The synthesis of mixed tethered alkyl uranium metallocenes has been investigated by examining the reactivity of the bis(tethered alkyl) metallocene [(η5-C5Me4SiMe2CH2-κC)2U] (1) with substrates that react with only one of the UC linkages. The effect of these mixed tether coordination environments on the reactivity of the remaining UC bond has been studied by using CO insertion chemistry. One equivalent of azidoadamantane (AdN3) reacts with 1 to yield the mixed tethered alkyl triazenido complex [(η5-C5Me4SiMe2CH2-κC)U(η5-C5Me4SiMe2-CH2NNN-Ad-κ2N1,3)]. Similarly, a single equivalent of CS2 reacts with 1 to form the mixed tethered alkyl dithiocarboxylate complex [(η5-C5Me4SiMe2CH2-κC)U(η5-C5Me4SiMe2- CH2C(S)2-κ2S,S′)], a reaction that constitutes the first example of CS2 insertion into a U4+C bond. Complex 1 reacts with one equivalent of pyridine N-oxide by CH bond activation of the pyridine ring to form a mixed tethered alkyl cyclometalated pyridine N-oxide complex [(η5-C5Me4SiMe2CH2-κC)(η5-C5Me4SiMe3)U(C6H4NO-κ2C,O)]. The remaining (η5-C5Me4SiMe2CH2-κC)2− ligand in each of these mixed tethered species show reactivity towards CO and tethered enolate ligands form by insertion. Subsequent rearrangement have been identified in [(η5-C5Me4SiMe3)U(C5H4NO-κ2C,O)(η5-C5Me4SiMe2C(CH2)O-κO)] and [(η5-C5Me4SiMe2CH2NNN-Ad-κ2N1,3)U(η5-C5Me4SiMe2C(CH2)O-κO)].
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