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

Abstract

The reductive reactivity of the cyclooctatetraenide ligands in [(η5-C5Me5)(η8-C8H8)U]2(μ-η3:η3-C8H8), 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 C8H8 and the bimetallic complex [(η5-C5Me5)(η8-C8H8)U]2(μ-η1:η1-C12H8N2), 2. X-ray crystallography showed that the heteroleptic metallocene unit [(C5Me5)(C8H8)U]1+ adopted an η1-coordination mode with the phenazine dianion rather than the η3-coordination previously found with the homoleptic f element metallocene cations [(C5Me5)2M]1+. Complex 1 also reacts as a two-electron reductant with PhEEPh (E = S, Se, Te) to form C8H8 and the heteroleptic complexes [(η5-C5Me5)(η8-C8H8)U]2(μ-EPh)2 (E = S, 3; Se, 4; Te, 5).