1H, 13C and 31P NMR studies of some (C6H5)3-nPRn and (C6H5)3-nPRnCr(CO)5 (n=0-3; R=H, CH3, C2H5, i-C3H7, t-C4H9) derivatives

Article abstract of DOI:10.1016/0584-8539(80)80031-6

The 31P chemical shift of the (C6H5)3-nPRn and (C6H5)3-nPRnCr(CO)5 (n=0-3; R=H, CH3, C2H5, i-C3H7, t-C4H9) derivatives is dominated by the steric effect.A small inductive effect is also operative but there are no indications of notable (d_Cr<*>d_p)? back-bonding.The 13C chemical shift of the phenyl carbon atons indicates that (p_ring-d_p)? electron delocalization is unimportant.The 13C chemical shift of the carbonyl atoms, which is mainly governed by the mean excitation energy, confirms the conclusion that there are no notable changes in (d_Cr<*>d_p)? back-bonding in this series of compounds.