text: Indenyl like effects are also observed in a number of non indenyl substituted metal complexes.  In fluorenyl complexes, associative substitution is enhanced even further than indenyl compounds.  The substitution rate of Mn(η-CH)(CO) is about 60 times faster than that of Mn(η-CH)(CO)
  Veiros conducted a study comparing the rate of substitution on [(η-X)Mn(CO)] where X is cyclopentadienyl, indenyl, fluorenyl, cyclohexadienyl, and 1-hydronaphthalene.  Unsurprisingly, it was found that the ease of η to η haptotropic shift correlated to the strength of the Mn-X bond.