Evidence for Restricted Rotation in the 1H and 19F Nuclear Magnetic Resonance Spectra of Cyclopentadienylperfluoroalkyliron and Nickel Complexes

Several series of compounds CpFeCOLRF, CpNiPPh3RF, and mer-Fe(CO)3LRFI (RF = CF3, CF2CF3, CF(CF3)2; L = PPh3, PMePh2, PMe2Ph), some of them new compounds, have been prepared and characterized. Evidence for restricted rotation about both metal–alkyl and phosphorus–aryl bonds is deduced from the variable temperature 1H and 19F n. m. r. spectra of the complexes. The presence of two vCO in the i. r. spectra of the pseudotetrahedral iron complexes suggests that these compounds exist as diastereomers, the coordinated phosphine and the nickel constituting chiral centers.