NMR-spektroskopie an paramagnetischen komplexen : XVIII. Kobaltocene: Nicht-starre paramagnetische π-komplexe

Temperature dependent paramagnetic ¹³C and ¹H NMR spectra of six cobaltocenes (RC₅H₄)₂Co (R = H, Me, Et, i-Pr, n-Bu, t-Bu) are reported. The signals for the substituted five-ring carbons as well as for the substituent ¹³C and ¹H nuclei which are separated from the five-ring by two bonds show a strong departure from the Curie law. This is due to a time-dependent change of the interaction between the five-ring carbons and the metal classifying cobaltocenes as nonrigid molecules. It introduces the previously unknown dynamic paramagnetic ¹³C NMR.