A variety of 13C-enriched metal carbonyl clusters (Fe3(CO)12, Ru3(CO)12, Os3(CO)12, Rh6(CO)16, and Ir4(CO)12) have been examined by magic-angle spinning 13C nuclear magnetic resonance spectroscopy. The results yield both the isotropic chemical shifts and the principal components of the chemical shift tensor for each crystallographically distinct carbonyl site, as well as their spin-lattice relaxation times. With the 0.25-ppm resolution obtained at high field (8.45 T), effects from 13C-13C and 13C-103Rh J coupling, as well as incompletely averaged 13C-191Ir/193Ir dipolar coupling, can be discerned. The chemical shift tensor components, obtained from analysis of spinning sideband intensities, are shown to be in generally good agreement with values previously obtained from broad-line spectra. The motionally averaged chemical shift tensor components for Fe3(CO)12, which is fluxional at room temperature, are shown to be consistent with a previously proposed exchange process.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of physical chemistry|
|State||Published - Dec 1 1989|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry