Water Oxidation Catalyzed by a Dinuclear Cobalt–Polypyridine Complex

Abstract

The dinuclear Co complex [(TPA)Co(μ-OH)(μ-O2 )Co(TPA)](ClO4 )3 (1, TPA=tris(2-pyridylmethyl)amine) catalyzes the oxidation of water. In the presence of [Ru(bpy)3 ](2+) and S2 O8 (2-) , photoinduced oxygen evolution can be observed with a turnover frequency (TOF) of 1.4±0.1 mol(O2 ) mol(1)(-1) s(-1) and a maximal turnover number (TON) of 58±5 mol(O2 ) mol(1)(-1) . The complex is shown to act as a molecular and homogeneous catalyst and a mechanism is proposed based on the combination of EPR data and light-driven O2 evolution kinetics.

A Water‐Soluble Copper–Polypyridine Complex as a Homogeneous Catalyst for both Photo‐Induced and Electrocatalytic O2 Evolution

“…Moreover,t he solution was still transparent even after 2d ays. [12] Together with differences in particle formation and deactivation behavior in the comparison of 1 with Cu(ClO 4 ) 2 ,t hese observations imply that 1 performsa sareal catalyst for water oxidation. Quite as imilaro ccurrence was observed with Co(ClO 4 ) 2 as an alternative catalyst, consistentw ith the analysis obtainedf rom DLS.…”

Hexagonal nanoplates of NiO/CoO/Fe2O3 composite acting as an efficient photocatalytic and electrocatalytic water oxidation catalyst

“…52 Porous NiO nanostructure powders were obtained by annealing as-prepared Ni(OH) 2 beam diameter 2 cm) through a transmitting glass filter (λ ≥ 420 nm) at room temperature. Purified water (18.2MΩ cm) for the preparation of solutions was provided by a Milli-Q water purification system (Millipore, Direct-Q 3 UV).…”

Scalable Synthesis of Piperazines Enabled by Visible‐Light Irradiation and Aluminum Organometallics

“…[1] Deactivation of some important oxidation catalysts are linked to oligomerization,[2] which we aim to address using new piperazine ligands. Piperazines decorated with pyridine (and related) substituents are analogues of pyridylamine ligands relevant to water oxidation,[3] epoxidation of olefins,[4] and C–H oxidation of alkanes. [5] Although these heterocycles are ubiquitous in inorganic chemistry,[6] medicinal chemistry,[7] and natural products,[7a, 8] at the onset of our work only long syntheses with problems regarding stereocontrol could be foreseen towards piperazines functionalized at all carbon positions.…”

“…[5] The complex 7 is an active catalyst that performs metal-centered (non-Fenton) stereoretentive oxidation using aqueous H 2 O 2 , with a 60 % increased activity compared to that of FeTPA. Taking advantage of the basic difference between FeTPA and 7 (which we believe is a consequence of its dinuclear design), we plan to develop more elaborated (and active) catalysts for this[5] and other oxidation reactions[3, 4] based on the singular, rigid, three-dimensional topology defined by the densely functionalized piperazines which are now available. [14a,c]…”