The First Triple‐Decker Complex with a Carbenium Center, [CpCo(μ‐C 3 B 2 Me 5 )RuC 5 Me 4 CH 2 ] + : Synthesis, Reactivity, X‐Ray Structure, and Bonding

The first derivative of the methylium cation with the triple‐decker substituent, [CpCo(C 3 B 2 Me 5 )RuC 5 Me 4 CH 2 ]PF 6 ( 2 PF 6 ), was synthesized from the reaction of the triple‐decker complex CpCo(C 3 B 2 Me 5 )RuCp* ( 1 ) with the salt of the trityl cation [CPh 3 ] + . The X‐ray crystal structure of 2 PF 6 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 η 6 ‐fulvene‐ruthenium. Reactions of 2 PF 6 with nucleophiles OH − , Ph 3 P, Et 3 N led to the corresponding derivatives of 1 in high yields. Aromatic amines PhNEt 2 and 4‐MeC 6 H 4 NH 2 react with 2 PF 6 to give the electrophilic aromatic substitution products quantitatively. Chemical reduction of 2 PF 6 with Zn powder in tetrahydrofuran leads to the formation of the bis(triple‐decker) derivative (CpCo(C 3 B 2 Me 5 )RuC 5 Me 4 CH 2 ) 2 ( 10 ) with a CH 2 CH 2 ‐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.