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

Despite their technological importance for water splitting, the reaction mechanisms of most water oxidation catalysts (WOCs) are poorly understood. This paper combines theoretical and experimental methods to reveal mechanistic insights into the reactivity of the highly active molecular manganese vanadium oxide WOC [MnVO(OAc)] in aqueous acetonitrile solutions. Using density functional theory together with electrochemistry and IR-spectroscopy, we propose a sequential three-step activation mechanism including a one-electron oxidation of the catalyst from [Mn Mn ] to [MnMn ], acetate-to-water ligand exchange, and a second one-electron oxidation from [MnMn ] to [Mn ].

Spectral Signatures of Oxidation States in a Manganese-Oxo Cubane Water Oxidation Catalyst.

We report IR and UV/Vis spectroscopic signatures that allow discriminating between the oxidation states of the manganese-based water oxidation catalyst [(Mn O )(V O )(OAc) ] . Simulated IR spectra show that V=O stretching vibrations in the 900-1000 cm region shift consistently by about 20 cm per oxidation equivalent. Multiple bands in the 1450-1550 cm region also change systematically upon oxidation/reduction.

A 3d-printed composite electrode for sustained electrocatalytic oxygen evolution.

We report the facile design and fabrication of 3D-printed microstructured electrodes for electrocatalytic oxygen evolution. ABS polymer-based mesh scaffolds are chemically functionalized to enable electroless nickel metal deposition and subsequent catalyst (nickel iron hydroxide) immobilization. The resulting composites show sustained oxygen evolution with low overpotentials and high stability.

The Reactivity and Stability of Polyoxometalate Water Oxidation Electrocatalysts.

This review describes major advances in the use of functionalized molecular metal oxides (polyoxometalates, POMs) as water oxidation catalysts under electrochemical conditions. The fundamentals of POM-based water oxidation are described, together with a brief overview of general approaches to designing POM water oxidation catalysts. Next, the use of POMs for homogeneous, solution-phase water oxidation is described together with a summary of theoretical studies shedding light on the POM-WOC mechanism.

Crystal structures of 4,4'-(disulfane-1,2-diyl)bis(5-methyl-2-1,3-dithiol-2-one) and 4,4'-(diselanane-1,2-diyl)bis(5-methyl-2-1,3-dithiol-2-one).

The two title compounds, CHOS and CHOSSe, are isotypic with very similar cell parameters. The complete mol-ecules constitute the asymmetric units, despite being chemically perfectly symmetric. The most prominant differences in the metrical parameters arise from the distinct sizes of sulfur and selenium in the dichalcogenide bridges, with C-S-S-C and C-Se-Se-C torsion angles of 70.

Pd/PTABS: Catalyst for Room Temperature Amination of Heteroarenes.

A mild and highly efficient catalytic amination procedure for chloroheteroarenes at ambient temperature using the Pd/PTABS catalytic system is reported. The protocol is selective for the amination of chloroheteroarenes using secondary amines such as piperidine, pyrrolidine, and several others. The exceptional mildness of the developed protocol is beneficial for the synthesis of a crucial Buparlisib intermediate as well as the formal synthesis of Alogliptin in competitive yields.

The Goldilocks principle in action: synthesis and structural characterization of a novel {Cu4(μ3-OH)4} cubane stabilized by monodentate ligands.

A {Cu4(μ3-OH)4} compound, where four copper(II) and four μ3-bridging oxygen atoms occupy alternate corners of a slightly distorted cube, has been prepared and structurally characterized. This species, formulated as [Cu4(μ3-OH)4(Htmpz)8](ClO4)4·1.5Et2O (Htmpz = 3,4,5-1H-trimethyl pyrazole), can be classified as belonging to type I Cu4O4 cubane complexes, and is better described as two Cu(II)-(μ-OH)2-Cu(II) units held together by four long Cu-O bonds.