886451-39-4Relevant academic research and scientific papers
Synthesis and electrochemical, spectral and catalytic properties of diphosphine-polypyridyl ruthenium complexes
Sussuchi, Eliana M.,De Lima, Andréia A.,De Giovani, Wagner F.
, p. 1457 - 1463 (2006)
Two new ruthenium aqua complexes containing phosphines and polypyridine as ligands were synthesized: [Ru(L)(totpy)(H2O)](PF6) 2 (L = 1,2-bis(dimethylphosphino) ethane and 1,2- bis(dichlorophosphino)ethane; totpy = 4′-(4-tolyl)-2,2′:6′, 2″-terpyridine). The synthetic routes for both complexes are similar. The complexes were characterized by elemental analysis, cyclic voltammetry and differential pulse voltammetries, UV-Vis and EPR spectra. Epa versus pH studies are consistent with a one-electron, one-proton transfer; at high pH, potentials become pH independent. Catalytic tests with benzyl alcohol, cyclohexanol, cyclohexene, ethylbenzene, 1,2-butanediol and 1,4-butanediol were carried out using the oxo complexes, which are electrochemically generated from the corresponding aqua complexes, in solution and immobilized in carbon paste and ITO/Nafion electrodes. In the presence of excess substrates, the cyclic voltammograms of the complexes and of the modified electrodes show an enhancement of the oxidation peaks and a decrease of the reduction peaks upon potential reversal, indicating catalytic activities. Plots of the anodic peak currents (Ipa) against organic substrate concentrations showed straight lines, indicating pseudo-first-order kinetics behavior. For the modified electrodes the plots of Ipa versus ν1/2 showed that the anodic peak currents change linearly with the square root of the scan rate; this is characteristic of surface electrocatalysis with the catalyst confined to the electrode surface with diffusion control of the substrates.
