear copper-polypyridine complexes, [20][21][22][23][24] copper-peptide complexes, [25][26][27][28] copper-porphyrin complexes 29 and copper complexes with a binuclear, [30][31][32][33][34] trinuclear or tetranuclear [35][36][37][38][39][40][41] structure have been developed to realize water oxidation with modest overpotentials.…”