To test this hypothesis, we studied the correlation between reaction kinetics and C-H BDEs. According to the Evans-Polanyi model, the log of rate constants should parallel the reaction energy within a set of atom transfer reactions, including many HAT reactions. The differences in reaction energies are usually taken as the differences in the C-H BDEs. In our case, the d-HAT reaction involving photoexcited CdS QD gel reacting with various C-H substrates should also follow this rate/C-H BDE correlation.