K. Mizuguchi et al., ELECTROCHEMICAL STUDIES ON ETA-DIKETONATO)(DIMETHYLSULFOXIDE)DIOXOURANIUM(VI) IN DIMETHYLSULFOXIDE, Journal of alloys and compounds, 271, 1998, pp. 163-167
Electrochemical studies on (UO2)-O-VI(beta-diketonato)(2)dmso [beta-di
ketonate=dibenzoylmethanate (dbm), trifluoroacetylacetonate (tfacac),
hexafluoroacetylacetonate (hfacac), dmso=dimethyl sulfoxide] complexes
in DMSO containing tetrabutylammonium perchlorate (supporting electro
lyte) have been carried out using cyclic voltammetry (CV) and normal p
ulse voltammetry (NPV). As a result, it was found that the (UO2)-O-VI(
tfacac or hfacac),dmso complexes are reduced to U(V) species reversibl
y and that the (UO2)-O-VI(dbm)(2)dmso complex is quasi-reversibly redu
ced to U(V) species. The formal redox potentials (E degrees/V, vs. Ag/
AgCl and vs. ferrocene/ferricinium in parentheses) for the U(VI)/U(V)
couple are -0.44 (-0.97) for (UO2)-O-VI(hfacac)(2)dmso, -0.52 (-1.05)
for (UO2)-O-VI(tfacac)(2)dmso, and -0.83 (-1.36) for (UO2)-O-VI(dbm)(2
)dmso. Furthermore, the E degrees values were found to correlate with
the pK(a), values of beta-diketones, i.e. the E degrees values decreas
e with an increase in the pK(a), value. (C) 1998 Elsevier Science S.A.