ENTERING LIGAND-DEPENDENT DISPLACEMENT OF ACETONE FROM (ETA-C5R5)(AC)(CO)FE(COME) BY ORGANIC NITRILES - QUANTITATIVE-ANALYSIS OF LIGAND EFFECTS (QALE)

The entering ligand displacement of acetone (AC) from the cation radicals (eta-C5R5)(AC)-(CO)Fe(COMe)+ (R5 = H5, Me5) by a series of organic nitriles (R'CN; R' = MexH3-xC (x = 1-3), p-ZPhCH2 (Z = H, Me, MeO, Cl), Ph2CH, Ph2MeC) at -41-degrees-C has been studied using a combination of square wave and cyclic voltammetry coupled with computer simulation methods. Although the two complexes exhibit similar reactivities toward the nitriles, the Cp* complex is more reactive than the Cp complex toward all the nitriles studied. The kinetic data were correlated with various pairs of stereoelectronic parameters, and it was found that the the correlations are all similar in quality, except where E(s) was used as the steric parameter, in which case the quality was significantly lower. The two complexes exhibit indistinguishably different electronic and steric sensitivities.