Synthesis and characterization of actinide-exchanged Preyssler heteropolyanions [AnP5W30O110]n- (An=Th, Am, Cm)

Interest in the use of heteropolyoxometalate clusters as actinide complexants motivates our studies of the Preyssler heteropolytungstate anion, [NaP5W30O110](14-), and its actinide-exchanged derivatives, [AnP(5)W(30)O(110)](n-). Under specific conditions, substitution of Na+ is possible by La3+ and Th4+ as well as by U4+ and the transuranics Am3+ and Cm3+. Both [AnP(5)W(30)O(110)](11-) (for An = Th4+, U4+) and [AnP(5)W(30)O(110)](12-) (for An=Am3+, Cm3+) as well as [LaP5W30O110](12-) exhibit remarkable redox properties and form heteropoly blues. Although similar, the electrochemistry of the An(3+)/La3+- and An(4+)-exchanged anions are different and distinguishable by cyclic voltammetry in aqueous mineral acid electrolytes. The synthesis of the new Preyssler anion complexes of La3+, Th4+, Am3+, and Cm3+ will be described along with results from cyclic voltammetry measurements. (C) 1998 Elsevier Science S.A.