Copper(II) Catalysis of Water Oxidation

Abstract

As the terminal step in Photosystem II (PSII), and a potential half-reaction for artificial photosynthesis, water oxidation (2 H 2 O!O 2 + 4 H + + 4 e À ) is a key reaction, but it imposes a significant mechanistic challenge in its requirements for both 4 e À /4 H + loss and OÀO bond formation. Rapid progress has recently been made based with single site polypyridyl Ru [1][2][3][4] and Ir [5][6][7] complexes, pre-prepared Mn oxide clusters, [8] Co and Ni clusters that spontaneously form in solution, [9,10] Co 3 O 4 (spinel) particles, [11] cobalt-based polyoxometallates, [12,13] colloidal IrO 2 ·n H 2 O, [14] amorphous iridium oxide deposited from organometallic precursors, [15] and, most recently, copper-bipyridine complexes. [16] There is a continuing need for stable, rapid, and easily accessible catalysts for this reaction, ideally based on earth-abundant elements.Cu II has both a well-defined coordination chemistry and an extensive redox chemistry based on reduction to Cu 0 and Cu I , and oxidation to Cu III or even Cu IV . [17][18][19][20][21][22][23][24] With a propensity for square-planar coordination, d 8 Cu III is found as an intermediate in reactions of organocopper compounds and [**]

Efficient Chemical and Visible‐Light‐Driven Water Oxidation using Nickel Complexes and Salts as Precatalysts

“…Chemical water oxidation catalyzed by Ni complexes As multidentate N-donor complexes of Ru, [43][44][45][46][47] Fe, [31][32][33] Co, [18][19][20][21][22][23][24][25] and Cu [34][35][36] are known to be active catalysts/precatalysts for water oxidation, we have prepared a series of Ni complexes that bear various hexa-, penta-, and tetradentate pyridyl/tertiary amine ligands [NiL] 2 + (L = L 1 -L 6 , Scheme 1) to test their efficacy as WOCs.…”

“…[1][2][3][4][5][6][7][8][9] The bottleneck in artificial photosynthesis is water oxidation (2 H 2 O!O 2 + 4 H + + 4 e À ), which can provide an unlimited source of protons and electrons for the production of solar fuels such as H 2 , CO (CO 2 + 2 H + + 2 e À !CO + H 2 O), or methanol (CO 2 + 6 H + + 6 e À !CH 3 OH + H 2 O). [16,17] So far a number of Co, [18][19][20][21][22][23][24][25] Mn, [26][27][28][29][30] Fe, [31][32][33] and Cu [34][35][36] WOCs have been reported. However, to be economically viable, the catalysts should be made from inexpensive, earth-abundant materials.…”

Carbonate Ions Induce Highly Efficient Electrocatalytic Water Oxidation by Cobalt Oxyhydroxide Nanoparticles

“…[7,8] In the last decade, many efforts have been devoted to develop water oxidation catalysts as OEC models, especially efficient, earth-abundantc atalysts with low overpotential and sufficient robustness to fabricate artificial photosynthetic deviceso fp racticalu se. [8][9][10][11][12][13] Such laudable studies have yielded varioust ypes of complex and oxide catalysts based on earth-abundant metals,s uch as cobalt, [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] manganese, [30][31][32] copper, [33][34][35] nickel, [36] and iron. [28,37,38] However,a ttention in most of these studies has been paido nly to the composition and structure of active sites in the OEC models, even though the cofactors are also essential for water oxidation at the photosynthetic OEC.…”

Activation pathways taking place at molecular copper precatalysts for the oxygen evolution reaction

“…Due to substantial faster ligand dissociation kinetics at these first row transitions metals, control over the catalyst structure is considerably more cumbersome. Nevertheless, molecular catalysts in case of manganese [17], iron [18][19][20], cobalt [21] and since very recently copper [22][23][24][25][26][27][28][29][30] have been reported. Especially in case of the latter, lig- * Corresponding author.…”