Synthesis and structure of the monometallic cationic complex [Cp(CO)2Fe{η2-(CH2CHCH2CH3)}]PF6 (Cp = η5-C5H5)

The bimetallic carbocation complex [{Cp(CO)2Fe}2(μ-C4H7)]PF6 reacted with trifluoroacetic acid to give the mononuclear cationic complex [Cp(CO)2Fe{η2-(CH2CHCH2CH3)}]PF6, which formed yellow orthorhombic crystals in the space group P212121 with a = 7.652(4), b = 13.422(7), c = 14.037(7); α = β = γ = 90.00 and Z = 4. The carbocation is coordinated to the metal in a η2-fashion forming a chiral metallacyclopropane type structure. The β-CH carbon (C9) is disordered over two positions (C9A and C9B), each having about 50% occupancy. This is attributed to there being both the R and S enantioface isomers in equal amounts in the crystal sample. NMR data indicate that the metallacyclopropane structure observed in the solid state is preserved in solution.