Structural changes of uranyl moiety with reduction from U(VI) to U(V)

Redox behavior of (UO2)-O-VI(dbm)(2)DMSO (dbm = dibenzoylmethanate, DMSO = dimethyl sulfoxide, 2(VI)) and structural properties of (UO2+)-O-V complexes have been investigated with cyclic voltammetry and IR spectroelectrochemical technique, respectively. As a result, it was confirmed that 2(VI) is quasi-reversibly reduced to [(UO2)-O-V(dbm)(2)DMSO](-) (2(V)) without any Successive reactions, and that 2(V) is stable in DMSO. The formal potential for the redox couple, 2(V)/2(VI), is - 1.362 V vs. the ferrocene/ferrocenium ion redox couple. The IR spectra measured at various applied potentials show a shift of the peak due to the asymmetric stretching (nu(3)) of O=U=O from 906 to 775 cm(-1) with the reduction from 2(VI) to 2(V). From the nu(3) peak positions, U=O distances of 2(V) and 2(VI) were estimated as 1.82 and 1.76 Angstrom by Badger's rule.