Here, we used an unconventional idea of cooperative vibrational strong coupling of solute and solvent molecules to enhance the rate of an esterification reaction. Different derivatives of p-nitrophenyl benzoate (solute)...

Strong light-matter coupling offers a unique way to control chemical reactions at the molecular level. Here, we compare the solvent effect on an ester solvolysis process under cooperative vibrational strong coupling (VSC). Three reactants, para-nitrophenylacetate, 3-methyl-para-nitrophenylbenzoate, and bis-(2, 4-dinitrophenyl) oxalate are chosen to study the effect of VSC on the solvolysis reaction rates. Two solvents, ethyl acetate and cyclopentanone, are also considered to compare the cavity catalysis by coupling the C=O stretching band of the reactant and the solvent molecules to a Fabry-Perot cavity mode. Interestingly, both solvents enhance the chemical reaction rate of para-nitrophenylacetate and 3-methyl-para-nitrophenylbenzoate under cooperative VSC conditions. However, the resonance effect is observed at different temperatures for different solvents, which is further confirmed by thermodynamic studies. Bis-(2, 4-dinitrophenyl) oxalate doesn't respond to VSC in either of the solvent systems due to poor overlap of reactant and solvent C=O vibrational bands. Cavity detuning and other control experiments suggest that cooperative VSC of the solvent plays a crucial role in modifying the activation freeenergy of the reaction. These findings, along with other observations, cement the concept of polaritonic chemistry.

deciding the reaction channel, are probed/can be probed under VSC conditions. We hope that with further progress in the field, one can unambiguously distinguish the results, errors, and uncertainties associated with the measurement conditions.

Recent understanding of light-matter strong coupling brought a new niche in molecular-level control of chemical reactions. Vibrational strong coupling is unique in this category that overcomes the issue associated with coherent chemistry. Here, a vibrational transition is coupled to a standing wave of electromagnetic field, result in strong interaction, generating vibro-polaritonic states. This process reshuffles the entire energy-reaction coordinate. The chemical reaction rate can be boosted, stirred, or decelerated with this unconventional tool. Here, we used the idea of cooperative vibrational strong coupling of solute and solvent molecules to enhance the chemical reaction rate. This process is called cavity catalysis. Different derivatives of p-nitrophenyl benzoate (solute) and isopropyl acetate (solvent) are cooperatively coupled to an infrared Fabry-Perot cavity. The apparent reaction rates are increased by more than six times at the ON resonance condition, and the rate enhancement follows the lineshape of the vibrational envelope. Very interestingly, strong coupled system doesn't follow a linear free-energy relationship. The nonlinear rate enhancement can be due to the reshuffling of energy distribution between the substituents and the reaction center. Thermodynamic parameters suggest an entropy-driven process for the coupled molecules. The free energy of activation decreased by 2-5 kJ/mol, suggesting a clear role of vibrational strong coupling in catalyzing the reaction. Here, the enthalpy of the system compensates for the entropy by preserving the isokinetic relationship. These findings will help further understanding of chemical reaction control in polariton chemistry. TOC

Strong light-matter coupling offers a unique way to control chemical reactions at the molecular level. Here, we try to compare the solvent effect on a solvolysis process under cooperative vibrational strong coupling (VSC). Two solvents, ethyl acetate and cyclopentanone are chosen to study cavity catalysis by coupling the C=O stretching band of the reactant and the solvent molecules to a Fabry-Perot cavity mode. Interestingly, both the solvent system catalyze the chemical reaction under cooperative VSC conditions. However, the resonance effect on catalysis is observed at different temperatures for the two solvent systems, which is further confirmed by thermodynamic studies. Cavity detuning and other control experiments suggest that cooperative VSC of the solvent plays a crucial role in modifying the transition state energy of the reaction. These findings, along with other observations, cement the concept of polaritonic chemistry.