Dept. of Chemistry and Biochemical Sciences
Oregon Graduate Center
Copper (I) forms Ï complexes with olefin-containing metal complexes in aqueous solution. Reduction of a series of pyridinepentaammineruthenium (III) ions, where L is a pyridine or 4-substituted pyridines, was studied. For the (NH[subscript 3]) [subscript 5] Ru (III)-4-viny1pyridine ion it is possible to measure separately preequilibrium binuclear ion formation and electron transfer. The electron transfer pathway is determined to be intramolecular from comparison with rate behavior of (NH[subscript 3]) [subscript 5] (III)-4-ethylpyridine, Cu (I) and (NH[subscript 3]) [subscript 5] (III)-pyridine, Cu (I) redox pairs. Rate parameters are also determined for the reverse reaction. Cu (II) catalyzed autoxidation of the (NH[subscript 3]) [subscript 5] (II) - 4-vinylpyridine ion. The redox equilibrium constant determined from the kinetic data agrees reasonably with that calculated from the redox potentials of the reactants. Qualitative models have been advanced from which it is suggested that the entropy of activation gives a measure of the probability for electron transfer in the activated complex, values near zero indicating that electron-tunneling is not rate-limiting. Cu(I)-olefin containing binuclear ions of (NH[subscript 3])[subscript 5]Co(III)L, where L is an alkylpyridine or alkylamine, undergo efficient intramolecular electron transfer when irradiated in the Cu(I)-olefin(n*) absorption band. The results of photoredox studies of a series of alkylamine and alkylpyridine containing binuclear ions are reported. The quantum yields for Co (II) production is shown to falloff monotonically for increasing number of methylene carbons in the chain. Binuclear ions containing polyisoprenyl bridging ligands were also investigated. Mixed solvent studies show decreased quantum yield with increasing ethanol content of the aqueous media. Medium and chain configuration effects are discussed.
Norton, Kenneth A., "Thermal and photoinitiated electron transfer in copper(I) containing binuclear ions" (1980). Scholar Archive. 59.