rameters of the CTD-catechol complex relative to the other complexes may signal such an activation, which affords a substrate molecule capable of reacting with dioxygen directly. That such a mechanism is chemically reasonable is supported by recent observations of iron(II1)-catalyzed cleavage of catechols in chemical system^.^^.^^ en)BzO data. (1982)(1983)(1984)(1985)(1986) and an NIH Research Career Development Awardee (1982)(1983)(1984)(1985)(1986)(1987). We thank Dr. P. Nizin for collecting the Fe(sa1-(32) White, L. S.; Nilsson, P. V.; Pignolet, L. H.; Que, L., Jr.The C12-radical produced by pulse radiolysis of aqueous sodium chloride solutions oxidizes U(V), Np(V), Pu(III), and Am(II1).The respective rates (M-I s-l) are (6.5 * 2) X lo*, (2.38 0.10) X lo6, (4.8 * 0.4) X lo7, and (3.2 0.4) X los. The mechanism for the oxidation of U(V) and Np(V) is discussed in terms of the Marcus theory. There is an unexpected linear free energy correlation with the measured rate parameters in the oxidation of U(III), Ti(III), Pu(III), and Am(II1). tration at 0.0,4.78, and 9.84 "C. At an ionic strength of 3.0, the values at 1 M CIwere extrapolated to 25 "C. From the measured ionic strength dependencies, the 25 "C value was corrected to unit ionic strength. The synthesis of (Pc)Th(acac)z and (Pc)U(acac),, where Pc is the dianion of phthalocyanine and acac is the anion of 2,4-pentanedione, is reported. These are the first examples of 1:l actinide-phthalocyanine complexes. NMR data suggest that the metal is out of the plane of the porphyrin ring and that the two acac ligands are in a cis geometry about the metal. Electrochemical, spectroelectrochemical, and ESR studies on these complexes were performed and demonstrate that both (Pc)U(acac), and (Pc)Th(acac)z can undergo two ring reductions and two ring oxidations.
