Reductive Reactivity of the Tetravalent Uranium Complex [(η⁵-C₅Me₅)(η⁸-C₈H₈)U]₂(μ-η³:η³-C₈H₈)

The reductive reactivity of the cyclooctatetraenide ligands in [(η 5 -C 5 Me 5 )(η 8 -C 8 H 8 )U] 2 (μ-η 3:η 3 -C 8 H 8 ), 1, was examined with polycyclic hydrocarbons, phenazine, and the diphenyldichalcogenide compounds PhEEPh (E = S, Se, Te). Complex 1 does not reduce anthracene, acenaphthylene, or benzanthracene, but it acts as a two-electron reductant with phenazine to form 1 equiv of C 8 H 8 and the bimetallic complex [(η 5 -C 5 Me 5 )(η 8 -C 8 H 8 )U] 2 (μ-η 1:η 1 -C 12 H 8 N 2 ), 2 . X-ray crystallography showed that the heteroleptic metallocene unit [(C 5 Me 5 )(C 8 H 8 )U] 1+ adopted an η 1 -coordination mode with the phenazine dianion rather than the η 3 -coordination previously found with the homoleptic f element metallocene cations [(C 5 Me 5 ) 2 M] 1+ . Complex 1 also reacts as a two-electron reductant with PhEEPh (E = S, Se, Te) to form C 8 H 8 and the heteroleptic complexes [(η 5 -C 5 Me 5 )(η 8 -C 8 H 8 )U] 2 (μ-EPh) 2 (E = S, 3; Se, 4; Te, 5 ).