The deviation between the results with different functionals is even more pronounced in the calculations on the mechanophores than in the polymeric compounds. The overall RSDs for F max , E max and Fracture strain are all above 10 %, E max even passing the 35 % mark. However, this is attributable to the strong deviations for the unzipping reactions of 9. The other mechanophores investigated show similar discrepancies among the functional dependent predictors as observed for the polymeric compounds.