Synthesis of a Rotaxane Cu^I Triazolide under Aqueous Conditions

We describe the serendipitous isolation of a stable, neutral, monomeric mechanically interlocked Cu^I triazolide under aqueous conditions. This “trapped” intermediate of the CuAAC catalytic cycle is sterically protected from reprotonation by the rotaxane architecture, which renders the Cu^I–C bond stable toward moisture and aireven carboxylic acids protonate the Cu^I–C bond only slowly. The isolation of this remarkably stable Cu^I organometallic points toward potential applications of mechanical bonding in the study of reactive intermediates

Synthesis of a Rotaxane Cu^I Triazolide under Aqueous Conditions

We describe the serendipitous isolation of a stable, neutral, monomeric mechanically interlocked Cu^I triazolide under aqueous conditions. This “trapped” intermediate of the CuAAC catalytic cycle is sterically protected from reprotonation by the rotaxane architecture, which renders the Cu^I–C bond stable toward moisture and aireven carboxylic acids protonate the Cu^I–C bond only slowly. The isolation of this remarkably stable Cu^I organometallic points toward potential applications of mechanical bonding in the study of reactive intermediates

High-Throughput Synthesis and Electrochemical Screening of a Library of Modified Electrodes for NADH Oxidation

We report the combinatorial preparation and high-throughput screening of a library of modified electrodes designed to catalyze the oxidation of NADH. Sixty glassy carbon electrodes were covalently modified with ruthenium­(II) or zinc­(II) complexes bearing the redox active 1,10-phenanthroline-5,6-dione (phendione) ligand by electrochemical functionalization using one of four different linkers, followed by attachment of one of five different phendione metal complexes using combinatorial solid-phase synthesis methodology. This gave a library with three replicates of each of 20 different electrode modifications. This library was electrochemically screened in high-throughput (HTP) mode using cyclic voltammetry. The members of the library were evaluated with regard to the surface coverage, midpeak potential, and voltammetric peak separation for the phendione ligand, and their catalytic activity toward NADH oxidation. The surface coverage was found to depend on the length and flexibility of the linker and the geometry of the metal complex. The choices of linker and metal complex were also found to have significant impact on the kinetics of the reaction between the 1,10-phenanthroline-5,6-dione ligand and NADH. The rate constants for the reaction were obtained by analyzing the catalytic currents as a function of NADH concentration and scan rate, and the influence of the surface molecular architecture on the kinetics was evaluated