Facile Reduction of a Uranyl(VI) β-Ketoiminate Complex to U(IV) Upon Oxo Silylation

Reaction of the uranyl β-ketoiminate complex UO2(tBuacnac)2 (1) (tBuacnac = tBuNC(Ph)CHC(Ph)O) with Me3SiI, in the presence of Ph3P, results in the reductive silylation of the uranyl moiety and formation of the U(V) bis-silyloxide complex [Ph3PI][U(OSiMe3)2I4] (2). Subsequent reaction of 2 with Lewis bases, such as 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen), and tetrahydrofuran (THF), results in a further reduction of the metal center and isolation of the U(IV) complexes U(OSiMe3)2I2(bipy)2 (3), U(OSiMe3)2I2(phen)2 (4), and [U(OSiMe3)2I(THF)4][I3] (5), respectively.