Introducing the Perfluorinated Cp* Ligand into Coordination Chemistry

The reaction of AgBF(4) and [Rh(COD)Cl](2) (COD=1,5‐cyclooctadiene) in presence of [NEt(4)][C(5)(CF(3))(5)] afforded the fluorocarbon soluble complex [Rh(COD)(C(5)(CF(3))(5))] by salt metathesis. This complex represents the first example for a successful coordination of the weakly basic [C(5)(CF(3))(5)](−) ligand, since its first synthesis in 1980. In addition to [Rh(COD)(C(5)(CF(3))(5))] also the byproduct [Rh(COD)(C(5)(CF(3))(4)H)] was isolated and fully characterized. Accompanying DFT studies showed that the interaction energy of the [C(5)(CF(3))(5)](−) ligand towards the 12‐electron fragment [Rh(COD)](+) is ≈70 kcal mol(−1) lower in comparison to [C(5)(CH(3))(5)](−) due to reduced electrostatic interactions and weaker π‐donor properties of the ligand. The quantitative but reversible substitution of the [C(5)(CF(3))(5)](−) ligand by toluene, converting it into a weakly coordinating anion, experimentally proved the extraordinary weak bonding interaction.