Organometallic Chemistry Laboratory and Advanced Catalyst Research Team, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
J Am Chem Soc. 2011 Apr 20;133(15):5712-5. doi: 10.1021/ja200540b. Epub 2011 Mar 29.
Tetranuclear cubane-type rare-earth methylidene complexes consisting of four "Cp'LnCH(2)" units, Cp'Ln(μ(3)-CH(2)) (4-Ln; Ln = Tm, Lu; Cp' = C(5)Me(4)SiMe(3)), have been obtained for the first time through CH(4) elimination from the well-defined polymethyl complexes Cp'Ln(μ(2)-CH(3))(2) (2-Ln) or mixed methyl/methylidene precursors such as [Cp'(3)Ln(3)(μ(2)-Me)(3)(μ(3)-Me)(μ(3)-CH(2))] (3-Ln). The reaction of the methylidene complex 4-Lu with benzophenone leads to C═O bond cleavage and C═C bond formation to give the cubane-type oxo complex Cp'Lu(μ(3)-O) and CH(2)═CPh(2), while the methyl/methylidene complex 3-Tm undergoes sequential methylidene addition to the C═O group and ortho C-H activation of the two phenyl groups of benzophenone to afford the bis(benzo-1,2-diyl)ethoxy-chelated trinuclear complex [Cp'(3)Tm(3)(μ(2)-Me)(3){(C(6)H(4))(2)C(O)Me}] (6-Tm).
首次通过明确的多甲基配合物Cp'Ln(μ(2)-CH(3))(2)(2-Ln)或混合甲基/亚甲基前体，如Cp'(3)Ln(3)(μ(2)-Me)(3)(μ(3)-Me)(μ(3)-CH(2))，从甲烷中消除，得到四核立方烷型稀土亚甲基配合物Cp'Ln(μ(3)-CH(2))(4-Ln；Ln = Tm，Lu；Cp'= C(5)Me(4)SiMe(3))。亚甲基配合物 4-Lu 与二苯甲酮反应导致 C═O 键断裂和 C═C 键形成，得到立方烷型氧配合物Cp'Lu(μ(3)-O)和 CH(2)═CPh(2)，而甲基/亚甲基配合物 3-Tm 则经历亚甲基对 C═O 基团的连续加成和二苯甲酮两个苯基的邻位 C-H 活化，得到双(苯-1,2-二基)乙氧基螯合三核配合物[Cp'(3)Tm(3)(μ(2)-Me)(3){(C(6)H(4))(2)C(O)Me}] (6-Tm)。
