Ferrocene derivatives, part 6757Fe-NMR spectroscopy of ferrocenes

57Fe NMR-spectra of 28 mono and disubstituted ferrocenes with a natural abundance of57Fe have been measured relative to internal ferrocene. Most of the resonances appear at the high frequency side. The shielding influence of the various substituents is discussed qualitatively.57Fe shifts are very sensitive to ring tilting as occurring in [3]ferrocenophanes.