Bridging μ‐η 5 :η 4 ‐Coordination of an Indenyl Ligand and Reductive Coupling of Diazabutadienes in the Assembly of Di‐ and Tetranuclear Mixed‐Valent Ytterbium Indenyldiazabutadiene Complexes

The redox reaction of [Yb(C 9 H 7 ) 2 (thf) 2 ] with the diazabutadiene PhNC(Me)C(Me)NPh (DAD) has been found to depend on the molar ratio of the reactants. Reaction in a 1:2 molar ratio affords the dinuclear mixed‐valent complex [Yb 2 (μ‐η 5 :η 4 ‐C 9 H 7 )(η 5 ‐C 9 H 7 ) 2 {μ‐η 4 :η 4 ‐PhNC(Me)C(Me)NPh}] containing an indenyl ligand with an unusual μ‐η 5 :η 4 bridging coordination. Reaction of equimolar amounts of these compounds results in an organolanthanide‐mediated reductive coupling of the DAD ligands and formation of the tetranuclear mixed‐valent complex [Yb 2 (μ‐η 5 :η 4 ‐C 9 H 7 )(η 5 ‐C 9 H 7 ) 2 {μ‐η 4 :η 4 ‐PhNC(CH 2 )C(Me)NPh}] 2 with a novel tetradentate tetraimine ligand.