Fig. 5.

a The highest proton affinity of the most stable tautomer computed for a series of substituted benzene analogs familiar to all organic chemists together with a qualitative ranking of their reactivities. The values are given in units of kcal/mol. b Two examples from a showing the proton affinities of the unique reaction centers. c Computed proton affinities for the 535 molecules in our data set as the energy difference between the unprotonated and most stable protonated form using the most stable tautomer. d Examples of molecules with predicted low, medium, and high reactivity based on the highest proton affinities