Scaling Relation between the Reduction Potential of Copper Catalysts and the Turnover Frequency for the Oxygen and Hydrogen Peroxide Reduction Reactions.

Changes in the electronic structure of copper complexes can have a remarkable impact on the catalytic rates, selectivity, and overpotential of electrocatalytic reactions. We have investigated the effect of the half-wave potential () of the Cu/Cu redox couples of four copper complexes with different pyridylalkylamine ligands. A linear relationship was found between of the catalysts and the logarithm of the maximum rate constant of the reduction of O and HO.

Mechanistic Study of the Activation and the Electrocatalytic Reduction of Hydrogen Peroxide by Cu-tmpa in Neutral Aqueous Solution.

Hydrogen peroxide plays an important role as an intermediate and product in the reduction of dioxygen by copper enzymes and mononuclear copper complexes. The copper(II) tris(2-pyridylmethyl)amine complex (Cu-tmpa) has been shown to produce HO as an intermediate during the electrochemical 4-electron reduction of O. We investigated the electrochemical hydrogen peroxide reduction reaction (HPRR) by Cu-tmpa in a neutral aqueous solution.

Fast Oxygen Reduction Catalyzed by a Copper(II) Tris(2-pyridylmethyl)amine Complex through a Stepwise Mechanism.

Catalytic pathways for the reduction of dioxygen can either lead to the formation of water or peroxide as the reaction product. We demonstrate that the electrocatalytic reduction of O by the pyridylalkylamine copper complex [Cu(tmpa)(L)] in a neutral aqueous solution follows a stepwise 4 e /4 H pathway, in which H O is formed as a detectable intermediate and subsequently reduced to H O in two separate catalytic reactions. These homogeneous catalytic reactions are shown to be first order in catalyst.

Synthesis and Avidin Binding of Ruthenium Complexes Functionalized with a Light-Cleavable Free Biotin Moiety.

In this work the synthesis, photochemistry, and streptavidin interaction of new [Ru(tpy)(bpy)(SRR')](PF) complexes where the R' group contains a free biotin ligand, are described. Two different ligands SRR' were investigated: An asymmetric ligand where the Ru-bound thioether is a -acetylmethionine moiety linked to the free biotin fragment via a triethylene glycol spacer and a symmetrical ligand containing two identical biotin moieties. The coordination of these two ligands to the precursor [Ru(tpy)(bpy)Cl]Cl was studied in water at 80 °C.

Turning on the red phosphorescence of a [Ru(tpy)(bpy)(Cl)]Cl complex by amide substitution: self-aggregation, toxicity, and cellular localization of an emissive ruthenium-based amphiphile.

Coupling the notoriously non-emissive complex [Ru(tpy)(bpy)Cl]Cl (tpy = 2,2':6',2''-terpyridine, bpy = 2,2'-bipyridine) to a C alkyl chain via an amide linker on the 4' position of the terpyridine yielded a new amphiphilic ruthenium complex showing red emission and chloride-dependent aggregation properties. This emissive complex is highly cytotoxic in A549 non-small lung cancer cells where it can be followed by confocal microscopy. Uptake occurs within minutes, first by insertion into the cellular membrane, and then by migration to the peri-nuclear region.