The First Triple‐Decker Complex with a Carbenium Center, [CpCo(μ‐C₃B₂Me₅)RuC₅Me₄CH₂]⁺: Synthesis, Reactivity, X‐Ray Structure, and Bonding

Abstract

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

Molecular Orbital Insights of Transition Metal-Stabilized Carbocations

“…Another extensively studied carbocation-metal complex is α-metallocenylmethylium cation (Hill and Richards, 1961; Davis et al, 1971; Gleiter et al, 2007; Bleiholder et al, 2009; Minić et al, 2015, 2017; Espinosa Ferao and García, 2017; Muratov et al, 2017; Preethalayam et al, 2017; Fomin et al, 2018). Two different resonance structures have been proposed: (1) the cation acts as an L-type ligand by donating its filled p orbital electron density to the metal center, and (2) the cation acts as an LX + ligand by donating its filled p orbital electron density to the metal center through carbenium backdonation (Figure 10A).…”

Oxidatively-induced C(sp3)–C(sp3) bond formation at a tucked-in iron(iii) complex

“…Offering context, a Cambridge Structural Database (CSD) search provides fewer than 5 examples of structurally-authenticated Cp*-based compounds featuring a bridging {–H 2 CCH 2 −} unit. 24,38–43 Using pre-formed ligand constructs, Wang and co-workers reported a set of polymeric Ir complexes bridged by {C 5 Me 4 –(CH 2 ) n –C 5 Me 4 } ( n = 2, 3, 4); 40 while Brintzinger and co-workers synthesized monometallic complexes of the type [(C 5 Me 4 –(CH 2 ) 2 –C 5 Me 4 )MCl 2 ] (M = Ti, Zr). 41 Another example has been accessed by Cp*{H˙} removal – Severin and co-workers utilized [OAl(C 6 F 5 ) 3 ]˙ − in the presence of Al(C 6 F 5 ) 3 to perform H-atom abstraction of , generating a [(η 5 -C 5 Me 4 )(·CH 2 )]Fe(Cp*)] radical, 38 which dimerized to give [{η 5 -C 5 Me 4 –(μ-CH 2 )}Fe II (Cp*)] 2 .…”

Charge-compensated nido-carborane derivatives in the synthesis of iron(ii) bis(dicarbollide) complexes

“…6 One or more carbon atoms in the cyclopentadienyl ligand may be replaced by boron, nitrogen or phosphorus atoms, as well as various combinations thereof. 7–11…”