SYNTHESIS, CHARACTERIZATION AND REACTIVITY OF SOME NOVEL DINUCLEAR MIXED-LIGAND PEROXOURANIUM(VI) COMPLEXES

Novel anionic dinuclear mixed-ligand peroxo complexes of the type [(UO 2)(2)(O-2)(3)L(H2O)(2)](3-) (L = Histidinate, aspartate, salicylate, I midazolate and glutamate) have been synthesised from the interaction o f uranyl ion (UO22+) with peroxide (O-2(2-)) in the presence of the re spective coligand (L) at pH 9-10. The sparingly soluble complexes were characterized by elemental analyses, FT-IR, laser Raman (LR) and UV-v is spectroscopy and solution electrical conductance measurements. Base d on these studies, a double bridged dinuclear structure involving one peroxo and the mixed ligand L (via-COO-) has been tentatively propose d. Infra-red coupled with LR spectra evidenced structurally different metal bound peroxides (eta(2) and sigma:sigma). An aqueous solution of the salicylate and aspartate complexes have been shown to convert tri phenylphosphine (PPh3), cyclohexene, styrene and SO2 to the correspond ing OPPh3, 1,2 cyclohexanediol, phenylethyleneglycol and SO42-, respec tively. (C) 1997 Elsevier Science Ltd.