Multi-electron reduction from alkyl/hydride ligand combinations in U4+ complexes

The U4+ mixed alkyl hydride complex (C5Me5)U[mu-C5Me3(CH2)(2)] (mu-H)(2)U(C5M5)(2), 1, which contains a cyclopentadienyl ligand with two metalated methylene substituents, can effect four, six, and eight-electron reductions in which the combination of the two H1- ligands and the [C5Me3(CH2)(2)](3-) moiety delivers four electrons and forms (C5Me5)(1-). The reaction is formally equivalent to an alkyl hydride reductive elimination, a transformation common with transition metals not previously observed with f element compounds. This type of alkyl hydride reduction reactivity is also observed with a combination of U4+ alkyl and hydride complexes, (C5Me5)(2)UMe2/[(C5Me5)(2)UH2](2), which reduces benzene to make [(C5Me5)(2)U](2)(C6H6), a U3+ complex formally containing a (C6H6)(2-) ligand.