We report the temperature dependent NMR of two Diels-Alder adducts of furan: one formed with maleic anhydride and the other with N-methylmaleimide. These adducts are the products of so-called ‘click’ reactions, widely valued for providing simple, reliable, and robust reactivity. Under our experimental conditions, these adducts undergo a retro Diels-Alder reaction and we use our temperature dependent NMR to determine the rates of these reactions at multiple temperatures—ultimately providing estimates of the activation parameters for the reversion. We repeat these measurements in three solvents. We find that, in all solvents, the barrier to reversion is larger for the adduct formed with N-methylmaleimide. The barrier to reversion for this adduct is relatively insensitive to changes in solvent while the adduct formed with maleic anhydride responds more strongly to changes in solvent polarity. The differences in reaction barrier and solvent dependence arises because the adduct formed with N-methylmalemide is more stable—leading to a larger barrier to reversion—while the adduct formed with maleic anhydride experiences a larger change in dipole during the reaction—leading to a larger solvent dependence.

We demonstrate the ability of photothermal heating by hexanethiol-protected gold nanoparticles to drive a retro Diels-Alder reaction in an 8.47 mM 1,1,2,2-tetrachloroethane solution of the adduct formed between furan and maleic anhydride. We find that the presence of the thiol-based protecting ligands of the nanoparticle acts as an inhibitor of the retro Diels-Alder reaction for the adduct, which creates an avenue for greater control over the reaction behavior. However, even in the presence of these inhibiting ligands, photothermal heating provides an estimated 2.45 × 10 7 -fold enhancement of the instantaneous rate constant for this reaction, demonstrating the efficacy of photothermal heating in dilute organic solutions with ligandprotected particles.