Systematic Method for the Incorporation of the {(η⁶-Arene)Fe} Fragment into Carborane Cages via [(η⁶-Arene)Fe]²⁺ Dications. A Series of [3-(η⁶-Arene)-closo-3,1,2-FeC₂B₉H₁₁] Complexes. Reliable Synthesis of Polymethylated [(η⁶-Arene)₂Fe]²⁺ Cations

Developed was a systematic method for the incorporation of the {(η⁶-arene)Fe} fragment into a carborane cage. Reactions between [(η⁶-arene)₂Fe](PF₆)₂ salts and Tl₂[nido-7,8-C₂B₉H₁₁] in refluxing (CH₂)₂Cl₂ generated a series of [3-(η⁶-arene)-closo-3,1,2-FeC₂B₉H₁₁] neutral complexes with variable types of polymethylated arene ligands in the structure. The structures of durene and hexamethylbenzene complexes were established by X-ray diffraction analyses. The work also shows that the original high-temperature method for the preparation of the [(η⁶-arene)₂Fe]²⁺ dications fails for mesitylene and durene compounds, which was overcome by a reliable room-temperature modification.