Rh NMR studies of organometallic rhodium(I) derivatives

Organometallic rhodium(I) derivatives have been studied by 103Rh NMR. The chemical shift range extends from 609 ppm ([Rh.cp.cod]) to 2714.7 ppm ([Rh.fod.cod]). These results are supported by 13C and 31P NMR results, and give information about the bonding in these derivatives. Most of the complexes contain the cycloocta‐1,5‐diene ligand. For these complexes a linear correlation is observed between δRh and δC (olefinic carbons) (27 points, R = 0.960). For the phosphine derivatives a linear correlation is found between δRh and 1J(RhP) and, also, between δRh and parameters characterizing the basicity of the phosphine ligand. The correlation of δRh with ligand properties has been extended to a wider range of complexes by using the ‘influence parameters’ defined previously (10 points, R = 0.947). The sensitivity of δRh to steric factors is also proved.