Extraordinary Acceleration of an Electrophilic Reaction Driven by the Polar Surface of 2D Aluminosilicate Nanosheets

Small. 2023 Mar;19(11):e2205857. doi: 10.1002/smll.202205857. Epub 2023 Jan 9.

Abstract

To increase chemical reaction rates, general solutions include increasing the concentration/temperature and introducing catalysts. In this study, the rate constant of an electrophilic metal coordination reaction is accelerated 23-fold on the surface of layered aluminosilicate (LAS), where the reaction substrate (ligand molecule) induces dielectric polarization owing to the polar and anionic surface. According to the Arrhenius plot, the frequency factor (A) is increased by almost three orders of magnitude on the surface. This leads to the conclusion that the collision efficiency between the ligands and metal ions is enhanced on the surface due to the dielectric polarization. This is surprising because one side of the ligand is obscured by the surface, so the collision efficiency is expected to be decreased. This unique method to accelerate the chemical reaction is expected to expand the range of utilization of LASs, which are chemically inert, abundant, and environmentally friendly. The concept is also applicable to other metal oxides which have polar surfaces, which will be useful for various chemical reactions in the future.

Keywords: aluminosilicates; anionic surfaces; collision frequency; dielectric polarization; electrostatic interaction; inert surfaces; metal coordination reaction; porphyrin.