Evidence of two-state reactivity in water oxidation catalyzed by polyoxometalate-based complex [Mn3(H2O)3(SbW9O33)2]12−

Activation by oxidation and ligand exchange in a molecular manganese vanadium oxide water oxidation catalyst

“…As in Siegbahn's studies of the OEC in photosystem II, 28,29 calculations were carried out using the high-spin conguration and assuming that antiferromagnetic effects do not signicantly affect either the reaction barriers or the geometry of the complex. 30 Geometries were optimized using DFT and the B3LYP functional 31,32 as widely used in other studies of OEC model systems [33][34][35][36][37] and polyoxometalate WOCs 24,[38][39][40][41][42][43][44][45] combined with the def2-SVP basis set. 46 Local minima were conrmed by the absence of imaginary frequencies.…”

Reactivity and Stability of Polyoxometalate Water Oxidation Electrocatalysts

“…They proposed a detailed mechanism for both species, which consists of an electron transfer, a proton transfer, and one PCET step leading to the active S2 state, followed by nucleophilic attack by H2O, the rate-determining step, and two further PCET steps to yield O2. The authors also linked the experimentally observed higher catalytic activity of [Co4(H2O)2(VW9O34)2] 10-compared to {Co4} to increased orbital coupling between the d orbitals of V and Co. Yan, Lang and colleagues [58] have employed DFT to study the water oxidation cycle of [Mn3(H2O)3(SbW9O33)2] 12-, also finding that nucleophilic attack by H2O is the rate-determining step. Likewise, the water oxidation cycle of [Mn(H2O)GeW11O39] 5-was investigated in detail, [59] describing two possible mechanisms, via nucleophilic attack by H2O or via intramolecular O-O bonding, respectively.…”

“…[63] To sum up, we have seen that theoretical methods are capable of handling a wide variety of problems in the study of POM WOCs, demonstrating that fundamental insights into the mechanistic details of water oxidation on POM catalysts can be gained through their application. It appears that DFT is the method of choice, as with few exceptions all mechanistic studies presented here adopt hybrid functionals [32,49,[51][52][53][55][56][57][58][59] and implicit solvent models [32,[49][50][51][52][53][54][57][58][59] for their simulations. For a more comprehensive overview of theoretical methods used in POM research, the reader is referred to the excellent review by López et al [64] Considerable progress has been made in elucidating the water oxidation cycles of some WOCs in great detail, especially those of {Ru4} and {Co4}.…”

Activation by oxidation and ligand exchange in a molecular manganese vanadium oxide water oxidation catalyst

“…As in Siegbahn's studies of the OEC in photosystem II, 28,29 calculations were carried out using the highspin configuration and assuming that antiferromagnetic effects do not significantly affect either the reaction barriers or the geometry of the complex. 30 Geometries were optimized using DFT and the B3LYP functional 31,32 as widely used in other studies of OEC model systems [33][34][35][36][37] and polyoxometalate WOCs - 24,[38][39][40][41][42][43][44][45] combined with the def2-SVP basis set. 46 Local minima were confirmed by the absence of imaginary frequencies.…”