Marcus inversion is observed for excited state proton transfer in the adiabatic limit using naphthol based photoacids

Marcus theory is applied on ESPT reactions in the adiabatic limit, using cyano-naphthol derivatives. A systematic variation of the reaction exergonicity is achieved by changing the proton donor, solvent (acts as base) and the temperature. Marcus inverted regions are observed for the proton recombination steps when the solvent is changed and temperature variation was used to vary the reaction exergonicity.