A 13C Nmr investigation of stereochemical non rigidity in hydrido olefinic carbonyl clusters of ruthenium

13C n.m.r. spectra of hydrido olefinic carbonyl clusters of ruthenium show that localized scrambling of the carbonyls occurs with different energy barriers which depend on the nature of the bonding between the ligand and the metal cluster and on the nature of the substituents in the olefinic chain. Resonances of carbons “sigma” bonded to one ruthenium and “pi” bonded to a second one are in the lowfield region (198-162 ppm).