Effective charge maps rates

Effective Charge Map for a Putative Stepwise Process. Effective charge maps can also be employed to discount a stepwise process if estimates of the effective charge change from reactant and product to putative intermediates are not consistent with expectation. Consider the Bronsted dependence for reaction of substituted phenolate ions with 4-nitrophenyl acetate (Figure 6). The value of Pnu is approximately 0.80 for attack of substituted phenolate ions on 4-nitrophenyl acetate when the second step of the putative two-step mechanism (decomposition of the putative tetrahedral intermediate) would be rate limiting (pA pA a ) (Scheme 11). 

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