Introducing the Perfluorinated Cp* Ligand into Coordination Chemistry

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