LAUSR

Synthetic studies of bimetallic uranium nitride complexes with the N(SiMe3)2 ligand have generated a new nitride complex of U(III), which is highly reactive toward C-H bonds and H2. Treatment of the previously reported U(IV)/U(IV) nitride complex [Na(DME)3][((Me3Si)2N)2U(µ-N)(µ-2-C,N-CH2SiMe2NSiMe3)U(N(SiMe3)2)2], 1, with 2 equivalents of HNEt3BPh3 yielded the cationic U(IV)/U(IV) nitride complex, [{((Me3Si)2N)2U(THF)}2(µ-N)][BPh4], 3, by successive protonolysis of one N(SiMe3)2 ligand and the uranium-methylene bond. Reduction of 3 with KC8 afford-ed a rare example of a U(III) nitride, namely, the U(III)/U(IV) complex, [{((Me3Si)2N)2U(THF)}2(µ-N)], 4. Complex 4 is highly reactive and undergoes 1,2-addition of the C-H bond of the N(SiMe3)2 ligand across the uranium-nitride moiety to give the U(III)/U(IV) imide cyclometalate complex, [((Me3Si)2N)2(THF)U(µ-NH)(µ-2-C,N-CH2SiMe2NSiMe3)U(N(SiMe3)2))(THF)], 5. Complex 4 also reacts with toluene at -80 °C to yield an inverse sandwich imide complex arising from C-H bond activation of toluene, [{((Me3Si)2N)2U(THF)2(µ-N)][{((Me3Si)2N)3U(µ-NH)U(N(SiMe3)2}2(C7H8)], 6. Complex 4 effects the heterolytic cleavage of the C-H of phenylacetylene to yield the im-ide acetylide [{((Me3Si)2N)2U(THF)}2(µ-N)][((Me3Si)2N)2U(1-CCPh)(µ2-NH)(µ2-η2:η1-CCPh)U(N(SiMe3)2)2], 7. Com-plex 4 also reacts with H2 to produce an imide hydride U(III)/U(IV) complex, [{((Me3Si)2N)2U(THF)}2(µ-NH)(µ-H)], 9. These data demonstrate that nitride complexes of U(III) are accessible with amide ligands and show the high reactivi-ty of molecular U(III) nitrides in C-H bond activation.