Multiple Syntheses of (C5Me5)3U

Several new synthetic routes to the sterically crowded (C 5 Me 5 ) 3 U complex have been developed. (C 5 Me 5 ) 3 U can be prepared by (a) reaction of [(C 5 Me 5 ) 2 UH 2 ] 2 with tetramethylfulvene, (b) reduction of (C 5 Me 5 ) 2 Pb with (C 5 Me 5 ) 2 UH(DMPE), (c) reaction of [(C 5 Me 5 ) 2 U(L)] + (L = THF, DMPE) with K(18-crown-6)(C 5 Me 5 ), and (d) reaction of [(C 5 Me 5 ) 2 U][BPh 4 ] with KC 5 Me 5 . Reaction of (C 5 Me 5 ) 2 UH(DMPE) with C 8 H 8 forms the product of the (C 5 Me 5 ) 3 U/C 8 H 8 reaction, [(C 8 H 8 )(C 5 Me 5 )U] 2 (C 8 H 8 ). The X-ray crystal structures of the (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ] and [(C 5 Me 5 ) 2 U][BPh 4 ] precursors used in this study are reported, as well as the convenient synthesis of a new trivalent uranium precursor, (C 5 Me 5 ) 2 UMe 2 K.