A Lewis acid catalytic core sandwiched by inorganic polyoxoanion caps: selective H2O2-based oxidations with [Al-4(III)(H2O)(10)(beta-XW9O33H)(2)](6-) (X = As-III, Sb-III)

The Al-III-containing polyanions [Al-4(III)(H2O)(10)(beta-XW9O33H)(2)](4-) with X=As-III (1) and Sb-III (2) feature four aluminum(III) centers sandwiched by two trivacant (beta-XW9O33) Keggin units, and trigger peroxide catalysis as well as substrate coordination via multiple Lewis acid site interactions.