Natural abundance 17O NMR spectra of carbonyl metal clusters of the iron triad

¹⁷O NMR spectra (in natural abundance) have been recorded, at room temperature, for a variety of polynuclear iron, ruthenium and osmium carbonyl clusters. Rather sharp linewidths have been observed for stereochemically rigid species, whereas linewidths as large as about 200 Hz have been obtained for fluxional molecules. Even though the observed chemical shift range for terminal CO groups is not very large (about 50 ppm), taking into account linewidths, metal triad and substituent effects have been observed to different extents.