Peter Osvath

Cyclic voltammetry of cage compounds incorporated in Nafion® films on graphite electrodes

Abstract A range of structurally different cage complexes are shown to be incorporated in high concentrations in thin (ca.0.5–5 μm) Nafion® films covering graphite electrodes. The incorporated cage complexes show well-defined cyclic and square-wave voltammograms with reduction potential shifts which reflect the biphasic hydrophilic and hydrophobic composition of Nafion®. The large partition ratios relative to aqueous electrolyte solution also have interesting analytical perspectives. Finite film-thickness effects are reflected in deviations from linear Randles-Sevcik plots at small scan rates. The concentration dependence of the apparent diffusion coefficients obtained from the linear part of the Randles-Sevik plots points to mobility of the cage complexes rather than electron hopping as the dominating charge transport mechanism. Both diffusion and migration appear important. Nafion® + cage compound electrodes in contact with buffer solutions containing cytochrome c or plastocyanin have so far not shown voltammetric signal changes compared with the signal from the Nafion® + cage compound electrodes in protein-free buffer. However, the question of cage compound-protein electron exchange is unresolved at present. Glucose oxidase is denatured at the interface with subsequent transport and adsorption of the flavin group in the Nafion® film region.

Energy vs. electron transfer processes involving a novelcobalt cage complex

A novel cage complex, [Co(Me 2 -N 3 S 3 absar)] 3+ , able to undergo fast and efficient electron transfer reactions, is examined as an electron transfer agent in photocatalytic systems aimed at generating H 2 ; its electrochemical behaviour and excited state quenching properties are described.

Synthesis of a large cavity homoleptic thioether cage and its cobalt(III) complex

The cobalt(III) complex of the large hexathioether cage (1,9-dimethyl-3,7,11,15,18,22-hexathiabicyclo[7.7.7]tricosane) shows substantially different redox and spectral properties relative to the smaller homologous [6.6.6]icosane.

Cobalt(II) and cobalt(III) complexes of a novel homoleptic thioether cage

Low-spin hexadentate cobalt(II) and cobalt(III) complexes of the hexathioether cage (1,8-dimethyl-3,6,10,13,16,19-hexathiabicyclo[6.6.6]icosarie) have been synthesised, their redox and spectral properties have been investigated, and the encapsulation of the cobalt(II) ion has been established by an X-ray crystal structure determination, which shows the metal ion to be coordinated to six thioether sulphur atoms at distances ranging from 2.265(3) to 2.354(2)A.