Nanoscale heat for organic transformations: a photothermally driven retro Diels–Alder reaction

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 ligand-protected particles.