The First Triple-Decker Complex with a Carbenium Center, [CpCo(μ-C₃ B₂ Me₅ )RuC₅ Me₄ CH₂ ]⁺ : Synthesis, Reactivity,...

The first derivative of the methylium cation with the triple-decker substituent, [CpCo(C₃ B₂ Me₅ )RuC₅ Me₄ CH₂ ]PF₆ (2PF₆ ), was synthesized from the reaction of the triple-decker complex CpCo(C₃ B₂ Me₅ )RuCp* (1) with the salt of the trityl cation [CPh₃ ]⁺ . The X-ray crystal structure of 2PF₆ reveals that the methylium carbon is bound to the ruthenium with Ru-C bond length of 2.259 Å and corresponds to the description of its structure as η⁶ -fulvene-ruthenium. Reactions of 2PF₆ with nucleophiles OH^- , Ph₃ P, Et₃ N led to the corresponding derivatives of 1 in high yields. Aromatic amines PhNEt₂ and 4-MeC₆ H₄ NH₂ react with 2PF₆ to give the electrophilic aromatic substitution products quantitatively. Chemical reduction of 2PF₆ with Zn powder in tetrahydrofuran leads to the formation of the bis(triple-decker) derivative (CpCo(C₃ B₂ Me₅ )RuC₅ Me₄ CH₂ )₂ (10) with a CH₂ CH₂ -bridge. The structures of complexes 4, 7-10 were determined by X-ray diffraction. Density functional calculations support the crystallographically determined geometry of 2 and allow rationalization of some characteristics of its structure, spectroscopy, and reactivity.