The indenyl ligand effect on the rate of substitution reactions of Rh(η-C 9 H 7 )(CO) 2 and Mn(η-C 9 H 7 )(CO) 3

Carbonyl substitution by triphenylphosphine (PPh3) in the indenyl compounds Rh(η-C9H7)(CO)2 and Mn(η-C9H7)(CO)3 proceeds by a second order rate law which is first order in complex and first order in PPh3 and in both cases the rates are much faster than for the corresponding cyclopentadienyl complexes; for rhodium a rate enhancement of 108 is found for the indenyl compound over the corresponding cyclopentadienyl compound.