Studies on polyoxo and polyperoxo-metalates - Part 7. Lanthano- and thoriopolyoxotungstates as catalytic oxidants with H2O2 and the X-ray crystal structure of Na-8[ThW10O36]center dot 28H(2)O

The effectiveness of salts of [Ln(III)W(10)O(36)](9-) (Ln = Y, La, Ce, Pr, Sm, Eu, Gd, Dy, Er, Lu) and [(MW10O36)-W-IV](8-) (M = Ce, Th) as catalysts with H2O2 for alcohol oxidations and alkene epoxidations has been studied. It appears that catalysis arises from the polyperoxotungstates formed from H2O2. The X-ray crystal structure of the title complex shows that in the [T hW10O36](8-) anion the thorium has square antiprismatic geometry in which e ight oxygen atoms from two W5O18 moieties form vertex-sharing bonds; Raman data suggest that the structure of the anion is retained in aqueous solutio n. New P-31[H-1]-NMR data for [Ln(III){PW11O39}(2)](11)- (Ln = Y, La, Ce, P r, Nd, Sm, Eu, Tb, Ho, Er, Yb, Lu) and [Ce-IV{PW11O39}(2)](10)- in the soli d state, in water and in H2O2 solution are presented; these species have al so been used for oxidation catalysis. (C) 2000 Elsevier Science S.A. All ri ghts reserved.