text: Metal carbonyls are often characterized by C NMR spectroscopy. To improve the sensitivity of this technique, complexes are often enriched with CO. Typical chemical shift range for terminally bound ligands is 150 to 220 ppm. Bridging ligands resonate between 230 and 280 ppm. The C signals shift toward higher fields with an increasing atomic number of the central metal.
  NMR spectroscopy can be used for experimental determination of the fluxionality.
  The activation energy of ligand exchange processes can be determined by the temperature dependence of the line broadening.