SYNTHESIS OF THE TRISCYCLOPENTADIENYL(HYDROXO)URANIUM(IV) COMPLEXES [U(C5H4R)3(OH)] (R = SIME3 OR (T)BU) AND THEIR TRANSFORMATION INTO MU-OXO BRIDGED DERIVATIVES - CRYSTAL-STRUCTURE OF THE TRINUCLEAR COMPOUND [(U(C5H4SIME3)2(MU-O))3]

The U(IV) hydroxo-complexes [U(C5H4R)3(OH)] (R = SiMe3 or (t)Bu) have been prepared, either by hydrolysis of the corresponding hydrides [U(C5H4R)3H] or by treatment of the cationic compounds [U(C5H4R)3][BPh4] with sodium hydroxide. Reaction of [U(C5H4R)3(OH)] with [U(C5H4R)3H] gave the mu-oxo derivative [{U(CH4R)3}2(mu-O)] (R = SiMe3) and thermolysis of the hydroxo-complexes afforded the trinuclear compounds [{U(C5H4R)2(mu-O)}3]. The crystal structure of [{U(C5H4SiMe3)2(mu-O)}3] has been determined.