Cavity Catalysis by Cooperative Vibrational Strong Coupling of Reactant and Solvent Molecules

Abstract

Here,w er eport the catalytic effect of vibrational strong coupling (VSC) on the solvolysis of para-nitrophenyl acetate (PNPA), which increases the reaction rate by an order of magnitude.T his is observed when the microfluidic Fabry-Perot cavity in whichthe VSC is generated is tuned to the C=O vibrational stretching mode of both the reactant and solvent molecules.T hermodynamic experiments confirm the catalytic nature of VSC in the system. The change in the reaction rate follows an exponential relation with respect to the coupling strength of the solvent, indicating acooperative effect between the solvent molecules and the reactant. Furthermore,the study of the solvent kinetic isotope effect clearly shows that the vibrational overlap of the C = Ov ibrational bands of the reactant and the strongly coupled solvent molecules is critical for the catalysis in this reaction. The combination of cooperative effects and cavity catalysis confirms the potential of VSC as anew frontier in chemistry.

Ground state chemistry under vibrational strong coupling: dependence of thermodynamic parameters on the Rabi splitting energy

“…For example, mode selective chemistry experiments have shown that TS control of the reaction can be modulated by anisotropic forces either to enhance or suppress a particular reaction path [38]. In other words, the role of strong coupling could be more important in determining the position and structure of the TS as shown in recent experimental [6,8] and theoretical studies [23,24].…”

“…Light-matter strong coupling is evolving as a physical tool for chemists to control chemical reactivity [1][2][3][4][5][6][7][8][9][10]. This was triggered by the modified spiropyran-merocyanine photoisomerisation dynamics under the electronic strong coupling (ESC) [2] and further fuelled by the development of vibrational strong coupling (VSC), where the vibrational mode of a molecule is strongly coupled [11][12][13][14][15][16][17][18].…”

“…The retarded kinetics of the desilylation of 1-phenyl-2-trimethylsilylacetylene (PTA) provided the first evidence for a VSC-controlled chemical reaction [3]. Subsequent experiments under VSC showed that the reactions can be accelerated [7,8], and the chemical landscape could be modified in such a way that the product branching ratio is altered [6]. Remarkably, the reactivity can also be controlled by the strong coupling of solvent vibrational modes [8,9].…”

“…Subsequent experiments under VSC showed that the reactions can be accelerated [7,8], and the chemical landscape could be modified in such a way that the product branching ratio is altered [6]. Remarkably, the reactivity can also be controlled by the strong coupling of solvent vibrational modes [8,9]. Various theoretical models have been developed recently, which support the modified chemical dynamics under strong coupling [19][20][21][22][23][24][25][26].…”

“…Various theoretical models have been developed recently, which support the modified chemical dynamics under strong coupling [19][20][21][22][23][24][25][26]. However, the mechanistic details of chemical reactions under VSC are not well understood, although a clear change in the activation barrier is observed in experimental [3,[6][7][8] and in theoretical studies [24][25][26]. The present study aims to provide further insights into the transition state (TS) changes under VSC by monitoring the thermodynamic parameters of the desilylation reaction of PTA as a function of the strong coupling strength.…”