Yb(II) Triple-Decker Complex with the μ-Bridging Naphthalene Dianion [Cp^Bn5Yb(DME)]₂(μ-η⁴:η⁴-C₁₀H₈). Oxidative Substitution of [C₁₀H₈]^2– by 1,4-Diphenylbuta-1,3-diene and P₄ and Protonolysis of the Yb–C₁₀H₈ Bond by PhPH₂

Abstract

Two synthetic approaches to the new three-decker Yb(II) complex [CpBn5Yb(DME)]2[μ-C10H8] (1) were successfully employed: the reaction of [CpBn5Yb(DME)(μ-I)]2 (2) with 2 molar equiv of [C10H8]−·K in DME and the reaction of [YbI(DME)2]2[μ-C10H8] (3) with CpBn5K in a 1:2 molar ratio in DME. Complex 1 was proved to be a Yb(II) binuclear triple-decker complex containing a dianionic naphthalene ligand bridging two CpBn5Yb(DME) fragments in a μ-η4:η4 fashion. An oxidative substitution of (C10H8)2– by trans-(1E,3E)-1,4-diphenylbuta-1,3-diene afforded the three-decker Yb(II) complex [CpBn5Yb(DME)]2(μ-η4:η4 -PhCHCHCHCHPh) (4) with a dianionic μ-η4:η4-bridging diphenylbutadiene ligand and naphthalene. The reaction of 1 with excess P4 also occurs with oxidation of (C10H8)2–, whereas Yb remains divalent. The reaction results in the formation of the trinuclear Yb(II) complex with a μ-bridging P73– ligand [CpBn5Yb(DME)]3(P7) (5). Protonation of the Yb–C10H8 bond in 1 with PhPH2 (1:2 molar ratio) afforded the dimeric phosphido complex [CpBn5Yb(THF)(μ2-PHPh)]2 (6) in 64% yield, while an attempt to obtain a phosphinidene Yb(II) species by reacting equimolar amounts of 1 and PhPH2 in DME resulted in the isolation of the metallocene complex CpBn52Yb(DME) (7).