Improvement in 13C NMR Measurements of Ring-Substituted η5-Cyclopentadienyl Metal Complexes

Abstract

z1.5 Time-consuming 13C NMR measurements of sparingly soluble ring-substituted cyclopentadienyl metal complexes can be avoided if INEPT techniques are applied. In particular, polarization transfer based on long range 13C—1H couplings (nJ(13C1H); n = 2, 3) can be used to observe 13C NMR signals of quaternary 13C nuclei, which are difficult to observe in normal 13C NMR spectra. The improvement in the signal-to-noise ratio enabled to observe satellites due to 77Se- 13C and 125Te—13C couplings. Some typical ferrocene derivatives as well as η5-cyclopentadienyl-manganese- and -rhenium tricarbonyl derivatives were selected to demonstrate that the recommended methods are independent of the metal and of the type of ring substitution.