Robert H. Lane

Mercaptide-bridged intramolecular electron transfer from copper(I) to cobalt(III)

Aqueous CuI binds tightly to the sulphur atom of O,S-mercaptoacetatobis(ethylenediamine) cobalt(III) to yield a binuclear ion which undergoes intramolecular electron transfer decay with k= 2·0 × 10–3 s–1(25 °C, 0·10M HClO4), ΔH*= 21·4 ± 0·4 kcal mol–1 and ΔS*=+ 1·0 ± 2·5 cal K–1 mol–1.

Rates of chelate ring closure and opening at a chromium(III)–thiol bond

The rates of chelate ring opening, (70[H+]+0·6)× 10–6[Cr(H2O)4(SCH2CO2)+], and closure, (70 + 0·8[H+]–1)× 10–7[Cr(H2O)5(O2CCH2SH)2+], at the Cr–S bond appear to parallel other substitutions at CrIII with no apparent abnormalities associated with the mercaptan function and a 100-fold rate advantage for chelate closure by both paths.