The uranyl moiety (UO22+) is the main form of uranium in nuclear waste and is a highly soluble environmental contaminant. In addition to having a strictly linear O=U=O geometry, the two U=O interactions are very strong. Therefore, oxo ligand functionalization and cleavage of the uranyl ion can be rather challenging. However, reaction of UO2(dbm)2THF (dbm = OC(Ph)CHC(Ph)O) with 2 equiv R3SiH (R = Ph, Et), in the presence of B(C6F5)3, results in the formation of U(OB{C6F5}3)(OSiR3)(dbm)2THF (R = Ph, 1  ; Et, 2  ), which were isolated as red-orange crystalline solids in good yields. Interestingly, the addition of 1 equiv of H(dbm) to 2  results in cleavage of the uranyl oxo ligand and formation of U(OB(C6F5)3)(dbm)3 (3  ), in 33% yield, along with formation of HOSiEt3. Also, addition of HOSiEt3 and 1 equiv THF to 3  , results in the formation 2  , showing this process is reversible. This is a rare example of controlled uranyl oxo ligand cleavage at ambient temperature and pressure. Complexes 1  , 2  , and 3  , have been fully characterized, including analysis by X-ray crystallography.

Reductive silylation of a uranyl dibenzoylmethanate complex: A controlled example of uranyl oxo cleavage

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.